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HDR, Panoramas and Tone Mapping Merging several different exposures into a single image

HDR vs. Layer masks

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  #1  
Old 12-10-2008, 11:33 AM
_ck _ck is offline
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HDR vs. Layer masks

I think I'm unclear as to the science of HDR, but how is HDR different to simply overlaying three layers - each containing a different exposure of one scene - and applying layer masks in such a way that different areas of the photo reveal varying combinations of each of these layers ? e.g. reveal more of the overexposed layer for shadowy areas and more of the underexposed area for the highly lit areas...
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Old 12-10-2008, 01:42 PM
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Frank Lopes Frank Lopes is offline
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Re: HDR vs. Layer masks

I think you essentially are right: if you were to superimpose the layers and pick and choose what part of each layer is visible, you would accomplish pretty much that same effect.

Using masks, however, you will need to be very precise or you end up with very strange halos and this is where the dedicated HDR solutions shine.

What most HDR packages do is take the luminosity of the different areas of the image as "masks" to make the appropriate adjustments.

Does that make sense?

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Originally Posted by _ck View Post
I think I'm unclear as to the science of HDR, but how is HDR different to simply overlaying three layers - each containing a different exposure of one scene - and applying layer masks in such a way that different areas of the photo reveal varying combinations of each of these layers ? e.g. reveal more of the overexposed layer for shadowy areas and more of the underexposed area for the highly lit areas...
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Old 12-10-2008, 03:53 PM
ktg222 ktg222 is offline
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Re: HDR vs. Layer masks

I am probably being heretical here, but 95% of the HDR/tone mapping work I see is not very good. The images look unrealistic or the image is so washed out because of the tone mapping software. That said, I have seen some very, very good HDR/TM images, but primarily exterior landscape photos. I did some experiments with an architectural photographer I work with and we could not replicate the results we got using manual masking with a popular HDR/TM product. Frank is right, if you manually mask the images you have to be very careful with the masking. I haven't totally given up on using HDR/TM software, but I think it will take a very specific workflow and massaging of the tone mapped image to surpass what I have been doing manually; at least for me and my client.
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Old 12-10-2008, 04:37 PM
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TommyO TommyO is offline
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Re: HDR vs. Layer masks

_ck,

That is how we did it before HDR algorithms came about. A little more care and adjustment, but that was the basic premise. It's also how it was done with film.
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Old 12-10-2008, 07:15 PM
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0lBaldy 0lBaldy is offline
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Re: HDR vs. Layer masks

_ck, I will chime in and agree with all of the above.. just adding one little caveat... use all the tools at your disposal not just masking... When I HDR_tone map something I still combine with the originals and pick and choose different areas with masking and blending modes, color corrections, etc.. to get a good overall image.

It sounds like Ktg222 is doing precisely as you suggest.. when he says he is doing it manually he could also state he is doing Selective tone mapping
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Old 12-11-2008, 06:55 AM
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Re: HDR vs. Layer masks

To avoid some of halo problems, I sometimes create black and white versions of the image and use them as masks on the layers.

This avoids most of the halos.
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Old 12-11-2008, 07:00 AM
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Re: HDR vs. Layer masks

You are right.

No doubt that most of the HDR examples are so over the top that they lose all together what the technique was intended for: to increase the luminosity range of the image.

Instead people create these surreal, ultra saturated, cartoon like images that, even still have their own beauty, have very little to do with dynamic range.

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Originally Posted by ktg222 View Post
...
but 95% of the HDR/tone mapping work I see is not very good
....
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Old 12-11-2008, 09:30 AM
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Re: HDR vs. Layer masks

Quote:
Originally Posted by Frank Lopes View Post
Instead people create these surreal, ultra saturated, cartoon like images that, even still have their own beauty, have very little to do with dynamic range.

Whoops, guilty, but in all fairness i don't know a awful lot about dynamic ranges etc. just what I like and don't

Palms
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Old 12-11-2008, 02:11 PM
MrRyan MrRyan is offline
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Re: HDR vs. Layer masks

Quote:
Originally Posted by ktg222 View Post
95% of the HDR/tone mapping work I see is not very good.
Agreed. In my workflow, I'll sometimes use HDR to add some punch to my photos, but not as a poster child for the technology. In my professional opinion, having a full range of exposure in the Darks, Mids, and Lights, looks horrible.

As for the original post. You are technically correct, that would make an image SIMILIAR to HDR, but it wouldn't be very good (in terms of HDR.) Shooting at the scene at different exposures, allows for WAAAY more detail, which is one of the main positives for HDR. A nicely balanced HDR image truly is beautiful, as the longer you look at it, (or play with it on the computer), you realize there is clean detail in ALL of the ranges.
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Old 12-11-2008, 03:41 PM
Hatsa Hatsa is offline
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Re: HDR vs. Layer masks

Hi Guys!

Remember, HDR is future. These displays we're using now, cannot show HDR image as they really are. Check internet for HDR tech and you will understand.
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