XTi or D30?

David Dyer-Bennet wrote:

I'd have to try the camera to see, but I very frequently shoot at ISO
1600 f/1.2 and a shutter speed low enough I have to rest the camera on
the back of a spare chair and lose a lot of shots to subject motion.


You need a much larger sensor (like three times as large
in linear dimension) so you can use a lens with three times
the focal length and the same diameter aperture. This would
allow use of a prism beamsplitter assembly and three CCDS,
no absorptive filters. Or, of course, a same-size B&W sensor
with no filter at all. And, of course, a winning lottery ticket.

Doug McDonald

On 22 mrt, 21:52, David Dyer-Bennet wrote:
J. Clarke wrote:
David Dyer-Bennet wrote:
Bill Funk wrote:
On Thu, 22 Mar 2007 10:23:48 -0500, David Dyer-Bennet
wrote:

How small are the smaller APS-C digitals now? Sorry, but talking
about "the smaller digitals" while demanding a much larger sensor
than they have is silly.
What makes you think the physical sensor size is the limitation on
the size of those cameras? I see no reason to believe that -- in
particular, the Olympus XA supported a full-frame 35mm sensor
(film). There's plenty of room in the body that size.
It seems to me that the problem, size-wise, isn't the sensor, but the
lens.
I think that's generally right.

The very small 35mm film cameras had very small lenses; today, that
doesn't fly. 3x zooms are the entry-level lenses now, and for APS-C
sensors, these aren't going to fit on an XA size body.
Well, they might fit *on*, but they'd stick out a lot :-).

Marketing realities being what they are, an APS-C-sensored body must
have features that set them apart from the run-of-the-mill 3x zoom
P&S cameras. Image quality won't do it alone; those who buy P&S
cameras aren't, on the whole, impressed with image quality above
what they get now, as it's really pretty good for the use they are
put to. That means extras like a bigger zoom range, which means
bigger lenses, which means bigger cameras.
But you knew that.
There is, or at least was, a kind of a market niche that isn't P&S in
the normal definition; it's not for casual snapshooters. Right where
the XA and the Rollei 35 fit, in fact. There's *so* much more
activity in cameras these days that it may not be exactly
recognizable as a separate niche; although arguably the Fuji F10/F11
went into that niche.

I suspect a lot of people would pay nearly the D40 price for a 28mm
APS-C small camera with a fairly fast lens.

Sigma seems to be trying something not enough like this to stand a
chance with the DP-1; and if Sigma is trying it, maybe I'm wrong :-).
(The lens is f/4, which to my mind kills the idea. Also theFoveon
sensors seem to be a losing proposition.)

I can't see where f/4 in a digital camera kills the idea. A 28mm lens
isn't going to give you a whole Hell of a lot of depth of field control
at any reasonable aperture, and the higher ISOs available with digital
should let you use any shutter speed with an APS-C sensor and a f/4 lens
that you could use with film and an f/2.8. Sure, one can "push" film
but one can "push" digital as well and it seems to go a lot farther.

I'd have to try the camera to see, but I very frequently shoot at ISO
1600 f/1.2 and a shutter speed low enough I have to rest the camera on
the back of a spare chair and lose a lot of shots to subject motion.

You make pictures in the dark?

Have you tried IR?


From that perspective, an f/4 lens doesn't seem useful.