These two camera are very much alike.
the G9 has more megapixels.
The S5 has more optical zoom.
As far as low light or nighttime shooting:
Neither has any advantage over the other.
Amy ISO setting over 100 will have some noise.
Any ISO setting over 400 will have too much noise.
If you want to use higher ISO settings with low noise, you will have to buy a DSLR camera.
For taking good (low noise) low light and nighttime photos you need to understand "exposure" and the elements that affect it.
And you absolutely need a tripod.
Here is the camera set-up for taking Christmas lights.
Turn the flash OFF.
Use the "Aperture Priority" mode.
Set the aperture to the f/2.8
Set the ISO to 100.
Put the camera on a tripod.
Frame the shot.
Set the shutter to use the 10 second delay.
Press the shutter down and then take you hands off the camera.
After 10 seconds - when the shutter trips, it can be several seconds before the image is captured; so wait up to 15 seconds before you touch the camera.
Here is a comparison of both cameras:
I'm trying to decide between the Canon G9 and S5 IS, but haven't seen any direct comparisons between the two, and am not sure about which group of users each of the two cameras is designed for, or what factors should be the primary ones I should consider in making my decision.
I'm an enthusiast who doesn't want to shell out the $$ for a dSLR. I have no interest in taking videos with my camera, so video-shooting problems don't bother me. I'd like to be able to take photos that can be blown up to 8 x 10 size, and am particularly fond of shooting in low-light or nighttime conditions (for example, during Xmas, I love to shoot houses with tacky light displays). I'm not concerned about the price differences between the G9 and S5 -- will buy whichever one is the better camera for me.
I like the S5's use of AA batteries, its zoom range, and its extendable monitor, but was disturbed by the amount of noise that showed in the sample pix in the DigitalCameraReview.com review of the S5, as compared to the sample pix in the same site's review of the G9. I also am concerned about the continuous-shooting mode in each camera -- the DigitalCameraReview piece on the I5 complained about how slow the LCD screen is to catch up with the lens during continuous shooting, and I haven't seen any reviews that address this issue on the G9.
I see lots of reviews that mention RAW format, but I've never used it, and don't know if it makes sense for me to use its availability (or lack thereof) as a criterion for making a purchase decision. The G9 has it, the S5 doesn't seem to. Also, the G9's ISO range goes up to 3200; the S5's only goes to 1600, which is a factor that causes me to lean toward the G9.
I'm not sure what an electronic viewfinder does or how it differs from the LCD screen or an optical viewfinder. If anyone would be willing to enlighten me, I'd appreciate it.
Please share any thoughts you might have that will help me decide. If you need more information to help you give advice, feel free to ask.