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.

Click here if you found this article helpful!

Video version:

You Tube

You Tube

[Not a Number]

sn't this true only for pre A 3rd party lenses with an anodized mount ?

Most screwmount lenses have anodized mounts or a small enough diameter to not touch the contacts. Other than electrical contacts how is the camera going to determine the type of lens or even if a lens is mounted?

[Pentaxis]

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-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. Unfortunately, it has been discontinued and can only be purchased second-hand. However, 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), 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-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. Also, avoid auto ISO.

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).
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", 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.

Click here if you found this article helpful!

Video version:
How to use a manual lens (M, K, or M42) on a Pentax DSLR - YouTube

Regarding the use of M series lenses on modern digital SLRs, like the K-1:

I am not sure from the video, when the aperture ring is rotated, is the aperture is stopped down instantaneously or is it stopped down only when the exposure is made? In other words, during the photo composition phase, is the scene viewed through the lens in a stopped down condition ?
I am sorry that I have not understood this fully.

Thanks in advance for any advice.

[Adam]

Regarding the use of M series lenses on modern digital SLRs, like the K-1:

I am not sure from the video, when the aperture ring is rotated, is the aperture is stopped down instantaneously or is it stopped down only when the exposure is made? In other words, during the photo composition phase, is the scene viewed through the lens in a stopped down condition ?
I am sorry that I have not understood this fully.

Thanks in advance for any advice.

The viewfinder doesn't darken with K-mount lenses, only M42 lenses. So in other words, the aperture is stopped down only when the shutter is open.

[fotograffiti]

I can only speak for the K-50:

Using K-mount lenses with no "A" setting, you follow the information above, set the camera's mode button to "M", use the green button to stop down the lens and get a meter reading before shooting. It's usually within a stop or two of being correct, but I find adjustment is necessary almost every time to get a proper exposure. Regardless of the aperture setting, the iris remains open for focusing, and only closes down when the actual shot is taken or the green button is pushed.

Using M-42 mount lenses, you do NOT use the green button. Set the camera's mode dial to "AV" (or "TAV", but limit your ISO), choose the aperture you want on the lens, and the camera does the rest—well, you have to compose and focus, of course. With M-42 lenses, the aperture opens and closes as you turn the aperture dial. Focusing at f/8 and smaller apertures (higher numbers) can be a challenge, but exposure is usually right on the money—it's a bit like shooting with an automatic lens. Therefore, I actually prefer my M-42 lenses to my K-mount. Exposure is more accurate, and there's no futzing about with the green button.

[Pentaxis]

Many thanks for your advice, fotograffiti.

---------- Post added 04-21-16 at 09:43 AM ----------

Thank you very much, Adam.

[sunilgupta]

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-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. Unfortunately, it has been discontinued and can only be purchased second-hand. However, 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-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. Also, avoid auto ISO.

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).
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", 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.

Click here if you found this article helpful!

Video version:
How to use a manual lens (M, K, or M42) on a Pentax DSLR - YouTube

Thanks for the great discussion & contributions. A question I have is about the need to press the Green button - do I have to do this for EVERY shot, or will the camera remember this for a series of shots? Typically we take a set of shots of the same subject & setting, so you know what I mean.

Also, can we use bracketing to take a few shots with different exposures with manual lenses without the 'A' setting?

[ntrao]

Thanks for the great discussion & contributions. A question I have is about the need to press the Green button - do I have to do this for EVERY shot, or will the camera remember this for a series of shots? Typically we take a set of shots of the same subject & setting, so you know what I mean.

Also, can we use bracketing to take a few shots with different exposures with manual lenses without the 'A' setting?

For your first question, mostly it works, if there is no change in lighting or subject or circumstances. You need to press the green button again, even if you change the aperture.
Bracketing I never tried it.. but love to experiment

[Adam]

Thanks for the great discussion & contributions. A question I have is about the need to press the Green button - do I have to do this for EVERY shot, or will the camera remember this for a series of shots? Typically we take a set of shots of the same subject & setting, so you know what I mean.

Also, can we use bracketing to take a few shots with different exposures with manual lenses without the 'A' setting?

I'd still recommend pressing it is before every shot, but if the ambient lighting conditions don't change, you can easily get away with using the same exposure settings throughout the day.

And yes, you can use bracketing.

[marcusBMG]

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

Google translate: "I would like to put on record my views on this subject. I bought the B & H two adapters rings to use my old lenses 42mm thread, the Pentax K-r I just purchased. I got the rings Bower M42-PK, and try to use them, I had very serious problems. In the first attempt, the ring was caught in the machine body and it was very difficult to remove it. I was getting desperate when luckily and both try, got it. I have been searching the internet and found the information that is necessary to remove a small screw and lock it safe, a small spring steel. The screw is higher than it should be in reality and with it, comes inside the thread, damaging the objective if not pay attention to this detail. I removed the screw and shortened. Until then, everything seemed to be resolved. I put the adapter into the lens and wedged it into the machine. When I tried to remove the lens, this left leaving the adapter attached to the machine body. So if they want to use this adapter, please withdraw the bolt and latch, or have serious problems. The lens will not be caught in the machine, but there is no danger of it is released by simply taking a little care.
I hope that this observation is of some use."

[plooksta]

Weird. I have a total reciprocity failure when I use this system on my K5 iiS. Have tried it on two different lenses (Pentax M-100 macro and Voigtlander Ultron 40 SLii). Green button stop down works at large apertures, and progressively underexposes as I close down the aperture. For example, with the camera setup at the same target, in M, fixed ISO, etc etc. I get:

f2: 125
f2.8: 60
f4: 30 .... so far so good....
f5.6: 20
f8: 15 .... What...
f11: 13 .....the....
f16: 13 ...heck.....
f22: 13 ....????... (correct exposure should be 1.3" here, as checked in Av mode)

Needless to say, the latter apertures are way underexposed. Same story with the M-100mm macro. Also, the switching the DOFP lever trick mentioned in the article does not meter for me (I have it set to optical preview). I used it on the Voigtlander merely to test, as it works as an A lens in fact. And I have checked from the front that the aperture blades are stopping down correctly.

I'm stumped. Any ideas?

[D1N0]

I'm stumped. Any ideas?

Sticky aperture only in stop down metering?

Better open a topic here Troubleshooting and Beginner Help - PentaxForums.com

This thread is too long as it is.

[wlin1011]

Hi guys, I bought a Irix 15mm for pentax used on ebay, It won't allow me to change aperture in aperture mode, I enabled aperture ring already and set E-dial M green button to Tshift. I'm still getting error F--. This lens don't have aperture ring on it so I can't change it manually, any help or hint would be help, thanks!!

I have tried on K-1 and K3ii both have same result.

[D1N0]

Lens must be faulty then. Take it up with the seller.

[marcusBMG]

Most often this is due to a problem with the electrical connection of the third contact - #6 in this pic - try eg a bit of rolled up alu foil wedged in there.

[barefootdesigns]

Well, I'm a 50's kind of girl. Started out with nothing but a Spotmatic and the venerable f4/50 lens, developing my own b/w film. Over some 50 years (YEA GADS!) I've migrated to the DSLRs. I gave my Kx (which worked great with the old glass) to my son for his jewelry business, and bought a K-50 to compliment my beloved K-01. I have >15 good 50mm lenses, which I prefer to shoot with, but I keep the K-50 for the things (like my dogs and family events) that I can't do well with the K-01 and manual glass.

Unfortunately, I haven't been able to figure out how to make the 50s work on the K-50 when I don't want to carry two bodies, but never even get a click out of that camera.. After many false starts, today I spent untold hours trying to fix that, scouring the web, reading extremely long and technical posts from all over--learned a LOT, but still couldn't get the K-50 to snap a picture with a manual lens. I considered dumping the K-50 out of unalloyed frustration!!

Tonight I found the answer here and finally solved the issue by setting the adjustment ring to "2". FIXED!!!

Now, on a brief vacation, I can finally test the SMC Pentax 1`:1.7/50mm against the SMC Pentax 1:1.4/50mm. And now I have one day left to do that. I'm tickled that the 1.4 Pentax is so good; I got it, along with a Spotmatic body, for $9 at Salvation Army! It's almost dead mint and takes awesome pix!! I'm also waiting for my copy of the Helios MC 44M-6/58mm to arrive. I've been searching for a real 44-6 for a long time and think I have found a very clean copy. So given all this, the K-50 debacle was driving me mad.

Can't tell you how many times this forum has benefitted me. I think it's time for another donation--as soon as I replenish my kitty. Har!

Thanks again, all!! This forum is terrific!