I knew about your custom-DS screen but somehow forgot about the rest of the story (so I didn't check the archives).
My primary reason for buyign a Katzeye screen is for manually focussing (mainly my newly acquired A50/1.7 from a list member) and so you explanation is *very* welcome for me. I'll defenitely go without the Optibrite thingie. One last question: with a Katzeye screen, you still get AF points in the viewfinder in red? If yes, I don't care about AF brackets (and money saved). Thanks, Godfrey. 2007/2/11, Godfrey DiGiorgi <[EMAIL PROTECTED]>: > On Feb 11, 2007, at 7:56 AM, Thibouille wrote: > > I know with the D/DS/DL the Optibrite made the camera overexpose > > quite a bit. > > However on their website, they specificaly say that with the K10 (as > > well as DL and K100) their was no metering difference with the > > Optibrite. They do not write that for D/DS/DS2. > > > > Is there any feedback concerning the use of Optibrite screens in a > > K10D? I understand the non-Optibrite screen works well. Is the > > Optibrite thing really any that good after all? > > > I think I posted about this a week or two back, but I'll restate it > briefly: > > I have a Katz Eye screen custom made for the DS with no focusing > aid .. just simpler markings and a plain matte focusing surface, no > OptiBrite. It introduces no differences in metering when used in the > DS body compared to the Pentax OEM focusing screen, just gives me a > simpler, cleaner framing view with a slightly nicer focusing surface. > > Since the DS and K10D screens are physically interchangeable, I did a > set of metering calibration test shots with the DS, then switched to > the K10D. Did a metering calibration test with the OEM screen, > switched the screen to the KatzEye and repeated the test. > > The results showed that the K10D with OEM screen metered a reference > neutral gray reflectance target just about right on the money, the DS > metered it and returned results about .3EV underexposed. Fitting the > KatzEye into the K10D produced consistent underexposure of .7 to 1 EV. > > I phoned Rachael Katz and discussed this with her. It seems that the > way the K10D screen's scatter has been tuned delivers more light to > the eyepiece and less to the metering sensors, and the metering > calibration has been tuned to that difference for the OEM screen. > More light getting to the sensors than expected causes underexposure. > The standard DS screen and standard KatzEye screen are very similar > in scatter characteristic so produce on-calibration results for the > DS metering sensors, but the K10D's metering sensors are expecting > less light. > > The OptiBrite treatment does a similar thing: it tunes the Katz Eye > screen's scatter to direct more light at the eye piece which will > have the result of reducing the light going to the metering sensors, > with a result that the DS calibration curve adds exposure to > compensate resulting in overexposure. So the conjecture is that the > Katz Eye OptiBrite screen would produce closer to calibration target > results more similar to the K10D OEM screen. But of course I'd have > to buy one to test this theory out ... and since the advantage I'm > looking at is really very small, given the quality of the K10D's OEM > screen, I elected not to and will just use the standard screen or > Pentax replacement with the reticle crosshairs. > > The OptiBrite treatment raises screen brightness with a small > decrease in focusing surface contrast. Whether that's what you want > or not depends upon how you intend to use your camera. I wanted a > better surface for manual focusing, that's why I elected not to buy > it when I ordered the screen for the DS. Most people buying the Katz > Eye screens are buying them to use the optical focusing aids and > screen contrast is less important, they just want it bright. > > Godfrey > > > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > -- Thibault Massart aka Thibouille ---------------------- *ist-D,Z1,SuperA,KX,MX, P30t and KR-10x ;) ... -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
