[VAE]

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Last edited by VAE; 03-10-2014 at 12:32 PM. Reason: deleted

[elliott]

The anodized black mount will cause a problem on newer bodies, the aperture won't stop down because the body sees it as an M42 lens. It needs to short the contacts work properly with K mount lenses. This is an issue with any body since the K-x and K-7.

[Mistlefoot]

They look pretty nice. I am guessing they will work fine (even with anodization) with lenses with Aperture rings and as Macro shots are usually manual focus that won't be an issue. And I've read articles on here about scraping off contacts so they'll work with new equipment, should you have issues as they are. Not sure if you could do that with these should the need arise....

[elliott]

I am guessing they will work fine (even with anodization) with lenses with Aperture rings.

That is the problem, the aperture stays open no matter where the ring is set.

[hks_kansei]

That is the problem, the aperture stays open no matter where the ring is set.

are you sure about that?

I would have thought they'd work just the same as an M lens, so would mean stop down metering.

But even stop down metering gives open aperture composition, only stopping down during the exposure (the rings have the aperture lever, so will stop down)



The only reason M42 lenses won't stop down on a K adapter is that there's nothing to press the stop down pin on the back.

[elliott]

are you sure about that?

I would have thought they'd work just the same as an M lens, so would mean stop down metering.

But even stop down metering gives open aperture composition, only stopping down during the exposure (the rings have the aperture lever, so will stop down)

The only reason M42 lenses won't stop down on a K adapter is that there's nothing to press the stop down pin on the back.

These have the lever, so they are held open by default as soon as they are mounted. The camera doesn't see it as an M lens without the contacts shorted, so it doesn't release the lever to allow the lens to stop down.

When you hit the green button on a newer body with a non-conductive M42 lens mounted it is silent, the actuator doesn't move.

[Mistlefoot]

These have the lever, so they are held open by default as soon as they are mounted. The camera doesn't see it as an M lens without the contacts shorted, so it doesn't release the lever to allow the lens to stop down.

When you hit the green button on a newer body with a non-conductive M42 lens mounted it is silent, the actuator doesn't move.

As I think about this more I get more confused. I thought than M Lenses were manual aperture and manual focus. A Lenses are auto aperture and manual focus. It should not be able to open the aperture on an M lens. I am still somewhat new at this so thanks for any clarification here.....

[hks_kansei]

These have the lever, so they are held open by default as soon as they are mounted. The camera doesn't see it as an M lens without the contacts shorted, so it doesn't release the lever to allow the lens to stop down.

When you hit the green button on a newer body with a non-conductive M42 lens mounted it is silent, the actuator doesn't move.

M lenses don't have electrical contacts at all though.

[thechumpen]

Yep, you need to sand them down to be able to use stop down metering and the A mode properly on your lens. I have a similar set and I used a dremel to sand off the surface to expose the metal underneath. I just did that on the couple of inches where it meets the contacts on the camera. They work great now.

[elliott]

M lenses don't have electrical contacts at all though.

All but one body contact sit above the surface of the mount so they touch the bare metal of the M lenses. The A contact is recessed in the body mount and is the only one that really requires a corresponding contact on the lens. Without the A contact shorted it sees something shorting all other contacts as an M lens, without anything shorted it sees an M42 lens because most M42 lenses have an anodized mount. In A lenses they have insulators on the mount to isolate certain contacts, that is how the camera knows the minimum and maximum aperture values of the lens.

You can see the lens type in the EXIF data when using M and M42 lenses, it says "K or M lens" or "M42 or no lens".

[Not a Number]

The simple non-destructive test for the "Doubting Thomas" is to use a piece of metal foil over the contacts to short them out.

[thechumpen]

The simple non-destructive test for the "Doubting Thomas" is to use a piece of metal foil over the contacts to short them out.

Which is exactly what I did to test it before getting the dremel out