Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-28-2014, 12:53 PM   #1
New Member




Join Date: Nov 2012
Posts: 7
Why won't my adapted Leica R lenses meter?

Hello all,

I'm curious about something. I adapted two Leica R lenses using two generic LR-to-PK adapter mounts (bought separately). Then I tried them on some K mount cameras. But none of them would meter with the lenses attached (the "can't meter" lights would flicker on all of the cameras).

1. The cameras will meter and work with native K mount lenses.
2. The cameras will also meter and work with m42 lenses (adapted using both original Pentax and generic adapters).
3. The cameras will even meter with unadapted Nikon mount lenses!
4. The R lenses will meter and work on Canon and Nikon cameras.

I am curious to understand why this happens. Do I need a special kind of mount adapter? Or do K mount cameras just do not meter for lenses with particular types of K mounts (if so, what would that be)?

These are the cameras I have tried the lenses with:
Pentax K-r
Pentax K5
Pentax P30
Pentax MX
Pentax ME Super
Ricoh KR5 Super II

I'd really like to use the 28mm Elmarit on the compact Pentax MX body and 50mm Summicron on the Pentax P30. So I am grateful for any pointers or advice.

Thanks in advance.

06-28-2014, 12:58 PM   #2
Senior Moderator
Loyal Site Supporter
Parallax's Avatar

Join Date: Apr 2008
Location: South Dakota
Photos: Gallery
Posts: 15,621
https://www.pentaxforums.com/forums/58-pentax-beginners-corner-q/110658-using...x-dslrs-f.html
06-28-2014, 01:05 PM   #3
New Member




Join Date: Nov 2012
Posts: 7
Original Poster
Thanks for the link! Now the lenses seem to work on the K5 (well, I set it on A mode, snap a photo and it comes out properly exposed, at any rate). Haven't tried it on the K-r as it's not mine, but as long as it works on my K5 I'm happy.

The lenses are still not metering on the film bodies, though. (There's no "Shoot without lens" menu item to select, hehe).

And the thread I skimmed through doesn't seem to touch on film bodies. Ah well. I'll read through more thoroughly later.
06-28-2014, 02:37 PM   #4
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,233
QuoteOriginally posted by Ruhayat Quote
And the thread I skimmed through doesn't seem to touch on film bodies. Ah well. I'll read through more thoroughly later.
On film bodies, non-Pentax lenses need to have manual aperture diaphragms and aperture rings in order to meter properly (otherwise, the camera will assume wide-open exposure). Stop-down metering is not a supported feature since film bodies weren't "crippled". Then just shoot away in Tv or M mode


Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

06-28-2014, 04:12 PM   #5
New Member




Join Date: Nov 2012
Posts: 7
Original Poster
QuoteOriginally posted by Adam Quote
On film bodies, non-Pentax lenses need to have manual aperture diaphragms and aperture rings in order to meter properly (otherwise, the camera will assume wide-open exposure). Stop-down metering is not a supported feature since film bodies weren't "crippled". Then just shoot away in Tv or M mode
Do you mean they need those pin thingies like on the m42 lenses? Because the Leica R system didn't have autofocus, so all the lenses have manual apertures and aperture rings. On the K5 they work correctly now with aperture priority (and manual, of course). No problems.

The main point is that on the K5 the meter works. On the film bodies the meter won't work, period. It doesn't matter whether I stop down the apertures or not, the LED just blinks the way it does when the camera can't meter.

I have been using the 28mm Elmarit-R on the Pentax MX using Sunny 16 and it exposes according to whatever I set, meaning the lens works on the body and the camera lets in light through the lens. It's just that the built-in meter doesn't function, which is a great incovenience. So it's either Sunny 16 or carrying an external meter (which I don't have).
06-28-2014, 04:14 PM   #6
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 4,863
QuoteOriginally posted by Ruhayat Quote
Thanks for the link! Now the lenses seem to work on the K5 (well, I set it on A mode, snap a photo and it comes out properly exposed, at any rate). Haven't tried it on the K-r as it's not mine, but as long as it works on my K5 I'm happy.

The lenses are still not metering on the film bodies, though. (There's no "Shoot without lens" menu item to select, hehe).

And the thread I skimmed through doesn't seem to touch on film bodies. Ah well. I'll read through more thoroughly later.
The film cameras you list all have a tab in the upper right of the mount that fits into a slot in a real K mount lens. The slot has a corresponding tab that moves with the aperture ring on the lens. When the aperture ring is set to something like f5.6, the camera's tab moves right along with it. The camera's meter reads that tab position so it knows what aperture the lens is set to, while the lens is still wide open on the camera for focusing.

Your LR to K adapter may not be setting this tab correctly. The Pentax M42 to K adapter moves it all the way to one side when the adapter is installed, so the camera's meter thinks the lens is wide open. Then you use stop-down metering on the lens. But if the tab doesn't move, the meter will be wrong.

My theory sounds great except for Nikon lenses work. I don't have any Nikon lenses or batteries to test in my film camera. So it's just an idea.
06-28-2014, 04:30 PM   #7
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,233
QuoteOriginally posted by Ruhayat Quote
Do you mean they need those pin thingies like on the m42 lenses? Because the Leica R system didn't have autofocus, so all the lenses have manual apertures and aperture rings. On the K5 they work correctly now with aperture priority (and manual, of course). No problems.
Basically, the requirement is that the aperture diaphragm needs to close as you turn the aperture ring. If it stays open or is held open by the camera, metering won't work.

Back in the day, for cameras that didn't support open-aperture metering, Takumar lenses had a A/M diaphragm clutch.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

06-28-2014, 04:30 PM   #8
Site Supporter




Join Date: Jun 2011
Location: Texas
Photos: Gallery
Posts: 1,149
Yes - the Leica R lenses will stop down as the aperture ring is moved when on an adapter mount, as there is no camera linkage to open the diaphragm. So it should meter just like an M42 Super Takumar on Manual setting. Don't operate the Depth-of-field preview lever; just set the aperture ring on the desired f-stop. Used that way both my MX and LX will meter properly with these lenses. (If I press the DOF preview lever as I would to stop down a K-mount lens the metering is way off.)
I don't have any Pentax film bodies newer than the LX - so later models could have other issues.
I haven't "Leitaxed" my R lenses as I still shoot them on film with Leica R bodies - which are pretty cheap these days. I plan to get a Sony A7 to use them on digital, rather than adapt them to K mount.

06-28-2014, 04:35 PM   #9
Pentaxian
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,263
Here is a K1000 body with and without the M42 adapter installed. The arrow indicates how the adapter engages the aperture control lever. If the LR to PK adapter does not engage the lever in a similar manner then stop down metering will not work.




The adapter should work in any of the "crippled" autofocus bodies (MZ-30/ZX-30, MZ-50/ZX-50, MZ-60/ZX-60, *ist).
06-29-2014, 04:33 AM   #10
New Member




Join Date: Nov 2012
Posts: 7
Original Poster
QuoteOriginally posted by Not a Number Quote
Here is a K1000 body with and without the M42 adapter installed. The arrow indicates how the adapter engages the aperture control lever. If the LR to PK adapter does not engage the lever in a similar manner then stop down metering will not work.
The adapter should work in any of the "crippled" autofocus bodies (MZ-30/ZX-30, MZ-50/ZX-50, MZ-60/ZX-60, *ist).
I see. I have noticed that tab before and always wondered what it did. Never realised that the original Pentax m42 adapter I have drags it along as it is set in. Heheh.

Thank you all for the info. I will digest this and fiddle around with the film cameras and lenses. If I can finally use the 50mm Cron on Pentax P30 with metering -- better yet, 28mm Elmarit on Pentax ME Super and get an ultra compact, AE point and shoot! -- I would be ecstatic.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
adapter, cameras, leica, lenses, meter, mx, nikon, p30, pentax, pentax help
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
My K-R won't focus amayers3 Pentax K-r 9 09-18-2013 04:41 PM
Why won't my videos transfer!?!?!?! aghostwriter Troubleshooting and Beginner Help 8 01-11-2013 06:23 PM
Dumb Question: Adapted Leica lenses on film bodies? Why not??? DanielT74 Pentax SLR Lens Discussion 10 10-26-2011 12:05 AM
Why won't my lightmeter on my Ashai Pentax 6x7 work? yoav Pentax Medium Format 4 10-21-2011 05:35 PM
Light Meter won't work on my Asahi Pentax KX AnthonyG Troubleshooting and Beginner Help 3 12-04-2009 03:14 PM



All times are GMT -7. The time now is 03:09 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top