bit depth of cameras - gamma settings

pdb

I have 2 rather technical questions on the ASI-120MM-S. Maybe Sam can clear this out.

1. Some time ago Sam stated that highspeed should be switched of for the cameras to work in 12bit (or does this only apply to the cameras with Sony chips). Did some testing with the 120MM-S and examined the SER files. High speed on or off does not make a difference (unless for speed ;) ) both SER file clearly seems to have data in 12 bit. On the ASI178MM turning on/off there does not seem to give speed difference in FireCapture, so i leave it off for that camera.

2. Seen several times that gamma level should be set to 50. What is the reason for this. I was reading the instruction from the F-Hunters solar program and they require scientific data which has not been altered and is as raw as possible. (Only stacking, no enhancements ...) The guide state to put the gamma at 100. I notice that with gamma 100 the histogram moves right, but i was wondering why gamma 50 is advised for the ASI cameras.

Kind regards,

Paul

riklaunim

Gamma 50 is just the default value for the camera. You should change that only when really really needed.

With 12-bit capture the data stream is bigger so faster speed mode won't be that faster so it can be just disabled (likely to get bit lower read noise or something).

pdb

Did some further testing with both cams. HighSpeed setting indeed increases speed (as expected) an no changes to bit depth on ASI-120MM-S. On the ASI178MM setting seems to have no influence at all. (Was exepcting lower bit depth, but as far a i can see from the files, bit depth stays as 14 bit and is not reduced to 10 bit)

Rgrds,

Paul

Sam@ZWO

"high speed" for ASI120 or ASI120-S won't change the ADC bits

set the gamma to 50 is to make sure the data is raw data and won't loss by gamma