On Thu, 26 May 2005, Mark Roberts wrote:
"Collin Brendemuehl" <[EMAIL PROTECTED]> wrote:
is a body modification that will allow the "A" connection to be turned on
within the body. Perhaps a piece of foil to short the pin to the mount
Shorting is the normal condition for the "A" pin. You need to *insulate*
it from the lens mount to fool the camera. If you did so with a K or M
lens you wouldn't be able to meter properly on the ist or ist-D.
--
Actually, as I look at it, I think he's (almost) right. Shorting
the pin to ground tells the camera it's 'A'. The difference is that the
pin is *recessed* on the camera. In order for the lens to short it when
set to 'A', the pin comes out further than flush on the lens to make
contact with the recessed pin in the body.
Even if you phonied this up, it wouldn't meter correctly. The one
possible way this could work is in the manner I described in my other
post. Basically:
- Modify the K lens to have the 'A' contacts... including the spring
loaded one that comes out further than flush to activate 'A' mode.
- In 'M' mode, dial up the same f-stop as what the lens is set to.
This would only work correctly if the distance the aperture
actuator lever moves in 'A' mode is as far or farther than necessary to
actuate the 'K' lever to where the lens's internal stop is set. I haven't
figured out what the log/linear distances would be and if it's possible.
There are a lot of issues with the scenario. It would be a *LOT*
simpler if the camera would just allow you to manually set the f-stop when
using an A lens in non-A mode (i.e. a modified K lens).
Phew... that was ugly... :)
-Cory
*************************************************************************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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