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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[Not a Number]

From button customization in the Rec Mode 3 menu select green button

See page 151 in the K-01 manual.

[dmazimoto]

Great forum! My first Pentax DSLR paired to a Super Takumar 55mm 1.8 (awesome construction)

I have the same problem programming the green button. I have a K30 with the latest firmware (1.04) and when I go to button customization I only see the following three:

RAW/Fx - One Push File Format
AF/AE-L - Enable AF1
AF/AE-L (with a film camera icon on top) - Enable AF1

I got everything else but the setting for the green button I have not been able to get.

Any pointers are greatly appreciated!

PS. I have the flange adapter (waiting on my non flange to get here, ordered after I found this thread). Does the flange short the auto focus contacts on the camera? I mean does it damage the camera in any way?

[dmazimoto]

Great forum! My first Pentax DSLR paired to a Super Takumar 55mm 1.8 (awesome construction)

I have the same problem programming the green button. I have a K30 with the latest firmware (1.04) and when I go to button customization I only see the following three:

RAW/Fx - One Push File Format
AF/AE-L - Enable AF1
AF/AE-L (with a film camera icon on top) - Enable AF1

I got everything else but the setting for the green button I have not been able to get.

Any pointers are greatly appreciated!

PS. I have the flange adapter (waiting on my non flange to get here, ordered after I found this thread). Does the flange short the auto focus contacts on the camera? I mean does it damage the camera in any way?

So, here's what I found to set the green button properly on the new firmware (from Pentax):

"Press the Menu button

Using the buttons on the four-way controller on the back of the camera, navigate to the [Rec. Mode 4] menu, select [E-Dial Programming]. Press the right button twice on the four-way controller.

Press the down button to highlight the line beginning with “M” and press the right button on the four-way controller. Highlight [P Line] and press the right button on the four-way controller. Highlight [Tv Shift] and press the OK button. Press the Menu button three times to exit the menu.

(This setting allows easy and accurate exposure metering using older lenses without an "A" setting on the aperture ring. When the Green button is pressed in Manual exposure mode, the lens "stops down", the camera's meter measures the light passing through the lens, and an appropriate shutter speed is automatically set based on that measurement)."

Hope this helps others with new firmware on K30!

Also, avoid Auto ISO on K30 since the camera won't function in manual mode if Auto ISO is enabled

[ankh]

I got a genuine Pentax adapter from Adorama yesterday -- it was on back order, originally placed the order in February.
They emailed me three or four times asking me if I wanted to cancel the order. I waited them out.

If anyone has clear directions for using the screwmount lenses on the K200D Pentax
or a pointer, I'd much appreciate it. I've gone through all of them I think, but nobody's specific to the K200D yet.

The camera is new to me, and I am not sure how to interpret the instructions posted for various other Pentax digital cameras.
The buttons and the menus and the firmware are different.

[D1N0]

You don't need to change anything for shooting with Takumars and m42. Since there is no physical connection to the aperture you can just shoot in Av mode. Focus wide open, close aperture to the preffered stop and press release.

[wildred5273]

"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 (#21 on the K-7, #27 on the K-5), 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.

K-30 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."


Photolady Directed me to this post but I cant figure out how to set the green button action in the menu and I also looked in the manual, I simply don't see it nowhere, if anyone has any ideas or where that is let me know lol.

Thanks In Advance,
Billy

[wildred5273]

"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 (#21 on the K-7, #27 on the K-5), 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.

K-30 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."


Photolady Directed me to this post but I cant figure out how to set the green button action in the menu and I also looked in the manual, I simply don't see it nowhere, if anyone has any ideas or where that is let me know lol.

Thanks In Advance,
Billy

Well I read below and figured out that part but Im still lost with this lens lol

[dmazimoto]

See my post two posts up

[wildred5273]

Allready read it and thanks figured out the green button settings

[ofer4]

I realize that this thread is somewhat dated, but since it seems to be "the" place for M42 usage discussion, I'll add this info here...

I recently got ahold of a small pile of m42 lenses to use on my K-r. Using a genuine Pentax adapter, I mounted one of the lenses and immediately had problems. In short, I was getting mirror flop all over the place. A half-press of the shutter would trigger it. Any other button on the camera would trigger it! Suffice it to say that I was confused.

After more time than I'd care to admit, I realized that the camera was set to autofocus on the body. Switching to manual took care of the problem.

So, in addition to what Adam so kindly posted, I'll add: Make sure that your camera body is set to manual focus!

Edit: Hmmm...maybe this wasn't the problem after all. I'm still occasionally getting the same problem on manual focus. Strangely, switching to live view fixes the problem, even after switching back out of live view. This one is confusing enough that I'll post for help elsewhere.

----------------------

Edit follow-up: It appears that my K-r was suffering from the dreaded "mirror flop". The lack of electrical contacts on the m42 lenses only exacerbated the problem. It's being fixed now.

[6BQ5]

This information never gets old! Thanks for posting this!

[TropicalMonkey]

I bought a Rikenon EE 135mm/f2.8 M42 lens from eBay. This lens has no Auto-Manual slide switch for Aperture control, rather it is always set in the auto mode. On the mount itself there is a lever in addition to the standard M42 pin (as shown in the picture). How can I use this lens on a Pentax DSLR say K20D? I mean how can I stop down the aperture? One option is to glue the auto-aperture pin to pressed position :-)

Edit:
I got the following link from another site.
http://chris.stingray.free.fr/Tuto/Modif_H44M4/Pinoche_H44M-4.html
Looks like there is no elegant solution for this.

[a96agli]

This is profoundly stupid question, but here goes anyway: I have three manual focus lenses, a 50mm Pentax prime, a 40-80mm Pentax lens and a weirdo Japanese 70-200mm Sun telezoom. I have taken loads of pictures with the 50mm and K30, and love it. I would love to get some use out of the 40-80mm as well (I remember loving it when I was still using a K1000). My question is, how do I set the focal length in the camera? The camera obviously asks for this when I turn it on, but which value should I go with? Should I keep changing it?

[D1N0]

Just use it with the sr in the shortest focal length of the lens if you don't want the hassle. It will not be ass effective. Using a sr setting that's too high will overcompensate and blur your image instead of deblurring it. Also you could just not use sr and adjust shutter speed accordingly. Otherwise adjust the setting everytime you zoom.

[bluenose]

This is profoundly stupid question, but here goes anyway: I have three manual focus lenses, a 50mm Pentax prime, a 40-80mm Pentax lens and a weirdo Japanese 70-200mm Sun telezoom. I have taken loads of pictures with the 50mm and K30, and love it. I would love to get some use out of the 40-80mm as well (I remember loving it when I was still using a K1000). My question is, how do I set the focal length in the camera? The camera obviously asks for this when I turn it on, but which value should I go with? Should I keep changing it?

From the Pentax USA site: Using K-30 With Older Lenses | Pentax Support

From the last paragraph:

"The Input Focal Length screen will appear. Use the rear e-dial to select a focal length which is closest to the focal length of the lens you are using. If you are using a zoom lens, choose a focal length close to the midpoint of the zoom range of the camera. Press the OK button when you have made a selection."