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01-06-2015, 05:38 AM   #1
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panorama exposure issues
Lens: Sigma 18-125 DC HSM Camera: K-x Photo Location: Murchison River Mouth, Western Australia ISO: 400 Shutter Speed: 1/160s Aperture: F10 

I enjoy stitching panoramas with PTGui, but have issues with sky exposure. The shot below is an 8 shot composition, hand-held, taken a midday, using a polarising filter.I held exposure with AE lock, and manual focus. It still comes up with varying skies which upset the final product



01-06-2015, 06:16 AM   #2
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1. Don't use polarising filter on wide angle, or the sky will not be even color.
2. If you are not using Lightroom which correct the vignetting, you might want to try to shoot with the focal length and aperture combination which has minimum vignetting of your lens.
3. Don't use auto exposure, use manual exposure. To ease the pain, set the Av first, say f/8, look through the viewfinder and pan around, keep eye on the shutter speed changes. And use average shutter speed for M mode.
01-06-2015, 08:06 AM   #3
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QuoteOriginally posted by ranmar850 Quote
I enjoy stitching panoramas with PTGui, but have issues with sky exposure. The shot below is an 8 shot composition, hand-held, taken a midday, using a polarising filter.I held exposure with AE lock, and manual focus. It still comes up with varying skies which upset the final product
taowang is right.
Ultra wide angle lenses may cause vignetting, which will cause problems if you sticht the shots together. I had the same problems with the Sigma 10-20mm on my K5. For panorama shots I now rather use a focal length of above 30mm + I leave the rest to lightroom / Photoshop, the results are usually good.
01-06-2015, 03:08 PM   #4
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Thanks for the replies. I was using Av mode, so the Ae lock should just hold the shutter speed, but I should just look for an average shutter speed across the scene, and set in M. I hear what you are saying about the polarising filter changing sky colours across a wide angle of view, but I have had exactly the same issue without the filter. Focal length was 63mm, and PP was in Lightroom. The pano stitcher will not handle RAW files, so I do the Develop work on a key frame, then copy those settings to the rest of the frames in question. I, too, have found issues with trying to use short focal lengths for panoramas, rule of thumb is to stay at 50 mm or above.

01-06-2015, 11:55 PM   #5
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Is it possible that PTGui algorithm is not optimal which causing the problem? I used Lightroom CC & Photoshop CC for stitching panorama, it quite smooth. There is a option of removing vignetting, but without using it most time, I still got smooth stitching. Here is one of my result of stitching 27 photos.



If you are using Lightroom CC, you are likely have Photoshop CC as well. Just give PS a try. There is an integrated menu in LR for this. Just select all the photos for stitching, and right click, "Edit In" => "Merge to Panorama in Photoshop...".

I did the same thing as you are in develop. I will develop one of the frame, and sync the settings to the others, and might adjust the settings for some frames and might sync again, then using PS to stitch those frames, after saving the result, I might adjust more in LR before I export the final.
01-07-2015, 02:41 AM   #6
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Excellent panorama of the harbour from an unusual angle. I was not aware that you could stitch in PS, I have it in CC but have not yet dipped a toe in the water, so to speak--getting my head around LR first. I should start reading the manual...
01-07-2015, 11:40 AM   #7
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You need to overlap the images more. What you're seeing is the effects of light fall-off on the edges of the image. I used to have this problem and then I changed my style. Now when I do a panorama I move the object from the center of the frame to the left side and repeat. That gives me 50% image overlap for each frame and eliminated color crop-off.
01-07-2015, 04:36 PM   #8
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QuoteOriginally posted by ranmar850 Quote
Thanks for the replies. I was using Av mode, so the Ae lock should just hold the shutter speed, but I should just look for an average shutter speed across the scene, and set in M. I hear what you are saying about the polarising filter changing sky colours across a wide angle of view, but I have had exactly the same issue without the filter. Focal length was 63mm, and PP was in Lightroom. The pano stitcher will not handle RAW files, so I do the Develop work on a key frame, then copy those settings to the rest of the frames in question. I, too, have found issues with trying to use short focal lengths for panoramas, rule of thumb is to stay at 50 mm or above.
I could be wrong but I think firing the shutter deactivate the AE lock which is why manual exposure is the way to go.

I had some older panoramas from my early days of digital photos with mixed exposure in the sky, I originally stitched them with the bundled Olympus software but recently tried restitching them with photoshop and it did a decent job of blending together the layers and evening out the sky.

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