What is the cause of the color overlap in the final HDR image?

[Bags]

I am new to HDR. I use the Photomatix 4.1 program and so far I have made a few decent images. Presently the only post processing software I use is Canon's DPP, which I believe is somewhat limited. In the attached photo to the upper left of the building there is a diagonal line of orange sky. when I look at all of the source images, this doesnt exist. Can I assume that this is one of the things that tone mapping and merging creates? I am sure it could be corrected in a better PP program, but if any knows how to correct this in DPP please advise.



Also, after processing in Photomatix, which is best to save the image, as a Tiff file or Jpeg and please explain why.

Regards Bags.

[FrankMi]

Hi Bags! Nice composition. I use Photomatix as well but haven't noticed anything like this - it seems to continue to the right just above the pier as well.

I would try processing in Photomatix a second time using several of the defaults to see if it shows up in all of them or just the one you originally used. It would also be worthwhile to 'pixel-peep' the original file to see if it is there before you ran Photomatix. If you did a conversion to JPG from RAW before you ran Photomatix, see if it is in the original RAW (if you shoot RAW) or JPG SOOC image.

I save my images out of Photomatix as JPG as it is easier to work with than TIFF and I always merge back into the original using selections and masks. Hope this helps!

Sorry, but I can't help you on DDP. I'm sure others will chime in though.

[Bags]

Thanks for the feed back. I will check the original images again. I have never seen this before on any image this camera has produced so I am inclined to believe that it may be a anomoly. I need to find a published workflow for HDR and PP. Any sugestions?

Steve

[dje]

Hi Steve

I agree with Frank, try it again with different settings in Photomatix. There must be something in the original images that the TM is accentuating. Also you could have a look at one of the single images and boost the colour saturation significantly in a test to find something that is causing this abnormality. The other strange effects I notice are the yellow bands in the upper right side of the image.

On another note, the image lacks sharpness to me. I wonder was this a focus issue with the individual shots or perhaps a slight mis-alignment in the HDR process ? Did you use a tripod ?

As for DPP, I think you could say it is primarily a RAW processor. It would be worth investigating other pp software such as Photoshop, Photoshop Elements, Lightroom etc.

Cheers Dave

[FrankMi]

I need to find a published workflow for HDR and PP. Any sugestions?

Hi Steve, when I started using Photomatix, I used the workflow in Trey Ratcliff's free HDR tutorial and Photomatix tutorial at: http://www.stuckincustoms.com/.

[Bags]

Thanks Dave, the yellow streaks are definetly clouds that were bright and taking on color from the sunrise. They do look awkward but they are real. I always use a tripod. the problem is this lens is not the greatest. I use a Canon 40D and use the live view mirror lock up feature. In the hunt for a better wide angle zoom. I will try another go at the HDR process and let you know how I make out. if it's worthy I'll upload the new image.

cheers
Steve

[dje]

Steve, if you use a tripod, then there shouldn't be any alignment issues with HDR. Maybe the image just needs some extra sharpening. I usually apply some sharpening in the RAW processing software (eithr DPP or ACR) and then apply more in Photoshop. As others have pointed out in this forum, it's also important to apply some final sharpening after re-sizing the image down for the web.

I'd be inclined to explore this angle before rushing out to buy a new lens (although that's always a pleasant experience )

Cheers Dave

[Bags]

Dave,

Just some background. In the film world I was knowledgable and a confient photographer. I had many lenses from 24 to 400. all "L" canon glass. when I jumped to digital, I purcheased a kit with a non "L" lens, and as you know these standard consumer lenses are not crisp. But you are spot on that I need to learn how to get the most out of my post processing. I was in film morning for some time... but I am coming around. Please see my second version and please let me know what you think.

Best regards

Steve

[dje]

Dave,

Just some background. In the film world I was knowledgable and a confient photographer. I had many lenses from 24 to 400. all "L" canon glass. when I jumped to digital, I purcheased a kit with a non "L" lens, and as you know these standard consumer lenses are not crisp. But you are spot on that I need to learn how to get the most out of my post processing. I was in film morning for some time... but I am coming around. Please see my second version and please let me know what you think.

Best regards

Steve

Steve I think that's much better. Nice image. And the artefact you were concerned about has gone !!

I think there's a bit of a misconception with RAW shooting in regard to sharpening compared to jpeg shooting. RAW shooting generally requires more sharpening in software than jpeg because with jpeg there is a fair bit of sharpening done in camera. It is not an un-natural thing to do sharpening on digital images, it's just part of the overall processing chain of events.

Cheers Dave

[Bags]

Thanks for your help

Steve

[FrankMi]

I will try another go at the HDR process and let you know how I make out.

Great! Looks like you were able to address the problem. Were you able to determine what caused the issue?

[Bags]

Frank,

I could not. None of the source images had anything like that on them. Even if I increased the contrast or played with the exposures, it never showed up. Just a fluke I guess, or perhaps over use of one of the sliders in photomatix?

Cheers

Steve

[Bags]

I think I know what the problem is, and I am curious to hear your opinion of it.

HDR combines the best attributes of each cource image. You would think it would do this pixel by pixel, however I think it doesn't work that way. I believe in areas such as a nearly featureless sky, it takes areas. So through the light smoothing slider, I found that on a different but similar shot, the line appeares when the smoothing slider is used to extreme. And the line appeared in an area of the sky where the tones were changing from lighter to darker. this appears to be a logical "seam" of the areas of the sky from two source images.

Your thoughts?

Steve.

[FrankMi]

I think I know what the problem is.

You may have a point there, Steve. I rarely touch the Smoothing slider and when I do, I don't go over 1.0. At one point I took a number of images and starting out with some recommended settings for the sliders, played with each one from one extreme to the other and in combinations with other sliders and settled on the following as basic starting settings.

a. Strength – set to 100
b. Color Saturation – set to 70
c. Luminosity – set to 1.0 Sliding left can increase localized Halos in the image.
d. Microcontrast – set to 4.0
e. Smoothing – (if I change it at all) set to no more than 1.0

I have also created a set of my own presets and for a new image, try looking at them in several of the default and personal presets. Often I will make copies of the image with several presets and load the as layers into Photoshop. After choosing a 'base' image (and it's often none of the tonemapped copies), I blend in the best piece from each tonemapped copy I had made. My list might say something like Sky - Smooth, Foreground - Painterly, Subject shadow area - personal setting #3, and so on. Often I will find that I don't blend in anything from several of the tonemapped copies. Whew! Longwinded!

All this to say that having found what works for me in several kinds of images, I tend to avoid combinations that have issues, such as using the Smoothing slider so you may very well have identified what was causing your issue. I suppose you could try to go back and recreate the problem based on what you now know but... would it be worth the time and effort? Hope this helps!