What to do.

Hi all, got some old Pentax primes,all M's
f3.5 28mm
f1.7 50mm
f3.5 135mm
f4. 200mm
f4 50mm macro
thinking of selling the 28mm & 50mm, would I notice a big difference if I got a couple of A's or should I leave things as they are.
thanks for your time

You don't say what camera you intend using them on. I have some of th eM primes you mention and they are fully manual on my K10D, though the 135mm is a fantastic lens and using the green button at your selected apature does set the shutter speed. A lenses allow for the use of Av mode and does provide lens info for exif data.

I use them on k100d, but I want to upgrade later in the year.
thanks

Hi Dtours, many of the M and A series lenses were optically identical so you'll notice no difference in image quality (the M's are generally considered to be better built, the A's certainly more convenient when used on a modern body). If you go to the K-mount bible at Bojidar Dimitrov's site you can cross reference optical designs to see if you're getting like-for-like.

Welcome to the forum by the way

The normal 50mm primes are the same design whether they are "A" or "M" so optically it shouldn't make a difference.

There is no "A" 28mm F3.5, this lens is often regarded as ultra sharp but I found it hard to focus.

There is no "A" 135mm F3.5, this is a very good lens and the "A" 135mm F2.8 is supposed to be garbage, one of the worst Pentax ever made so I'd keep the "M".

The 50mm macros are of completely different designs. personally I'd go for the "A" version as it's F2.8 (easier to focus) and more convenient to use.

The "A" and "M" 200mm lenses are I believe the same, the "M" is certainly a very good lens so the "a" would only be more convenient.

Thanks for that guys,I was in two minds what to do, I think I'll keep what I have,