Using Older Lenses on Pentax K10D, K200D, K20D
Q: Can I use older Pentax lenses on my Pentax DSLR?
Pentax A-series lenses (with an "A" setting on the aperture ring), can be used as manual-focus lenses in all exposure modes on a Pentax DSLR.
Pentax K-mount, M-series and S (screw) mount lenses without auto-aperture control (an “A” setting on the aperture ring) can be used in Manual exposure mode using stop-down metering and manual focus. This is the exposure mode which will give accurate exposures when using these older lenses on our digital SLRs. If older lenses without an "A" setting on the aperture ring are used in Av (Aperture Priority) Mode, an exposure error may occur.
Note: Using Pentax S (screw) mount lenses on a Pentax DSLR requires the use of a Pentax Mount Adapter B.
To set up your Pentax K10D, K200D or K20D to use older Pentax lenses:
Press the Menu button
Go to Custom Settings
Step down to Green button in TAv & M (K10D/K20D).
Step down to Green button in Manual (K200D)
Press the right arrow and select Tv Shift
(This setting allows easy and accurate exposure metering using older lenses without an "A" setting on the aperture ring. When the Green button is pressed in Manual exposure mode, the lens "stops down", the camera's meter measures the light passing through the lens, and an appropriate shutter speed is automatically set based on that measurement).
Step down to Preview Method
Press the right arrow and select Optical Preview
(This setting enables the camera to "stop down" the lens to a selected aperture when the On/Off button is rotated clocwise).
Step down to Using aperture ring
Press the right arrow and select Permitted
(This setting allows the camera to operate with older K-mount or S-mount lenses that do not have an “A” setting on the aperture ring).
If Shake Reduction is enabled when using an older lens, you will need to manually select the closest matching focal length from the Shake Reduction (K10D) or Input Focal Length (K20D/K200D) menu. Press the Menu button, step down to Shake Reduction (K10D) or Input Focal Length (K20D/K200D) then press the right arrow. Scroll left and right to select the closest match for the focal length lens you are using. Press OK, then Menu.