Oh the Weather Outside is Frightful – or Not

Posted on May 18, 2012 by Steven Christenson

One of the necessary tools a night (or landscape) photographer must have in their tool bag is a decent weather forecasting tool. Though I’ve been known to ignore the forecast for some events, like the Annular Solar Eclipse on Sunday, May 20th, I definitely am more inclined to go where the weather is clearer (Nevada) than where it will be cloudy (Crescent City, CA).

A forecast like this despite how detailed it seems to be is all but useless to me:

After all how partly is partly cloudy and how clear is clear? Besides, knowing how sunny it is during the day does not help me plan for the night, or sunrise for that matter. Indeed, the above is from Wunderground.com and shows “Clear” on Sunday, but when you dig down, well it ain’t so sunny after all – see below.

NOAA to the Rescue (no Ark)

Fortunately the US National Weather Service provides a nicely detailed “click point” forecast with charts of the hour-by-hour conditions.

There is quite a lot to take in here but it’s all good stuff.

Where do you find this great tool. Start here:

Once you get to the forecast, look for a link named : Hourly Weather Graph. It will be text only and cleverly hidden down and off the page where only a geek will find it. But that, my friend, is where the good stuff is. Before you rush off on the hourly thing, though, take a look at the little map window. You can get a forecast for any specific area by clicking! Here I started by searching for San Jose, CA, but then clicked on Los Gatos. If you’ve lived in the San Francisco Bay area you know that the temperature can be four, eight or ten degrees different in just 8 miles or so!

Wunderground Classic

Another tool I frequently use is the OLD WeatherUnderground. At Weather Underground they apparently decided that the most useful page was “too busy” and you have to go to “Wunderground Classic”.

A portion of a day looks like this. Note this is a portion of the same day that is marked “Clear” in the simple forecast shown earlier. Apparently it’s clear only at 2 am!

Good luck on your prognostication.

May the wind not be at your back or in your face, may the road not be muddied by rain and may the clouds gather only when you really want them i.e. at sunrise and sunset.

Posted in Astronomical Event, Maps, Tools, Travel, Weather | Tagged forecast, graphical, hourly, NOAA, NWS, weather, wunderground | Leave a comment

Graduated Neutral Density Filters

Posted on May 16, 2012 by Steven Christenson

In a Flickr discussion, a poster asked whether he should get a hard stop graduated neutral density (GND) filter or a soft one. But wait, perhaps you would first like to know what a GND is so that I can explain to you why you probably DON’T need one. Here is a concise article, I’ll wait for you to come back.

In a nutshell, let’s dissect the words: Density means darkening – the denser the darker. Graduated means the amount of darkening changes from top to bottom. Neutral means that while darkening, the color is unchanged. A neutral density filter is one that darkens the scene to allow a longer exposure – e.g. of a waterfall or ocean to get the “silky water” effect. A good neutral density filter will not distort the color in the scene. The Cokin GND I’ve used, for example adds a purple cast (hue) to the captured image. Usually photographers employ a GND to darken the sky in a daytime scene so that the sky brightness is not so significantly different from the landscape. By darkening the sky a single exposure can capture sky details (e.g. bright clouds) as well as details in the landscape.

All that’s left now to describe is the difference between a HARD and a SOFT GND. If you read the linked article you already know, but if you didn’t, here is an easy way to disentangle the words: hard is ABRUPT while soft means GRADUAL. That is, a hard filter has an sharp transition between the dense area and the clear area while a soft filter has a smoother transition.

Can you use a GND at night? Yes! But normally you will end up using it in the opposite way of the normal use: e.g. to darken city lights at the ground but leave the night sky undarkened.

Here is an example where you might think of using a GND

The lights on the bridge deck and towers are very bright compared to the night sky. A GND in theory could be used to mask the lower portion of the bridge to control the brightness. And while it will work, it will not work well because somewhere there will be a transition between the darkened part at the bottom and the sky above. If there were no tower, the GND could be used to knock down the lights on the fences and deck with a relatively minor sacrifice.

This scenario repeats itself in daylight situations too. Imagine a lovely tree in your daylit scene instead of a tower and it quickly becomes clear that nature affords very few situations where there is a linear and sharp distinction between the dark area and the light area… the ocean being one clear possibility or perhaps a landscape in a flat-as-flat-can-be field in Kansas.

Here is a better candidate for use of a GND – but still far from ideal:

A GND could knock down the excessive city lights. But it would also darken the mountain.

While it is certainly desirable to knock down the excessive city lights there is no orientation for a GND that won’t also knock down the brightness of the mountain or a portion of the sky. A triangular GND – if it existed could control the overbright part but since every scene is different the chances of getting a well matching GND are slim.

90% of the time using bracketed exposures and High Dynamic Range processing techniques makes more sense than using a GND. Also by not using a GND there is no additional opportunity for glare, flare, reflections or color cast – and nothing additional to carry lose or break or spend money on!

But before I completely pull the plug on GNDs, here are a few extra tidbits you can employ to get the most out of a GND that you may have:

You can turn a hard GND into a soft one, by moving it up and down while shooting. For this to work, you need a longish exposure and you must be careful not to shake your camera. You also won’t be using the filter holder.
A lower tech approach that works is black carding. Instead of using a neutral density filter you use a flat black card. You hold it for a time (keeping it moving a bit) over the light part of the scene and then remove it. This is exactly analogous to the “dodging” and “burning” process used long ago by Ansel Adams when he wanted to tone down (or up) an area of a photographic print.

The effects of the GND can be duplicated on the computer – and better yet, without the tell tale darkening of things like trees and mountain tops that cross the transition area of the GND filter. Tools like Photomattix and Adobe’s Photoshop Merge-to-HDR can automate the merging of exposures, but to my eye the result is usually somewhere between bizarre and odd looking. A more effective process is to hand merge your HDR as described by Harold Davis in his book The Photoshop Darkroom 2 or his latest book dedicated to HDR processing - which begins shipping July, 2012.

In Summary

GNDs work, but seldom does one find a bright area separated from a darker area by a straight line – whether gradual or otherwise. Trees, hills, mountains and man made things like to poke up into the sky and look “weird” when darkened via a GND.

The advantages to bracketed HDR photos are many, the drawbacks are few – and it’s one less filter, filter holder, and pouch to take along and one less source of additional reflections, flare, vignetting, or color problems.

In fact, I’m not really sure where my GND is anymore, or the holder for it which was a beast to manage.

More Resources

Jim Goldstein does great work and has an article on GNDs worth a read.
Ron Niebrugge’s discussion, but also note the tell-tale dark areas where the foreground transitions to the water and glacier.
Here is an example of a “hand HDR” technique which won me an international award. I’m quite sure a GND would not have “cut it” for this shot.

Postscript

I did NOT use a GND on the Mary Avenue Bridge picture! I used a technique that will be covered in an upcoming webinar on Photo Manipulation for the Night Photographer. The very next webinar on photo manipulation is June 7, 2012.

Posted in Creativity, High Dynamic Range (HDR), Photo Tip, Photoshop | Tagged GND, Graduated Neutral Density FIlters, HDR, high dynamic range | Leave a comment

Solar Eclipse… May 20th.

Posted on May 14, 2012 by Steven Christenson

If this is the first you’ve heard of this event, it may be too late to be properly prepared to photograph it. The maximum occurs at around 6:33 PM for those in the San Francisco Bay Area (and at most a few minutes before or after that for everyone else in California). Be sure to go out at least 5 minutes prior, though. To get a more exact time, click the map below then double click on your location. Don’t let the date of May 21st fool you! The time shown will be “UTC” the time in *London*. Those in the Pacific Time zone must SUBTRACT seven hours from UTC. If the time of maximum is listed as: 2012/05/21 01:33:24 then the Pacific time is seven hours EARLIER or 18:33:24 (6:33 PM).

What NOT To DO

DO NOT look at the sun even during the maximum period. This is an Annular eclipse so much of the sun will NOT be covered.
If you MUST see the eclipse make sure you have proper eye protection. A camera obscura may work. A Camera Obscura is a box with a pinhole in it that allows you to observe the sun by looking in through the SIDE of the box at the projected image (not through the pinhole!)
For many more NOTs see here.
Here is one “not” illustrated for you. For this I took a pair of low power binoculars held the safe solar filters against the eyepiece and pointed the unit at the sun. See the pinhole burned through the plastic… imagine that is your eye, now blinded. Don’t Do It.
What NOT to Do! See that hole burned by the sun? That could be your eye!

Here is a page describing how to observe safely, including building a pinhole “camera obscura”.

For more information about Solar Filters please see my “Solar Filters” blog entry.

Posted in Photo Tip | Tagged annular, annulus, apogee, eclipse, new moon, partial, planning, solar | Leave a comment

Skies Ablaze – Capturing Fireworks

Posted on April 30, 2012 by Steven Christenson

Photo 1: Abstract Sausalito fireworks (aka Pod People)

Several times a year Americans (and others around the world) find an excuse to gratuitously burn large amounts of black powder in spectacular displays that serve no real purpose except to create awe and wonder. For that reason alone, I love fireworks.

Fireworks are an interesting subject for Night Photography and require a little patience and experimentation to do well. And I have found some new approaches to photographing fireworks that make them even more interesting – as shown in Photo 1, above. Yes… that is a firework burst! For information on how I achieved that effect, see below.

Challenges with Fireworks

Fireworks come with their own set of issues. From the ephemeral nature of the light to the selection of a site to photograph them from. I generally favor more distant locations where I am able to switch between telephoto and wide angle lenses to alter the composition of the shot. At greater distances the flashes of the fireworks are also a little less challenging photographically.

Brief Intense Light

Firework bursts are brief lasting seconds or less, but surprisingly they are very bright. Because they are so brief catching them at just the right moment may at first seem daunting. As with all things night photography the camera is quite inadequate at metering or adjusting for fireworks in a way that will capture the drama and grace. So the first tip:

Tip 1: Stay in MANUAL mode and do not let the camera try to adjust anything.

I generally prefer settings that are approximately like this: 200 ISO, f/9, 10 seconds. But may change those dramatically based on the outcome of a shot or two, and how much background I’m trying to grab. For example, I will often choose shorter exposures at higher ISOs, and sometimes I use BULB mode. More on that in a moment.

Location, Location, Location

As in real estate, location is everything. Fireworks, in my opinion look better against a city skyline, reflected in water, or next to the moon or a snowy mountain peak. But creating an exposure to include those background elements is tricky, sometimes very tricky.

Nearly every event in which fireworks are employed is massively crowded (think 4th of July) so finding a clear view and a safe hassle free space to set up a tripod takes a little creativity and patience. Fortunately fireworks can be viewed from near or far – and far is often a bit better.

Photo 2: Fireworks and the San Francisco Skyline

Weather may also be problematic – as in the San Francisco area where fog in the summer evenings and mornings is normal. Four years of shooting produced only one year with moderate haze (as in Photo 2). Two years were complete shutouts. Photo 2 could be improved with a brighter background – either by taking a longer exposure at the time or by combining with an exposure taken earlier or later in the evening.

The minions in the Night Photography group were clamoring to shoot fireworks, but thrice burned equals twice shy despite a fantastic location found years earlier.

Tip 2: A good location is always the better choice. Location, location, location!

Composition

Wide shot or tight shot?

Photo 3: Tight coverage of a burst

Photo 4: Wide shot with fountain and pond

Straight shot or creative shot:

Photo 5: Focus adjustment during exposure

Fortunately there is no rule that says you can not try a number of different approaches in the same event – provided the event lasts long enough. However it is best to start with trying to get a pleasing result that is conventional in nature that is, more like Photo 4, above.

Timing

As in comedy, timing is important. Start the exposure too soon and you’ll catch the bright burst of the firework which may very well overwhelm the camera and produce a “white blob”. There are three approaches to the timing problem, and sometimes I use all three in the same night:

Set the camera up with an intervalometer/locked remote shutter and just let it run.
Manually release the shutter using a fixed exposure length as soon as you see a burst.
Manually control the shutter in bulb mode.

The main reason to use a fixed exposure length is if you intend to stack or animate your photos – keeping the background exposures the same produces a more pleasing, flicker free result. However if your only goal is to “get the boom”, option 3 is probably the best. I recommend shooting after the initial “boom” because what makes the firework appealing is the light spreading and then falling over time. How long to expose depends on a lot of things, of course, including how bright the background is and how many fireworks are blowing up at a time. The Finale is usually a good time to take your eye off the camera and enjoy the show because finale’s usually end up a washed out mess.

Tip 3: Start the exposure immediately AFTER the boom.

Creative License

So how did I get the strange effects in Photo 1 and Photo 5? I adjusted the focus while exposing. I have also played with the zoom while exposing. In Photo 1 the shot started focused and I defocussed it. In shot 5 it was the other way around – it started out of focus and finished less out of focus.

Once you start playing with the focus, do not expect to have sharp images which is why I recommend you get the conventional exposure first before you get all creative.

Posted in Creativity, Image, Photo Tip | Tagged creative focus, fireworks, focus, long exposure, night, shutter release, skylines | Leave a comment

Struck by Lightning – an Interview with Phil McGrew

Posted on April 18, 2012 by Steven Christenson

My friend, and fellow moonatic*, Phil McGrew found himself instantly thrust into the international spotlight for an image he captured from his office window. The occasion was a rare display of violent weather in the San Francisco Bay Area.

The photo has gone viral with over a 200,000 views on Flickr (1,474″favorites”) as well as international appearances. For mysterious and unfathomable reasons, Phil’s photo didn’t make it to the famed “Flickr Explore” which clearly is not measuring how phenomenally great a photo is!

Photo by Phil McGrew - The Sizzle Heard Around the World. Used with permission.

More than just a few people have “honored” Phil by copying his photo and posting it among their own work. I understand the temptation. But that’s just plain wrong (not to mention a violation of copyright law). Phil has given me permission to show his photo and tell his story.

You may be here because you’re looking for some specific information. If so, here is the cheat sheet – or just read on for more interesting data.

Can I Buy this Photo? How Much?
Can I Use this Photo on My Desktop?
How did you catch Lightning?
How did this photo become so Famous?
Is this photoshopped? Is it Real?
Who and What Inspires Your Photography?
Did I see Phil on the news?
Tell us a little about Phil

Is this Photoshopped? Is it Real?

First let’s get a few things right – lots of speculation and conjecture about the photo has swirled on various social networking sites. None of that related to anything Phil ever said or wrote. All of it due to misquotations and assumptions.

Phil took the photo from his office window. Those “dots” are rain on the window because Phil wasn’t too eager to put his brand new Canon 5D Mark III out in the elements. The ISO was set to 100, and f/10 was the f-stop. The photo was captured using an intervalometer that continuously snapped 20 second photos. He didn’t try to “time it”.

Here is how Phil describes it:

The photograph is a single, 20-second exposure. The Daily Mail interview implied that all 8 strikes hit at the same time. There are actually 9 strikes, and some people argued that the lightning didn’t all hit at once. All I can say with certainty is that there are no strikes on the photo before or after this one, so all the strikes had to have occurred within the 20 seconds. Some people commented that the photo must have been compiled in Photoshop because it didn’t look like there were any cars on the bridge. However, in a 20 second exposure, car headlights and taillights appear as a streak. Because our vantage point is higher than the traffic deck that streak of car lights also seems to blends in more so it looks like part of the bridge.

What Was the Most Difficult Part of Getting this Image?

The most difficult thing was getting my office completely dark so I could eliminate reflections on the window. I have five computers, six monitors, a mini cell tower, and a router. Like a lot of home offices, it’s full of lots of electronic things with blinking lights.

Can I Buy This Image?

Phil is overwhelmed with requests at the moment but he is feverishly trying to set up to sell and license the image. Check Phil’s website:

http://www.philmcgrew.com

He hopes to have an order page set up soon.

Can I Use this Photo on My Desktop?

Not legally, no. Making a personal copy is a violation of copyright law. However the Google Photos Screen Saver is able to pull and display photos from Flickr and other sources. For example if you add this to the “Google Screen saver” it will pull in the latest of Phil’s shots.

http://api.flickr.com/services/feeds/photos_public.gne?id=56674458@N08&lang=en-us&format=rss_200

How Did You End up on the News?

You may have seen Phil’s shot. It was featured on the NBC Nightly News with Brian Williams, and his shot has been widely shown on local, national and international news stations. Here is how that came about.

My girlfriend Sherry urged me to contact the NBC Bay Area news the first night because we knew they’d be featuring the storm, and by the time I realized I had lightning and that it was in focus and not overexposed, there was still time to make the 11:00pm broadcast. I had a contact number for the assignments desk because I had contacted them previously to let them know about a great story featuring Eric Harness. (NOTE: That is Eric Harness of StarCircleAcademy!) He’d found a camera in a creek bed while hiking in Yosemite and used social media to post a few of the photos in an attempt to locate the camera’s owner. I called the assignments desk again to tell them about the photo, and posted it to my Flickr account so they could see it. They decided they’d like to use it during the broadcast. We thought it’d probably just appear once at the beginning of the weather segment, and we were shocked that they actually showed it four times during the broadcast, mostly as an interstitial, but still, it was fun to see.

Are You Really 49 Years Old, You Seem Much Younger?

I think one thing Phil definitely regrets is being made several years older needlessly. When I asked him whether he was indeed 49 his answer was:

No, but I hope to be someday so I wasn’t too upset when the Daily Mail listed me as 49. I thought it made me sound more experienced.

It’s also a good case of “don’t believe everything you read.”

Is This Lightning Strike Your Favorite Shot?

Definitely not. My favorite shots are the ones I’ve had to work for. Lunar and solar alignments require some effort to plan. As a former nuclear engineer, I love the challenge of doing calculations to figure out where the moon or other planets are going to be and when, then scouting out the best location and angle to get an interesting shot. Then, of course, you have to hope for clear skies, which is never a given here in the Bay Area. The lightning show was more of a “I’m going to set up the camera and see what happens, maybe I’ll get lucky” event. In fact, once I set it up, I went into the other room and watched TV for a few hours. Don’t get me wrong, the attention that it’s gotten has been an amazingly fun and overwhelming experience, and I’m really grateful for all the kind words and interest people have shown in it. I never thought I’d be on local or national news, or appear in back-to-back issues of San Francisco Magazine, without having committed a serious crime. However, I’d have to say that one of my favorite photos is the full moon over the Transamerica building in San Francisco with the Golden Gate Bridge in the foreground. It took quite a bit of planning and the sky ended up with some really amazing colors. It was kind of a “magical” moment where everything just went right.

Photo by Phil McGrew. Used with Permission

What Subjects Most Interest You?

I gravitate towards night photography. But I’m still trying to figure out what kind of photographer I am so I always try to shoot a variety of subjects. My Flickr account is a little all over the place because just about everything interests me. Night scenes, animals, landscapes. The only thing I don’t really shoot much is people. I think that’s because I’m actually pretty shy and I’m never really sure how to approach them.

Are You Surprised About Your Instant Fame?

I can’t think of anything that hasn’t surprised me. The first night I thought it was great that the local NBC late news showed it four times during the broadcast. I still have no idea how an image clearing house in the UK found it on Flickr, but I was surprised when they called me later that evening to ask if they could distribute it. The next morning, it appeared in the Daily Mail and people started forwarding it to me, and obviously, their other friends. It just sort of took off from there. Before the Daily Mail article, my main goal for that day had been to try to catch the jet fly over for the Giants home opener. I certainly wasn’t expecting to get hundreds of emails and Twitter posts, much less do interviews with local news stations. The whole thing has been one surprise after another.

What Photographs and Photographers Most Inspire You?

I didn’t study photography formally so I’m probably not as familiar with the “greats” as other people are. However, I’m always inspired when I surf Flickr and see the amazing night photography featured. I get assistance and inspiration from a variety of photographers I interact with whether they know it or not. The greatest influences thus far are people I’ve personally shot with and they include Steven Christenson, Harold Davis, and Fred Larson. There are so many people out there with interesting views and great composition that it doesn’t seem fair to only name a few but that’s the top three.

NOTE: Steven and Harold are also founders of StarCircleAcademy – thanks for the plug, Phil!

More Exposure for Phil

Phil Appears on CBS News, San Francisco

The Man Who Shot The Bay Bridge Lightning Strike (Article, NBC Bay Area)
Local NBC Bay Area (video – not found)
Daily Mail (article, photo)
Local CBS interview (video)
Nightly News (video)
Yahoo (Front Page view and article)
SFGate (photo and article)

Posted in Creativity, Interview, Photo Tip | Tagged Bay Bridge, fame, famous, intervalometer, lightning, long exposure, office, timing, viral, worldwide | 4 Comments

Solar Filter: Why You Want to get one SOON

Posted on April 9, 2012 by Steven Christenson

NOTE: This article was originally published on April 9, 2012. As it is now May 18, 2012 it is almost certainly too late to get your hands on proper solar filter materials for the Annular Solar Eclipse on May 20th unless there is a Telescope store in town – and trust me, most of them are sold out. PLEASE DO NOT attempt to photograph or observe the sun if you are not properly prepared. PERMANENT BLINDNESS or DAMAGE TO EQUIPMENT may result.

I have been asked a lot lately about solar filters and why I am strongly encouraging people to get them. First let me explain how you might use them, then I’ll talk about the different kinds of solar filters and their costs.

Here are several shots of the sun rising behind Lick Observatory on Mount Hamilton, San Jose, CA. All shots are without any filter.

The upper exposures are pretty conventional. The exposures at the bottom, however, are clearly MUCH shorter and exhibit excessive flaring mostly due to IR light. Indeed, here are the settings from upper left to lower right:

ISO 200, f/11, 1/80
ISO 200, f/11, 1/640
ISO 200, f/11, 1/8000
ISO 100, f/36, 1/2000

What is probably immediately obvious is the glare / flare and color fringing. Compare the above shots to this one:

This is NOT a single shot, it’s a blend of two shots. The thing to notice is how much better tamed the violently bright sun is. Another important consideration is that a solar filter provides a boatload of protection to both the eyes and the camera equipment more on that in a moment. The bottom line is that the flare is well controlled and the sun exposure is sufficient that if there were a large sunspot on it, you’d be able to see it.

What Can I Do With A Solar Filter?

So glad you asked. Consider these:

Safely capture the Annular Solar Eclipse coming on May 20, 2012.
Why: Because it’s cool and solar eclipses visible from any given area are relatively rare.
NOTE: Don’t be fooled when you see a date of May 21 – that’s Universal Time (London Time). 1:30 May 21 in London is 6:30 PDT, May 20.
Safely capture the Transit of Venus on Tuesday, June 5, 2012.
Why: Because this event won’t repeat for another 105 years! It’s rarer than Halley’s comet and it’s visible from everywhere in the continental United States.
Capture sunspot activity.
Why: We are approaching the solar maximum where sunspots and coronal mass ejections are at their most active.
Composite a nicely formed sun into your shots. You can use my “Easy HDR” method described in a prior column.
Seek solar alignments where the sun forms the back light to silhouette a foreground object.
Catch the International Space Station (or other spacecraft) as it hurtles across the face of the sun.
Use the solar filter as an “ultra stopper” to make extremely long daytime exposures.

For some good background on how to observe an eclipse, see here.

Do I Need Protection?

For your eyes, absolutely. For your camera, HIGHLY recommended. People often go “over the top” in their worry that a big lens will burn an instant hole in the sensor or camera body should they aim it at the sun. The image projected is onto a broad area at least as big as your sensor. In a short period of time i.e. a 1/4,000 of a second exposure nothing horrible is likely to happen to the sensor at least. The combination of a mirror and shutter in a DSLR provides SOME protection to your camera and sensor from “certain doom” however if you were to ask my advice, I’d say DON’T use your camera to photograph the sun unless you have a SOLAR FILTER. Most especially do not use live view (or a point and shoot camera) pointed at the sun. That tactic is very likely to damage your camera.

When I zoom in on the sun, isn’t that concentrating the light even more?

Well actually, just the opposite. Instead of focusing all the energy on one spot, you’re spreading it over the sensor surface. So in fact, the sunlight is more concentrated when you don’t use a telephoto lens.

DO NOT look through the viewfinder to compose your shot unless you have a proper solar filter! Permanent eye damage may result. Even then be careful. And we just figured out that it’s not a good idea to use Live View to compose a shot.

What Kinds of Filters Are There? What Do They Cost?

Protection For Your Eyes

There are filters that you can wear or hold over your eyes. I highly recommend you get a pair. These are rated “ND 5″** and allow only 1/100,000 of the energy to pass through. Alternatively you can use a welders mask (though I bet not many of you have one!) #13 or greater. Cost of wearable / simple filters ranges from $1 or so to $20 and more depending on the type. Wearable filters are usually made of black polymer which blocks all wavelengths of light (important to prevent eye damage from non-visible light) and renders the sun a yellow-orange color. Most locations only sell the personal filters in bulk (10 or 25 are the usual minimums). I purchased a stock of 60, for example and have sold them all.

**IMPORTANT NOTE: There are at least FIVE different standards for measuring the transmissiveness of filters: “Neutral Density: ND, Optical Density – also often called ND, Shade Number – for welders glass, transmissiveness, and stops). For a photographer who is familiar with the ND scale used to rate Neutral Density filters this is NOT the same scale as the “Optical Density” scale used to rate solar filters! An ND3.8 (photo solar filter) in the optical density scale is equivalent to the ND8192 neutral density filter! An ND8 filter for your camera is 3-stops of light. For safe visual viewing you need about 14 stops! So an ND8 is woefully short of light snuffing capabilities. Moreover neutral density filters used with cameras may or may not extinguish harmful Infra-red and Ultraviolet radiation.

What about using an 8-stop Vari-ND (ND2-400 Filter)?

At the maximum 8-stop setting (ND400) the filter is passing 0.4% of the sun’s energy. That’s more than 40 times the recommended energy for PHOTOGRAPHIC use. A photo filter should transmit less than 0.01% (1/10,000). Even a 12-stop reduction in light (ND4096, Optical Density 3.6) passes too much energy for safe and effective photographic use. 13-stops which is the same as Density 3.8 or ND8192 is preferable.

What about the “Big Stopper” by Lee or Hitech?

10-stops sounds like an impressive reduction in light but the resin filter (Hitech) passes quite a lot of IR and UV light. And 10-stops still really isn’t enough. I haven’t see the response curve for the Big Stopper. It would be UNWISE to assume the Big Stopper or any filter is safe if it isn’t solar specific – especially if you plan to try to take more than a few shots. These filters certainly aren’t visually safe.

In addition to not reducing the light to safe levels, having an insufficient energy reduction means that you’ll have problems with flare / glare.

Photographic and Visual Filters

There are several varieties of solar filters that can be used for photography.

Black polymer screw-in solar filters – pre-made you order them to screw in on the end of your lens(es). There would be little point in getting such a filter for any lens that is less than about 200 mm effective focal length. It might be worth making your own from an existing UV filter.
Black polymer “covers” or black polymer solar sheets from which you can make filters.
Silver solar mylar sheets (make your own) which render the sun a more natural white to a blueish cast. Mylar is less durable than polymer.
Glass solar Filters in a housing to fit over a lens hood or dew shield (ND 5.0)
ND 3.8 (Photographic) solar filters which are NOT suitable for visual observing. This type generally only comes in sheet form and you must make your own filter. Not suitable for visual use because it allows too much of the suns energy to pass through to your eyes.
Tuned solar filters (also called Hydrogen Alpha) – like those found in the Coronado solar telescope. I don’t have a background in these, but normally you will need a set of filters and they are primarily designed for use with telescopes. The cost is upward of $600.

Normally when you buy a solar filter, you select a size that will cover your lens hood (or for a telescope the “dew shield”). Fit on filters should be snug so that they cannot come off if bumped or buffeted by wind. You really do NOT want your eyesight destroyed by a gust of wind! The filter should also seal out light leaks since most solar filters are reflective.

Filter Costs

Since the upcoming events all require solar filters, they are in short supply. It may take literally MONTHS to get a filter from some suppliers.

Costs depend on the size and quality of the filter. For the average telephoto lens expect to pay from $60 to $100 for the glass type filters. For very large lenses or for telescopes that cost could reach up to $200 and more.

Black polymer or silver mylar sheets will run you about $35 not including shipping. The ND 3.8 Baader photo filter is about $90 for a 19 x 39″ sheet. I also ordered a “natural color” Mylar polymer sheet (12″ x 12″) for about $30 from RainbowSymphony. RainbowSymphony also has the solar glasses at minimums of 25 pieces. Finding things on the RainbowSymphony site is a bit tedious.

There are many references on the web for building your own solar filter if you choose not to buy a glass filter.

As with all things, quality varies quite a bit. I do not have the resources to exhaustively test all filters, but so far my best photographic results have come using the Baader Astrosolar Film (PHOTO) and hand made filters. This filter passes enough light to keep the exposures fast at low ISOs and is optically superior to any other mylar or polymer material I’ve tried. The glass (visually safe) filter I have darkens the image to make it visually safe and renders the sun an orange color (which it isn’t by the way). Somewhat longer exposures are needed for this.

Resources

I’ve placed these in order according to my experience surfing and buying from the company.

OPT Really fast to ship. Also has smaller sheets of ND 5 and ND 3.5 films available. Shipping is about $10, however.
Thousand-Oaks Optical A little slow to ship (due to demand) and you have to know what you want exactly to use their website.
RainbowSymphony Difficult to navigate website, but efficient and inexpensive otherwise.
Orion Slowest to ship, least communication. Note this link is to a specific filter, you may need to find a different size – which is, unfortunately, not as easy to do as it should be.
Astro-physics.com - Large sheets of Photo density filters (ND 3.5) – placed an order but Astro-physics lost my payment information. They have an excellent reputation for high quality scopes, but I am worried about a process that “loses” payment data. There are also some significant flaws with their website / ordering process.

Recommendations

If your goal is photos, get a Baader Astrosolar filter. It is not eye safe, but it does allow higher shutter speeds and versatility. Practically this means you’ll have to make your own filter from sheets as there are few resources with pre-made photo transmissiveness filters. Making your own filter is not that hard.

Second choice based on quality is a glass filter that seals well over your lens hood (you do have one, right?). The “outside diameter” of your lens hood must be about the same as or slightly smaller than the inside diameter of the glass filter you’ll put over it. Since most glass filters are designed for visual use, you’re shutter speeds will be a bit slower but good quality glass will keep your photo sharp.

Get a pair of solar glasses for your eyes regardless of what else you do.

Posted in High Dynamic Range (HDR), Photo Tip, Review, Trivia | Tagged Annular Eclipse, eclipse, nd 5, solar, solar filter, Sun, Transit of Venus, venus, visual | 14 Comments

Playing with Fire

Posted on March 29, 2012 by Steven Christenson

Who doesn’t love fireworks? Not you. Stop reading. Really, you’ll be bored to tears.

Still here?

Well we’ve got just the thing for you. I started a column long ago about photographing actual fireworks as in the Fourth of July (in the United States), or New Years Day (just about everywhere). But those events do not happen all that often. What if you could MAKE YOUR OWN fireworks. Well now we would be talking, right? But I am NOT talking about explosives. Merely hot burning steel. And YES it could be dangerous to you or your camera. There are dozens of good resources on the internet to learn how. Because I do not want you suing me for getting you, your equipment, neighborhood or small country destroyed I am not going to describe how to do it. I will merely refer you to others whom you can sue the pants off of when bad things happen.

I will point out a few obvious things. Obvious to everyone except teenagers. Sorry kids. I didn’t mean to single you out, but people who go riding on cafeteria trays towed by speeding cars clearly are lacking something in the area of sound judgement.

YOU COULD START A FIRE. And it might not go well after that.

First I want to thank my confirmed pyro lunatic buddy for thinking of me. I’m talking Andy who is apparently scared by Photoshop, but not molten metal. If Andy never existed, there would still be my partner in many crimes, Eric “Mr. Panorama and Pyromania” Harness.

Obligatory Photo Taking Notes

Like all things night photography there are many variables in this sort of exposure. The shot above was a six second exposure at ISO 250, f/13, 35mm. If you’re not the one doing the spinning, I recommend BULB mode with an intervalometer. Though it may be tempting to collect light for the entire duration of the spin, experimentation is in order – both in length of exposure, as well as settings. A lot depends on the ambient sky conditions (some light is preferable to no light), how close you are to the excitement, and so on. Stopping down helps to keep from blowing out details, and it also helps to resolve some minor “offness” in getting a good focus.

How to Get Burned

Quirky Video… Decent Explanation by Evan Sharboneau
Lots of inspiring photos. See the Wire Wool Group – as the Brits are known to call it or the Spinning Wool group (WARNING: Not my photos and I can’t guarantee the content)
My Pyro buddy has some wild images, too.
And Ben (aka Tackyshack) goes to great lengths to make elaborate pyro designs with a pond in the foreground to reflect the light he uses.

Here is something else you can do… does not involve fire, but does require a green laser that can put your eye out. That’s Eric Harness “Stayin’ Alive”. I supplied the green and my photo buddy Phil (of ISS Mooncatching fame) is providing the red glow – from his camera!

If you’d like to know how I did it, leave a comment.

Oh, and in case you were looking for some unconventional treatments of conventional fireworks, take a look at these. Click the images for details and tips.

Posted in Creativity, Photo Tip | Tagged fireworks, metal, slinging sparks, spinning steel, steel wool, wire wool | 5 Comments

Easy (HDR) Blending with Stacking Sofware

Posted on March 10, 2012 by Steven Christenson

I’ve been teaching a “Catching the Moon” webinar approximately monthly. The focus of that course is to teach how to properly expose for the moon, how to catch the moon aligned with your favorite landmark, and how to determine the optimum light scenarios. The webinar is based on my Alignment 1 and Alignment 2 articles with a healthy dose of additional material including some private material for students only.

One of the most difficult aspects of getting a moon alignment is that there is a pretty small optimum time window for getting an exposure. Shooting earlier or later makes the foreground illumination and the moon illumination all but impossible to get both exposed properly in a single shot.

Here is an example of a single shot where the lighting was pretty close to perfect (though you can see the moon is a bit over exposed).

However later that evening the sunset occurred quite a while before moon rise, so the sky and foreground were much darker. The photographer faces a conundrum. Expose for the foreground or expose to preserve moon features.

On the left is a 30 second exposure prior to moon rise (though a tiny bit of the moon is in fact visible). On the right a 1/25th of a second exposure. Both taken on a tripod at f/9, ISO 250, 444mm effective focal length. The problem is that a longer exposure renders the moon as a white featureless blob or streak (see below for an example). However exposing for the moon as on the right renders the foreground all but invisible.

What to Do?

There are a couple of simple alternatives. One is to bring both images into Photoshop. Make both images layers, the moon on top of the background and combine the two images using “Lighten” blending mode. That will work very well and it’s essentially what happens when using the StarCircleAcademy Stacking Action. But that action, and even Photoshop are overkill for this situation.

Free Solution!

Fortunately Markus Enzweiler offers a free solution called StarStax that runs on Windows, Linux and Mac that makes it trivially simple to combine these two exposures – assuming they were taken on a tripod and the zoom, focus and direction does not change between shots. StarStax is tailored to stacking star trails, but it does the same operation that Photoshop (and Image Stacker and StarTrails.de do).

And fortunately you can make it do a little more with almost no extra effort… as in this example. When the first image was taken it was quite dark and required a long exposure to capture foreground details. Then all the moon images were taken with identical settings using an intervalometer. It’s interesting to note how the moon darkens and deepens in color as it sinks in the atmosphere.

So how do you create the simple or “stacked” motion images? Easy.

And here is the result.

Obviously to create a descending or ascending moon sequence you merely need to combine exposures taken at the appropriate interval. What is that interval? The moon travels roughly its diameter in two minutes. About 2 minutes, 14 seconds to be more precise. I recommend taking exposures twice or four times as often as that, however and just use every-other or every fourth shot.

Since I took a simple approach to blend the images I also elected to go simple in presentation. Rather than fight the many different colors inherent in urban night scenes, I used Picasa3 to convert to monochrome, crop and frame the combined image – here using an earlier shot than the “Golf Ball on a Tee” shot above.

Here is one last example of a descending crescent moon combined using Photoshop. Here I didn’t wait a full moon diameter time between images because it was a crescent moon:

This also illustrates why taking more frequent exposures gives more creative latitude.

Posted in Class, Contest, High Dynamic Range (HDR), Photo Processing, Stacking | Tagged alignment, blending, exposures, HDR, moon, stacking, StarStax | 1 Comment

Learn from the HDR Pro

Posted on February 27, 2012 by Steven Christenson

I’ve said it before, but it bears repeating. Were it not for what I learned from my friend and mentor, Harold Davis, my Astronomy Photographer of the Year, 2010 win would not have happened.

It is really just not possible to capture the wide range of exposure latitudes without post processing. Moreover processing with traditional tools does not result in as pleasing a result. It took application of the Hand HDR blending technique I learned at one of Harold’s workshops (and from his book) to make the image possible. I hope you’ve also noticed that the image above bears none of the hallmarks of “typical HDR” imagery.

Harold is teaching an HDR workshop on March 24, 2012 in Berkeley, California. For details please see “Photography with Harold Davis” Harold has a book on the subject scheduled to publish in July, 2012. You can pre-order it now for a quite modest price. The Hand HDR techique is also covered along with several other powerful tips in his book The Photoshop Darkroom: Creative Digital Post Processing.

Here is the same subject using automated HDR processing:

And another example that “screams” HDR with its “gritty” texture and surreal look.

But you do NOT have to make images like that. You can if you wish. Harold will show you both!

If you’d like to see all of my images of and around the marvelous location, take a look here.

Posted in Class, Photo Processing, Photoshop, Workshop | Tagged Berkley, California, hand blending, Harold Davis, HDR, high dynamic range, Techniques, workshop | Leave a comment

Lost Camera – the rest of the story

Posted on February 10, 2012 by Eric Harness

I would like to sincerely Thank all of the people who viewed the post about the lost camera. I would like to especially acknowledge Thomas Hawk for re-posting on Google +. I have located the owner after about 4 hours of intense emailing, checking, googleing and fact checking. The short story is my own search and the folks one the internet helping me search converged to the same point at about the same time, let me tell you how we got there.

After pulling the camera out of the mud briefly looking it over, I pried the battery door open and found a pristine battery and memory card compartment. After arriving home late on Sunday, Posted on Facebook that I had found a camera and was downloading the photos. I dragged a photo to stolencamerafinder.com but no luck. It was late so I went to bed. Monday during the day I got slammed a work. Monday night, I looked a little bit but nothing popped out.

Tuesday night, I got my first chance to take a good look at the photos. There was about >1000 files on the camera, the first place I started was the EXIF data which told me a few things about the camera and the date the photos were taken. But no owner, no geo tags, just a few fragments I summarized on the photos the first photo was number in the 200′s and dated 5/8 the last was dated 7/22/2011. This told me the camera was new and the day it was lost was 7/22/2011 on a rafting trip on the Merced River with All Outdoors. I called the rafting company All Outdoors no luck, not open, I wanted to talk to a person not surf through the computer menu. I thought I would call back in the morning. I watched and re-watched all of the videos. Nothing. no names, no places, nothing in the end I decided that I was starting to make up audio. I seemed to be convincing myself people were talking and making stuff up. Kinda like when you play a record backwards. After a few hours of watching the rafting videos I was getting motion sickness and hearing things so decided I was not getting anywhere.

Wednesday, I got slammed at work AGAIN and never ended up calling All Outdoors . Wednesday night I focused on the photos and collected the data off of all the buildings numbers names, places and attaching them to the photo. I took some notes. The camera had 2 months of photos all in CA the suggested the owner was from CA. The photos were from mostly So Cal so that narrows the region. I looked up some info on the Palm Springs Film Fest but I didn’t find any photos that looked like anyone in the photos. What troubled me was something I know too often the owner of the camera is usually behind the camera not in front of it. So I was assuming most of the photos might no have photos of the owner. The reoccurring people maybe the ticket and if I could find one of them they might be able to lead me to the owner. Especially, the group shots you usually pose in groups right?! Judging from the videos and photos I think I nailed the owner. But who were they. I was pretty exhausted. I was concentrating hard on the photos looking for names on tables, or an address on a scrap of paper. The little hints but nothing solid. This was WAY too slow. I collected the data, tagged the photos. Tomorrow, I decided I was asking the internet.

Thursday, I uploaded the photos to my Flickr account and Google + and wrote a short explanation on the Star Circle Academy Blog. I published them all at the same time. I started with some of my CA Flickr contacts briefly emailing and asking for help. I was running late for work and had a lot to do, I figured I could finish at work. I called All Outdoors still the computer menu…Grrrr, well they officially open in a few min I might be able to reach them or it could be off season and no one is answering the phones. I will just go to work start on some Google + contacts then start my day.

I was not really prepared for what happen next. In the brief time between me leaving for work, making a cup of coffee, Thomas Hawk moved my plea for help from Flickr to Google +. Lets just say it exploded people were sharing it, +1-ing it the comments the emails. I shifted from reading comments, to emailing people to fact checking, there was a lot of encouragement, and tons of good info, lots of you should do “this” (and the “this” was redundant). Between some of the comments I tried the Malibu Surf Shop, after a short explanation all I got was they didn’t really keep computerized records. Grrr…that was a dead end.

Just when it was getting really interesting I had to leave, you know “work” meeting.

While I was working people had been working on the photo that contained a badge that read ShortFest in Palm Springs. They had posted a link to some of the photos of attendees one of which was looked a lot like the person I though was the owner. It was good but who was she??

Before lunch, I took a short break and tried All Outdoors rafting company again. I got a person!! A real person! I was a little surprised.

Hello Can, I help you?

Ah? I sure hope so.

I think I surprised her with my surprise and excitement! I explained the story to Diane. She seemed a little stunned, one that a camera survived, and two I was contacting them. She asked, How do you know it is us? I replied. “Well, it is written all over your boat, the paddles, your life vests”. I also mentioned that the date of the trip was 7/22/2011. She quickly pulled up the date and said “That’s great we only had one trip the day. And we have all the email addresses of the participants.” I gave her my contact info and passed on. A solid lead finally!!

While I left for lunch an email from All Outdoors to all of the attendee from the day the camera was lost For the next 45 minutes things churned in cyberspace.

The near miss, an email from a person in the boat:

I received your email, but the camera is not mine. Someone on my raft did lose a camera, but I can’t remember the lady’s name. I hope that you are able to track down the couple and that they get their camera back.
I know they were disappointed when it fell off her life jacket as she was being pulled back in the raft.

About an hour later I had an email, a very excited one indeed!! In her own words (edit to protect privacy):

Eric,

This is the most amazing email I have ever gotten! My underwater camera was my most favorite things and I was so upset when I lost it and all the pictures of our trip. Thank you so, so much for going to these lengths to find me! It is a total miracle that it worked, and how amazing of you to do such detective work!

Googleing, the recipient everything started to check out but I still had my doubts. Started to assemble the questions to verify it was her camera. Things I could ask about the photos that only she would know. However, this was unnecessary, I got confirmation from Google +, Craig Richmond had cross referenced the owner through the Shortfest Photo and surfed around until he confirmed with a separate photo which was connected to her name. He got the same result as I did and helped me confirm from that, we came to the same conclusion. My response was “Bingo”. If he would have been about 40 minutes Earlier I would have been emailing the owner not her emailing me.

During some correspondence over email, she also confirmed some other details that made me confident the camera was hers. That was it, it was an interesting ride and fun to be involved in the search. All Outdoors really came through in the end and I am so happy that they do not close for the season and someone answered the phone. Thank you, Craig Richmond who also helped me confirm which was a large part of fact checking. And a very large Thank you to Thomas Hawk because this story would have never got off the ground without his response.

That is the end of the story. I am heading to the post office today and will put the camera and SD card in the mail. I am going to end with her own words (edited for privacy):

“Wow, the whole thing is so crazy I can hardly believe it! Amazing work. Wow. I am just so, so grateful that you went to all the trouble, it is so lovely. Eric, I feel like you know so much about me – Where do you live? where do you work? what can I do to repay your kindness?……..Also would it be OK if we took most of the pics down and just left up the one below for the sake of posterity? only because I am slightly mortified to have me and my family’s analog life on public view – probably why it was so unnecessarily hard to find me! I don’t really use any of these technologies. I hope that is not ungrateful – because I am so thankful to you for all the trouble you went to! It is just such an act of generosity, you’ll have to let me write you up something for the end of the story about how thankful I am to everyone who helped with the detective work!

Thank you again so much, and please tell me if you are coming down so we can have you to dinner – I think we’re destined to be friends now, right?”

Yes I do believe we are destined to be friends.
PS. Since the owner has asked me to remove her photos I will be responding to her request….I would also ask that you please do the same. This is also why I have decided to identify her as just the owner to also protect her privacy. I would not want to ruin a new friendship now would I? She has allowed me to keep one photo up for the sake of posterity (but I am going to ask for a second I love this one). Thank you. The end.

Posted in Guest Column, Uncategorized | Tagged Found owner, Lost Camera, Lost owner | 7 Comments