Discussions (78)

EXIF and EV Offset

view profile

Trevor Dennis says:

I have not even installed DP HDR yet, but have been using Photomatix for a few weeks amd enjoying the whole HDR thing.

A point that I would appreciate clarification on, is the HDR software's need to determin the EV offset. This comes from a review of version 3 that noted DP-HDR's inability to read EXIF as a weakness, and other refferences I have seen trawlling the Internet.

My problem is that - in my so far limited experience with the genre - the most dramatic HDR images come from extreme contrast scenes. Where the sun is actuall inthe shot for instance. To avaid blown pixels I handle such a scene with full manual, using anything up to 'plus 2 to minus 4 (or even minus 5). so there would be no EXIF.

The following scene would be typical of what I mean, and in fact I was unable to produce it with a single pass conversion. So I had to make two versions and composite them in Photoshop to prevent the area around the sun being blown, but having sufficient brightness in the shadow areas.

Vines & Sunrise
4:51PM, 11 April 2009 PDT (permalink)

view photostream

secretsamba is a group administrator secretsamba says:

I'm not sure the ability of the software (dphdr or photomtix) to determine the EV offset really does anything; I've come to realize that even if your most underexposed shot covers all the highlights and the most exposed shot gets good exposure on the dark area, you will most likely get blown pixels in the resulting hdr ( when doing landscape with a sky and even more true if the sun is there).

As I started to better understand HDR and became more critical about it, I realized that when a sky is involved, it's better to do 2 HDR versions and merge them. And I think that that's what most good HDR photographers do.

Not only for the matter of blown pixels but because I think a sky dosn't look good with heavy tone mapping but that can work well for the rest of the scene.

In this photomatix HDR I took 2 shots (0ev, -2ev) and while the histogram for my -2ev shot showed that I covered all the highlights I got blown pixels on the white of the clouds on the left near the trees. So what I did was to create a second HDR only from the -2ev shot casting 3 jpgs from the raw (-1ev, 0ev, +1 ev) and used that to patch the other one.

Originally posted 114 months ago. (permalink)
secretsamba (a group admin) edited this topic 114 months ago.

view photostream

Gary Simmons says:

That is an interesting idea that I hadn't occurred to me... That was the exact problem I have in shots like this one:

"Benched" by Gary Simmons [?]

I tried to strike a balance in the shot with the sun and much darker bench. I thought it came out ok, but the technique you mention here would give a much better result.... Back to the drawing board this weekend to try it out.
113 months ago (permalink)

view photostream

Amery Carlson says:

I have never found it necessary to merge two different versions no matter what software I have used. It should be even easier to get good results in DPHDR compared to Photomatix.
110 months ago (permalink)

Would you like to comment?

Sign up for a free account, or sign in (if you're already a member).