Lens Adapter Problem: I have some M42 screw mount lenses that I would like to adapt to a digital camera and play with but (see photo) there is an aperture activation pin on the lens...

PJHHobbit Loc: Kansas City, Missouri

I have some M42 screw mount lenses that I would like to adapt to a digital camera and play with but (see photo) there is an aperture activation pin on the lens that must be held in for the aperture adjustment to function also none of them have auto/manual controls on the lens. There are plenty of adapters for M42 to Sony full frame e-mount but none of them mention anything about this aperture pin........

What do I do now?

imagemeister Loc: mid east Florida

You have to look very close at the description of the adapters - some do have a provision for activating the aperture pin and say so - in so many words ......

rehess Loc: South Bend, Indiana, USA

PJHHobbit wrote:

... also none of them have auto/manual controls on the lens.

Amongst Pentax lenses, "auto" setting on lenses came some time after Pentax moved from M42 to K-mount

imagemeister Loc: mid east Florida

rehess wrote:

Amongst Pentax lenses, "auto" setting on lenses came some time after Pentax moved from M42 to K-mount

All Pentax Takumar m42 lenses have the auto/man switches - the OP's lenses are third party ....

rehess Loc: South Bend, Indiana, USA

imagemeister wrote:

All Pentax Takumar m42 lenses have the auto/man switches - the OP's lenses are third party ....

So, what was the purpose of that switch?

PJHHobbit Loc: Kansas City, Missouri

rehess wrote:

So, what was the purpose of that switch?

One possible use - Some M42 cameras do not have a depth of field preview button. This switch will allow DOF preview with lens at shooting aperture. The viewfinder may be quite dark but at least you can see DOF.

imagemeister Loc: mid east Florida

PJHHobbit wrote:

One possible use - Some M42 cameras do not have a depth of field preview button. This switch will allow DOF preview with lens at shooting aperture. The viewfinder may be quite dark but at least you can see DOF.

:thumbup: :thumbup:

haroldross Loc: Walthill, Nebraska

Look for an adapter with the flange such as this one:

http://www.ebay.com/itm/Lens-Adapter-For-M42-Mount-to-Canon-EOS-Pixco-GE-1-EMF-AF-Confirm-Flange-/391100092172?hash=item5b0f61cf0c:g:FNYAAOSw7aBVGmGJ

PJHHobbit Loc: Kansas City, Missouri

haroldross wrote:

Look for an adapter with the flange such as this one:

http://www.ebay.com/itm/Lens-Adapter-For-M42-Mount-to-Canon-EOS-Pixco-GE-1-EMF-AF-Confirm-Flange-/391100092172?hash=item5b0f61cf0c:g:FNYAAOSw7aBVGmGJ

I'm pretty sure that I found what I need. Thanks for the help everyone!

http://www.amazon.com/gp/product/B0054EORJC?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

busmaster2 Loc: College Point NY

PJHHobbit wrote:

I have some M42 screw mount lenses that I would like to adapt to a digital camera and play with but (see photo) there is an aperture activation pin on the lens that must be held in for the aperture adjustment to function also none of them have auto/manual controls on the lens. There are plenty of adapters for M42 to Sony full frame e-mount but none of them mention anything about this aperture pin........

What do I do now?

All the m42 to emount adapters hold the pin in so there's no problem as they're then fully stop down mode.

PJHHobbit Loc: Kansas City, Missouri

busmaster2 wrote:

All the m42 to emount adapters hold the pin in so there's no problem as they're then fully stop down mode.

Sorry to inform you that I bought one a while back for M42 to Sony A mount that did not hold the pin in. I thought about gluing the pin in but did not want to ruin the lens for future film use. There are some out there that don't............

imagemeister Loc: mid east Florida

PJHHobbit wrote:

Sorry to inform you that I bought one a while back for M42 to Sony A mount that did not hold the pin in. I thought about gluing the pin in but did not want to ruin the lens for future film use. There are some out there that don't............

:thumbup:

Architect1776 Loc: In my mind

PJHHobbit wrote:

One possible use - Some M42 cameras do not have a depth of field preview button. This switch will allow DOF preview with lens at shooting aperture. The viewfinder may be quite dark but at least you can see DOF.

Also when using bellows and other accessories that were not "automatic ".

alfeng Loc: Out where the West commences ...

PJHHobbit wrote:

Sorry to inform you that I bought one a while back for M42 to Sony A mount that did not hold the pin in. I thought about gluing the pin in but did not want to ruin the lens for future film use. There are some out there that don't............

¿ What about simply using some tape OR a small piece of plastic over the pin held on by some tape or secured with dabs of tub-and-tile-caulk-or-equivalent adhesive which can later be removed to hold the pin down?

Leitz Loc: Solms

PJHHobbit wrote:

Sorry to inform you that I bought one a while back for M42 to Sony A mount that did not hold the pin in. I thought about gluing the pin in but did not want to ruin the lens for future film use. There are some out there that don't............

With the switch on "MAN" there is no reason to hold the pin down.