fewer megapixels on larger sensors in consumer cams?

[pianoplayer88key]

Which is better to go with?

1. Camera that has a slower lens, but takes cleaner pics at high ISOs
2. Camera that has a faster lens, but is somewhat noisy when you crank the ISO up

Even if it only "opens" up to F/2.8, I don't want it to be stopping down to F/4.8 or 5.2 or whatever. F/4.0 would be pushing the limit, with F/3.something being more acceptable.

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pianoplayer88key wrote:

Which is better to go with?

1. Camera that has a slower lens, but takes cleaner pics at high ISOs
2. Camera that has a faster lens, but is somewhat noisy when you crank the ISO up

Even if it only "opens" up to F/2.8, I don't want it to be stopping down to F/4.8 or 5.2 or whatever. F/4.0 would be pushing the limit, with F/3.something being more acceptable.

It all depends on how much faster and how much noise. In the example above the C5050 has about 1.5 stops advantage due to the faster lens. What I can take at ISO 64-80 would require ISO 200 on say G-series. There is certainly more noise at ISO 200 on any Canon G camera than C5050 at ISO 80 or even 100 (5050 cannot be manually set at ISO80). In this particular case C5050 wins. There is more to it than just image noise. Wider apertures decrease depth of field which IMO is desirable on a digicam since the depth of field is already huge. Faster lenses also allow you to shoot in brighter conditions with the lens stopped down a stop or two which usually improves optical performance. Finally, cleaner pictures sometimes means too much in-camera processing, which smoots out image detail. You can do much better job in post processing using software like Neat Image. This does not apply to DSLRs that achieve low noise due to much bigger sensors.

[pianoplayer88key]

In my particuar case I might like a little more depth of field, actually.

To my eye, the indoor portrait no flash image of the Toshiba PDR-M81 from imaging resource at ISO 400 looks pretty clean. That camera stops down to F/4.8 at max zoom, though.

The Ricoh RDC-7 is a bit noisier at ISO 400 but it only stops down to F/3.4 at max telephoto.

Judging from the cleanness of the Toshiba's image, would it be possible that I could underexpose with that camera by a few stops, then brighten, and after resizing to 1200x800 (I wouldn't print larger than 4x6 and for my use 200dpi is probably enough ; most pics I would take would be displayed on a computer screen), still have a decent image?

btw, I have about 4 128MB smartmedia cards that I use for my mp3 recorder that I'd be willing to share with a camera, as well as a 1GB, 512MB, 256MB, 128MB, and 64MB (slow) CF cards.