Photo stacking

[Dan Robinson]

I've become a big fan of stacking lightning images. This technology has taken a few otherwise boring storms and made then into some interesting images. But there's a debate as to whether this is a legitimate technique to use as a photographer, as it shows many lightning strikes in a single image that did not actually happen all at the same time. I make the case in favor of stacking with images like these:

That image isn't a stack - it's a single 10-minute exposure on slide film, taken during my Plains chase trip in Texas in May of 2002. Shots like those (long time exposures of nighttime storms) have been around as long as photography has. The only limitation of the long exposure method of capturing multiple lightning bolts is that it must exclude ambient light sources, such as the moon, city lights, streetlights and so on. This is because those ambient light sources will overexpose terribly in multi-minute exposures. Stacking is a way to finally perform long exposures in scenes containing ambient light, using the benefits of our technological advances. I think the results are pleasing, and the response to these images is nearly always positive. Isn't that the goal of fine art photography?

I went into some more thoughts on my blog:
http://stormhighway.com/blog2012/august1612a.shtml

As to how stacks are done, there are many tutorials on the web on how to do it. I use Smart Objects in Photoshop CS4 to produce mine. I believe standalone apps like Photomatix can also do it.

 

[Rob H]

Nice writeup, Dan. I've been discussing this with a few people lately, and I'm still not sure how I feel about doing it myself - I couldn't care less what other people do, for the record.

From an artistic angle, it's a completely valid technique and can produce some stunning images. From a journalistic angle it might be pushing the boundaries of a realistically documented scene. Taking a look at some stacked lightning picture threads on Reddit and Facebook reveals widespread confusion as to whether the image is real or not and how it was made. I also worry that it may cheapen those experiences where the lightning is literally striking all around you incessantly. Techniques like this start to blur the line between photojournalism and art, but I think it's an interesting conversation with no right or wrong answer. Unless you start submitting "art" to the NWS as photo evidence of an event.

Finally, some food for thought - what if people start stacking tornado pictures to create multi-vortex/satellites that never truly existed? I get the feeling there might be a significant backlash against that

 

[Dan Robinson]

Rob, those are valid concerns. I think it boils down to intent, end user perception, and probably the biggest is if the image is being presented editorially or as fine art. Editorial standards are extremely strict, as in no editing power lines or lens flares out, selectively desaturating colors, etc. Editorially, stacking probably wouldn't fly at all. Fine art is much more flexible and subjective. Even so, I always 'fully disclose' stacked images. With lightning, stacks (to me) stay in the the genre of numerous strikes in a time exposure - something that's already been in existence and generally accepted. My modern-day digital stacks look the same as my old film long exposures - just different methods used to reach the same end. Now if I were to stack a lightning bolt from another storm in the Plains into a shot over a city, I'd think that would cross a line IMO - though if someone did it, was honest about what was done to the image, and still got people to buy prints of it, then IMO no ethical boundaries were crossed as long as the work stays in the realm of fine art.

I think if one managed to get a series of tornado stills without moving the camera, with the tornado moving left to right across the frame while changing shape/size. etc, it would make for an amazing stack! Purely artistic, of course, but I'd imagine that would be a very popular one! That to me would be similar to the anallemma composites of the sun or strobe photography of a golf swing.

 

[Greg Campbell]

I've got to agree with many of Bob's points. FWLIW, I see photography as a literalistic media, one that should at somewhat approximate what I'm seeing and experiencing. (The definition of 'somewhat' being open to all manner of 'discussion!') From that POV, squeezing multiple strikes onto a single image is a little too surreal for my taste.

Not surprisingly (people are always rationalizing their perceptions!), my sense of aesthetic doesn't agree either. IMO, a good lighting shot doesn't need 'bling' bolts; it should stand as a pretty landscape shot that just happens to have some nice lightning going on. If the clouds are bleak and featureless, or the terrain is too dark, or filled with ugly urban junk, I'm just not interested, and no amount of bolts are going to help. It's like turning the saturation / volume / brightness up to 11 in an attempt to compensate for a crappy photograph / boring music / or bad TV programming. I'm not saying that's what you're doing with your images; most of your blog shots are neat, but in the end, I think they're just too 'loud.'

 

[Dan Robinson]

Greg, I definitely see your point. In the end though, what convinced me to accept stacking is the positive response and acceptance by viewers. The print sales from a few of my stacked shots this year got me within range to afford the Canon 10-22mm, a lens that was previously past my price point for a leisure purchase (I previously bought and sold one just to use it for a few months). I generally have never sold more than a print every year or so, all the way back to my first shots in 1993. I figure if the audience/customer accepts the image knowing it's a stack composite, I can't find much of a reason to not accept it myself.

 

[Terrence Cook]

What the hell is going on with your avatar Rob...

Jesus Christ that makes me want to vomit, can we bring GIF's into this conversation. I hate them


As for photo stacking, beauty is in the eye of the beheld and sometimes it is overkill, Dan's avatar (which does not inspire suicide) is a prime example of a beautifully stacked image or one impressive long exposure!?

Star trails are my main stay so stacking tis a god send.

 

[Darren Addy]

I see photography as a literalistic media, one that should at somewhat approximate what I'm seeing and experiencing. (The definition of 'somewhat' being open to all manner of 'discussion!') From that POV, squeezing multiple strikes onto a single image is a little too surreal for my taste.

I used to think the same thing. Now I realize that literalistic is only one way to use the medium. Photography is a tool, like a paintbrush and a set of paints. To define a Real Painting as only rooted in realism would be considered by almost anyone as narrow. The fact that photography can do a great job at realism (and that is required for fields such as photojournalism) does not preclude its use in other ways.

This lesson was driven home to me, back in the FILM days even, by the creative darkroom work of Jerry Uelsmann. As a digital muse for opening your eyes to the SUBJECTIVE way that photography can create incredible imagery, I suggest looking at the works of Ursula I Abresch: http://ursula.pixu.com/ and http://1x.com/artist/ursula/photos
Her works are mostly created IN CAMERA with multiple exposures and I find them quite striking. If you google defocusing techniques and her other inspirations you may find a whole new exciting door opens to you in terms of seeing what is possible from what you formerly thought of as restricted to realism.

 

[Andrew Pritchard]

This is an interesting topic that I recently converted to the dark side on. That said, I haven't used it much for lightning. I first really got into stacking images with astro-photography. Star trail images have been some of my favorite shoots for the last few years for a few reasons. I love the imagery, but I also love the experience of sitting around at some rural spot for a few hours shooting the night sky.

I did play around with stacking an image similar to Dan's above with a storm that was spitting out cg bolts from across the IL/IN state line back in July. In most cases I do prefer the single image approach with lightning, but there are exceptions to every rule.

 

[D. Vance]

I don't see anything wrong with stacking, necessarily, as long as it is disclosed. Most guys just go "Oh, here's a shot I got last night", and don't tell you that they've stacked them.

 

[Joshua Nall]

I copied and pasted this from your blog post Dan.
"As far as lightning is concerned, stacking multiple exposures yields identical results to that of a single long exposure, a technique that has been used throughout the history of photography. For instance, if you were out in the Arizona desert with no city lights in view, you could do a single 20-minute exposure of a storm and capture 50 bolts of lightning on that one exposure. Alternatively, you could do forty 30-second exposures (each with one or two lightning bolts in them), or 20 one-minute exposures, then digitally "stack" them all into one image. In the end, both of those techniques will yield exactly the same result: a single photo showing 50 lightning strikes."

You say identical results and exactly the same results, but I don't see how that can be. I think there is a difference with stacking other than just not having to deal with exposure from ambient light sources. With stacking you can pick a photo with a nice bolt in it, one in which you like the general look of the clouds. Then you stack all the other shots of lightning on that image and you can control how the clouds sort of blend together or hide behind this picture you like, to create a realistic looking image with tons of bolts. I'm just assuming that is how it works from what I've seen and read about it. On the other hand, a long exposure with several strikes, especially if there are clouds in front of or to the side of the lightning, will look choppy. Every time the clouds are illuminated by the different strikes, and clouds generally move, that new image is recorded in the camera. This causes a choppy unappealing look to the clouds.

I guess my main point is, if I'm understanding correctly how this works... is that it is much easier to get an impressive looking photo that someone would appreciate or want to buy when stacking. I have many long exposures with lots of strikes, but the clouds just don't look right or natural in any of them really. On the other hand I have 2 photos, after years and years of doing this that I am happy with, that have multiple close strikes. In these two images there are 5 or so bolts and all of them happened with in a second or so of one another. That is like a once every 3 year type of shot for me I guess, haha. Actually longer than that but I do it more now than 10 years ago. I'm just saying that stacking lightning images is causing shots like that to seem not so great. Especially to the general public. They don't care how it came to be, just so long as it looks cool. But instead of spending years to get a really great shot, and I'm sure you have some of those, some one can set up and take multiple shots over the course of 20 minutes then stack them and all the work is done on a computer... and it looks sharp. I'm not saying that it shouldn't be done, or that someone shouldn't use any tools they want to for artistic purposes. I'm just saying they don't produce Identical results. That is if I'm understanding correctly how stacking is done and you can manipulate the photo to the degree I am assuming you can.

 

[Dan Robinson]

Yeah, the scene definitely has to be right to be stackable. Too much cloud material makes it look bad. If not though, the results do end up looking just like a long exposure.

It's pretty clear to me that this will probably always be controversial. For that reason I clearly label my stacked shots, as well as posting the non-stacked ones right alongside them. Viewers and buyers can then decide for themselves which ones they'll accept. I can say that the general public accepts them readily, and at this point that's good enough for me. FWIW, I haven't sold a single non-stacked lightning photo in over 10 years.

I will say that stacking in general seems to be gaining acceptance. Look at all of the ones we saw with the meteor shower recently. Just about every pro photog did it for the Geminids, and no one raised an eybrow about those. Even though those required not only stacking, but some more involved compositing/masking/alignment of numerous layers.

 

[STexan]

My only goal is to capture "the mood and the moment" as I viewed it, as accurately as possible. Lightning is difficult, day, dusk, or dark to capture the light accurately, the clouds, the visible landscape, etc wether you stack or do long exposures. Shooting raw, I'm able to boost the shadows, and not have to shoot to the point much of the close-strike bolt is blown out. I personally prefer to shoot with long (but not too long exposures) and capture the moment. Maybe 3+ separate strikes get recorded, maybe one, but I feel tweaking raw images is perfectly ethical given the inherent issues shooting lightning and other low light subjects. Stacking is ok too if the final image result is what the photographer was going for, although I've yet to try this technique.