[gordonb]

The eVolt 620 has a sensor 4032 x 3024 pixels so the native aspect ratio is 2x3 like most DSLRs. Most of these other aspect ratio modes are gimmicks to facilitate printing JPEGs and they throw away pixels to crop to a specific aspect ratio. Sensors in point-and-shoot cameras are typically a 4x3 aspect ratio which, strangely doesn't fit a common print size like 5x7 easily so they usually are cropped. A DSLR's 3x2 aspect ratio fits perfectly on a 4x6 (which is the size most photolabs are set to).

Common photo print sizes are:
4x6 (2x3)
5x7
8x10 (4x5)
11x14
16x20 (5x4)

These sizes are left-overs from the film days where a 35mm film camera had the 3x2, a 5" x 7" was a common negative size for medium format cameras and large format "View" cameras were the larger sizes.

So if you have to crop the picture to print anyway then I would suggest shooting at the native aspect ratio. Having said that I do find the 2x3 mask on my G10 is useful for framing images that I will print at 4x6 so I get the image to fill the frame without going over the print borders.

This aspect ratio confusion continues into Digital Photo frames where some have a 4x3 (sort of) aspect ration similar to a point-and-shoot sensor and others match a DSLR's sensor with a 2x3 (sort of again) aspect ratio.

 

[gordonb]

Sorry, but wrong. Olympus dSLR cameras are all 4:3 aspect ratio (1.33). It even states that on the link you provided!

My bad

Anyways, if you are shooting in RAW, then use the camera's native 4:3 ratio, since all other aspect ratios are just software conversions/crops anyways. If you shoot in the 4:3 aspect ratio, you will have the max data from which to do your own crops to other formats if you so desire. On the other hand, if you are shooting a whole bunch of snaps for 4x6 prints, then it may save you time to shoot in 3:2 mode.

The problem, as I stated, with shooting in 4:3 when your target print is 3:2 is that you may frame it with not enough headroom at the top or bottom so when you go to crop it you run in to issues.