Using Older Lenses with the PENTAX K-7
Q: Can I use older PENTAX lenses on my K-7?
A: Yes. 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 K-7.
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 the K-7. 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 K.
To set up your PENTAX K-7 to use older PENTAX lenses:
Press the Menu button to enter the Rec. Mode menu.
Rotate the rear E-dial to step over to page 3.
Make sure the box for Digital Preview is not checked. Press the OK button.
(This setting enables Optical Preview which allows the camera to "stop down" the lens to a selected aperture when the On/Off button is rotated clocwise).
Rotate the rear E-dial to step over to page 4 in the Custom Setting menu.
Use the four-way controller and step down to Green button in TAv & M (setting #28).
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).
Turn the rear E-dial and select page 6 in the Custom Setting menu.
Step down to Using aperture ring (setting #37)
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 Input Focal Length menu. Press the Menu button to enter the Rec. Mode Menu. Use the four-way controller and step over to page 4 of the menu and step down to Input Focal Length. Use the rear E-dial to scroll left and right to select the closest match for the focal length lens you are using. Press OK, then Menu.
(This setting optimizes Shake Reduction to match the focal length of the lens in use).