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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[Kmerza]

Thanks man.

I have a K-x that I am using with a SMC Asahi 50mm f1.4 manual. Great images...although the aperture setting on the lens does not seem to make a difference. It has a very shallow DOF at any f stop. Also the images are very soft.....anybody know how to fix this?

Any help would be great....and again thanks.

Khurram.

[Adam]

Don't use AV mode with it.

[KFrog]

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)

Your first and only Tak was the SMC 85mm f/1.8? Arguably the finest Tak ever made?! Boy are you spoiled! No place to go but down from there!

[Kmerza]

Thanks Adam.

Using M was the key. However when I hit the Green button....it does not automatically set the shutter speed. I end up pressing the Green button and adjusting the aperture ring to get the correct exposure. What am I doing wrong?

[Kmerza]

Ok I think I got it.

I went into the menu and put the Green Button on P line. Now when I hit the Green button it automatically sets the shutter speed according to the Program line.

[pdcphoto]

Thanks Adam. I was seriously thinking of buying the 1.4 50mm, but now I think I'll use the 1.4 super tak from my dad's old spotmatic. It's in mint condition to boot!

I just bought a super tak 50 1.4. What a beautiful lens. The crop is a little to get used to, but once you get accustomed I think you'll love it.

[BSandu]

Hello everybody,
Just got an Auto Revuenon 1:3.5-4.5 35-100mm for my K-7. I followed step by step the indications from this topic, but, unfortunately, still doesn't stop down to the selected aperture. Is the lens defect or am I doing something wrong? Below is the picture of the lens mount.
Thank in advance!

Attached Images

 

[Kmerza]

BSandu,

Are you sure you are in M mode on your camera? And also check what your "green button" is set to in your camera.....you can do that on #4 drop down menu in your Rec settings. Mine is set to P-line. Also check that your C setting #4 page. 22. Using Aperture Ring....blah,blah...is set to permitted which should be #2.

Best of luck.

[BSandu]

Yes, 100% sure. Done all that. It meters for full aperture (which is normal, as the aperture is fully opened), but no matter I set a different aperture, it won't move the small lever of the lens and shoots at 3.5 . By the way, I also have a Tokina (A) 28mm 2.8 and works perfectly, even when the lens is not set on A. Maybe the Revuenon lens is wrong? But, when the lens is off the camera, rotating the ring modifies the aperture! I was thinking to cut the small lever ?! I'm so lost... What is wrong??? My only thought is maybe the mount is not Pentax K (although it looks so) but something really looking like.
Waiting for thoughts.
Sandu

[pdcphoto]

I have a similar issue with my pentax-m 28 2.8. I can use the green button or dofp to close the aperture, but when shooting in M it doesn't seem to stop all the way down yielding finicky results. on the other hand, shooting with my m42s is a dream, but it's not as user friendly to go back and forth with and without adapter ring.

[Kmerza]

BSandu,

If you have done all that and your other manual lens is working fine.....then I am thinking it's the lens. Did the lens come with a manual(instructions)? Read that thoroughly.

Good luck man.

[BSandu]

My problem is worse than pdcphoto presented. Green button or DOF doesn't close the aperture at all. Thinking more serious to cut the damn lever. Although focusing will be a nightmare. I prefer to keep it as the last solution. Anyway, probably is a mount very similar to K mount, and the camera refuse to action the lever (it's smarter than me ). Any other thoughts?
By the way, the lens were purchased second hand, without any manual/instruction at all. Just the lens. That's it.

[BSandu]

Does anyone have the drawing (specifications) with dimensions of the K mount? Looking over the internet, but only the connectors/pins diagram I found.
Thanks

[rojaba]

guys, where is the setting to allow for these lenses hiding on the K-5? does anyone know? i screwed a helios 44m on but "F --" keeps flickering and it won't fire

[Adam]

It's in the custom function menu, same place as on all the other cameras.