Sigma SD1 Merrill from ISO 100 to 6400

I needed to use a high ISO to capture a flower in broad daylight around noon today, and it made me wonder what the various ISO settings do to the photos. Since I had never checked this with my SD1, I decided to shoot a series with all the ISO settings. I ended up shooting a few. Here is one set:

ISO 100

ISO 200

ISO 400

ISO 800

ISO 1600

ISO 3200

ISO 6400

The photos above are just OOC jpegs. Below is that last image processed into B&W from the raw file with SPP 6.4.0:

ISO 6400 processed from raw to B&W in SPP 6.4.0

Here's another series:

ISO 100

ISO 200

ISO 400

ISO 800

ISO 1600

ISO 3200

ISO 6400

Here is that first image from the raw file with some local sharpening in GIMP:

ISO 100 from RAW (with local sharpening in GIMP)

Now you might ask, "What in the world would make someone want to shoot at ISO 6400 in broad daylight?!?" My answer is that sometimes you need to shoot with a high shutter speed to freeze motion. In this case it was a little windy, and even my tripod was moving/vibrating. The low ISO shots really don't hold as much detail as they probably would have if that was not the case. Another reason is that some people want to shoot at f11 to get a greater depth of field. If you're reporting an event, even a daytime event, like a race, you just might want to shoot at 1/4000 second and f11. In such a case a high ISO is necessary. YES, you CAN shoot sports to some degree with an SD1 Merrill. Laurence Matson has shot sailing and other sports with Sigma cameras, and I've seen moving race cars shot with Merrill cameras here from time to time. Then there are the animals. All sorts of animals move quickly, and high shutter speeds are necessary to freeze their motion, whether it be a monkey swinging from a tree or a pair of cranes leaping in broad daylight. Add some clouds blocking the sun a bit, and you get a situation where high ISO can be really necessary.

As far as the results I see, I think ISO 800 is surprisingly usable, and even ISO 1600 could be used in a pinch. I would not use ISO 3200 for anything but B&W, and it would take a lot for me to shoot at ISO 6400 . . . like I'd have to REALLY want the photo bad, even though I know it would look like hell. Still, a less blurry photo that is really noisy and only B&W is sometimes better, so I guess it's possible that I would use ISO 6400.