The GetDPI Photography Forum

Great to see you here. Join our insightful photographic forum today and start tapping into a huge wealth of photographic knowledge. Completing our simple registration process will allow you to gain access to exclusive content, add your own topics and posts, share your work and connect with other members through your own private inbox! And don’t forget to say hi!

Super long exposures with MF Digital Backs

GrahamWelland

Subscriber & Workshop Member
Be sure to read the fine print ... that's only with Photoshop CS Extended Edition which is a $350 upgrade from CS5.

I remember seeing this and contemplated whether the upgrade was worth it. Well, I guess that the image stack features might well push me over the edge although I think I'll give it a whirl with the eval version first.
 

Joe

New member
The median filter in PS is not only good for removing random moving objects -- it also can virtually eliminate random noise artifacts by stacking multiple exposures. Try averaging (medianing) 8 short high ISO shots vs one long low ISO shot with dark frame exposure.
 

ondebanks

Member
So, assuming Phase One did let you disable the dark-frame subtraction, am I correct in assuming that you could effectively accomplish almost the same thing with this software by capturing a dark-frame at a more convenient time (say, after you have made a couple of exposures) and stacking them post-exposure?
Yes, exactly. This is what astrophotographers do. The last thing we want to be doing on a clear starry night is losing 50% of our long exposure opportunity time to the enforced taking of long dark frames. :eek:

I know that, ideally, the dark-frame image should be made under identical conditions, but I wonder how close close-enough would get you? Being able to capture the dark-frame during downtime (say, when moving the camera to a new position or new location) certainly would be a lot more convenient, even if the results might not be quite as good as they are using the present methodology...
There is some leeway (several degrees) in the temperature matching; DSS for example has an option to try to scale dark frames to the observed intensity distribution of hot pixels in the scene frame. Also, many astrophotographers simply shoot a "library" of dark frames at different temperatures and choose the nearest match.

Ray
 
Top