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use of pentax K mount lenses on Pentax K10D

Bob Bates , Feb 29, 2008; 06:14 p.m.


I am thinking of getting a pentax K10D but I already have several Pentax K mount lenses ( including 28mm 50mm 135 and 70-150mm zoom) previously used with a film camera.

Has anyone used K mount film lenses on the K10D?

Would it be sensible just to buy the body to use with the old K mount lenses (allowing for the difference in effective focal length given the smaller sensor)or would I get better results with the 18-45mm digital zoom lens that comes with the K10D kit?

I mostly do landscape, nature (bird) and some portrait photography very much as an amateur.




Ed Nicholson , Feb 29, 2008; 10:04 p.m.

Just slap 'em on and shoot away. Pentax is very proud of the fact that just about all lenses with the Pentax bayonet mount can be used on all bayonet mount Pentax SLRs and DSLRs. Thje only problem is that Pentax M and A lenses won't give you the automatic exposure and focus features. But you can use tham by using the manual controls. Good Shooting!

Danny Schuleman , Feb 29, 2008; 10:15 p.m.

I have used a Pentax *ist DL for a while and have amassed a rather large stockpile of old Pentax lenses. All Pentax A lenses, lenses that on the aperture ring have an A (usually green and past the smallest aperture), will meter perfectly, but not AF. I also have many screw mount Pentax lenses and use them with an adapter. They also meter, even though the exposure isn't always perfect. Have fun with your shooting!

Bob Bates , Mar 01, 2008; 04:30 a.m.


Thanks for the information and reassurance.

Body only it is.



Godfrey DiGiorgi , Mar 01, 2008; 11:05 a.m.


As Danny intimates, all generations of Pentax lenses can be used on the K10D successfully.

All lenses from the Pentax-A series onwards are a no-brainer ... just stick them on, set aperture ring to the A position set camera to Manual Focus, focus, meter and shoot. All the metering options are fully supported, and if you power cycle the camera when you change lenses, it will automatically ask you what focal length for the shake reduction when you power it back on. (You can set it manually too using the menu.)

Prior series K-mount lenses require a little setup and understanding. In the Custom Settings, set the option to permit use of the aperture ring (do this once ... leave it that way). When you fit the lens, set the camera to Manual exposure mode and Manual Focus. Focus, set the aperture you want to use on the lens. Only cw averaging and spot metering modes are available. Frame your subject and press the green button ... the camera will stop the lens down briefly and set an exposure time. When your setting is near wide open, this is pretty accurate, but if you've stopped the lens down a bit you'll learn by experience that it is a bit over-exposed and you'll tweak the setting a bit to compensate. I usually do a test exposure using the digital preview function with the histogram enabled. The camera will also do Av autoexposure mode with these lenses but the lens will *always* remain wide open for the exposure, the aperture setting will be ignored. (The shake reduction setting will be the same as for the A series lenses.

For M42 thread mount lenses, the setup is the same as for the K-mount lenses but the iris is controlled 100% manually. This means that you must set the lens opening to the desired setting with the A-M switch on the lens set to M ... the viewfinder will become dark as you stop the lens down. The upside of this is that if you choose to use Av metering mode, you can use other than wide-open aperture ... the camera knows nothing of the actual lens opening and will just set an exposure time to suit.

The Pentax bodies are quite flexible at this and work well. Many people I know bought their Pentax DSLR bodies exclusively to use the older series Pentax lenses they already had.

The one thing that you should keep in mind, however, is that the DSLRs have a smaller format than 35mm cameras. The sensor is 16x24mm in size, not 24x36, so a 35mm wide angle lens on your Pentax film SLR will be a normal lens on the DSLRs. what this means is that if you want wide angle field of view, you will need to buy a shorter focal length lens. The field of view of that old 28mm lens on your film SLR is pretty close to what you'd get with an 18-20mm focal length lens on the DSLRs. Similarly, what you used to see with a 20mm lens on your film SLR will require a 14mm focal length on the DSLR.


Jeff Polaski , Mar 02, 2008; 05:52 p.m.

Pentax's backward compatibility is unmatched by any other manufacturer.

Pentax-M 200mm f/4 on a K10D

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