First, read the brief description of the
SMC Correction Lens Adapters in our own Accessories Forum, this
Marketplace Listing or the
K-Mount page. Click the thumbnails for a larger image.
There were basically three versions made:
- A rubber eyecup for the pre-Spotmatic and Spotmatic bodies. You had an optometrist grind a glass correction lens and inserted it into the eyecup assembly, then attached the eyecupo to the viewfinder frame;
- Plastic framed attachments for the VF frame that came with pre-ground correction diopters in increments of 1 from -5 to +3. These were initially sized to fit all the bodies through the K-series. These are marked with the correction in white.
- When Pentax introduced the smaller M-series bodies they slightly enlarged the viewfnder frame, so they changed the Correction Lens Adapters to fit. These are marked on the inside (rear)of the frame with an embossed "M" inside a small circular depression. They are marked with the correction in white in 7 diopters, -5 to +2.
- This latest version will fit all Pentax bodies since the M-series, including the dSLR's
If you don't go to an optometrist I suggest you start now if you are using reading glasses, if only to have a glaucoma exam. You will also learn the proper correction for your current vision.
Since these are vintage items you basically wait until the right one comes along and bid what you are willing to pay (or get in the first PM here
). I had a +1 for the K bodies for sale here recently, and have a K -1 and a -3 for the M bodies. I use +2 and have several.
Nikon still makes them, and they fit the M bodies such as your cameras - that is an easier solution. They're often found on ebay but you can get them in a camera store.