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05/17/2004 01:08:54 PM · #1 |
Hello everybody,
I have taken several shots of a subject from exactly the same point. Each of the shots has a different aperture value. So, in the first shot there are underexposed, overexposed and correctly exposed areas. In the second photo occurs the same, but the before under or over exposed areas are now all right and the before correctly exposed areas are now under or over exposed. And so on with all the shots.
The question is, how can I merge these photos in order to obtain a correctly exposed scene? Is there a specific software, can I use Photoshop?
Thak you very much.
Best regards,
Sergio |
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05/17/2004 01:16:53 PM · #2 |
Copy and paste them on top of each other as separate layers in photoshop and then erase the parts from each layer that you don't want, for example erase the sky from one layer and the foreground from the other. Use sufficient feathering to make the transition unnoticable.
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05/17/2004 01:52:27 PM · #3 |
One of the tutorials uses the Photoshop highlight selector to create an overexposed, regular, and underexposed copy and then describes how to blend the images. This works nicely, but is limited to 8 bits in 8 bits out. If you have 3 separate images you start with 24 bits.
If you use raw mode on any Canon DSLR you can always have 3 or more presentations of your image, drawn from 16 bits, at various exposure levels from -2 to +2. You can blend these presentations as follows using Photoshop levels:
Create two new levels: name one dark and one light.
1. Place the normal exposure in the base level.
2. Activate the dark level and paste a copy of an underexposure image. Screen blend adjusting transparency to increase detail in highlights.
3. Activate the light level and paste a copy of an overexposure image. Multiply blend adjusting transparency to increase detail in dark areas.
4. When satisfied, merge levels.
What you are effectively doing is using the full detail that 16 bits provides on an 8 bit pc photo jpeg and pc photo handling capability.
Now, if you do not have a Canon DSLR, you can accomplish the same thing by bracketing exposure and getting three separate images. I do not know how the basic contest rules would handle this. Is it 1 or 3 original images? As the camera or subject can move or the light change between exposures, one could claim it to be 3 original images and the superimposure would also suffer.
After the contest, I will post an illustration of using this technique. My contest picture did not use this technique, but I have since improved it considerably through the use of this technique.
Message edited by author 2004-05-17 13:56:16.
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05/17/2004 02:05:05 PM · #4 |
See This great article from Luminous Landscape
I would love for this technique to be legal, at least for member challenges. But I am afraid that it still isn't :( |
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05/17/2004 02:09:59 PM · #5 |
Also see this site for another alternative. I've used this software with pretty darn good results.
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05/17/2004 02:43:39 PM · #6 |
As to the legality for challenges, as long as one uses one single original image and one does not use selection masks, I do not see that the rules are broken.
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05/17/2004 03:07:50 PM · #7 |
Originally posted by sersal:
Hello everybody,
I have taken several shots of a subject from exactly the same point. Each of the shots has a different aperture value. So, in the first shot there are underexposed, overexposed and correctly exposed areas. In the second photo occurs the same, but the before under or over exposed areas are now all right and the before correctly exposed areas are now under or over exposed. And so on with all the shots. |
to get a good merge you should use the same aperture and differing shutter speeds, so that the focus/DOF is consistant. unless you are photographing something moving or on a windy day, you won't be able to tell the difference in shutter speed. |
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