High Dynamic Range Photography!

[errantember]

Normal pictures can only show about 7 EV (levels) of difference between the darkest and brightest part of a picture. This can make it hard to photograph things like a mountain sunset, since the sun is very bright but everything else is more than 7 EV away in the dark. By taking several pictures at different shutter speeds and combining them mathematically, it's possible to get a final picture where both the sun and the mountains are visibly exposed. This technique is called High Dynamic Range photography. The upper-left picture is the final result, while the other three show the range of exposures taken for reference. Notice that both the highlights of the darkest and shadows of the brightest originals are all present in the finished product. This picture shows details from over an 11 EV range squashed down to fit onto a normal computer monitor, which can only display about 1/2 of that dynamic range.

Thanks to Ryan Hayes for turning me onto this.

Comments

[jb-27.livejournal.com]

HDR is super-cool. A challenge, currently, is that it only works with static subjects, as multiple exposures are needed. A second challenge is that current display devices and output media have far less than even 7 EVs of dynamic range. The first problem, at least, can be addressed via technology. I have heard rumors of the development of HDR digital cameras, capable of capturing an entire scene's worth of data all at once. This is very exciting to me. Imagine being able to shoot without worrying at all about exposure. Set whatever F-stop you want for DOF and whatever shutter speed you want for motion-stop or blur. Then shoot away and don't worry about under-exposed shadows and blown highlights. Choose your curves in post-processing. Voila!

[jb-27.livejournal.com]

Oh, and a second challenge: my Minolta 7D can only do up to 5 bracketed shots, and at a maximum of 1/2 stop increments. Argh. For HDR, it would be very convenient to be able to do e.g. 7 brackets in 1-stop increments. I'm hoping for a firmware update to fix this, but I don't hold my breath.

I do all my bracketing manually

[errantember.livejournal.com]

...right now, which is a pain. I think my Sony only does 3 brackets, and I haven't checked the increments yet. Still farting around to figure out how to get the best images with the smallest number of shots, and also how to do the post-processing to get the best 8bpc image when I'm done. I finally figured out the functional basics of the Local Adaptation settings in CS2 to do my example picture, but there's obviously more to learn.

[apryl-knight.livejournal.com]

This is awesome! I am really lusting after a digital camera with manual controls; mine's pretty basic. I'd love to be able to do stuff like this!