On Sep 16, 2005, at 10:15 AM, Barry Rice wrote:
I'm now learning how to think "digitally" with my *ist-DS. The
thing that
perplexes me is setting the sensitivity. I'm used to shooting with
Velvia
since minimal grain and nice saturation are important to me. What
sensitivity do people use? I'm no stranger to taking 15 second
exposures to
maximize my DOF in my botanical fieldwork, but I'm intrigued at the
notion
of cranking up the sensitivity on the camera to take big DOF images
with a
short exposure. Could it be that I don't have to worry about the wind
anymore????? At what point would I expect to see noise? I don't see
this
addressed in the manual, except in broad terms.
ISO 200 will always return the best quality as it is the 'native'
sensitivity of the sensor, all other settings are going to increase
noise and decrease dynamic range by some amount. However, in
practical terms, I find settings up to ISO 800 produces extremely
good image quality, ISO 1600 gives good quality, and ISO 3200 is
usable in some circumstances where speed and capturing the image at
all is more important than finest quality rendering.
If you're after the finest quality rendering, you must store
exposures in RAW format and do the post-processing to RGB yourself,
tailoring the process to the particular scene dynamics. This becomes
more and more important as ISO setting is raised.
In general, the rule of thumb is to use ISO 200 when quality matters,
and higher ISO as situations require. I find the difference between
200 and 400 to be slight, so I set the 'ISO Sensitivity Warning'
custom function to light the ISO reminder when the camera is set to
ISO 800 or higher, and use 200-400 interchangeably.
Of course, the bottom line can only be obtained by doing some testing
yourself. Only you can decide what sensitivity and exposure
combination produces the results that satisfy your aesthetic or
technical needs.
Godfrey
