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01-28-2012, 08:32 PM   #1
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Using older lenses with K-r

I recently bought a used Pentax 50mm f2 and Tokina 28-70mm f3.5-4.5 zoom, plus I have an old Vivitar 135mm f2.8 I hope to use with my K-r. I've read some of the threads about using older lenses and realize I need to use them with the camera ser to manual. I still have a few questions.

First, when using an older lens on Manual mode, what in-camera features are still available to me? Second, I know that after you set the aperture on the lens, you hold down the green button on top so the camera can meter and set the shutter speed, but can you also still set the shutter speed manually?

Finally, any tips or suggestions for shooting with older lenses, such as things to keep in mind, best situations for using them, anything else you can think of or suggest, are welcome and most appreciated.

Thank you in advance for your help.

01-28-2012, 08:38 PM   #2
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The complete guide is found here:
https://www.pentaxforums.com/forums/pentax-lens-articles/110657-how-use-meter...k-x-k-7-a.html

Unless it's a screwmount lens, you can only use it in M mode. After you press the green button, you don't need to set the shutter speed since that's what the green button does for you

You have to get used to shooting with manual lenses, but stopping down to meter really isn't that much of an inconvenience. Practice it a little and you'll have it down in no time! If shooting outside, you'll actually probably be able to take many shots at the same settings, i.e. w/o having to stop down first.

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01-28-2012, 09:01 PM   #3
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In manual mode you can certainly change any of the exposure settings you want. Metering with the green button gives you a starting point, and often it's correct enough, but you can still change shutter speed or ISO normally. Changing aperture will have to be done using the aperture ring on the lens, for any lens that doesn't have an A position on that ring.

You don't "hold down" the green button, just a quick press will meter the exposure. Depending on the metering mode you select (Spot, Center Weighted) you may sometimes want to meter against something in the scene other than your subject, and then recompose. Much like the focus and recompose method for framing your shots. This takes experimentation, but can give you better exposures where there is a lot of shadow or contrast in the scene.
01-28-2012, 09:16 PM   #4
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Adam,

I read the thread you linked to; that's what led me to decide to pick up the Pentax and Tokina lenses. They are both K-mount, though the Vivitar is a Tx mount with screwmount adapter. I've used the stop down mode to take a couple of shots just to make sure the lenses functioned as advertised but wondered about being able to change the shutter speed (and the exposure) after metering.

Philoslothical,

Your response carries me a little further down the road. Thanks. I haven't experimented with metering mode. I'm thinking spot mode might be what I would want to try for what I'm asking about. Looks like I need to go back to owner's manual for some re-familiarization.

One more question, since the K-r has what I believe is a 1.5x crop factor, making the 50mm effectively a 75mm lens on the camera, I will likely look for something to go a bit wider. Budget, though, is a real consideration. Any suggestions on an older, wider-angle lens to look for? I'm not looking to go fish-eye, but being able to shoot a wider landscape shot would be nice. I can't afford a new lens at this point, but if I can find something faster than the kit lenses for not too much money, I'd be a happy camper. Thanks.

01-28-2012, 09:19 PM   #5
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Also keep in mind you don't have to use the Green Button on the K-r. You can use the AV+- button to set the P Line exposure. You can set the Green Button to do something else, like Optical Preview or a different exposure mode (AV Shift / TV Shift).

This only works when using the aperture ring. With KA lenses (with A setting) the AV+- button switches between Shutter Speed and Aperture.
01-28-2012, 11:22 PM   #6
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Recently I bought 2 lenses without the "A" settings. This is the first time I use lenses without "A" on DSLR. The lenses are the M-135 F3.5 and a Tokina ATX 28-85 F3.5-4.5.

When I use the Tokina on my Kr, when I pressed the green button, the VF will dim out for a while and the shutter speed with be selected by the camera. The shutter speed selected is usually quite accurate.

While on the M-135, as I pressed the green button, the VF will NOT dim out, however it still set the sutterspeed, the only problem is the shutter speed selected by the camera will treat my lens at max aperture, regardless my aperture ring setting. I have to slow down the shutter speed to correspond to the aperture setting I set on the lens.

Does anyone who have M-lenses having the same kind of situation and while using other lenses like the Tokina will do stop down metering correctly? I'm just trying to determine whether it is a lens problem or the body itself.
01-29-2012, 12:07 AM   #7
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chongmic, what's the lens mount like on that M 135? Is it black painted/anodized, or silvery metal? If it's black and non-conductive, I think you'll need to buff the paint off a spot near the bottom of the lens mount, so as to short at least one of the data pins on the camera. If I remember rightly (and I could be mistaken on this) it's the pin closest to the six o'clock position on the camera's mount, the gold pin in this image:



I'm trying to find additional info on this for you, but it's proving difficult. I know it has been discussed several times here, but I don't remember exactly where.
01-29-2012, 02:23 AM   #8
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QuoteOriginally posted by WaltH Quote
I haven't experimented with metering mode. I'm thinking spot mode might be what I would want to try for what I'm asking about. Looks like I need to go back to owner's manual for some re-familiarization.
With A-type (including AF) lenses on your Kr, you can use any Auto metering mode, as well as M, X, B. With non-A-type lenses, any Auto mode (Tv, Av, Sv, P) defaults to AV mode. With A- and M-type lenses, you can use M mode and the Green button for stop-down metering and exposure. When using M-type lenses, I'll often leave the mode switch on my K20D set to TAv, right next to the M setting -- on your Kr, I think that would be Tv. I can shoot wide-open in Auto (remember, it defaults to Av) and then easily quick-switch to M for stop-down shooting.

QuoteQuote:
One more question, since the K-r has what I believe is a 1.5x crop factor, making the 50mm effectively a 75mm lens on the camera, I will likely look for something to go a bit wider. Budget, though, is a real consideration. Any suggestions on an older, wider-angle lens to look for? I'm not looking to go fish-eye, but being able to shoot a wider landscape shot would be nice. I can't afford a new lens at this point, but if I can find something faster than the kit lenses for not too much money, I'd be a happy camper. Thanks.
If you're used to 135/FF shooting, a 50mm lens on APS-C has the FOV of a 75mm lens on 135/FF, but it remains a 50mm lens. The smaller camera frame crops the image; the lens is just an innocent bystander.

'Normal' focal length is defined by the diagonal of the frame. On 135/FF that's 43mm. On nominal APS-C it's 30mm; on my K20D, it's 28mm. So what was wide on a Spotmatic is just normal on our dSLRs. Unfortunately, wideness on APS-C ain't cheap. Here are my suggestions, mostly based on my own experience.

* 28-31mm 'normal' are best for undistorted 'scapes, stitched-together into panos as desired. I see edge distortion in EVERY lens wider than 28mm. Good cheap 28s abound, and the not-cheap DA31Ltd is reputedly a gem.

* 24mm has the FOV of a 35mm lens on 135/FF -- just a bit wide. Vivitar-Kiron 24/2 in PK-M mount can be had for maybe US$150. Various 24/2.8s may be much cheaper. You may even find a bargain M42 Lentar-Tokina 25/3.5.

* 19-20-21mm have FOV ~equivalent to 28mm on 135/FF -- getting wide. My M42 Lentar-Tokina (also sold under other names) 21/3.8 is a joy and can be had for under US$100. The not-cheap pancake DA21Ltd is another reputed gem.

* 18mm: The best deal for glass covering 18-28mm is... the kit DA18-55. Everything else this wide or wider costs more, often much more. Its slight barrel disotortion at the wide end is easily fixed in PP. This should be your basic wide lens.

* 16mm: The best deal on wider glass is the Zenitar-K2 16/2.8 for about US$200. (K2 means PK-M mount.) This is pretty fishy on 135/FF, slightly fishy on APS-C, with an FOV the same as a 12mm rectilinear. Sharp, fast, cheap, wide -- I love it!

* Wider: I can't talk about the 14-15-16mm recitlinear primes. I *can* discuss UWA (ultrawideangle) zooms (and I'll skip the DA10-17 fisheye). I had a choice a year ago -- I could have bought any of the leading contenders, whether new or old Sigma 10-20s, DA12-24, or Tamron 10-24. I chose the Tamron because of 1) focal range; 2) warranty; 3) price; and 4) Sigma's known QC issues. I am happy. With a coupon, it was US$375 shipped. Now it gets more use than my other wide glass combined.

My recommendations: If you want undistorted 'scapes, stitch panos from 28mm shots. If you want wide and don't mind a little fishiness, the Zenitar 16 can't be beat. If you want a wide usable range, spend more on a Tamron 10-24. Good luck!


Last edited by RioRico; 01-29-2012 at 06:51 PM.
01-29-2012, 02:21 PM   #9
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Thanks, RioRico! That gives me plenty to work with.
01-29-2012, 07:39 PM   #10
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QuoteOriginally posted by Philoslothical Quote
chongmic, what's the lens mount like on that M 135? Is it black painted/anodized, or silvery metal? If it's black and non-conductive, I think you'll need to buff the paint off a spot near the bottom of the lens mount, so as to short at least one of the data pins on the camera. If I remember rightly (and I could be mistaken on this) it's the pin closest to the six o'clock position on the camera's mount, the gold pin in this image:
Philoslothical, my M-135 have the silvery metal mount. When I first got the lens, the pin contacts area have a piece of tape over it, then I removed it but it still won't do stop down metering like the Tokina did.

I read the Kr manual it says it will do open aperture metering regardless of the aperture ring setting, I was just wondering why the Tokina is able to stop down metering while both mount look exactly the same.
01-29-2012, 07:58 PM   #11
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Depending on how old your M-135 is, it could be tarnished around the lens mount. As was stated above, there must be electrical contact to those pins on the camera body.
Try cleaning the area on the lens that will touch the pins on the camera mount. A pencil eraser should work, although some users have stated that they had to use fine sand paper for really oxidized metal. Don't let any of the dust from the eraser get into your lens or camera.
01-29-2012, 08:08 PM   #12
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Agreed, I think I'd go with fine silica sandpaper, but however you do it should be alright as long as you clean it well before using it on the camera.
01-30-2012, 06:08 AM   #13
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It seems to be some glue residue left by the tape that cause the pins can't be shorted. The solutions is some lens cleaners to dissolve the residue and cotton swap to scrap them off.

Now it works like a champ, stop down metering is accurate. Thanks everyone, you guys saved my day. I'm a happy camper now.
04-26-2012, 07:33 AM   #14
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I am wondering if I am about to do some serious damage to my camera. I could seriously appreciate some info to make sure I dont wreck it.

I bought my K-r recently and found an M 50mm f1.7 lens on craigslist. when i first got the lens I set my green button to stop-down, but kept getting a lot of slightly-out-of-focus pics and currently I am using it like this:

Av mode: I set my camera to Av, choose my apperture (to get decent depth)
Manual: nothing weird here, i just pick the settings and go.

here is the trick, I just figured out that when I am about to shoot, I hold the shutter release half way and focus until the "autofocus" beep lets me know im in focus, then shoot. Is this a feature of the camera? or is this something that could damage it? I havent read of anyone using it this way, and I am not sure if I should be using it like this.
04-26-2012, 01:10 PM   #15
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QuoteOriginally posted by bigcuce Quote
here is the trick, I just figured out that when I am about to shoot, I hold the shutter release half way and focus until the "autofocus" beep lets me know im in focus, then shoot. Is this a feature of the camera? or is this something that could damage it?
That is exactly how it is supposed to work. No damage will result. Don't worry, be Hopi.
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