Issue with Darks with Canon DSLRs

[Diane Miller]

I've made extensive notes on the basics of processing, thanks to information in response to my earlier post, and have a request in for a trial license.

I've read about issues with using Darks with Canon DSLRs, but it may be somewhat dated now.  I have a Canon 7D Mk II, which is claimed to have lower dark current than earlier models (along with the 6D).  I've seen recommendations to use bad pixel mapping instead of normal dark frame subtraction.

What is the recommendation for dealing with this using PI?  (And I would need newbie information on how to implement it if it differs from the usual dark master workflow.)

Thanks in advance!

[chrisvdberge]

Personally I've seen people add noise to their image by using darks more often than reducing the noise, so my advice (to beginners) always is to not use darks.
The best way to get rid of thermal noise/dark current is to use dithering while you are shooting.
bad/hot pixels can be easily removed in the integration process by choosing an appropriate pixel rejection method.

I've written down my basic workflow, this might be helpful for you;
http://dslr-astrophotography.com/basic-dslr-workflow-pixinsight/

[Diane Miller]

Thanks, Chris -- yes, I studied your post in great detail yesterday and saw that advice.  (A wonderful and extremely helpful tutorial!) 

I can certainly omit darks starting out.  Just wondering if PI has some equivalent to bad pixel mapping or deals with things differently. 

[pfile]

you can use a master dark together with the CosmeticCorrection process to remove hot and cold pixels from your subs. it has a realtime mode so you can look at a preview on your subexposure at 1:1 and see which pixels it's correcting before applying it to all your subs.

rob

[chrisvdberge]

Thanks, Chris -- yes, I studied your post in great detail yesterday and saw that advice.  (A wonderful and extremely helpful tutorial!) 

I can certainly omit darks starting out.  Just wondering if PI has some equivalent to bad pixel mapping or deals with things differently.

I've never used it as I use dithering and get rid of bad pixels in the regular integration process, even without pixel rejection.

[Geoff]

I can certainly omit darks starting out.  Just wondering if PI has some equivalent to bad pixel mapping or deals with things differently.

There is CosmeticCorrection which Harry explains in his video on Batch Preprocessing and DefectMap which (surprisingly) has documentation.
Geoff