"RPS" wrote in message
...
Could somebody please explain the jargon used to denote the sensor size?
I mean numbers like 1/1.7. How does this translate to actual size
(dimensions or area)?

It actually doesn't translate very well at all, and is a goofy system that
should have been abandoned long ago. The fraction refers to the old video
tube size in inches, which is the way such sensors are traditionally sized
but obviously has nothing to do with digital still cameras.


What is the typical size for DSLR?

Those are not described in that way; only compact cameras use the fractional
inch method. Nikon and some other DSLRs mostly use a sensor of either 23.7 x
15.6 mm or 23.6 x 15.8 mm, in either case roughly the same as the full APS-C
format and often referred to by that term. Most Canon DSLRs s have a
slightly smaller sensor than that, some other makes are smaller still, and a
very few are larger.

For ZLR?
For good P&S?

Both of those types use sensors in the fractional inch sizes, though often
the "inch" is omitted and "type" is substituted. So for example one
manufacturer may call a particular sensor "2/3 inch" and another may call
the same sensor "2/3 type."

Whatever it's called, the 2/3 type is the largest sensor generally found in
any digicam. Its actual size is about 6 x 8 mm.

Other common sizes are 1/1.8 and 1/2.5 -- there are several other sizes as
well, but those appear to be the ones most often used today. I have read of
sensors as small as 1/3.2 but have never owned a digicam with that small a
sensor myself.

In high-end compact cameras of the type you call ZLRs, such as the Nikon
Coolpix 8800, the 2/3 type was common. Most of today's superzoom ZLRs use
much smaller sensors than that, however.

For a very good but more compact camera such as the Nikon P5000, the 1/1.8
type is used and is undoubtedly the best choice. Smaller sensors than that
are more likely to give problems with noise at the higher ISOs, all else
being equal. But where extreme compactness is important it's usual to see
sensors of 1/2.5 type or smaller. Also, many of the superzooms today use
1/2.5 type sensors. It is adequate for most ordinary use.

Camcorders of course have much smaller sensors than these.

Neil