4/3 vs. 3/2 - Noobie question

So how do you "know" if a camera is 4/3 or 3/2 (or 4:3 or 3:2 I guess). I realize that 3:2 is traditional 35mm size....are most DSLR 4/3 or 3/2? Examples D200 or Cannon E30D...would those be 4/3 or 3/2?

And other than print size, does it make much difference?

4/3rds is a system developed by Olympus and a few other manufacturers. The size of the sensor is 1/2 the size of a 35 mm film negative. Most dSLRS are close to size of the old APS film negative. This is a 1.5x crop of a 35 mm negative. Cannon of course makes several cameras that are known as full frame; or the same size as a 35 mm negative.

2/3rds is a size of a digital sensor that is used in some consumer digicams. It is much smaller than the 4/3rds sensor. dpReview has a chart somewheres that shows a number of these sensor sizes in comparison.

Confusing this is that the ratio of a 35 mm sensor and an APS size sensor are, I believe, in a ratio of 2/3rds. Which may be what you have heard of as 2/3rds.

Any of the dSLR formats can give you excellent results. I wouldn't worry about which system to use. Instead decide which manufactures system of camera's and lenses you want to use. Be sure to make sure housings are available to take the camera you like underwater. Also remember that the lenses you will want to use UW are probably different than those you would use on land.

I think he was meaning the ratio of the image dimensions.

As rule of thumb, most P&S (consumer) cameras have a 4/3 ratio that fit the computers screen, most of the DSLRs have 2/3 ratio like the 'old' film cameras.

There are exceptions of course and some models can be configured to work with the other ratio also.

Good posts. Yes, I think he was referring to the pictures aspect ratio.

All DSLR's are 3:2 aspect ratio except for the Olympus models, which I believe can do the 4:3

From a practical standpoint no matter what, I always set my camera at 3:2 as it's a heck-of-a-lot easier to make 4x6 prints as you don't have to crop every one.

Both require cropping to make 5x7, 8x10, and 15x20 prints...

Cheers

James