Moon on April 3, 2009

[Bill Boehme]

This is from a stack of 18 images with mean value processing in CS3. I was mainly trying to see what kind of results i could get with the Canon EF 400mm f/5.6L USM plus two teleconverters to give a total FL of 1120 mm. Focusing was really sensitive and it took a number of tries to get it just right. Exposure time for each image was 1/50 second and ISO 100 at f/16.

Click twice on the image below to see a full scale crop.

http://www.pbase.com/bill_boehme/image/110992996/large.jpg (http://www.pbase.com/bill_boehme/image/110992996/original.jpg)

[Bernoulli]

That's a great shot! Very crisp and true color.

I've been stacking too (usually 10 - 12 images) and I found that it really helps with noise but not so much with focus. I use it all the time now.

[Bill Boehme]

That's a great shot! Very crisp and true color.

I've been stacking too (usually 10 - 12 images) and I found that it really helps with noise but not so much with focus. I use it all the time now.

Thanks for the comments. This is the largest stack that I have tried -- normally, I do 10 to 12 images which seems quite adequate. I agree about focus -- if stacking could fix focus problems, then there would be no need to focus -- just take lots of pictures. However, in addition to camera noise, there is atmospheric disturbance noise and all of these things affect perceived image sharpness. Ordinary filtering of a single image just results in loss of detail while stacking cleans up all noise without losing any sharpness.