50mm Primes f2

Hi,

I've just got a 50mm Pentax-A f2 lens at a good deal. Is there much difference between this and the f1.7 version. Is it worthwhile still looking for the f1.7 as well?

Dan

The number of times you will use f1.7 doesn't warrant buying it. There is only one third stop in light gathering power.

Awww.... now you've done it! Everyone's going to go for the cheaper F2's on ebay and they won't be cheap any more, aarggghhhh!

Phew, just got mine in time then I got the Pentax-M version, but the A version is definitely more useful on a K digital.

The 1.7s are fetching well over their value on fleabay, IMHO. Either way, really happy with my f2, really sharp

One recent Fleabayer claimed the 2.0 was sharper and more contrasty than the faster versions. Is there any truth to this? I've not seen the claim made elsewhere. Most people think/assume the 1.7 is generally better, not just faster.

Compared to the A 1.7, the A 2.0 has five elements instead of six, making it cheaper to make and 20 grams lighter.

An item can't get over its value, by the way. If someone's prepared to pay a price, that price is the current value! Lens values fluctuate.

Interesting, but I've never owned both concurrently so couldn't say. Anyone got both?

I have an M f/1.7, M f/2 and a A f/1.4 but I have never formally compared them. I could if anyone is interested enough. Well formally in the sense of taking the same picture with different lenses that is.

Cheers, Kris.

Could be a moderately interesting exercise when the weather's too lousy to partake of your favourite kind of photography. If only to satisfy curiosity.

I have used all three in most versions. The f/1.7 is the best of the bunch optically and much more useful when abused with close up lenses, bellows and the like.

The f/1.4 is very contrasty and suits reportage very well, but has lower resolution so if it's fine detail you're after it's not the best choice. It's great for gritty, low light shots on Kodak Tri-X.

The f/2 is an excellent design but doesn't seem to have quite the same quality control so I've had good ones and not so good ones. A good one would be just about the same as the f/1.7 version.

The M and A series lenses seem to have a different "quality" of image than the SMC Takumar and K lenses. The older lenses have a very classical sort of feel to them, but gain their best performance at more like f/8 or f/11. The later lenses peak at around f/5.6 to f/8 and have a more "modern" more contrasty style.

The "quality" comment refers to that hard to describe overall optical quality that leads people to discuss the merits of German lenses as compared to Japanese ones.

Womble, I would be interested if it's not too much trouble to see the 2 and 1.7 compared.

Comparisons at f2, f4 and f5.6 would be most useful, I think.

Gotta be really careful each lens is focused accurately because the tiniest focusing error would dwarf any inherent difference.

That's fabulous, you really get to know your lenses, don't you John?

They are all good friends, but I'm not quite so sad as to give them names!

Here's a site with some resolution tests

The A f/2 is a very good at f/8 and beyond, personally I
wouldn't think they were quite that good.
The A series are better than the M series although my
f/1.7 A is miles in front of my M lens of which I have 2.

These seem to averages of up to 5 lenses.

I'm surprised at the results of the 50mm f/2.8 Macro, but
he only tested one sample and it would have been at 55x
= 2.75m probably not the best for a Macro. Still at f/5.6
it's only equaled by the 50mm A f/1.4. The latter seems to be
the one to go for if you want to shoot at f/2.8. I'll have to
compare that against the original 35-70mm MEF Zoom at 50mm
because that was razor sharp at f/2.8 and didn't improve on
stopping down, probably because it was the first AF lens it
had to be at it's best wide open.

Another site

Here the smc PENTAX-FA 50mm f/2.8 macro (FA50/2.8macro, #3709***)
thrashes everything.

shim