50mm f1.4, M or A

Does anyone know which one is of a better quality the pentex 50mm f1.4 M, or the pentex 50mm 1.4 A. I want to buy one, am not looking for a better price. Just the better quality lens. Thank You.

This is a moot point - some might argue that the M lens is slightly better made, having less plastic in its construction. I think the optical cell is exactly the same so the quality should be the same, notwithstanding some variation from example to example.

I would use the A lens by preference if you are going to use it on modern film and digital SLRs. This is because it has the "A" setting needed for full compatibility.

The M lens will fit aesthetically and ergonomically with the M series bodies.

Hi,
I would agree with John. I don't think either performs better optically. In fact, many people consider the 1.7 to have a better optical performance. Even Pentax say that the 1.4 are not very suitable for flat field or macro work. If you need the speed, I prefer the feel and operation of the M's as they feel smoother etc. However, if you need the automatic functions or wish to use it on a crippled mount camera, the A would be better.

Kim

Thank You for the reply. I have a K1000. I just was not sure if there was a big difference in the optical performance. I guess the M would be a better choice, but they are hard to find, even on e-bay, they sell like hot bread.

I have both lenses, and as far as I can tell they are optically the same. The A lens has a metal barrel, but there are electronics in it.

If you have a K-1000, either will do just fine.

There are no "electronics" in the A lenses. Most of the pins either short or insulate the contacts on the body to provide lens information and you can convert a K or M lens to do the same thing. One pin is a switch which tells the camera if the "A" mode has been set.

Kim

Kim, F/FA lenses contain a 'chip' so that suitable cameras know which lens is fitted - the data from my DL tells me that I was using my F35-135 and the exposure settings etc., for example.
Is this not also true for A series lenses? - not that it would matter on a K1000

I don't get that extra info when I'm using A lenses on the *istDS, so I would presume there is no chip in the lenses.

I think I can confirm that John, the only A lenses I have are both 50mm (an F2 and an F1.4) and I've just tried the F2 on my DL.
The information displays as an A series lens but the focal length is blank.
Therefore, in order to get the very best results from Programmed/Auto-pict modes, F or later lenses should be used.

I prefer to select settings manually, particularly when using MF lenses but I must say that the auto modes are pretty fool-proof.
I guess the 'chip' I was referring to was developed for the F lenses and SF series cameras. The SFX has sub-modes that automatically shift as the focal length changes, having never used a Super A or an A series zoom, I thought it may do the same - but obviously not!

Hi,
There is an extra pin used on the later lenses for the extra info. For info on the pins see here http://www.robertstech.com/matrix.htm This shows the extra data pin which is not used on the A's. I have taken of couple of A lenses apart and there is definately no micro circuits in them. F and FA's are different.

Kim