Using Older Lenses on the PENTAX K-50
Q: Can I use older PENTAX lenses on my K-50
A: Yes. PENTAX A-series lenses (lenses with an "A" setting on the aperture ring), can be used as manual-focus lenses in all exposure modes on a PENTAX K-50.
Early PENTAX K-series, 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 K.
To set up your PENTAX K-50 to use older PENTAX lenses:
STEP 1: (Customizing the Green Button)
Press the Menu button
Using the 4-way controller on the back of the camera, navigate to E-Dial Programming on pg.4 of the Rec. Mode menu.
Navigate to pg. 2 of the E-Dial Programming menu, highlight the first line and press the right button on the four-way controller. Press the down button to highlight the first line, then press the press the right button on the four-way controller. Press the down arrow on the four-way controller, highlight Tv SHIFT, press the OK button on the back of the camera, then press the MENU button several times to exit the Rec. Mode menu.
(This setting allows easy and accurate exposure metering using older lenses without an "A" setting on the aperture ring. When the camera's 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 2: (Enabling the use of the lens aperture ring)
Press the Menu button
Press the left button on the four-way controller once to get to pg. 4 of the Custom Settings menu.
Press the down button on the four-way controller and select Using Aperture Ring
Press the right button on the four-way controller, then the down button, highlight Enable and press the OK button.
Press the Menu button to exit the Custom Settings menu
STEP 3: (Setting Shake Reduction)
Shake Reduction is compatible with older PENTAX lenses (PENTAX M-series, K-series and Screw-mount lenses) but you will need to manually select the closest matching focal length from the Input Focal Length menu. To do this:
Turn the camera off. Mount the non-"A" series lens. Turn the camera on.
The Input Focal Length screen will appear. Use the rear e-dial to select a focal length which is closest to the focal length of the lens you are using and press the OK button on the back of the camera. If you are using a zoom lens, choose a focal length close to the midpoint of the zoom range of the camera.
STEP 4: (Using Older Lenses)
The camera has now been setup to use older (early K-series and M-series) PENTAX lenses on your K-50. To use these lenses:
a) Set the camera to Manual exposure mode and Manual focus.
b) Focus the lens and set the desired aperture (i.e. f/8) on the lens aperture ring.
Note: PENTAX screw-mount lenses used on the K-50 can be used when the camera is setup as described, however the lens must be manually stopped-down to the selected aperture (stopped-down metering) to obtain an accurate exposure reading.