HDRMT question

[JGMoreau]

Hi everyone,

I am having difficulty with the HDRMTransform process.
It appears to give different results when applied to cropped image vs full image, see :

http://www3.cablevision.qc.ca/astro/Clipboard01.jpg

Same with previews.

I must be missing something.

Windows 7, 64bits, 8 Gig ram

Thanks for helping,

Jean Guy Moreau
Quebec

[Enzo De Bernardini]

This is normal behavior. Try to make a preview from whole picture.

Greetings,

Enzo.

[ruediger]

It appears to give different results when applied to cropped image vs full image, see :

I think, because the median values of the overall picture and the preview are very different.

Often it is very odd, that a well-tested sequence of processes, carried out on a small crop of the picture to speed up processing time, can't be transferred to the whole picture because of very different results of HDRMT or others.

Rüdiger

[JGMoreau]

Hi Enzo, normal behavior ?   

I tried whole picture preview, no joy.
It seems related to the size of the image...

Rüdiger, thanks for the median value explanation.
Does this suggest a workaround, or a way to make good use of the process ?

Suggestions ?

Thanks,

JG Moreau

[ruediger]

Does this suggest a workaround, or a way to make good use of the process ?

A workaround in this particular case might be to test all parameters on a scaled down duplicate of your image.
I don't know how many processes can lead to different results dependent if executed on a preview or the full image. Perhaps it's possible to add additional options like "(x) take median value from ..." etc. to ensure you safely can transfer a process setting from a preview or a crop to the whole image and getting the same result.

Rüdiger

[JGMoreau]

Answering my own question here 

Simply deselect the Automatic Midtone Balance button, and adjust to taste, 0.15
for this image.

Ah! those automatic things

Bye,

JG Moreau