Auto exposure

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hipoh
Posts: 6
Joined: Fri Feb 05, 2021 9:56 am
Location: Hamburg/Germany

Auto exposure

#1

Post by hipoh »

Hi everyone,

how is it possible to use „auto exposure“?
Is this a pro feature? Or is it camera specific?

Regards,
Hipoh
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admin
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Re: Auto exposure

#2

Post by admin »

Hi,

Auto exposure is camera specific - camera manufacturers often (but not always) implement it, in which case SharpCap will enable you to tick the 'Auto' checkbox in the exposure control area. There is no need for a Pro license.

Note that in many cases auto exposure only works for relatively short exposures and only with the camera running in video mode.

cheers,

Robin
hipoh
Posts: 6
Joined: Fri Feb 05, 2021 9:56 am
Location: Hamburg/Germany

Re: Auto exposure

#3

Post by hipoh »

Hi Robin,

thanks for clarification of that point! So it is something which Canon or Nikon DSLR cameras should have...?

But a question to the developers of SharpCap: would it not be possible to implement that into SharpCap as an additional pro feature? The information is there and SharpCap has the ability to set exposure time, gain etc. to make a well exposed image.
Now I have to do that manually. As I am using SharpCap with an Allsky-Camara setting this would be very helpful...

Regards,
Hipoh
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Re: Auto exposure

#4

Post by admin »

Hi,

Auto exposure is not supported by any ASCOM based cameras (that includes the Nikon/Canon support via the ASCOM.DSLR driver).

I have considered adding auto exposure code into SharpCap, but it is a little harder than you would hope. Many cameras (especially when running at medium-high frame rates) show a delay between setting a parameter like exposure and the result showing up in the image - for instance you may update the exposure and then have to wait 4 frames before the image brightens. The camera manufacturers have the advantage of knowing when this is going to happen and how many frames the delay is (they designed the system). SharpCap has no way to get this information, which means that it would have to wait for a 'worst case' number of frames after each change to be sure the image has responded :(

cheers,

Robin
hipoh
Posts: 6
Joined: Fri Feb 05, 2021 9:56 am
Location: Hamburg/Germany

Re: Auto exposure

#5

Post by hipoh »

Hi Robin,

I just realized what you say: when updating exposure time (or another parameter) you have always to wait for several images that this takes effect. I was surprised and a bit disappointed by that. It makes it more difficult to find the right exposure time.
I understand your problem, however I hope you will an autoexposure feature someday. It would be very helpful even with the drawback of reacting with a considerable delay.

It is interesting that there is no ASCOM support for autoexposure! The ASCOM drivers are really sub-optimal ...

Maybe you could supply a list of cameras having the autoexposure feature?

Thanks!
Hipoh
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Re: Auto exposure

#6

Post by admin »

Hi,

of the main Astro targeted brands, auto exposure is available in

* Altair
* SVBony
* ZWO

cheers,

Robin
hipoh
Posts: 6
Joined: Fri Feb 05, 2021 9:56 am
Location: Hamburg/Germany

Re: Auto exposure

#7

Post by hipoh »

Thanks again for your fast reply, Robin!

In general I am quite pleased with the QHY 5-iii-485C, however the non existing autoexposure is a clear disadvantage when using it as Allsky camera.

Cheers,
Hipoh
Xplode85
Posts: 8
Joined: Wed Sep 04, 2019 10:40 am

Re: Auto exposure

#8

Post by Xplode85 »

I would love to see an auto exposure function too both for allsky and live broadcast with a QHY camera.

I setup a camera on the telescope to watch the sky through the dome opening and would have loved an auto exposure function that would just work through the night and stay within a set gain/exposure value range.
A delay in adjusting the exposure time would not be a problem for this kind of use.
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