Stacked output size varies slightly - problems with HDR
Posted: 22.08.2022 01:55
I make focus stacked HDR pictures, using Helicon but I have a problem with Helicon's stacked output file sizes.
Here is the background. To make a focused stacked HDR image, I take a series of photos at different focal points - as one typically does for Helicon - at one exposure. Focal points are chosen by Canon built-in "focus bracketing" on Canon R3 or R5 camera, and range from 2 frames to 100 frames. Then I change exposure (by say 1 f-stop) and take another set of frames at different focal points. I typically do this 5 times. This is for a landscape photo taken on a tripod.
Processing begins by using Helicon to focus stack the frames from each exposure level. This gives me 5 focus stacked frames, one for each exposure level. I then use HDR software to merge these into one HDR file.
The problem is that Helicon sometimes makes files of slightly different sizes. In a recent example, I had 5 exposure levels, and two of the frames came out at the original camera frame size of 6000 x 4000, and three frames came out at 5998 x 4000.
The problem is that HDR software (such as SNS HDR, or Photoshop) will refuse to merge files of different size - even if off by only 1 or 2 pixels.
I assume that the reason Helicon creates different sizes is some difference in image scaling, or image alignment. In a lot of cases the results have identical sizes but I run into this problem fairly often - a couple times this weekend, prompting this post.
Here are my questions:
1. Is there a way to make Helicon keep the sizes the same as the original (camera) image size? Or a setting where this would not occur?
2. I am not sure if the difference between the 6000 x 4000 and 5998 x 4000 frames is a scaling difference, or a crop. If I knew which one it was I could then process the images to either re-scale them, or crop them accordingly after stacking but before the HDR merge was attempted.
3. A different solution would be to make HDR files first. These would be 32 bit TIFF files, or EXR or HDR files from all of the frames taken at different exposures at a single focal point. Then I would use Helicon to focus stack the HDR files. I don't know if Helicon accepts HDR files as input, but I presume that the code uses an internal 32 bit or 64 bit pixel format, so in principle it ought to be able to stack HDR files with at most a change in importing and exporting.
Any other suggestions would also be welcome!
Nathan
Here is the background. To make a focused stacked HDR image, I take a series of photos at different focal points - as one typically does for Helicon - at one exposure. Focal points are chosen by Canon built-in "focus bracketing" on Canon R3 or R5 camera, and range from 2 frames to 100 frames. Then I change exposure (by say 1 f-stop) and take another set of frames at different focal points. I typically do this 5 times. This is for a landscape photo taken on a tripod.
Processing begins by using Helicon to focus stack the frames from each exposure level. This gives me 5 focus stacked frames, one for each exposure level. I then use HDR software to merge these into one HDR file.
The problem is that Helicon sometimes makes files of slightly different sizes. In a recent example, I had 5 exposure levels, and two of the frames came out at the original camera frame size of 6000 x 4000, and three frames came out at 5998 x 4000.
The problem is that HDR software (such as SNS HDR, or Photoshop) will refuse to merge files of different size - even if off by only 1 or 2 pixels.
I assume that the reason Helicon creates different sizes is some difference in image scaling, or image alignment. In a lot of cases the results have identical sizes but I run into this problem fairly often - a couple times this weekend, prompting this post.
Here are my questions:
1. Is there a way to make Helicon keep the sizes the same as the original (camera) image size? Or a setting where this would not occur?
2. I am not sure if the difference between the 6000 x 4000 and 5998 x 4000 frames is a scaling difference, or a crop. If I knew which one it was I could then process the images to either re-scale them, or crop them accordingly after stacking but before the HDR merge was attempted.
3. A different solution would be to make HDR files first. These would be 32 bit TIFF files, or EXR or HDR files from all of the frames taken at different exposures at a single focal point. Then I would use Helicon to focus stack the HDR files. I don't know if Helicon accepts HDR files as input, but I presume that the code uses an internal 32 bit or 64 bit pixel format, so in principle it ought to be able to stack HDR files with at most a change in importing and exporting.
Any other suggestions would also be welcome!
Nathan