John, scaling the picture of the OM-4 viewfinder in my copy of Shipman shows
that the diameter of the spot area is about 120f the diagonal frame dimension
(eyeballing the 97% viewfinder area). Lens angles of view quoted in that book
and in the OM literature are measure on the diagonal. So, the answer is
.....the 300 mm at a field of view of 8 degrees x 0.12 = 0.96 or essentially 1
degree. That said, there is nothing magic about one degree spot meters. I
usually use my 200/5 on my OM-4T when I am shooting my 4x5. That works out to
1.4 degrees and is just fine, and it is much easier to tote than a 300. Be
prepared to do some mental adjustments, since you will often run out of shutter
speeds on the low end in your OM-4 and have make your meter measurements at an
available marked speed.
Shooting that big camera is very different from shooting the OM, but is is also
great fun. Good luck! By the way, one of the tricks is to use the dark slide
to shade the lens. You have to pull it out anyway, might as well put it to
use, and it saves buying a big lens hood.
Gary Edwards
John Petrush wrote:
> First, a confession. I have succumbed to the lure and lust of large format
> photography with the acquisition of a used but not abused Horseman 450 4x5
> (5x4?) view camera. A marvelous instrument, well made and sturdy, with
> smooth geared movements. Weighs a bunch though! I also bought a 5 degree
> spot attachment for my Minolta IV meter but find it is still too wide an
> angle of view for critical measurement. So......
> Which focal length lens, in concert with an OM-4T, would provide the right
> angle of view to give a 1 degree spot measurement?
>
> John P
> ______________________________________
> there is no "never" - just long periods of "not yet".
> there is no "always" - just long periods of "so far".
>
> < This message was delivered via the Olympus Mailing List >
> < For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
> < Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|