On 11 May 2001, at 12:43, John A. Lind wrote:
> The viewfinder optics are what make the apparent distance about 6 feet (two
> meters). If it were 2cm (about 3/4 inch) your eye would not be able to
> focus on the screen unless you were very, very myopic (e.g. "Mr. Magoo"
> near-sighted).
Yeah, I didn't notice the "apparent" part. My mistake!
> It finally dawned on my why I require the -2 and -3 dioptric correction
> lenses for my right and left eyes respectively (they are 1.25 diopter
> different) instead of a -3 and -4 correction. My reading prescription is
> +1 diopter for both eyes and the _apparent_ distance of the focus screen is
> at the far end of the distance range for which I require reading
> correction, not infinity correction. I believe this is why there are
> sometimes mixed results in people trying to correlate the markings on the
> Eyecup 1&2 correction lenses with their prescriptions.
Also, AFAIK, the viewfinder has a +1 diopter built-in. So, if you get a
dioptric correction lens that's exactly as your prescription, you're gonna
be +1 diopter off.
> What the markings actually mean can differ by manufacturer too. A -1
> diopter Mamiya correction lens works perfectly for my right eye in the
> M645.
Really?!?!? I thought the correction factor was a matter of optics and
not manufacturer.
Thanks for the correction...
Regards,
Chris
---
I'm *not* a Zuikoholic.... I'm a Zuikohobbiest!
Chris O'Neill (coneill@xxxxxxxxxxx)
http://www.nucleus.com/~coneill
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