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12-12-2014, 07:58 PM   #1
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k10d focus confirmation using m42

I got a k10d yesterday and I've been testing it out. I prefer to use older pentax manual lenses. I put on my pentax A 50mm/2 and everything worked fine in both Av and M. Then I put on my pentax M42 adapter to test out my takumars. They also worked fine in Av and M, but I noticed that I was not getting the focus confirmation indication light (green hexagon) in the view finder. This only happened while using M42 lenses, The view finder in the k10d is much better than the K-x I've been using, so the focus on the k10d is easier to catch, but I still find myself waiting for the focus confirmation light. Has anyone had any similar troubles?

12-12-2014, 09:23 PM   #2
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QuoteOriginally posted by Knock Quote
Has anyone had any similar troubles?
I currently have a K-3, but from 2007 through this last spring, I shot a K10D with much of that being done with M42 lenses. Both focus confirm and CIF should work with no modification needed for your lenses or camera. I would suggest, however, that an aftermarket focus screen would be a better choice than depending on the AF system.


Steve
12-12-2014, 09:54 PM   #3
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QuoteOriginally posted by Knock Quote
I got a k10d yesterday and I've been testing it out. I prefer to use older pentax manual lenses. I put on my pentax A 50mm/2 and everything worked fine in both Av and M. Then I put on my pentax M42 adapter to test out my takumars. They also worked fine in Av and M, but I noticed that I was not getting the focus confirmation indication light (green hexagon) in the view finder. This only happened while using M42 lenses, The view finder in the k10d is much better than the K-x I've been using, so the focus on the k10d is easier to catch, but I still find myself waiting for the focus confirmation light. Has anyone had any similar troubles?
I've had better luck. When I use the plated brass m42 to k mount adapter on an m42 lens, it does give focus confirmation. If you are using a painted or anodized mount adapter, perhaps some electrical contacts are not conducting?? You do have to set the camera up a little, step 1 below.

Pentax K10D has good support for KA lenses if they are set to the A aperture position. You do get aperture indication, focus confirmation, PTTL flash, and so on.

However, if a lens is not in the A aperture position or does not have an A position (like, for example, M lenses, M42 lenses, extension rings, bellows, etc.), function is limited by camera firmware. You must follow these steps, and even then it's crippled.
1. First, set "Using Aperture Ring" to "Permitted", which you will find in the C Custom Setting Menu. The K10D won't work at all unless you do this.
2. Even if you set the "Permitted" option, you don't get all functions. If you set the exposure mode to any value other than Av or M, the camera will override your exposure mode to be Av, or if set to M, leave it at M. You don't get F stop display (shows only F--), nor automatic flash control, nor automatic setting of the focal length for Shake Reduction. You'll have no auto flash control, it's full on or off.

Refer to pages 208-210 of the K10D manual, which is online here:

http://c2b6d376b97bcc466063-5420c200a1f030d1394a9548df6eadbd.r5.cf2.rackcdn....402_manual.pdf

As you may know, Pentax made these restrictions in firmware. They say the restrictions are necessary because on Pre-A lenses, the aperture lever changed aperture opening differently than on A lenses. Essentially, on K and KM lenses the aperture motion was proportional to the diameter of the aperture, while on KA and later lenses motion was proportional to the aperture area. Thus on KA lenses, aperture steps were proportional to F stops, which is how we change aperture anyway.

A cynic might wonder if Pentax just wanted to sell newer lenses. Such a big fuss over one pin. But that's how it is.

Regardless of theory, you can make any pre-A lens pretend to be an A lens in at least two ways.

1. Modify the camera A pin to be always on by jamming foil under it. (At your own risk of course.) The camera will believe all lenses have A mounts.
2. Modify the lens to have a grounded contact at the A position. One way: Scrape or drill to bare metal and dab a bump of conductive epoxy at the A pin location, making sure the lens mount has some bare metal elsewhere for ground to the camera lens mount. (At your own risk of course :-)

If you search the forum, you will find examples of past efforts to do those mods. You may be able to shoot, but exposure may be wrong, because the camera can't really accurately set the aperture opening. So you do get some features back, but not all.

Last edited by slowhands95128; 12-12-2014 at 11:24 PM. Reason: Errors
12-12-2014, 09:57 PM   #4
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Do the lenses short the contacts? If not it won't work.

12-12-2014, 10:30 PM   #5
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errr focus confirmation in the viewfinder does work with M42 lenses on the K10d..

Check your firmware. I'm in 1.31, works a treat (green focus hexagon) with any lens in front of it.

But having said that, get a proper focusing screen. The stock one is rubbish.
12-12-2014, 11:31 PM   #6
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With my K10D I always find it takes some effort to get focus confirmation with any manual focus lens. It takes a lot of turning the focus ring back and forth before I can get the green dot to stay. I'll hear the beep and see the dot go on briefly most of the time. I found that moving the focus point slightly left and right over the object of focus helps. It may have gearing ratio on the manual focus helicoid and the contrast of the lens. I haven't found any difference between K-mount or screw-mount lenses in getting focus confirmation. Many times I just set the camera to manual focus or use the AF button programmed to disable AF and use my eyeball. When in manual focus the shutter will release without focus confirmation.

Are you focusing with the M42 lens wide open? If the screen is too dark focus confirmation will not work. I think the limit is around f5.6-f8.

With M42 lenses you should focus and compose with the lens wide-open. Stop-down the lens and in manual mode either press the green button (sets shutter speed) or operate the DOF preview and use the exposure bars in the viewfinder to set the exposure by turning the aperture ring and/or eDial for shutter speed. You can also stop-down the lens and shoot in Av mode but you'll probably find you need to add more exposure compensation than either of the previous two methods.

This will only work if the menu settings enable use of aperture ring, Green button in M and TAv mode set to Tv shift and DOF preview is set to optical.
12-12-2014, 11:36 PM   #7
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QuoteOriginally posted by slowhands95128 Quote
Sorry, you will have a very long wait for that focus confirmation light with a screw mount lens. It's not supported. This is explained in the K10D manual on pp. 208-210.
See my comments above (I own probably a dozen M42 lenses and have used all on the K10D, literally 10s of thousands of exposures)

QuoteOriginally posted by tromboads Quote
errr focus confirmation in the viewfinder does work with M42 lenses on the K10d..
What he said...

There may be some variability with firmware version. I did most of my shooting with v1.20. It makes no difference whether contacts are shorted or what color socks you are wearing. If the AF system is activated with shutter half-press or the AF button pushed, the focus confirm will work.


Steve

Last edited by stevebrot; 12-12-2014 at 11:46 PM.
12-12-2014, 11:42 PM   #8
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I get focus confirmation but I never pay any attention to it. I have a Katzeye screen which is the only way to fly with manual focus lenses.

12-12-2014, 11:45 PM   #9
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QuoteOriginally posted by slowhands95128 Quote
Regardless of theory, you can make any pre-A lens pretend to be an A lens in at least two ways.

1. Modify the camera A pin to be always on by jamming foil under it. (At your own risk of course.) The camera will believe all lenses have A mounts.
2. Modify the lens to have a grounded contact at the A position. One way: Scrape or drill to bare metal and dab a bump of conductive epoxy at the A pin location, making sure the lens mount has some bare metal elsewhere for ground to the camera lens mount. (At your own risk of course :-)
No! No! 1000 times No!

You can dupe the body, but not control the aperture. The is particularly true for M42 lenses where there is no aperture coupling. Believe me, I have tried all the tricks including setting the aperture on both lens and body with a shorted lens. They DON'T work.


Steve
12-12-2014, 11:48 PM   #10
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QuoteOriginally posted by VisualDarkness Quote
Do the lenses short the contacts? If not it won't work.
Not on the K10D.


Steve
12-13-2014, 12:23 AM   #11
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Thanks for all the replies. My previous (and limited) experience is with a K-x, which has an aftermarket focusing screen. I plan to get one for the k10d also, but I must admit the view finder on the k10d is better than the K-x. I don't necessarily rely on focus confirmation, but sometimes it helps my tired eyes know I'm at least in the ballpark. Firmware on the k10d is 1.30...I'm not very computer/tech savvy and I'd be nervous about upgrading to 1.31, but I'll look into it. Steve, I think I recall reading an older thread where you talked about CIF on M42's...I'll see if I can dig that up. Thanks for the help everyone.
12-13-2014, 12:54 AM   #12
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QuoteOriginally posted by stevebrot Quote
Not on the K10D.


Steve
Good call!
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