Tamron Adaptall-2 Mount Question

[rayallen]

I own a Tamron SP 70-210mm F/3.5-4 Model 52A which I currently use on my Spotmatics with an M42 Adaptall-2 mount. It is a fine lens but it lacks a manual/auto lever. The only way it stops down is when the pin on the mount is pushed in.
That means that it is virtually unusable on my K10D (except at maximum aperture).

My question is will it work on the K10D if I buy an Adaptall-2 PK mount? Or must it be a P-KA mount? Are there different PK Adaptall-2 mounts? Will some work and others not work?

Please excuse my ignorance of K-mounts. I jumped from Spotmatics to the K10D and it is my first K-mount.

[IS050]

Originally Posted by rayallen

I own a Tamron SP 70-210mm F/3.5-4 Model 52A which I currently use on my Spotmatics with an M42 Adaptall-2 mount. It is a fine lens but it lacks a manual/auto lever. The only way it stops down is when the pin on the mount is pushed in.
That means that it is virtually unusable on my K10D (except at maximum aperture).

My question is will it work on the K10D if I buy an Adaptall-2 PK mount? Or must it be a P-KA mount? Are there different PK Adaptall-2 mounts? Will some work and others not work?

Please excuse my ignorance of K-mounts. I jumped from Spotmatics to the K10D and it is my first K-mount.

Ray, the Adaptall2 to M42 mount will work with your K10D, but you will need to get a Pentax M42 to K adapter. Please see this link for the modification I did on the Adaptall2 to M42 adapter to keep the pin permanently depressed.
An Adaptall to M42 adapter modification

Good luck.
David

[F16]

Ray, you can use either a 'K mount' or 'K-A mount' adapter, either will work on the DSLRs. With any K mount lens without an 'A' setting, you will have to press a button to 'stop down' meter at the aperture you choose, with an 'A' lens this is not necessary. Nearly all of the K-mount film cameras do not require stop down metering with non-A lenses, Pentax stupidly removed this ability in its DSLRs so any non-A lens requires that extra step in metering. So either K adapter will work, the KA adapter/KA lenses are just more convenient. Without a KA lens you also lose some other features like TTL flash metering.

[rayallen]

Originally Posted by IS050

Ray, the Adaptall2 to M42 mount will work with your K10D, but you will need to get a Pentax M42 to K adapter. Please see this link for the modification I did on the Adaptall2 to M42 adapter to keep the pin permanently depressed.
An Adaptall to M42 adapter modification

Good luck.
David

David,
Thank you for the link to your neat modification to the M42 Adaptall mount. That is so simple and reversible. I think I might just go with that as it saves having to buy an Adaptall K-mount adapter which I probably would not use very often.

No problem with the Pentax M42 to K adapter - I already have one of those which I use frequently with my range of Takumars.

Problem solved. Thanks again.

[Nesster]

I have on order a new thing: a M42 to K mount adapter with an inner flange to hold down the pin. About time someone made one. $17 delivered.... I'll report once I have it and try it out. The guy selling them says due to lens varability some lenses won't stop all the way down, i.e. you may only get to f/11 instead of f/22

[rayallen]

Originally Posted by Nesster

I have on order a new thing: a M42 to K mount adapter with an inner flange to hold down the pin. About time someone made one. $17 delivered.... I'll report once I have it and try it out. The guy selling them says due to lens varability some lenses won't stop all the way down, i.e. you may only get to f/11 instead of f/22

Yes, I agree - about time someone made one. I'll be interested to read your report.

[F16]

The adapter with flange should work fine since it's basically just replicating the action of an M42 body stopping down the lens. One thing to watch out for is that the flange isn't so large that it contacts the rear element or surrounding metal on lenses that have large, protruding rear elements. Main concern will probably be faster wide angle through short telephoto lenses, just be careful when threading the adapter onto the lenses for the first time so it doesn't damage the rear element.

[res3567]

Originally Posted by F16

Pentax stupidly removed this ability in its DSLRs so any non-A lens requires that extra step in metering. So either K adapter will work, the KA adapter/KA lenses are just more convenient. Without a KA lens you also lose some other features like TTL flash metering.

You mean the match dial metering that use to work in my K1000?