Cropped sensor

I read somewhere on this forum (can't find it again) that a cropped sensor SLR camera is best for underwater photography. I read about sensors but I still don't understand why a cropped sensor would be better than a full sensor. Is a cropped sensor better for macro photography? Or does a shorter lens just fit in the housing better?

Not necessarily best, but preferred still by many for these reasons:

1. Better lens selection - the obvious is the tokina 10-17mm fisheye, or using a full frame fisheye (i.e. sigma 15mm) on crop sensor is a unique & excellent wide angle ability. also heard great things about the close focusing sigma 17-70mm macro DX mid zoom which seems to have no full frame equivalent.

1A/2. Heard corner sharpness issues with superwide rectilinears are exaggerated on full frame. i'm not sure why this is.

3. Better magnification with macros, a 1:1 reproduction ratio on macros are relative to sensor size. also arguably better DOF, though the larger the sensor/film, the less diffraction robs sharpness at a given aperture, so a smaller aperture can be used to achieve DOF, so people do debate this point. don't know the optical math involved so can't argue the either.

4. smaller sensor can mean smaller camera & housing, though there's really not much difference b/w a D300 & D700, just slightly bigger viewfinder.

these are by no means deal breaking, many people are now shooting full frame UW, including myself as of 2 weeks ago. hope that helps. cheers,

chris

Mucho gracias

I think one important item to add to that list is cost. A couple of years ago the cost differential to get full frame was a deal breaker for most. With the Canon 5D and now the 5D2 and Nikon D700 the financial leap to full frame is no longer that big compared to the top end crop cameras, especially if you consider the expense of housing, lenses and strobes.

Comparing the crop Canon 7D and FF Canon 5D2 the former has a number of advantages but none are due to it having a smaller sensor (perhaps with the exception of 8 fps which isn't that important underwater). If there would be two cameras with identical specifications, including same pixel size and quality, just one being cropped the other full frame, I think the full frame always wins out if you can afford it. One way to look at it is that with a full frame you get a one and half times bigger view on the world. You can keep all of it or crop it any which way you like later. With a cropped camera you only get the smaller part to start with.

Bart

With a cropped camera you only get the smaller part to start with...

Ahh...

.... but it's the best bit!

The important things about the sensor for underwater photography are, in my opinion and in order:

noise

high-ISO performance

power consumption

maximum resolution

They can be better on a full-frame sensor, but not necessarily so. Getting close with a cropped sensor is much better than cropping out from a full-frame image, anyway...

Tim

Ahh...

 

.... but it's the best bit!

 

The important things about the sensor for underwater photography are, in my opinion and in order:

 

noise

high-ISO performance

power consumption

maximum resolution

Hi Tim,

I heartily agree on it being the best bit. I am curious about the high ISO performance underwater though. Help me out, what kind of images are you thinking about and what do you consider "high"?

Cheers,

Steve

... I am curious about the high ISO performance underwater though...

I started out as a UK wreck-head, and low-noise 800-1600 ISO would be ideal for that. I definitely found that the performance of my D200 wasn't up to the German High Seas wrecks in 100' or so in September:

http://www.flickr.com/photos/timsdiving/se...57622309819947/

Tim