In article <caUBd.1308$>, news-reply@t-
onywoolf.co.uk says...
> "Bruce Graham" <> wrote in message
> news:. au...
>
> > my reading of the spec for the FZ3 cf. FZ20 is that the small
> > physical size for the FZ3 is obtained mainly by a significantly smaller
> > sensor than in the FZ20.
>
> Where do you find information on the sensor size?
>
from Panasonic web site, the FZ3 sensor size is not given, but it does
give the focal lengths of the lenses.
FZ3 f = 4.6-55.2mm (35mm Equiv.: 35-420mm)
FZ20 f = 6-72mm (35mm Equiv.: 36-432mm)
given the field of view is about the same, the sensor size ratio is
roughly 4.6/6 = 0.76 (same answer from the tele end). This is a linear
ratio, so square that to get the area ratio ( 0.76 x 0.76 = .5

. Now
the FZ3 has 3.1M pixels and the FZ20 has 5M, the ratio is .62 which is
close to the .58 estimated above. I had not done this arithmetic before
you asked, I had just done mental ratios.
> > That is offset pretty much by fewer pixels on
> > the FZ3, so if all else was equal (never true, but might be more or less
> > true given the Venus II family heritage) the 100% crop noise performance
> > of the two cameras might be similar, but a downsampling of the FZ20 image
> > to the FZ3 resolution would be better than than the straight FZ3.
>
> I have been looking at some sample pictures on Steve's Digicams review site.
> For a more valid comparison I re-sampled all the images to 4000 x 3000
> pixels. On the basis of that, the 200 ASA noise performance of the FZ3 and
> the FZ20 is extremely similar, but the FZ20 has, not surprisingly, slightly
> higher resolution. The resolution difference would probably be more obvious
> with lower ASA settings.
>
> I have rejected a Konica-Minolta Z3 because of noise and lack of sharpness
> at 200 ASA. Looking at the few 200 ASA pictures on the web, I think I can
> do better with the FZ3 or FZ20. But I may not approach the performance
> of my old 2 MP Canon, even when re-sampled to the same size. From
> looking at a lot of reviews, I notice that the noise performance of
> megazooms tends to come in for criticism. I wonder if megazooms have
> smaller sensors than normal zoom cameras in the same price range.
I think the sensor sizes for the FZ3 and FZ20 are in the normal range for
digicams. Obviously a x3 zoom will cost a lot less than the lens on
these cameras and will also be a lot smaller, so the big zoom cameras
will cost more and the sensor will be as small as possible to keep the
size and cost of the lens down. You can buy a 28-300mm zoom for your
Canon DSLR giving similar range on a 1.6x body like the Dreb but the size
and cost is much larger.
> It's not just noise, I think noise reduction software in the camera
> contributes to lack of sharpess at high ASA as well.
>
I would expect so, but I'm just a newbie. I know I have to use products
like Neat Image with care and adjust parameters for each image to avoid
destroying detail and texture. (I have used this mainly with film scans).