On Jul 14, 2005, at 1:57 PM, Dave Kennedy wrote:
Godfrey, Thanks for the tip on the Lightning.
Wow. I didn't know about that noise reduction technique in the camera.
Your comparison images are quite enlightening.
Glad to help.
So if you leave it off most of the time, do you turn it back on when
your shutterspeeds are slower than 1/25s?
Most of the time I leave it off. I turn it on when I'm specifically
going to be working at long exposure times for a particular effect.
A longer answer:
The test images were made at settings of ISO 200, f/22, 30 seconds in
Av mode, in other words the maximum timed exposure possible with the
camera, to exaggerate the DS' noise and show the maximum effect of
the DS' dark frame substraction. Most of the time, I'd open up the
lens and adjust the ISO to 800-1600 before I'd let the shutter time
run so long, with a consequent radical reduction in noise.
My usual photo range has me between 1/10 and 1/2000 second, in other
words, hand-held shutter speeds. Also, I normally process with ACR,
which does hot pixel removal and smoothing as well. So ... while it
might pose some value at the bottom end of my usual range, the amount
of noise there doesn't usually warrant switching the option very
often. If, however, I'm looking at long time exposures in the
multisecond range for waterfalls, etc, yes: I'll switch it on.
Another point: I generally save exposure in RAW format ... If I were
doing more of my shooting with the camera set to make JPEGs, I'd have
NR on more of the time.
Godfrey
