Where is the gamma button?

Discussions of using SharpCap for Solar or Lunar Imaging
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Maurits
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Where is the gamma button?

Post by Maurits » Mon Jun 25, 2018 2:40 pm

Hallo,
When I use SharpCap for solar Ha imaging with a ZWO 174MM or a ZWO 120MM there is no button any more for Gamma corection.

I have the exposure time and gain, but no gamma.

With a camera from the program as example for deepsky or for planets than there is a gamma button …

In the past, there was a gamma button when I take pictures from the moon!

Is this a normal ;) situation

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turfpit
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Re: Where is the gamma button?

Post by turfpit » Mon Jun 25, 2018 4:44 pm

A forum search for ZWO gamma returns 120 hits. The answer to your question is in there.

Dave

Maurits
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Re: Where is the gamma button?

Post by Maurits » Mon Jun 25, 2018 5:29 pm

Hi Dave , can I find the answer on the SharpCap forum or on the ZWO forum ?

Maurits
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Re: Where is the gamma button?

Post by Maurits » Mon Jun 25, 2018 5:52 pm

I saw the answer to my question with the above help, it's a shame that the button is gone.

Are there forum members who have influence at ZWO, and ask them to replace the "gamma button" …gamma is indeed very good to pop up the detail on Solar Ha imaging.

Thanks all for the information.
Maurits

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admin
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Re: Where is the gamma button?

Post by admin » Mon Jun 25, 2018 8:40 pm

Hi,

I believe that ZWO's theory is that gamma is destructive to data quality when applied to 8 bit imaging data - it's better applied at the end of the stacking process where you have a deeper effective bit depth and therefore the transformation is smoother.

If you want to pull up/down the midtones while viewing without affecting the saved data you can use the SharpCap 3.1 display stretch functionality (in the mini histogram on the right side).

cheers,

Robin

Maurits
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Re: Where is the gamma button?

Post by Maurits » Tue Jun 26, 2018 8:09 am

Thanks for the info Robin.

bgirrell
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Re: Where is the gamma button?

Post by bgirrell » Wed Oct 17, 2018 11:53 pm

I think one thing that should be remembered is that gamma is a software adjustment, not a hardware adjustment. The effect occurs after the A/D converter and therefore whatever the gamma control could do can also be done in post-processing software. It's exactly the same thing.

I truly, truly wish someone would design a camera with a nonlinear amplifier prior to the A/D converter, but I'm not holding my breath.

Bruce G

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