asi 120MM long expo problem

rosszfej

hello!

i am using an asi120MM (usb 2.0) camera. After i updated to the latest SharpCap i started to have problems with long expo photos. if i changed the exposure time to 30 sec or something, the first 2 photos was not successful. The countdown timer of sharpcap went to minus, until -10, then it started to take the photo again. After changing the exposure time, this happens 2 times, then i am getting the pictures.

i downloaded an old version or SharpCap, that worked fine. So, i managed to find the version, where it went wrong and i found the following release notes:

Improved ZWO camera support

SharpCap 2.5 uses the new ZWO SDK version 2, which provides better control over the cameras, particularly for newer cameras and easier control of long exposures

So, i downloaded your windows SDK, and i wrote a small c# application using the function ASIStartExposure. After changing the exposure time to 30 sec, and had the same problem. 2 times get Exp_failed before the image is ready, then i can record images normally.

Trying the videocapture function i experienced no problem.

Is this a known issue with this Exposure functions? Is there a workaround for this? thanks for your answer..

zsolt

Sam@ZWO

thanks, we will try to repeat this problem

yang

rosszfej wrote:
hello!

i am using an asi120MM (usb 2.0) camera. After i updated to the latest SharpCap i started to have problems with long expo photos. if i changed the exposure time to 30 sec or something, the first 2 photos was not successful. The countdown timer of sharpcap went to minus, until -10, then it started to take the photo again. After changing the exposure time, this happens 2 times, then i am getting the pictures.

i downloaded an old version or SharpCap, that worked fine. So, i managed to find the version, where it went wrong and i found the following release notes:

Improved ZWO camera support

SharpCap 2.5 uses the new ZWO SDK version 2, which provides better control over the cameras, particularly for newer cameras and easier control of long exposures

So, i downloaded your windows SDK, and i wrote a small c# application using the function ASIStartExposure. After changing the exposure time to 30 sec, and had the same problem. 2 times get Exp_failed before the image is ready, then i can record images normally.

Trying the videocapture function i experienced no problem.

Is this a known issue with this Exposure functions? Is there a workaround for this? thanks for your answer..

zsolt

what is the SharpCap version when the issue arise?

rosszfej

first version i noticed the problem was: Version 2.6.1844

but using the downloaded dll and c# class from your webpage, i also had the problem every time, if i used the StartExposure + GetExposureData and changed the exp. time to 10-20 sec or greater.

yang

rosszfej wrote:
first version i noticed the problem was: Version 2.6.1844

but using the downloaded dll and c# class from your webpage, i also had the problem every time, if i used the StartExposure + GetExposureData and changed the exp. time to 10-20 sec or greater.

can you send your c# program and the dll which have that bug

to info(at)zwoptical.com, it will help me to find the problem.

Thanks!

rosszfej

hi! i sent you a mail, with a download link where you can download the whole c# project.

regards,

zsolt

rosszfej

answer i got from ZWO in email:

Hi zsolt,

This issue did exit, for USB2.0 camera video mode is better,

you can adjust exposure to a short duration like 2s firstly,

and wait for exposure success and then make it longer.

Also we'll try to fix it.

hopefully this correction will come soon!

caracol_uk

I had the same problem myself and found it was only necessary to set the exposure value to something shorter. It wasn't necessary to actually call ASIStartExposure afterwards. It's certainly worth a try.

Simon