Hello,
Last night (Tue 19th August) I tried some long exposure, wide field imaging with the Canon 40D and Canon 400mm F5.6, despite a nearby almost full Moon. The lens was set to F5.6 (wide open) and no Flat Fields were taken. I used “In Camera Noise Reduction” after seeing the results of Bert’s tests with his 5D. The location was suburban Brisbane, some 7kms from the CBD.
I selected M8, M20, M21 and Comet Lulin as the target for the lens test. The final shot was a combination of 3 x 3 min and 5 x 2 min exposures, each captured with ICNR. Apart from a small tweak of levels, no processing has been done.
Here is an inventory:
- Raw Frames 3888x2592 aligned and combined in ImagesPlus and saved as full sized TIF.
- TIF opened in CS3, down sampled and saved as a 1600x1062 jpg.
- Sub-Frames cropped from full size TIF and saved as 1280x960 JPGs in CS3.
Needless to say, I was simply blown away with the performance of this lens, wide open and will certainly be looking forward to exercising its potential at a dark sky site. I particularly like the star colours! Oh the unbridled joy of wide field imaging!
Thanks to Clive and Roger for their help in teaching me how to generate the constrained crops for this exercise.
Warning: Large file sizes and 1600x1062 images.
Cheers
Dennis