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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[Toni60]

Good morning, I come back after a long period due to health problems. Please I need your help about M42 lens Helios 44-7 on my K5IIs. I use genuine adapter and the settings changed in the menu as suggested, I use MF and M program but the AF indicator (hexagon) and beep works fine until f8 and do not work at f11, f16. Thanks so much for your help.

[reh321]

Good morning, I come back after a long period due to health problems. Please I need your help about M42 lens Helios 44-7 on my K5IIs. I use genuine adapter and the settings changed in the menu as suggested, I use MF and M program but the AF indicator (hexagon) and beep works fine until f8 and do not work at f11, f16. Thanks so much for your help.

Focusing requires a certain amount of light, and often any aperture beyond f/8 does not supply that. A K-mount lens will open fully to its widest value until you press the shutter, but everything with a normal M42 lens is done fully 'stepped down'. I am not familiar with Helios lenses - with Pentax lenses, switching the "auto/man" switch to "auto" will cause the lens to open fully. In any case, I am not sure I would use the lens beyond f/8, because you may be entering diffraction territory on your K-5iis.

[Toni60]

Focusing requires a certain amount of light, and often any aperture beyond f/8 does not supply that. A K-mount lens will open fully to its widest value until you press the shutter, but everything with a normal M42 lens is done fully 'stepped down'. I am not familiar with Helios lenses - with Pentax lenses, switching the "auto/man" switch to "auto" will cause the lens to open fully. In any case, I am not sure I would use the lens beyond f/8, because you may be entering diffraction territory on your K-5iis.

Thanks for your wonderful explanation. Sorry I am late.

[Makx]

thanks

[stemked]

Helpful. Thank you.

[Clydesdalecoop]

So happy to see this. I just pulled my prime 50 out of mothballs last weekend. It's like I have a new toy all over again.

[JoelA]

I just wanted to take a moment and thank the contributors to this thread.

Learning about the "Green Button" has been transformational for me.

It's such a pleasure to be able to use the digital body just like my trusty old K2!

All of my lenses from the '70's and '80's are back in use (along with a few "new" ones that I've purchased here on the forum).

Many thanks!!!

[dadaa1]

I tried so long to get aperture ring working on k-30 M-lenses and then finally find this thread and the magic words:
Finally, ensure that auto ISO is disabled.Thank You!

[Weevil]

I tried so long to get aperture ring working on k-30 M-lenses and then finally find this thread and the magic words:
Finally, ensure that auto ISO is disabled.Thank You!

This is good to know ! TFS!

[mrushton]

OK, I am trying to use some old K-Mount lenses that I used with my K-1000 on a K-50 Camera Body.

The images (esp in cloudy days) are soft and seem to be too white.

I turned on the Use Aperture Ring, the older lens are working, but have some quality issues. Do I not use the Auto ISO giving it a range (like 100-400) and just give it a value ?

It was a very overcast day when shooting this. Maybe i have to tweak the Aperture.

Any ideas ?

[MarkJerling]

OK, I am trying to use some old K-Mount lenses that I used with my K-1000 on a K-50 Camera Body.

The images (esp in cloudy days) are soft and seem to be too white.

I turned on the Use Aperture Ring, the older lens are working, but have some quality issues. Do I not use the Auto ISO giving it a range (like 100-400) and just give it a value ?

It was a very overcast day when shooting this. Maybe i have to tweak the Aperture.

Any ideas ?

Welcome to the forum.

I'd suggest that you start a thread in this section of the forum: Troubleshooting and Beginner Help - PentaxForums.com

It would be good to include some sample images so that members can help you find the cause(s) of your issues.

[mrushton]

I was not getting good focus and my images were kind of washed out. I was trying to use some old K-Mount lenses on a K-50 body.

I was not focusing correctly.

You have to press the shutter button down halfway as you focus. When the focus is good, the camera beeps and the hexagon icon lights up. Fully depress the shutter and take the shot.

I hope we have a sunny day soon to test this.

I was taking shots of random things around the house like a light, a vase, I was even taking shots of the things in the yard .. in the rain ... in the dark.

I still may buy an af lens.

[reh321]

I was not getting good focus and my images were kind of washed out. I was trying to use some old K-Mount lenses on a K-50 body.

I was not focusing correctly.

You have to press the shutter button down halfway as you focus. When the focus is good, the camera beeps and the hexagon icon lights up. Fully depress the shutter and take the shot.

I hope we have a sunny day soon to test this.

I was taking shots of random things around the house like a light, a vase, I was even taking shots of the things in the yard .. in the rain ... in the dark.

I still may buy an af lens.

Mark’s point is still valid.
I will not try to diagnose your ‘problem’ in this thread,
but the information you give does nothing to “prove” out-of-focus.

Ignoring the words of an experienced member
does not help your case.
You cannot just run this place by the rules you wish were true.

[seppstefano]

Incredibly late to the party here... yet I switched to Pentax dslrs after starting with Canon several years ago (it was a 30D, go figure)!

But this evening I successfully tried on my K5 the given procedure: first green button, then fire the shutter with some of my M lenses. So far I used to not fully lock the lens on the bayonet, but this procedure (easy because you can simply use your lens in stop down with camera in Av and ISO auto) has a major drawback for the lenses having the black window on their rear.

I happen to have also an A-lens and "discovered" that it works quite easily in P mode, with lens in "A" and simply using camera commands to set the f/stop... what an idiot I used to be...

Thanks to all once more!

Stefano

[kypfer]

Incredibly late to the party here...
But this evening I successfully tried on my K5 the given procedure: first green button, then fire the shutter with some of my M lenses. So far I used to not fully lock the lens on the bayonet, but this procedure (easy because you can simply use your lens in stop down with camera in Av and ISO auto) has a major drawback for the lenses having the black window on their rear.
I happen to have also an A-lens and "discovered" that it works quite easily in P mode, with lens in "A" and simply using camera commands to set the f/stop... what an idiot I used to be...
Thanks to all once more!
Stefano

Welcome to the party
As you'll find out, a lens set to the "A" setting on the aperture ring will do everything but autofocus, not just "P" mode but Sv, TAv, Tv and Av as well
Not fully locking the lens onto the bayonet should never be necessary on a Pentax DSLR, they're designed to be used with legacy lenses as well as the latest wizz-bang AW HD WR ED AF RE AL models
Enjoy