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Many Pentax DSLR owners want to use M42 screwmount (Takumar) lenses, or M or K manual lenses, on their cameras because of the low cost and relatively high image quality of these lenses.

If you're wondering whether or not these lenses can be used with Pentax DSLRs (or the K-01), then the answer is yes! Pentax as well as third-party manual and screwmount lenses can easily be mounted on any Pentax DSLR (such as the K-1 series, KP, K-3 series, K-70, K-S2, K-S1, K-50, K-500, K-30, K-5 series, K-r, K-x, K-7, K10D, K100D, K200D, *ist D, etc.) Just follow this guide!



Modern Pentax DSLRs use the Pentax "K-mount", which employs a bayonet and therefore differs significantly from the M42 screw mount. The older manual M and K (SMC Pentax-M, SMC Pentax) lenses actually use the bayonet, so they will not need an adapter - you can skip straight to the lower portion of this article (starting at "Important!") for information on how to meter with those lenses. Screwmount lenses usually have "Takumar" in their names, and in order to mount screwmount lenses on your k-mount body, you'll need a Pentax k to m42 adapter. Pictured above is the genuine Pentax adapter, which is ideally the one you want to get. Similar third-party adapters are also available. Caution: Many third-party adapters, such as this one, have a protruding flange which will prevent you from focusing all the way to infinity. If you want to buy a third-party adapter (they're generally cheaper), make sure that they don't have this flange. Here's an example of a good third-party adapter.

Once you have your adapter, the next step is to install it on your camera (it can easily be put on and removed on-the-fly). Check out the m42 to k adapter manual.

After you've installed the adapter, you'll want to mount the lens. This is done by screwing it into the camera until the lens feels firmly attached. The focusing window and lens ring should line up with the camera just like any other lens. Now that your lens is mounted, let's talk about how to take photos with it.

Important! The hard part is to get the camera to actually fire when a manual lens is mounted. In order to accomplish this, enter your camera's custom function menu, select the "Using Aperture Ring" setting (usually at the end of the menu, #21 on the K-7, #27 on the K-5, #27 on the K-3, #26 on the K-1), and set it to 2 (allowed). Once you do this, the shutter will at least fire, as it wouldn't have with this setting disabled (you would simply have seen an F-- indication on the top LCD/info screen). The setting description should read: 'Shutter will release when aperture ring is not set to the "A" position' when "allowed" is selected. Also note that the mount on the lens must be conductive for electrical current so that it shorts the electrical contacts on the camera body. All Pentax manufactured lenses have a conductive mount, but some third party lenses do not in which case the area of the mount touching the contacts must be sanded down.

K-30, K-50, K-500, K-70, K-S1, K-S2 and K-01 users: make sure you also set your green button "action in M/TAv Mode" to Tv SHIFT. This is found under the button customization menu (page 3 of the main menu) on the K-01 or as a custom function on the K-30, K-50 and K-500. On the K-S2 and K-70, look under the e-dial programming sub-menu under button customization in the record menu.

Finally, ensure that auto ISO is disabled.

At startup, if your camera asks you for the focal length, enter the actual focal length as labeled on the lens. This will ensure optimal Shake Reduction performance. For zooms, you can use the lower end of the zoom range (this ensures that there will be no over-compensation), or the focal length that you shoot at most often.

Now, let's discuss metering. Since manual lenses don't feed aperture data to the camera, the only way for the camera to check how much light is being passed through the lens is to measure the light while the lens is stopped down. Follow this procedure to properly meter with a screwmount, M, or K lens:

___0. Ensure that the "Using Aperture Ring" custom function is set to "2 (allowed)" (K-30/50/500/01 users must also ensure that the green button is configured to Tv Shift in M/TAv Mode) as described above

1. Set your camera to M mode using the mode dial (your camera won't fire in other modes*)
2. Compose and focus your image.
3. Using the aperture ring (the ring at the very back of your lens; it will have numbers such as 2.8, 4, 5.6, 8 written on it), select your desired aperture setting. Note that the smaller the aperture number is, the more light passes through the lens, and the blurrier the out of focus areas of your photograph will be (and vice-versa). Note your lens will not stop down until step 5.
4. [Screwmount lenses only] Switch the diaphragm clutch on your lens to "Manual" (you can leave it on Auto when composing and focusing if you don't want a dark viewfinder).
5. Measure the light by either pressing the "Green Button" (older bodies may use the Av button), or pushing your power button to DOF preview mode (only available on high-end bodies). Your camera will automatically set the shutter speed for you.

All that's left now is for you to press the shutter release button to take your photo. Congratulations- you've now learned how to use M42 and M & K manual lenses with Pentax DSLRs!

*Screwmount lenses may also be used in Av mode since they are always stopped down to the aperture you will be shooting at (unlike M&K lenses, which are stopped down only when the shutter is released or when you meter as described above).

Note: if your aperture ring has an "A" on it, instead of doing stop-down metering as per this guide, you'll want to set the ring to "A" and use the camera's scrollweel to adjust the aperture via Av mode.

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[jac]

A small note. The OEM Pentax adapter can appear to be stuck even after pushing the lens release button; unscrewing the lens seldom draws the adapter along with it. A little bit of gentle but firm pressure with your figure(s) will get it to move. This is due to the fine tolerances in machining the plate.

Oops. Finger(s) not figures(s). iTouching w/one thumb.

[jeztastic]

A word of advice - remove the retaining spring from 3rd party adapters. It's not very accurate, you can end up with the lens or adapter stuck on the camera. It stays on fine without it if you screw it up tight enough.

[jva59]

This was v. helpful. I'd be interested in hearing about the difference between the manual and auto settings on many Takumar lenses.

[sewebster]

I have no screw mount lenses, but a major advantage of K+ lenses to me seems to be the fact that you can set your aperture and shutter speed (M mode) and then just compose and focus and take as many shots with the same settings as you want. It sounds like with screwmount lenses you have to keep manually stopping down and opening up the aperture if you want to be able to focus with full brightness...

[Ira]

I have no screw mount lenses, but a major advantage of K+ lenses to me seems to be the fact that you can set your aperture and shutter speed (M mode) and then just compose and focus and take as many shots with the same settings as you want. It sounds like with screwmount lenses you have to keep manually stopping down and opening up the aperture if you want to be able to focus with full brightness...

Once you hold an old M42 Tak in your hands, you'll understand.

[Spock]

Are m42 lenses then effectively more handy than A, M or K lenses?

Given that you can use M42 lenses in Aperture Priority mode, I'd say yes, they are more handy than M or K lenses (but not A lenses).

I have no screw mount lenses, but a major advantage of K+ lenses to me seems to be the fact that you can set your aperture and shutter speed (M mode) and then just compose and focus and take as many shots with the same settings as you want. It sounds like with screwmount lenses you have to keep manually stopping down and opening up the aperture if you want to be able to focus with full brightness...

It really isn't an issue (unless you want to take a lot of photos at F16 or smaller). So far I've mainly used my 'new' F1.8 screwmount lens wide open - or nearly wide open. Remember that people are used to modern lenses that usually only have an F4-5.6 maximum aperture! Also, IMHO, I think Aperture Priority is much easier to use than full manual. In any event I like it as my first SLR camera only had that option!

Once you hold an old M42 Tak in your hands, you'll understand.

+1

I just got my first screw mount Takumar yesterday - an SMC 85mm F1.8 - and I am mightily impressed with it! I think it's going to be my favourite lens! (Review here)

[sewebster]

Given that you can use M42 lenses in Aperture Priority mode, I'd say yes, they are more handy than M or K lenses (but not A lenses).

Ah, I see, yeah, that is a good feature. You can use K and M lenses in aperture priority mode too, but only wide open

[PentaxGreece]

I tried to mount a Helios 44-2 on my K-7 today. The result is: I get focus confirmation but I can't focus infinity . Is that a problem of the adapter I use? I bought this old adapter for 3 euros and I'm not sure about it's quality . Any advices? Try and find another adapter or am I doing something wrong.?

[Spock]

I would advise only using genuine Pentax screw mount adaptors. It's worth paying a little more. I have absolutely no problems with mine.

[chiane]

Ok, I installed the genuine Pentax adapter and have tried a few lenses. They all work great, but when I screw them in, the point they get tight to the body always leaves the lens numbers more in line with the red dot than the top of the camera. It's a bit odd. What am I doing wrong? Should the lens always finish it's screwing in centered?

[coolguy1004]

I observe the same behavior when I mount the Super Tak as well. The number is more in line with the red dot therefore it is a little bit off center with the camera. I also use the pentax adapter. I think this is normal , not sure.

[xetown]

Awesome thanks! You helped this DSLR newbie setup his new K-X

[jonhock]

I tried to mount a Helios 44-2 on my K-7 today. The result is: I get focus confirmation but I can't focus infinity . Is that a problem of the adapter I use? I bought this old adapter for 3 euros and I'm not sure about it's quality . Any advices? Try and find another adapter or am I doing something wrong.?

The adapters that allow "infinity" focus are generally thinner when looked at straight on, like the one in Adam's original post. The adapters that don't allow "infinity" focus have a flange around the outside edge like the one in this link..M42 Lens Adapter Ring for Pentax K mount K200D/K110D | eBay Some folks are mentioning removing the spring on the third-party adapters and I agree quite a bit more than %100. I had one break off(the screw holding it came out) in my k10. If I had not been paying really close attention I might have put another lens on with this piece of metal floating around and possibly ruining the camera or lens! I have a couple adapters- One Pentax, One Bower, and One "who knows who made it?!" brand. These all focus to infinity, but I'd beware buying one with no name. The Bower works good, and , OF COURSE, the Pentax adapter is just plain great(some of the reason being that you don't need a "tool" to get it off the camera.
While we're at it, here is a great post concerning the "pin" on the back of your Helios lens. (I have the 44M-4 version) 4https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/57058-helios-44m-4-auto-manual-aperture-control-conversion.html Enjoy!

[PentaxGreece]

^^ Thanks for the advice. I guess I'll buy a Pentax adapter after all.

[Paolillo]

Gostaria de deixar registrada minha opinião sobre este assunto. Comprei na B&H dois anéis adaptadores para utilizar minhas lentes antigas de 42mm rosca, na Pentax K-r que acabei de adquirir. Recebi os anéis Bower M42-PK, e ao tentar utilizá-los, tive problemas muito sérios. Na primeira tentativa, o anel ficou travado no corpo da máquina e foi muito difícil retirá-lo.Estava ficando desesperado quando por sorte e de tanto tentar, consegui. Fui pesquisar na internet e encontrei a informação de que é necessário retirar um pequeno parafuso e a trava que ele segura, uma pequena mola de aço. O parafuso é maior do que deveria ser na realidade e com isso, sai na parte interna da rosca, danificando a objetiva caso não se preste atenção a esse detalhe. Retirei o parafuso e o encurtei. Até aí, parecia estar tudo resolvido. Coloquei o adaptador na lente e encaixei-o na máquina. Quando tentei retirar a lente, esta saiu deixando o adaptador preso no corpo da máquina. Portanto, caso queiram utilizar esse adaptador, por favor retirem o parafuso e a trava, ou terão sérios problemas. A lente não ficará travada na máquina, mas não há perigo dela se soltar, bastando apenas tomar um pouco de cuidado.
Espero que essa observação seja de alguma utilidade.
Abraços,
Paolillo