Pentax screw mount lenses and DSLR

[Beemermark]

OK, I just picked up a K200 Pentax DSLR for the sole purpose of using my old screw mount Takumars. Everything I've read says these should work. However the lenses do not stop down for metering and do not meter correct when put in manual and stopped down. So what am I doing wrong? Get great pictures wide open, just can't stop down and meter.

 

[peterm1]

Hi I have been researching this also. I seem to recall there being a post on this on another thread when I googled it a week or two ago. From memory its a bit of a to-do!. First, I think a setting has to be changed in the camera's menu to make the shutter fire without a lens (as these have no chip). Which I presume you have done from your comments.

Then to actually take the image you need to first focus while the lens is open. Which you also seem to have got.

Then, comes metering. Using the manual / auto switch on the barrel of the Takumar lens slide it to manual to stop the lens to its working aperture (which of course you also need to set manually via the aperture ring).

Then (and this is what surprised me) I recall reading that you needed to flick the camera's manual stop down lever or button to take the actual exposure reading. I would presume its the last bit you are missing as I never expected this to be necessary myself. This may be because unlike the Nikon lenses when using an AI manual lens there is no aperture follower to tell the camera what working aperture is in use. In any event try that to see how it works.

 

[LKeithR]

In the Custom Settings Menu--not sure how it's named on the K200--set "Allow Use of Aperture Ring" to "Permitted" and set the camera and lens both to M. Pick your subject, focus, press the "Green" button (I think the K200D has one; if not I believe the AEL button performs the same function) and fire away. Exposure isn't always perfect this way but you'll get close.

You can download a full version of the factory manual in PDF format here...

http://pentaxcanada.ca/en/support/operating_manuals.php

 

[ChrisN]

Hang on everyone! He's talking about screw-mount, not K-mount lenses!

Mark (I assume) - look at your screw mount lens on the side that mounts to the camera. You'll see a little pin that protudes. Push that in and the aperture iris stops down. The old Spotmatics etc have a flap that pushes against that pin when you fire the shutter. The DSLR cameras don't have that, so they can't stop down the lens.

You can still use them! It's just that you have to stop down the aperture manually.

Most of your Takumar screw-mount lenses will have an Auto-Manual sliding switch on the lens body. Set that to Manual. Now when you set the aperture to f/8, the lens aperture will be stopped down to f/8. With the lens stopped down already, you will find that the viewfinder is a little dim, but you'll only use the smaller apertures in bright light anyway. Stick to f/5.6 and it's no problem.

Now (with the aperture stopped down manually) you can shoot in Aperture-Priority auto exposure mode. You can also shoot in manual exposure if you prefer, but you'll have to press the green button to meter (the camera will set the shutter speed to something close to correct).

I think I have that right - I'll play with a lens or two and get back if I've missed anything critical!


Edit to add: don't forget that you can also set exposure compensation if you find that the camera doesn't meter accurately with your Takumar lenses. They all seem to vary a bit; some of mine need half a stop under, and some need a bit over. Also - remember to set the focus mode switch (on the front of the camera) to MF - manual focus. If you don't, the camera won't release the shutter until it thinks you have it in focus.

 

[Doug]

Generally agreeing with Chris... As I've read in different places the hitch seems to be with the in-camera metering. The camera isn't able to give an accurate exposure even with the lens stopped down, considerably off at times. Inconsistent, I understand, a non-linear reaction to light level. I have not even tried it for this reason, sticking to KA, F, and FA lenses. Some folks suggest just using a hand-held meter and set the exposures manually.

I think it may well be because the body doesn't "know" what the max aperture of the lens is. Surprising that it would matter, but... With a current lens on the camera, I'd try setting it manually (using body controls) to the max aperture of the M42 lens you wish to use, take it off and mount the adapted screw lens, which may now meter correctly stopped-down in Manual mode.

 

[peterm1]

Any use?

http://www.robertsdonovan.com/?p=1181

http://www.pentaxforums.com/forums/...enses-all-pentax-dslrs-k-5-k-r-k-x-k-7-a.html

http://www.vn-trip.com/132-using-ol...nd-m42-lenses-on-pentax-dslr-with-images.html

http://www.pentaxforums.com/forums/821128-post3.html

Google "m42 lens on Pentax DSLR" and you will get lots of hits.

 

[Beemermark]

Thanks for the help. I have all the settings per the Pentax site. However the Pentax site implies that the lens will stop down when the preview button is pressed. Doesn't and I don't see how it could. Using the stop down metering method seems very inconsistent, which based on the answers maybe the norm. AE works fine, but the lens is aways wide open. If I stop the lens down (using the manual switch on the lens) everything is under exposed. Pentax ads and manuals state that the camera works with all lenses, including screw mount. Kinda true, but not really. My Nikon D200 works perfectly. I picked this up cheap because the gal stated that the AF was broken. I have a bunch of really nice screw mount lenses that I wanted to use. Seemed like a good marriage, now I'm not so sure.

 

[peterm1]

Thanks for the help. I have all the settings per the Pentax site. However the Pentax site implies that the lens will stop down when the preview button is pressed. Doesn't and I don't see how it could. Using the stop down metering method seems very inconsistent, which based on the answers maybe the norm. AE works fine, but the lens is aways wide open. If I stop the lens down (using the manual switch on the lens) everything is under exposed. Pentax ads and manuals state that the camera works with all lenses, including screw mount. Kinda true, but not really. My Nikon D200 works perfectly. I picked this up cheap because the gal stated that the AF was broken. I have a bunch of really nice screw mount lenses that I wanted to use. Seemed like a good marriage, now I'm not so sure.

To tell you the truth some months back I asked an aquaintance of mine who shoots with takumars on a DSLR what body I should buy for the same purpose - suggesting a pentax to him - but he recommended a Canon body even though he is a Pentax DSLR shooter. I cant now recall why he said that and I must ask him when I run into him next. Maybe this exposure issue is the reason. A couple of other threads I read on this subject suggested that its necessary to dial in some exposure comp when using pentax bodies and old manual lenses. But this obviously takes experience to know how much and when.

I also have a Panasonic L1 which I bought a few years back partly to use with my MF lenses and adapters, but I find it also tends to expose idiosyncratically with those lenses. In particular it over exposes all to hell when I shoot wide open. Besides which it has a small and rather dark viewfinder which makes manual focussing problematic. Hence my interest in a pentax or some other body to use for the purpose. An advantage of the L1 though is that I can use a wider range of lenses - Pentax, Nikon, Leica R etc.

 

[Beemermark]

[/quote] Maybe this exposure issue is the reason. A couple of other threads I read on this subject suggested that its necessary to dial in some exposure comp when using pentax bodies and old manual lenses. [/quote]
2 stops overexposure gives perfect exposure with my 35/2.4 Flexagon on AE. Which is good because 2 stops is the maximum. Have not figured out manual exposure settings yet. Strange thing is the shutter speed dispaly is off by maybe ten stops until I dial in 2 stops compensation, then is settles right down. Strange.

Girl was working at McDonalds to pay for college and dropped the camera. AF stopped working. She was asking $160 and I didn't have the heart to haggle for once in my life. Pretty beat up but it seems to work.

When I power it on it actually clunks. You can feel it. Is this normal?

 

[Crazy Fedya]

Clunking is normal: It cleans sensor on start-up. Select metering switch to center metering.Try setting lens and camera to M, then focus, and push green button. Meter the same situation with hand held meter, see if correct. If not, camera probably doesn't work right.
I used my Takumars with K10D a lot, and I never had any problems.

 

[Peter Klein]

I have had similar metering issues on Olympus DSLRs using OM Zuiko lenses. The issue is that when the lens is within a stop or two of its widest or narrowest apertures, the meter is not receiving the correct amount of light due to the different angles of the cone of light that the manual lens generates, vs. that of the lenses meant for the body.

The good news is that once you know what the correction factor is at the problem stops, you can apply it consistently, and all will be well. The bad news is that it's one more thing to deal with.

Using old lenses on a modern DSLR may seem attractive, but it is often too much of a hassle. It may work well if you use the lens at one or two stops in various situations--e.g. wide open for available light, at f/5.6 or f/8 in sunlight, or at the best stop for macro. You'll also find that manual focusing is more difficult on a modern DSLR, as the screen is optimized for autofocus with slow zooms, rather than for critical manual focusing with the lens wide open.

That said, Pentax has probably done the best job of all the DSLRs at making their old lenses usable, but K-mount lenses are better supported than screw mount. The micro 4/3 cameras like the Panasonic G series also take some of the pain out of it. I sometimes use OM and Leica-mount lenses on my G1, where the magnified electronic viewfinder makes focusing very easy. But even there, dealing with the stop-down metering slows you down.

 

[LKeithR]

Hang on everyone! He's talking about screw-mount, not K-mount lenses!

Mark (I assume) - look at your screw mount lens on the side that mounts to the camera. You'll see a little pin that protudes. Push that in and the aperture iris stops down. The old Spotmatics etc have a flap that pushes against that pin when you fire the shutter. The DSLR cameras don't have that, so they can't stop down the lens.

You can still use them! It's just that you have to stop down the aperture manually.

Most of your Takumar screw-mount lenses will have an Auto-Manual sliding switch on the lens body. Set that to Manual. Now when you set the aperture to f/8, the lens aperture will be stopped down to f/8. With the lens stopped down already, you will find that the viewfinder is a little dim, but you'll only use the smaller apertures in bright light anyway. Stick to f/5.6 and it's no problem.

Now (with the aperture stopped down manually) you can shoot in Aperture-Priority auto exposure mode. You can also shoot in manual exposure if you prefer, but you'll have to press the green button to meter (the camera will set the shutter speed to something close to correct).

I think I have that right - I'll play with a lens or two and get back if I've missed anything critical!


Edit to add: don't forget that you can also set exposure compensation if you find that the camera doesn't meter accurately with your Takumar lenses. They all seem to vary a bit; some of mine need half a stop under, and some need a bit over. Also - remember to set the focus mode switch (on the front of the camera) to MF - manual focus. If you don't, the camera won't release the shutter until it thinks you have it in focus.

Chris is correct. In my eagerness to respond I attributed the behaviour of K & M lenses to the screw mounts as well. Unlike K, M and A lenses which will afford you various levels of functionality, screw mounts are totally manual--which can make using some of them a lot of fun. Once you work with a lens a bit you get a feel for how the metering works and it really becomes a non-issue.

I have a Super Tak 55/1.8 which is a real gem but don't forget that, in addition to all the Pentax screw mounts, there are a ton of other M42 lenses out there. Helios, Mir, Opticam, Pentacon, to name just a few. One of my favourites is the tiny little Industar 50-2 50/3.5.

 

[David Hughes]

Alternative

Alternative

There's a worry free alternative and probably cheaper than the adapter. Go and look for a Pentax K1000 and some film...

Just my 2d worth.

Regards, David

 

[StaaleS]

To tell you the truth some months back I asked an aquaintance of mine who shoots with takumars on a DSLR what body I should buy for the same purpose - suggesting a pentax to him - but he recommended a Canon body even though he is a Pentax DSLR shooter. I cant now recall why he said that and I must ask him when I run into him next

I can only guess but... Canon DSLRs are something of the default choice when it comes to using quaint old manual-focus glass, whatever brand. The very short flange-to-sensor distance means that they can use almost anything that is out there via adapters (excepting, perversely, the old Canon-mount stuff) and they are pretty good about metering too. Get an old EOS 5D and a set of adapters for whatever mounts you want, and you are golden; digital full-frame in 12 megapixel glory! Throw in the Canon "S" course matte focus screen and you will even be able to focus properly.

 

[ChrisN]

Part of the fun of using old M42 lenses on a modern digital is overcoming the inherent difficulties. I think Mark is probably aware that if he is simply after good digital images with the least effort, there are simpler ways to go about it! Similarly, if speed is of the essence, any cheap modern autofocus lens for your mount of choice will do a better job than a screw-mount lens. I'm sure that with a little bit of effort and practice, Mark will master the steps necessary to allow him to get good images from his old favourite lenses.

2 stops overexposure gives perfect exposure with my 35/2.4 Flexagon on AE. Which is good because 2 stops is the maximum. Have not figured out manual exposure settings yet. Strange thing is the shutter speed dispaly is off by maybe ten stops until I dial in 2 stops compensation, then is settles right down. Strange.

Girl was working at McDonalds to pay for college and dropped the camera. AF stopped working. She was asking $160 and I didn't have the heart to haggle for once in my life. Pretty beat up but it seems to work....

Mark, I fear your generosity may have gotten the better of you, and the camera may have suffered some other damage. Can you borrow an autofocus lens (yes, I know the AF doesn't work - just focus it manually) or a manual-focus bayonet lens with an "A" setting on the aperture ring? The A setting allows the lens and the body to communicate the correct aperture setting (when set to "A"). That would at least allow you to verify that the camera is capable of exposing correctly with the lenses it is designed to work best with. I spent a few hours today shooting a Pentax-A 24/2.8 on the Pentax DSLR, using between 0 and -2 exposure compensation depending on the situation. As I said earlier, even with the best lenses some need for exposure compensation is inevitable at times.

 

[rjbuzzclick]

I shoot with SMC-M K-mount lenses all the time on my Pentax K110D, I've also used screwmount lenses time to time as well. The above folks are correct, screwmount lenses are manual stop down only, but the K-mount lenses will auto iris on my K110D for full aperture focusing. The one thing I've not seen mentioned, is that you also need to change the function of the preview lever (the rotating power switch around the shutter button). It has a third position that normally takes a preview shot and puts it on the LCD but doesn't write it to the card. Somewhere in the menu (sorry, don't have my camera with me at the moment), is a setting to change this to stop down metering. With this set, and a K-mount lens on the camera, when you move the power dial to preview, it will stop down the lens and turn on the meter circuit. With a screwmount lens, you'd first have to manually stop down the lens, but then the camera will still meter.

I've found that wide open, my camera seems to underexpose by a stop, but the error lessens with smaller apertures. I'm not sure why this is, maybe something to do with the lenses being designed for the larger 35mm film area instead of the cropped sensor or what. Regardless, I mostly run my camera in manual mode and overall it works really well.

Also, with K-mount lenses with an A (auto) aperture setting, my camera will work in aperture priority, and know what f-stop the lens is set at. This is the situation where I will bump up the exposure compensation to +0.5 or +1.0.

Oh, I should also add I purchased a Katz Eye focusing screen for my K110D which is a bit brighter than the original screen, but adds both a split-image circle and a microprism collar to aid in focusing.

 

[ronnies]

As many know, Pentax was the only SLR manufacturer who did not substantially change their lens mount or lens registration distance when they moved from manual-focus to automatic-focus film SLR camera designs.

Not true. Nikon didn't change either. 🙂

Ronnie

 

[ronnies]

Nikon and Pentax both retained the physical dimensions of the lens mount, including the lens registration distance. However, early Nikon manual-focus lenses require retro-fitting to work on modern Nikon AF cameras. Pentax lenses do not. That is not a knock on Nikon, they make excellent equipment. It so happens that when I found myself in possession of a reasonable number of M42 and P/K mount manual-focus lenses, it made more sense for me to purchase a Pentax dSLR body than any other brand. That is all.

Best Regards,

Bill Mattocks

That's true but some non AI lenses will fit the D40/D60 series bodies without modification (or metering). In fact Nikon lens compatibility can be a bit of a minefield at times. 🙂

Ronnie

 

[css9450]

As many know, Pentax was the only SLR manufacturer who did not substantially change their lens mount or lens registration distance when they moved from manual-focus to automatic-focus film SLR camera designs.

However, early Nikon manual-focus lenses require retro-fitting to work on modern Nikon AF cameras.

Right, but you're taking about two different changes - the AI/non-AI change predated the MF/AF change by a decade.

I think that's what makes the Nikon system so fun to collect. None of the changes were deal-breakers; more like a series of small changes over a period of decades.

 

[css9450]

"Fun to collect" and "easy to use" are often two entirely different issues. I like both, but they don't often coincide.

Well I might consider it easy to use but then again if I had, say, a 1962 vintage Nikon F (and nothing else) I might be disappointed by the lens lineup available down at Best Buy. Nothing would meter and I'd have no aperture rings! Most people aren't leaping across 5 or 6 decades like that though.