Can I use M42 screwmount lenses on my Pentax K-mount (D)SLR?

Yes, but you will need a Pentax screwmount adapter or a similar third party adapter. Please see this page for instructions on how to install the adapter: Pentax Screwmount Lens Adapter

Once you have installed the adapter, follow these easy steps:

1. Mount the lens. Make sure you tighten it so that all markings on the barrel are centered.

2. Compose your photo and adjust the focus.

3. If you're using a Super Takumar, S-M-C Takumar, SMC Takumar, or Super Multi Coated Takumar, you will need to set the diaphragm clutch on the lens to manual.

Then, select the desired aperture.

Note that your lens must be stopping down manually in order to get metering to work.

4. Meter the light. If you're using the K100D/K110D or the *ist DS/DS2/DL/DL2, press the AE-L button. If you're using the *ist D or K10D, press the green button. Make sure that the "allow aperture ring setting other than A" is set to yes.

When using a manual film SLR, meter as you would with any lens. Metering varies for later film SLRs.

5. Take the photo.

[Slowpoke Rodriguez]

I bought one from Adorama too. I have spent the last hour or so trying to get it on my camera with no luck at all. It is as if the adapter is about a half millimeter too big. I can get it on the lens just fine, but I can't then put the lens on the camera. Neither can I get it in the camera first, with the hopes of screwing the lens into the adapter once the adapter is seated. If it can be put on, it requires way more force than I feel comfortable applying to a camera.

[Blue]

Originally Posted by frogger

There is an ebay seller (jinfinance I think) that sells the originals but not cheap and they come from China.

Since these thread is active again I want to point out that if it is made in China, it isn't the "original" m42 adapter.

[Karn]

Got one at the same time as I ordered my camera, online shop in Sweden.
(cyberphoto) Costed me about 20 euro.

I'm pretty sure it's the genuine one, if not please tell. I'll share a picture.

[séamuis]

yes its genuine.

[chubasco]

I just got the genuine article too, but it doesn't look like I can get focus confirm for
M42 lenses. I've tried several different settings to no avail, this is using the *istD.

Bill

[wirrah]

Originally Posted by chubasco

I just got the genuine article too, but it doesn't look like I can get focus confirm for
M42 lenses. I've tried several different settings to no avail, this is using the *istD.

Bill

This is correct. You won't get focus confirm on an *istD unless the lens covers the electrical contacts on the mount. I believe this changed with the *istDS and later models.

greg

[edumad]

I just bought a Vivitar 200mm F3.5 screw mount Auto telephoto.
I has the A/M switch which works. But it has this pin so it can work in screw mount cameras.

Do I need to get rid of the pin or can I use straight with the adapter on my K10D?
Cheers,

[FHPhotographer]

I just found out (yeah, I'm late to the dance) that the adapter fits on the camera, not the lens. I thought one could get a lens, attach the adapter and leave it on; it works the other way apparently, it stays on the camera, and that means it has to be removed every time you go back to the other lenses.
FHPhotographer

[wirrah]

Originally Posted by edumad

I just bought a Vivitar 200mm F3.5 screw mount Auto telephoto.
I has the A/M switch which works. But it has this pin so it can work in screw mount cameras.

Do I need to get rid of the pin or can I use straight with the adapter on my K10D?

The pin won't cause any problems. Just make sure you put the lens in manual when taking a photo (otherwise you can only shoot at maximum aperture)

cheers

Greg

[OrenMc]

Originally Posted by FHPhotographer

I just found out (yeah, I'm late to the dance) that the adapter fits on the camera, not the lens. I thought one could get a lens, attach the adapter and leave it on; it works the other way apparently, it stays on the camera, and that means it has to be removed every time you go back to the other lenses.
FHPhotographer

You can leave the adapter on the lens if you so wish. Just remove the spring lock and off you go. Then get yourself a k-mount cap for that end.
I don't leave it on the lens becasue I have a couple lenses to use it on but I removed the spring anyway because it was kind of a pain to remove from camera.

[metroeloise]

I bought an adapter from Ace Photos. It was made by Bowen and was engraved with M 42 to Pentax K mount Adapter. I placed it on the lens. Easy. Then it would not fit my k20d. It'd drop in; it would not turn much; it would not click. I was faint of heart.

I called them and they were clueless as to the equipment so I sent it back. Before packing it up I figured I'd try again. Nope. Then I figured I'd try getting one of the back lens caps on to see if I could. I was more willing to twist the cap harder than the camera.

And it did click in! Thought I was on it until I tried to get the cap off!

Yep. Stuck.

If it wasn't for the flex of the plastic it would have stayed on. Wow! Then what?

I need some more guidance here! I want to use an old Sear lens now but more want to be in position to use M 42 lenses later. I read something about removing a spring clip that is on the rim. Is that what it takes?

Then there is this issue:

Originally Posted by OrenMc

You can leave the adapter on the lens if you so wish. Just remove the spring lock and off you go. Then get yourself a k-mount cap for that end.
I don't leave it on the lens becasue I have a couple lenses to use it on but I removed the spring anyway because it was kind of a pain to remove from camera.

As I understand it these are not to stay on the camera! How could that be? The question would be more about how many of the adapters you want to get. One per lens to make the changing easier? A few? just one and take the time to spin it onto each lens?

TIA

Ok I read directions on how to do this!

Before removing the adapter, you must screw off the lens. Next, use a ball-point point pen (or fingernail) as explained in the instructions to disengage the spring in the adapter and twist it off, pushing counterclockwise with the pen.

Warning: Certain non-Pentax screw mount lenses will get stuck when mounted on a Pentax auto-focus camera body and they can only be removed by a repair shop. Those lenses have a protrusion which will snap into the autofocus coupler hole or into the screw heads on the rim of the Pentax bayonet and thus lock the lens on the camera. Do not use any non-Pentax screwmount or bayonet lenses before you have verified that they have no irregular protrusions on the rear.

And now it makes more sense about why people think it "stays on the body since it doesn't simple come off the body like a regular k mount. Would have been nice to have directions with the product!

Still is confusing. Guess I'll have to buy another one! Try again. But which one?

[séamuis]

you would have gotten directions if you'd purchased a genuine Pentax brand adapter, and you would have no problems with anything getting stuck, as far as the adapter goes. I suggest the genuine adapter, nothing else. and unless you plan on using a lot of different m42 AND K mount lenses at the same time I see no reason to purchase more than one adapter, especially considering the price of the genuine article. the tip about removing the spring lock for easy removal of the lens without having to unscrew it (essentially making the lens a K mount) is a good tip, just keep in mind that the lens will no longer lock in place since the adapter doesn't utilize the K mount lock like normal K mount lenses. it wont necessarily come off super easy just be cautious.

[thanh_tan]

Hello,

I'm from Vietnam and I need to purchase a mount like this, anyone can help me?

[graphicgr8s]

PentaxWebstore Mount Adapter B (35mm Screwmount to Bayonet)
It's still available from Pentax but it's $31.00

[dlacouture]

Personnaly, I've just removed the clips, and either made a groove into the lens itself (hey, m42 lenses are quite cheap anyway...), or added a slim, giant washer-like flange made out of a jam lid (~0.3mm, I think) between the adapter and the lens, with a hole where the locking pin is located (ever saw these m42 adapters with a flange?).

Granted, the jam lid approach supposedly won't allow infinity focus (like the cheap ebay adapter with the giant flange), but I found that it's not the case... I guess I might just reach an hyperfocal distance this way...

The jam lid solution has two advantages:
- it allows the lens to lock into position without losing infinity.
- it allows those slim m42 lenses that doesn't overlap the locking pin and lens contacts to do so (thus allowing trap focus at the same time).

I converted all my 4 m42s into locking PK lenses this way...