Odd Zerene monochrome behavior

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Lou Jost
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Odd Zerene monochrome behavior

Post by Lou Jost »

I often need monochrome imagery, taken with a dedicated monochrome astrophotography camera, a QHY163M. It outputs 16 bit tiffs. The tiffs look fine in Zerene, as does the stack in progress. But the PMax and PMaxUDR files are flat with tonal range compressed, as if they have lost half their dynamic range. Any idea what is going on?

Here is Zerene correctly displaying the tiff output of the camera:
Image

Here is a stack in progress, everything is fine:
Image

But here is what the output looks like (PMax):
Image

The results are carried over into Photoshop, which shows the same difference between input and output images when the files are exported from Zerene.

By the way, these are microscopic orchid seeds.

JH
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Post by JH »

Hi
Could be one of the input pictures that is exposed differently.
Some times I have to turn of "Settings/Brightness"
The seeds looks promising
Best regards
Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

Lou Jost
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Post by Lou Jost »

That's a good point, maybe there was a black frame or a white frame somewhere, though I did edit the stack before running and I didn't notice anything. Also this happens every time (n=2 :roll:). I'll go back and look.

I'm happy with these seed photos and their full-color versions. These are the first seeds anyone has ever seen from this genus of orchids (Teagueia). I'll post some of the associated pictures soon.

rjlittlefield
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Post by rjlittlefield »

When the images look OK inside Zerene Stacker, but look washed out after they are saved, the problem always turns out to be the "Retain extended dynamic range" option.

Turn that off and re-save the image, or leave it set, save as 16-bit TIFF, and apply levels/curves adjustment to taste.

More info at https://zerenesystems.com/cms/stacker/d ... washed_out and the FAQ following that, "What does "Retain extended dynamic range" mean?"

--Rik

Lou Jost
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Post by Lou Jost »

I checked the exposures and all are fine. So it must be something else. I suspect there are different ways of coding monochrome 16 bit tiffs and perhaps Zerene is, by default, storing output using a different coding scheme than the input files. Rik will tell us what's going on soon.

rjlittlefield
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Post by rjlittlefield »

Lou, have you checked about the "Retain extended dynamic range" option? I'm wondering if you and I were posting at the same time.

If that's not it, then I'll need to see the files. Send them to support@zerenesystems.com , using DropBox, Google Drive, wesendit.com, or whatever other large file transfer service you like to use.

--Rik

Lou Jost
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Post by Lou Jost »

Rik, I hadn't seen your answer, must have arrived while I was typing mine.

I had never noticed this problem in RGB images. Will investigate. If I'm not actually losing any dynamic range, I will leave that check box checked. Thanks!

Oops, it happened again, you and I were posting --- at the same time -- about our posting at the same time...

I do have that option checked. If there is no real problem I prefer to leave it checked and just adjust the output files to taste, as you suggested.

rjlittlefield
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Post by rjlittlefield »

:lol: :smt023

--Rik

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