Chuck wrote:
>>My recollection is that the meter can be off by a small amount at the extreme
>>ends of the brightness range. Tim Hughes has written extensively on this in
>>the archives in his quest to develop the perfect silver oxide, mercury
>>battery simulator. (I didn't want to call it an ordinary adapter). Maybe Tim
>>will weigh in here.<<
Chuck is right, the diode mod or MR9 adapter can be a little bit off at high
EV's (~0.3EV) but the error drops off rapidly at lower EV's. I believe when
John does the diode adaption as part of a CLA, he usually fine adjusts the high
EV cal end point (mech setting) which helps a bit depending on diode, but there
is some small non-linearity left at the EV's just below full scale.
Here is probably more detail than you want summarising my old posts:
http://olympus.dementia.org/Hardware/PDFs/OM1DiodeVer2_1C.pdf
There is actually a much better way of doing this acurately without a diode,
which I have not put on the web. In fact, I think Chuck has done a few of his
cameras that way based on a description I sent him.
Regards,
Tim Hughes
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