Cory Papenfuss wrote:
Ah, I didn't know the details of this!
I still don't think it would work, though: If you made the camera think
an "A" lens was attached it wouldn't be able to do the "stop down and
meter" trick necessary for K and M lenses, if for no other reason than
the stop-down arm linearity issue.
In short: Multi-segment metering isn't going to happen with K and M
lenses on an ist-D or ist-DS. (Not a great loss, IMHO. I almost always
stick with center-weighted.)
Sounds true. I modified an old -M lens to try to get matrix
metering and perhaps P-TTL flash out of my -DS. I did not succeed... :)
As I understand it, matrix metering requires the *absolute*
aperture. With an 'A' lens set to 'A', this is known. With an 'A'
lens set to other than 'A', it *could* be known (by how much the
exposure changes when it's stopped down), but the camera doesn't do that.
One very simple workaround (albeit fiddly) would be to allow the
user to *tell* the camera what aperture the lens is set to. In other
words, make the f-stop indicator blink in 'M' mode with an M/K/A(in
non-A). If you dial in the correct number that you've got on the
lens, the camera knows everything it needs to do everything. Granted,
it requires setting the f-stop correctly in two places, but it would
be a simple thing to do. With that, stop-down metering wouldn't even
be necessary with an A in non-A or a modified K/M.
Gack..
-Cory
*************************************************************************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
*************************************************************************
--
A man's only as old as the woman he feels.
--Groucho Marx
