Page still under development
Using Vintage M42 "K", "M" and "A" lenses on Pentax
3. M42 lenses 1. Overview 2. M lenses
This is the third of three pages in which I try to provide a more comprehensive look at the ins and outs of using vintage lenses on Pentax DSLR's, specifically my K-r, than is currently (AFAIK) available on the web. It was my use of M42 lenses, and my appreciation that the ideal of easy, problem free usage of these lenses hasn't quite been realised by pentax, that has prompted these pages. Page 3 is the discussion of using these lenses with specific reference to the metering and connectivity issues.
Here is my K-r with my Panagor 135mm f2.8 M42 lens, mounted using my Japanese M42 adapter. With this adapter the lens aligns almost exactly.
M Mode
With no mechanical constraint on the aperture, rotating the aperture collar from f2.8 (with the A-M swith on M) closes the iris and the viewfinder gets dimmer and dimmer - it is as per "optical preview" with an "M" lens. Focus then with the A-M switch on A, holding the iris open.
As mentioned on page 2, the painted mount on the lens is non-conducting, with the result that, on my K-r, pressing the green button (or Av) does not produce the sound of the camera stopping (or trying to stop) the lens down. However a shutter speed will be set to match the metering. My practice, and that of most M42 lens users I think, is to make use of the A-M switch. With the aperture ring set on eg f8, having focusssed and composed wide open, flicking from A to M closes the lens down just before metering with the green button and pressing the shutter. These are the results going through the f stops:
using A-M switchA (Av) Mode
Metering issues with M42
K30 K50 comments http://www.pentaxforums.com/forums/120-general-technical-troubleshooting/230750-super-tak-metering-problem.html http://support.pentaximaging.com/node/1 copper wire trick http://www.pentaxforums.com/forums/122-lens-clubs/31601-takumar-club-125.html#post548307
Hacking Electrical Contact
Catch-in Focus
Catch-in focus doesn't work if there is no electrical contact. Even if the focus selector is on AF, the shutter button action defaults to shutter actuation.
Other Models
Other Pages, Threads and Posts on Using M42 Lenses
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