Confused over lens naming

Hi All
I'm really confused at the moment over the naming of Pentax lenses and what the codes mean.
Essentially when I'm looking at older manual focus lenses I can't work out which ones have the "A" button to lock the aperture into auto. I know I am supposed to be able to use any pentax K mount (or M42 with adapter) in manual mode but I'd rather not have to worry about the lense appeture when I can set it on the camera (if that makes sense)
In the same vein - did pentax make a 40mm pancake with thos auto apeture facility?
Thanks
Donut

SMC Pentax (with no suffix) were the original K mount names and are commonly referred to as 'K' series lenses. Then came SMC Pentax-M, -A, -F, -FA, -FAJ, -DA, -D FA, -DA L.

'K' series & -M lenses have no 'A' setting on the aperture ring.

-A, -F, -FA, & -D FA lenses have the 'A' setting on the aperture ring.

-FAJ, -DA, & -DA L lenses have no aperture ring at all.

Lenses up to and including -A are manual focus. The rest are auto focus.

There are * and non-SMC derivatives of various ranges also but the aperture ring usage is as per the other lenses.

Only -M and -DA 40mm Pancake's exist as far as I know.

You'd do well to get to know this site.

Wow, that was quick, thanks Mannesty - I'll take a look at the site in the link
Donut

Peter just about sums it up,

when you're looking at older Pentax glass, this site also comes in handy

http://stans-photography.info/