I currently have a 7Hi. The CCD has been replaced. The camera works
fine. I have been thinking about buying an A2. The anti-shake and
the great EVF are what have attracted me to it. My concern and my
understanding is that 8 mega-pixels on the same size CCD used in
the 7Hi only adds to the noise level. If this is true, is it much
worse? Is the A2 a better camera than the 7Hi? Is this even worth
thinking about?
The A2 is a better camera, and, with the latest firmware, it is quite speedy with RAWs --- at least, for its type it is.
Also, please don't worry about noise.
Whilst there are more pixels, and they are naturally smaller, which does increase noise when viewed at 100%........
........ 100% on screen is BIGGER than it is with 5MP,
because the pixels are smaller and there are more of them!
When that 8MP image is viewed same-size-on-screen as the 5MP image....
....(which is how you should be doing it when making comparisons)....
.... there are more pixels (per unit area) interpolated into the display of that 8MP image, and the process cancels the extra noise.
The same thing happens in printing, only more so, because printing itself tends to smooth out noise.
As to the relative ISOs, I cannot comment.
My experience is of D7ug and A2 only. I find they match, ISO-for-ISO, and they both match my Minolta flashmeter, too. Indeed, before I abandoned film entirely, I used to use my D7ug as a supplementary exposure meter, and as a kind of "electronic polaroid", when exposing 5x4" reversal sheet film.
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Regards,
Baz