Jump to content




Measured gain of SPC900NC


Recommended Posts

Hello, having nothing better to do I did some measurements of the SPC900NC webcam. I used SharpCap for capture and MaximDL for measurements. Here are the settings as saved by SharpCap

[Philips SPC 900NC PC Camera (LX Mode)]
Frame Rate (fps)=5.00
Colour Space / Compression=YUY2
Exposure (s)=0.3
Output Format=Fits files (*.fits)

I tried gain=32 and gain=63. The FITS files saved registered a maximum value of 32640 which is 128*256 so I am guessing that the 8-bit values from the camera are somehow multiplied by 128 by the time they end up in a FITS file.

I tried gain settings of "32" and "63" (the maximum). The measured gain was 0.02 e-/ADU at "63" and 0.045 e-/ADU at "32". That's FITS ADUs that go from 0 to 32640. In terms of 0-255 ADUs the numbers are 2.6 and 5.8, respectively.

As far as read noise is concerned, I measured 21.6 electrons at "63" (which doesn't make much sense to me). At the "32" setting, I just couldn't get any variation in the bias frames, presumably because of quantisation error. I think that means that the read error is less than 5.8 electrons.

Let me know if you've measured these yourself.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.