RE: Re[2]: zx-m focussing screen in zx5n

[Ed]

Ditto.

Thanks,
Ed

Alin wrote, inresponse to John's quirky AF on his ZX5N:

Snip.
>BTW, autofocus variations are not linked to the screen. I
>experience too AF inconsistencies with MZ-5n and FA 50/1.4.
Snip.

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Re[2]: zx-m focussing screen in zx5n

[John A. Hufnagel]

Alin,

My appologies if my earlier statements led you to believe that I faulted
the focusing erros to the screen.  I too have observed the errors with
the original screen, but had attributed it to my glasses being slightly
off perscription ( a condition that is now fixed.)  I remember in the
past hearing of others who had experienced or noticed the same type of
focusing erros, hence why I mentioned it.  It just became significantly
easier to see due to the range finder splitting my wife's roses in half!
=)
I noticed you observed the same with the same lense.  Have you any other
AF lenses to test with for focus error?  Unfortunately the AF50 is the
only one I have.  All my other lenses are MF.  In fact even the 2 news
ones I just bought are MF! (yes... I know... Why buy the 5n if I have
not AF lenses? Answer... The M is like my K-1000.. And I wanted some
newer features like bracketing and what not... Plus the ability to use
AF if/when I buy such lenses.  Plus, that pop-up flash comes in handy
sometimes!)

As I stated earlier I have as of yet to find any problems with the spot
meter and the range finder.  I'll see what the slide film develops
(pardon the pun) this weekend.

-- John


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Re[2]: zx-m focussing screen in zx5n

[Alin Flaider]

   Hi John,

   Have you done any spot meter comparisons between split prism screen
   and matte screen?
   I think this is the major issue, as spot sensor overlaps the split
   prism. Prism transparency differs visibly from the matte area and
   should affect the sensor reading - as this is calibrated for the
   latter.
   BTW, autofocus variations are not linked to the screen. I
   experience too AF inconsistencies with MZ-5n and FA 50/1.4.
 
   Servus, Alin

John wrote:

JAH> So far I've noticed no problems with the new screen. Pre- and
JAH> Post-screen install tests of the meter don't show any differences print
JAH> films are coming back w/o any problems.  I haven't had a chance to run a
JAH> roll of slide film through it.  Hopefully I'll get a chance to do that
JAH> this weekend.

JAH> Curiously the screen is demonstrating an interesting quirk in the AF
JAH> system...
JAH> If the lens Autofocuses from infinity to target, it's dead on.  If the
JAH> lens autofocus from closup to target, it undershoots focus by just a
JAH> hair.  The error isn't huge and I've determined that it's somewhere
JAH> between f1.7 and f2.0 on my 50mm/f1.4 lens (this by pressing the DOF
JAH> preview button on the camera.)  It doesn't happen all the time, and
JAH> seems to be a bit more frequent on targets w/o very distinct vertical
JAH> lines. Heh... With the f1.4 on there it could be me moving the camera
JAH> ever so slightly fore and aft! =)
JAH> I'll spend some time with the cam on a tripod soon and see if I can't
JAH> tie this down a bit more.

JAH> Very interesting.

JAH> Oh... By the way... The screen works FANTASTIC with my MF lenses... The
JAH> whole reason for this endeavour as it is! :P
JAH> The split-image doesn't go dark until around f6.7 on my big Sigma 75-200
JAH> f2/8~3.5 lens.  The matte screen area really lets things snap into focus
JAH> there too.

JAH> Overall, I'd say it's been a great < $10US experiment.


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