[Sticky] Creating a Bad Pixel Map

Yes, calibration needs to be done with the same binning then as well.

Hi Vincent,

One thing that is not clear to me is whether amp glow is a problem in darks captured for creating a bad pixel map.  Is it better to use long-exposure darks with visible amp glow? Or, are shorter exposure darks with little or no amp glow better to use (maybe with a greater number of them)?

Thanks

As far as I know, amp-glow is not a huge problem as the bad pixel map is a map of hot and cold pixels only. If you're unsure, I would just use one of your longest darks you have already and use that for the mapping.

Hello there, I have a question. 

All of the discussion here focuses on creating the BPM from raw flat and dark frames. 

If, instead, I have the master darks and master flats already created, my understanding was that, I could just load all the masters and create a BPM from them instead. Is that correct? 

Is there any functional difference between the two methods? 

The reason I ask is because I have the masters but not the raw frames. 

Posted by: @wvreeven

Posted by: @neverfox

Sorry if this has been asked and answered but:

• Does it matter which flats you use, as they would be potentially taken with different filters?

Yes that matters a lot. If you take, for instance, flats with an R filter and use them on B lights then the response of the sensor will be different which will introduce all kinds of artifacts in the calibrated image. Also the properties of at least a part of the optical train may differ when using different filters, especially small band versus broad band. In short: always take flats with the same filter as the lights that you want to calibrate.

Sorry, now a bit confused about creating a BPM in APP.  I can find plenty of information about the type of darks (long exposure, warm camera etc.), but only indirect info about making the flats.  As I understand it (only basic!), these flats are "generic", merely to give data about cold pixels.   So, am I wrong to assume that any recent flats from the camera (eg. diffuse light with histogram peak in the middle) will do?  To clarify, this is only with regard to creating a BPM - appreciate the importance of a "full light path" for ordinary use of flats. 

Thanks

Peter

PS Brilliant features in recent APP versions - thanks so much.

For the creation of a BPM, a regular good flat is fine yes. I would, I think, use a luminance flat then. Though I never used it for a BPM as cold pixels aren't a real issue anymore as far as I know.

@mabula-admin 

Hi, the "Calibration" button is not on the 2) CALIBRATE section anymore, where did it move or is there a new way of creating a bad pixel map?

No, this hasn't been a button for a long time, it's called "Create masters and assign to lights". When you already have masters, they will simply be used and when you have no lights, the masters will be created. Might be nice to call the button a bit different maybe.