Which meter pattern are you using? Matrix, Spot or CW Averaging?
Godfrey
On Jan 5, 2006, at 1:46 AM, Don Sanderson wrote:
The new screen requires you to use -0.5 exposure compensation
to get the same meter readings as the original screen.
IOW the camera thinks the scene is 1/2 stop darker than it is
and will overexpose without compensation.
This would indicate the meter is behind the prism as others
thought and not behind the mirror as I thought.
I haven't compared the results with the new/original screens
using TTL/PTTL flash yet.
I assume it would have no effect on TTL but may on PTTL.
In PTTL the preflash is before the mirror goes up and the
main flash is after. This is evident from the fact that you
can see the preflash thru the viewfinder.
BTW: Having this screen makes it _very_ obvious just how
inaccurate AF can be sometimes. Makes the DA lenses focus
clutch seem even more valuable for "touch-ups".
Don
-----Original Message-----
From: Shel Belinkoff [mailto:[EMAIL PROTECTED]
Sent: Thursday, January 05, 2006 2:39 AM
To: [email protected]
Subject: RE: MicroPrism ist-D Focus Screen is here!
Could you elaborate on that a bit? How does it increase
exposure? Does it
require a greater exposure time for the same results as the original
screen, or less?
The focus looks pretty good on the pics you posted ....
Shel
[Original Message]
From: Don Sanderson
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7573618765
Here are the focus accuracy results using the microprism center:
http://www.donsauction.com/pdml/istD_FocusScreen.htm
This is with a Sigma 50/2.8 macro wide open, focus point was the
highlight in the top birdies eyeball, manual focus.
Seems absolutely spot on to me, though the screen seems a bit
less bright than the original, focusing was very easy, the
microprism effect was quite pronounced.
Autofocus seems to not be affected in any way.
The new screen seems to increase exposure by about 1/2 stop.
All in all, a good $30.00 spent for a focus challenged person
such as myself. ;-)
One Caution: The new screen is a bit thicker so it loads the
springs on the closed retainer frame a bit more.
When you release it, be ready to catch it as it pops out!
