[stevebrot]

The 24mm tilt/shift is not fully compatible with the KX or MX, or, I assume, any other aperture-coupled manual bodies. Usable, certainly, but the mount is not correctly designed to allow stop-down metering on these bodies.

Are you saying that the mount does not have a "catch" to engage the aperture follower? It is hard to tell from the mount photo on the PF detailed review, but it appears that there is a machined indent and catch similar to that on the K-mount reversing ring I carry in my bag. Without a machined slot or trough, the lens would not even mount on a standard K-mount body. Can you confirm that there is no machined indentation running from 30° to 120° clockwise from the index dot on your copy? The trailing edge of such would engage the follower.


Steve

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Last edited by stevebrot; 12-18-2016 at 07:47 PM.

[Paul MaudDib]

Samyang works great on film cameras. I use my 35mm f/1.4 on my Pentax ME, it's a very, very nice viewfinder image.

Are you saying that the mount does not have a "catch" to engage the aperture follower? It is hard to tell from the mount photo on the PF detailed review, but it appears that there is a machined indent and catch similar to that on the K-mount reversing ring I carry in my bag. Without a machined slot or trough, the lens would not even mount on a standard K-mount body. Can you confirm that there is no machined indentation running from 30° to 120° clockwise from the index dot on your copy? The trailing edge of such would engage the follower.


Steve

The aperture is actually in the front part of the lens that does the tilting and shifting, not in the part that is fixed to the camera. In tilt/shift lenses it is very common for there to be no mechanical linkage from the aperture to the camera body because it would be very difficult to make that work properly. The distance between the mount and the aperture would change as you tilt and shift, so even a flexible cable would not work.

You need to go to an electronic aperture control like Canon EOS to get a tilt/shift lens that will stop down automatically. Otherwise you just stop it down by hand. It's just how T/S lenses work, and it's why they're not good general-purpose lenses.

[stevebrot]

The aperture is actually in the front part of the lens that does the tilting and shifting, not in the part that is fixed to the camera. In tilt/shift lenses it is very common for there to be no mechanical linkage from the aperture to the camera body because it would be very difficult to make that work properly.

That part, I understand. As far as I know the only T/S that does not have a preset or manual aperture is the recent Nikon product. My question for baro-nite was in regards to his statement that stopdown metering would not work on K-mount cameras having non-crippled mounts. Manual aperture K-mount lenses and accessories (e.g. M42 adapter, bellows, and specialty lenses) require a "catch" to engage the aperture-simulation follower on the body. The catch moves the follower to its full extent to emulate the wide-open position on the aperture ring. The is required for stop-down metering to work with non-crippled mount bodies.


Steve

[baro-nite]

Are you saying that the mount does not have a "catch" to engage the aperture follower? It is hard to tell from the mount photo on the PF detailed review, but it appears that there is a machined indent and catch similar to that on the K-mount reversing ring I carry in my bag. Without a machined slot or trough, the lens would not even mount on a standard K-mount body.

It has the open slot, the problem is that it is completely open and does not engage the camera's aperture coupling at all. By contrast, on a Pentax manual extension tube, the slot is mostly filled in by another piece, just leaving room for the camera's aperture coupling. Hence when you mount the extension tube the camera knows the lens is already stopped down; with the Samyang the camera acts as though it is open-aperture metering with a lens set to a very small aperture (smaller than the lens's actual smallest aperture, as I recall when I investigated this), hence massive overexposure.

Again, so as not to confuse anyone who comes on this thread later, this issue is only for the 24mm tilt/shift and only when it is mounted on a manual film body such as the KX or MX.

[stevebrot]

It has the open slot, the problem is that it is completely open and does not engage the camera's aperture coupling at all.

Well, that is lame.


Steve

[cpk]

No problem with mounting and operating the 24mm tilt/shift on a KX or MX; only issue is that the meter reading will be way off.

In such a case (the use of a tilt/shift lens) I think it would be wise to use a separate exposure meter rather than depend on the camera's built-in one.

[baro-nite]

In such a case (the use of a tilt/shift lens) I think it would be wise to use a separate exposure meter rather than depend on the camera's built-in one.

When I use the tilt/shift lens on a DSLR, metering is indeed less than perfectly reliable when the lens is shifted.

[Paul MaudDib]

When I use the tilt/shift lens on a DSLR, metering is indeed less than perfectly reliable when the lens is shifted.

Possibly due to polarization changes as the lens changes angles relative to the sun? That's how I would explain that observation. Not sure that a handheld meter would be that much more accurate though.