With any of the K mount lenses with aperture rings that ring would make
the lens work like a preset lens with two aperture rings. The first
ring had the markings, which is where you'd set the aperture of the
lens. Focus with the lens wide open, then just before exposure you turn
the ring without markings to close the aperture. The lens then stops
down to it's set aperture. It was actually not that difficult to do,
lots of T mount lenses used that system. I think there were even a
couple of rather expensive SCMP [K] series lenses that used that system
the K400 f5.6 and the K500 f4.5, but I'm not fully sure of that. The
only lenses who's set aperture you wouldn't be sure of would be those
without aperture rings.
On 3/16/2014 1:43 AM, Boris Liberman wrote:
Bill, my Novoflex (expensive) Pentax to Leica adapter has a ring. So
it can be used in at least two different ways:
1. The ring is at its close-most position. Then the lens would behave
like regular K-mount lens (no A-position) - you click, the aperture
closes right away, you focus, aim and take a shot. Camera measures
with closed aperture.
2. You set the lens at certain aperture, including, but not limited
to, the A position. Then you rotate the ring on the adapter thereby
setting any effective aperture you like. The shooting is the same
except that you control the aperture with the adapter ring. Since you
see what you get on the EVF - it should be rather easy, at least in
theory. The downside - the ring on the adapter has no markings, so you
close aperture to _some_ value, without really knowing what it is.
Generally I shoot by controlling the aperture on the lens, and not on
the adapter.
I suppose that technically my Novoflex should be no different than
yours except the target mount.
On Sun, Mar 16, 2014 at 4:01 AM, Bill <anotherdrunken...@gmail.com> wrote:
On 15/03/2014 6:24 PM, ma...@redwoodhorses.com wrote:
Am I to understand the Pentax A* lens fit the XT-1 Fujifilm X mount?
An adapter has to be used between the camera and lens. It is about an inch
thick, making up for the difference in registration distance.
Here is a picture of a cheap eBay one. For this price I wouldn't expect
precise registration, and wouldn't be surprised if I lost infinity focus, or
developed a bit of a lens tilt or some such, but you get the idea.
http://is.gd/hPVqPz
Also, you lose the A setting, and have to use the aperture ring. I don't see
why one can't be made with an aperture ring and control lever to run lenses
that don't have aperture rings.
bill
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