Widest zoom (7mm / FLM 34mm)
f/2, 1/30, 320
This test was done at my office. I didn't bring a tripod, so it's not the most accurate test, but that also helps draw a couple of other conclusions later on. Here's the test method:
1) Stand in the doorway such that the camera's lens is even with the threshold, at eye-level, centered between the L&R doorframe.
2) Aim at the spot between the two door handles at the far end.
Max. tele-zoom (21mm / FLM 102mm)
f/2.5, 1/30, 320
Things to note:
1) Widest zoom produces some barrel distortion (see top of doorframe in prev. pic.). This is expected.
2) One of the nice things about P&S digicams is the small lenses allow a lot of light in. Check the EXIF data and see how small the f-stop value is here. While you're there, note the ISO sensitivity set at 320 (in DSCs, increased ISO is done by amplifying the sensor's signal).
It's also worth noting that the S85 starts up slightly zoomed in WRT the widest soom (i.e. when you start it up, you can zoom out a bit). I believe that it starts at FLM 50mm - this is considered equivalent to the naked eye's 46Â° FOV. Using 50mm as a reference, this camera's zoom goes from 0.68x - 2.04x.
Oly E300 I
Max. tele-zoom (45mm / FLM 90mm)
f/5.6, 1/8, 400
Things to note:
1) Looks pretty bad. One disadvantage to bigger lenses is the amount of light they let in. At max. zoom this lens gives f/5.6.
2) This picture was taken with a 1/8 shutter speed, ISO set to 400. That's why this looks bad; at 1/8, I should be using a tripod, and this is what I get when I don't.
3) I should have taken this photo again with the shutter set at 1/20 and 1/30 just to see how the brightness compares with the S85. Maybe tomorrow morning.
Oly E300 II
Max. tele-zoom (45mm, FLM 90mm)
f/5.6, 1/25, 1600
You can force this camera to boost the gain on the signal all the way up to 1600. You can see here the graininess this causes. How could I have fixed this?
1) I should have tried shutter at 1/20 and ISO 800. It would have been less grainy, but probably a little more underexposed.
2) I don't know if the camera's noise reduction algorithm can handle this. I should have tried that, too. We'll learn more about noise reduction in another set of low-light / long exposure tests that I have planned for this camera.
Oly E300 III
Widest zoom (14mm, FLM 28mm)
f/3.5, 1/20, 400
Things to note:
1) The graininess here is about the same as that in the S85 version.
2) The barrel distortion is about the same (it probably would have been less if I'd adjusted the zoom to 17mm / FLM 34mm).
2) Note the difference that the extra zoom gives (34mm compared to 28mm).
3) Note the difference in white balance / colour saturation. This image more accurately reproduces what I saw with my eye; the incandescent spots in the room produce a fairly yellow light; the S85's "indoor" WB setting didn't quite match.
4) I had set the aperture to automatic. At wide zoom, it could have chosen f/2.8. Maybe that's 'cause I had left the exposure at 400 from the previous picture. A better picture would have resulted from using f/2.8 and either 1/30 or ISO 100.
Since we calculated the zoom factors WRT 50mm for the S85, might as well do it for this camera: FM 28mm - 90mm gives 0.56x - 1.8x.