Is High Dynamic Range feasible with large format film? That is, how close do the separate images have to register in order to avoid problems. I would imagine that the placement of the film in the camera will vary slightly from one exposure to another, and, more important, when scanning the separate images, they are unlikely to align exactly. I wondered if that causes any problems that the software can't deal with.
A few astronomers were reputed to be able to reinsert plates in telescopes in perfect registration for exposures over several nights. Certainly it should be possible, but rarely practical, in LF photography. HDR is mostly the digital photographer's attempt to equal the zone system and other traditional techniques.
Negative film is "HDR." Just shoot negatives.
The dynamic range of just about any negative film is miles beyond what's possible with one-shot digital.
It would be very difficult to do HDR in LF with common equipment. The big point of difficulty that I see is the "slop" of the film within the holder. That would make registration difficult.
I actually do this all the time. I've been able to take two shots, 4 stops apart and blend them pretty easily. It takes some practice cropping them before the blend to make sure they line up, but done correctly will yield fabulous results. I will still use grads when feasible, but HDR is certainly possible with LF.
It's expensive,though, especially in color!
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
Generally I think HDR looks terrible. If I ever wanted to do it I'd just shoot colour neg and scan it three times, each time with a different tonal range, then merge in an HDR program. Way faster/easier than shooting multiple images, and no risk of going overboard and making pure blacks look orange or something silly.
I sometimes take more than one shot of the same scene, like this one, where the water going over the weir was too bright and the shadows under the trees were too dark to fit on Velvia 100. So I took three shots and blended in small sections of the "under" and "over" shots into the "normal" exposure shot, in Photoshop.
But I wouldn't try using the "automatic" HDR software with whole images. Unless you are extremely skilled and adept, this usually leads to horrendous results that you can tell as HDR with your eyes closed.
I have done this a few times for transparency film in challenging conditions. Photoshop is capable of aligning two 2000dpi 4x5 scans well enough for HDR but instead of using an automatic local contrast enhancement script, I just use a luminosity blend (see below) and then just make any changes to the flattened 16bit file
Tim
p.s. To make a luminosity blend. Get your two pictures into photoshop with the darker one on top. lock the bottom layer and then select both layers and use edit > auto align layers.
Now add an 'exposure' adjustment layer between the two layers and tweak the 'gamma' until you can switch the top layer on and off and the shadows look fairly similar.
Now drag the RGB channel over the dotted circle in your channel pallete (load channel as selection). This creates a good enough luminosity mask selection.
Select your top layer and then use 'layer > layer mask > reveal selection'
If you now flatten the whole lots, you will have a file that looks like your top layer but with lots of shadow extension that will respond well to dodging and burning, shadow highlight, etc.
Still Developing at http://www.timparkin.co.uk and scanning at http://cheapdrumscanning.com
Probably more feasible with LF than smaller formats since most people use a tripod with LF. Not that a tripod is necessary, many people just handhold and let the software do the alignment which it can do surprisingly well. But I think you're ahead of the game if you use a tripod. The only problems I see with HDR and LF are the cost of the film and processing if you don't process yourself and the size of the files.
There's a big difference between scanning multiple times as one person suggested and using HDR. When you scan 3 times or whatever all you're doing is trying to use software to "correct" for the areas that weren't properly exposed in the first place, you aren't working with exposures that were optimized for each area as you are (or can be) with HDR.
HDR doesn't inherently look terrible. Sometimes people using it produce terrible results just as people sometimes make all types of photographs look terrible.
I've never used HDR in Photoshop. I've always used Photomatix. Photoshop's version had a reputation of not being very good. It supposedly has been improved in CS5 but you might still take a look at Photomatix, which IIRC can be downloaded on a trial basis.
Brian Ellis
Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
a mile away and you'll have their shoes.
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