DPChallenge: A Digital Photography Contest You are not logged in. (log in or register
 

DPChallenge Forums >> Photography Discussion >> Merge to HDR - 1 image in many exposures.
Pages:  
Showing posts 1 - 17 of 17, (reverse)
AuthorThread
03/15/2007 12:07:16 PM · #1
So with one image in RAW, using Lightroom I changed the exposure. I have 8 different pictures. When trying to merge to HDR it says there's not enough dynamic range. I saw an earlier post on this. Is this seriously just because of the exif file? I'd like to make an HDR image of a model standing in place. It's hard to get 8 exposures without movement.
03/15/2007 12:13:09 PM · #2
Not sure you really need 8. Three to five is usually more than enough.
In regards to the lack of dynamic range, this can come from how much of an EV change there is between each saved exposure, usually 0.75 to 1 EV per increment is sufficient in each direction from 0, and then each needs to be saved for web to strip the EXIF data from the image.

As an example, here is a true 3-exposure image shot specifically done for HDR:
and the 3 shots it came from:

Here are examples of what can be done with a single jpeg,
saved in 5 different exposures, compiled in CS2:


Saved exposure changes were -2EV, -1EV, 0EV, +1EV, +2EV

Message edited by author 2007-03-21 06:28:57.
03/15/2007 12:15:45 PM · #3
I have made HDRs from one exposure/photo using Photomatric Pro so it is possible but it still looks the best if you can setup exposure bracketing on your camera. That way you can get 3-4 shots in different exposures.
03/15/2007 12:16:00 PM · #4
You consider the possibility that there really ISN'T enough dynamic range within the image to need this technique?
03/15/2007 12:17:22 PM · #5
Photoshop's "Merge to HDR" reads the EXIF. Save the individual images without EXIF information and you should be good to go.

Edit: FWIW, 3 conversions (under, normal, over) is plenty from one RAW file. More won't really get you any additional quality.

Message edited by author 2007-03-15 12:18:42.
03/15/2007 12:22:56 PM · #6
Thanks for all the info fellas

Originally posted by stdavidson:

You consider the possibility that there really ISN'T enough dynamic range within the image to need this technique?


Nope...I'll try a different image.

03/15/2007 12:49:28 PM · #7
Working from a single exposure, as others have pointed out, one over and one under is all you can really use. That's all the dynamic range you have "extra" in RAW. Of course, if the source image is already your "over", you'd be creating a -1 and a -2 from that (for example) but the -1 would be, in your stack, the "0" image, and the other two the +/- images. In any case, if you need to cover more range than that you need multiple source exposures.

It's also correct that the EXIF data is the culprit with CS2's "merge to HDR" feature. While there may be more elegant ways to do it, a simple way to strip EXIF in PS is to open the image, select all, copy, open new blank image, and paste. There will be no EXIF on that new file. Do this three times (once for each variation) and you are good to go.

In Photomatix Pro, if it can't determine the exposure range from the EXIF, it prompts you to manually enter it in terms of +/- EV values.

The actual dynamic range of the individual images is irrelevant, the program is not looking at that.

R.

Message edited by author 2007-03-15 12:51:23.
03/19/2007 08:22:15 AM · #8
Originally posted by Bear_Music:



It's also correct that the EXIF data is the culprit with CS2's "merge to HDR" feature. While there may be more elegant ways to do it, a simple way to strip EXIF in PS is to open the image, select all, copy, open new blank image, and paste. There will be no EXIF on that new file. Do this three times (once for each variation) and you are good to go.


I find the easiest way is to just open the image and "Save for web" at 100%. Then do the same on one with the exposure bumped up and one with it bumped down. My Photoshop CS2 also asks what the exposure is on the shots before merging if it cannot find the EV in the EXIF.

As Robert said "The actual dynamic range of the individual images is irrelevant, the program is not looking at that." ... so you can use this method with any image.


Message edited by author 2007-03-19 08:24:34.
03/20/2007 03:36:35 AM · #9
Originally posted by Greetmir:

I find the easiest way is to just open the image and "Save for web" at 100%. Then do the same on one with the exposure bumped up and one with it bumped down. My Photoshop CS2 also asks what the exposure is on the shots before merging if it cannot find the EV in the EXIF.

As Robert said "The actual dynamic range of the individual images is irrelevant, the program is not looking at that." ... so you can use this method with any image.


The trouble with this approach is that if you want to merge to HDR, you want to be working with as much information as possible. When CS2 converts from RAW it creates a 16-bit file, which can only be saved (in 16-bit) as a TIFF or a PSD. When you "save to web" you are creating an 8-bit JPG file, and you really don't want to do that. There's MUCH more information in the 16-bit file.

AFTER you've done the merge and the tone mapping or shadow/highlight tweaking, then if you prefer to work in 8-bit (it's a lot faster) save the 16-bit merged file first, then change to 8-bit in "image/mode" and save as a new filename, so you have the 16-bit merged file to go back to if needed.

Working on these kinds of images, you really don't want to go to JPG until after you've finished all your work anyway, 'cuz you can't save layers in JPG and you will have at least several of them working as you tweak your image.

R.
03/21/2007 06:25:16 AM · #10
... well my camera, unfortunately, doesn't have RAW capabilities and takes images in jpeg format to start with. Would there be any advantage to changing the .jpg image to a .tiff image before modifying and merging? ... I wouldn't think so ...
03/21/2007 06:53:56 AM · #11
Originally posted by Greetmir:

... well my camera, unfortunately, doesn't have RAW capabilities and takes images in jpeg format to start with. Would there be any advantage to changing the .jpg image to a .tiff image before modifying and merging? ... I wouldn't think so ...


Even if you do that, there is no extra dynamic range in a JPG for the HDR. You could try shadow/highlight in Photoshop to bring the shadows up. If you want to do HDR, bracket a bunch of photos with different shutter speeds. I usually do around 9 (spaced a stop apart), that gives you lots of dynamic range.
03/21/2007 08:09:00 AM · #12
as Raziel said I don't think you would be gaining anything by converting to Tiff first. If you can do a bracketing the that is perferred...if not try this.

This shot:

is just as it was shot...well other than resize

-I took it into CS (don't have CS2) and did a layer of selective color
-Within that layer I selected the Neutral color field and dragged the Black value to -20 (brightens it) and hit ok.
-Saved that image as jpg full quality new name.
-Double click the layer and dragged the value to -40 and did the same.
-Double clicked again and went to -60 (probably didn't need to do this one but hey I was playin) and saved again.
-The last time I double clicked it and dragged the black the other way to +20 to darken it. Saved and proceeded to Photomatix plus.

When I created the HDR it looked like crap but I ignored it and went to Tone mapping.

In there I got a version of this:

I made adjustments to the luminosity, strength and black and white clipping till I came up with something I liked, hit ok and save.
Opened it in CS again and did a few more adjustments but finished with the gothic glow action (again just cause I was playin and wanted to see what it would do) and got:


Now it certainly isn't as good as shooting RAW or bracketing but I think it works pretty good...(would appreciate any feedback on my technique or results...I always look for new ways to do stuff)

I'm not familiar with just adjusting the shadows/highlights but it works for some people.

03/21/2007 08:12:23 AM · #13
Originally posted by Brad:

Not sure you really need 8. Three to five is usually more than enough.
In regards to the lack of dynamic range, this can come from how much of an EV change there is between each saved exposure, usually 0.75 to 1 EV per increment is sufficient in each direction from 0, and then each needs to be saved for web to strip the EXIF data from the image.

As an example, here is a true 3-exposure image shot specifically done for HDR:
and the 3 shots it came from:

Here are examples of what can be done with a single jpeg,
saved in 5 different exposures, compiled in CS2:


Saved exposure changes were -2EV, -1EV, 0EV, +1EV, +2EV


Great results ! Very nice !

I don't really understand the 2 night shots .... were they processed with the same technique ? I like the one on the right much better !

Thanks !
03/21/2007 08:48:07 AM · #14
Originally posted by LouiseB:

Originally posted by Brad:

Not sure you really need 8. Three to five is usually more than enough.
In regards to the lack of dynamic range, this can come from how much of an EV change there is between each saved exposure, usually 0.75 to 1 EV per increment is sufficient in each direction from 0, and then each needs to be saved for web to strip the EXIF data from the image.

As an example, here is a true 3-exposure image shot specifically done for HDR:
and the 3 shots it came from:

Here are examples of what can be done with a single jpeg,
saved in 5 different exposures, compiled in CS2:


Saved exposure changes were -2EV, -1EV, 0EV, +1EV, +2EV


Great results ! Very nice !

I don't really understand the 2 night shots .... were they processed with the same technique ? I like the one on the right much better !

Thanks !


From what I can tell, the first one was tonemapped from four separate exposures and the second from a single RAW exposure.
03/21/2007 09:10:20 AM · #15
To clarify:

The first sunset shot was 4 individual jpegs, taken at different exposures, and rendered in CS2's HDR feature.
Some additional basic post-processing was done after the merge.

The second sunset, was done from a single jpeg:
Exposure altered to +1 EV & saved for web
Exposure altered to +2 EV & saved for web
Exposure altered to 0 EV & saved for web
Exposure altered to -1 EV & saved for web
Exposure altered to -2 EV & saved for web
Then the 5 different exposures of the single image were then compiled in CS2's HDR feature, and again, some basic post-processing done after the merge.

This was also done in CS2's HDR: (no tone mapping)
(6 individual jpegs)

Vs. HDR and tone mapping:
(8 individual jpegs)

Message edited by author 2007-03-21 09:20:55.
03/22/2007 07:56:46 AM · #16
Thanks a lot for the clarification!
03/22/2007 08:49:14 AM · #17
Originally posted by Raziel:

Originally posted by Greetmir:

... well my camera, unfortunately, doesn't have RAW capabilities and takes images in jpeg format to start with. Would there be any advantage to changing the .jpg image to a .tiff image before modifying and merging? ... I wouldn't think so ...


Even if you do that, there is no extra dynamic range in a JPG for the HDR. You could try shadow/highlight in Photoshop to bring the shadows up. If you want to do HDR, bracket a bunch of photos with different shutter speeds. I usually do around 9 (spaced a stop apart), that gives you lots of dynamic range.


Yeah, well I DO shoot multiple exposures when possible ... but with a moving subject, I do what Brad did with his second sunset and local adaptation HDR merge or just bump up an image to 32 bit then back down to 16 bit using the local adaptation tone mapping technique that is in the tutorial. I find it easier to work with than shadow/highlights to balance out pictures with too much contrast ...
Pages:  
Current Server Time: 03/28/2024 02:00:48 PM

Please log in or register to post to the forums.


Home - Challenges - Community - League - Photos - Cameras - Lenses - Learn - Prints! - Help - Terms of Use - Privacy - Top ^
DPChallenge, and website content and design, Copyright © 2001-2024 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 03/28/2024 02:00:48 PM EDT.