I’ve been trying to figure out exactly what to say about my
Contax/Yashica to Pentax K-Mount lens adapter I received for Father’s Day. As
you can see from the photo above it clearly works. You might even say it works
pretty well. The only “fly in the ointment” is that when I close the aperture
(set it on anything other than f1.7, the widest lens opening), the view through
the viewfinder darkens. Apparently there
is no “open aperture” viewing with the adapter in place. f2.8 or even 3.5 is not
too bad but by the time I’m down to f8 or f16 it’s gotten so dark that it’s
almost impossible to focus properly.
Manual focusing is not my strong suite these days. 35 years ago
when I bought my first all manual 35mm SLR focusing was not a problem. These
days with progressive lenses and older eyes it’s a challenge in the best of
light. Having a viewfinder looking like a foggy dusk doesn’t make it any
easier.
Using the lens and adapter on the Pentax K-01 seemed great at
first until I realized that changing the aperture setting has no effect what-so-ever.
The phase detection focus assist makes focusing a snap but alas the lens can
only be used at its widest lens opening, in this case f1.7. The ZX-7 also has
focus assist but apparently it doesn’t work with the CY/K adapter so like all
my other SLR bodies it requires unassisted manual focusing made more difficult
by the “stopped down” mode of the lens.
Another thing I noticed is that the adapter seems to rob me of a
full f-stop on my exposure values. My first experiment was with Portra 400 film
and I noticed that the TTL metered exposure values were not what I would
normally expect from 400 films. I checked a few and the TTL metering on the
camera was consistently one stop slower than it should be. After doing a bit of
research online I realized that the adapter itself has a lens and not only does
it rob me of one stop it also “magnifies” the image slightly so that the 50mm
lens is really functioning like about a 55mm – 60mm lens with an “effective”
aperture of f2.8.
With that said, I guess the real question is whether the quality
of the Carl Zeiss 50/1.7 that the adapter allows me to use is good enough to
warrant the extra effort needed to use it. On the Pentax K-01 the answer is, “maybe.”
One aperture setting, especially f1.7,
is just not enough for practical use although for shooting shallow depth of
field portraits it is perfect and the combined focal length of the lens and
adapter with the 1.5 crop factor of the APS-C sensor provides for an excellent
portrait lens roughly comparable to an 85mm to 90mm lens on a 35mm SLR. An
85/1.7 Zeiss lens is still a pretty sweet thing to have in your camera bag even
if it is a “one trick pony.”
On my other bodies, the answer is “probably not.” I have a 50/1.8
which produces very good images without all the disadvantages of using this
adapter. It makes much more sense to me
to just use it instead on those bodies so I think the Zeiss lens and adapter
are officially assigned to the K-01 bag from now on.
Knowing what I know now would I buy the adapter if I had it to do
again – probably not. $40 is not a bad price for a dedicated, fast, high
quality 85mm portrait lens, but my Pentax 40mm f2.8 pancake lens (60mm
effective focal length on the APS-C K-01) does just as good a job with none of
the problems associated with using this set up and it’s an AF.
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