DSLR ISO selection during sensor analysis

[bgstott]

Hi Folks,

New user and first time poster on the ShapCap forums. I successfully ran the sensor analysis with my Canon 6D last night … *super* cool tool!

Is there a way to choose which ISO/Gain values are used for the sensor analysis? Here are the ISO values the sensor analysis tool selected for my 6D …

50, 125, 250, 400, 800, 1250, 2500, 4000, 8000, 12800, 25600

If possible, I would like to run the analysis with these ISOs …

100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600

Thanks in advance!
-Bret

[admin]

Hi Bret,

you cannot remove items from the list, but you can ask SharpCap to add additional gains to test via the Python based scripting (see this thread - viewtopic.php?t=4685 - the bug mentioned in the last post is now fixed).

To be honest, I am not sure that you will gain much - most sensor plots are fairly smooth curves (except for cameras that switch between HCG and LCG modes - I am not aware of any DSLRs that do that), so the value for ISO 3200 is unlikely to be very different from the value that you get by following the curve on the plot you already have. The thing is that the sensor analysis does take a lot of exposures (several hundred), and that has to be considered when using it with a camera with a physical shutter that may eventually wear out!

cheers,

Robin

[bgstott]

Hi Robin,

Thanks a bunch for the reply! Good point re: length of time and the shutter wear … probably good enough as is.

On a different, but related topic, I tried using the smart histo to measure sky flux and provide a recommendation. It worked well for short focal lengths, but for longer focal lengths that required longer sky flux measurement (i.e., 16 sec or longer), the frame capturing was nit working correctly … frames would be very dark, camera shutter clicks/durations didn’t seem to match exposures SharpCap was attempting.

On a DSLR, should I use Manual or Bulb? Should mirror lockup be off or on? Any other settings?

Thanks!
-Bret

[bgstott]

Scratch the above re: dslr long exposures. Im practicing inside and everything seems to be working using Bulb, mirror lock off, and the ‘LX Mode’ box checked on the camera control setting.

-Bret

[Antonio]

http://www.astrosurf.com/comolli/strum54.htm

Can this link be of interest? There are interesting aspects about the behavior at intermediate iso.

Antonio