[WorksAsIntended]

Come on... have you ever seen a Pentax 50mm lens (f/1.7, f/1.4 or f/1.2) that wasn't biting sharp from f/4 and smaller? in the case of the f/1.4 and f/1.7 they're very cheap - I have an M 50 1.4 that I've been trying to sell for months for 50 dollars and haven't had a single offer. M 50 1.7 lenses sell for 30 dollars these days. That is obviously cheap, and that glass is obviously sharp. Sharper than the FA 28-70mm f4, for sure - so to me it's quite obvoius that the OP is doing something wrong.

At f4 in center surely, but the FA 50 1.4 between 1.4 and 2.8 ist soft enough to bother me from time to time and I use my lenses regulary at apertures wider than 4.
The DFA on the other hand is a monster in sharpness (and size), way sharper than what I would consider good enough to not bother me.

I still use both (and a M50), because of the differences in size. I would not mind to have something in between those two, sharper and bigger as FA, but softer and smaller than DFA. I would propably sell both in this case.

[stevebrot]

The proof of the pudding is in the eating and it one can't get good results with non-modern kit, probably best to stay with more technically advanced gear. For my part, I seem to be doing pretty well with my vintage stuff. Those lenses form the core of what I use for serious work.


Steve

[UncleVanya]

The FA* 80-200 beat my DA* 200 on digital for fringing and such. Sharpness was identical.
The A* 85 f/1.4 was a monster. Hard to focus for me but superbly sharp when right - even close to or wide open.
The 70-210 A is remarkably good but hard to use without a tripod (push pull zooms are hard to use on digital for me due to difficulty focusing quickly).
A50 f1.7 and F50 f1.7 are excellent. Sharper earlier than fa 50 1.4 but not too much earlier. (f2.8 looks as sharp edge to edge as f4 on the 1.4) after f4 they are similar with a nod going to the f1.4 lens. Mind you the soft results at f1.4 can be good for some faces on digital on apsc.
Takumar Bayonet 135 f2.5 is known for a bit of softness by reputation but actual testing shows it is pretty good. LIkely the coatings aren't giving quite the contrast people want to see in some shots. oddly the Takumar Bayonet 135 f2.8 has been shown in some tests to exceed all other 135mm Pentax lenses (not including the A* which was not tested in that comparison).

On the other hand:
FA 80-320 -OK but inferior to the DA 55-300 particularly flare and contrast and fringing.
FA 35-135 - Needs a hood (as does the one above) and is soft soft soft wide open.
FA 28-200 - Soft 18-300 variants and 18-270 are much better if using apsc.
etc.

[stevebrot]

F F1.4/50mm - this autofocus lens should focus reasonably well, but shots made wide open through f2.8 may show a lot of softness compared to the DFA 50 1.4. The lens will also show larger vignetting and ca/fringing. However it should be sharp at higher 5.6 or so.

I have heard this claim before and while I haven't shot with the lenses in question (A 50/1.4, F 50/1.4, FA 50/1.4) all evidence is that they are the same optically and should have similar vignette, ca/fringing, and resolution allowing for sample variation. If there is any huge difference, it might be when compared to their f/1.7 stablemates.


Steve

[stevebrot]

i had a Tak 5mm f1.4 and a Helios 58mm f2, they are not famous for sharpness but rather smooth bokeh

If your Helios 58/2 is not center sharp at all apertures, there is something wrong with the lens. Mine are amazing.


Steve

[WorksAsIntended]

I have heard this claim before and while I haven't shot with the lenses in question (A 50/1.4, F 50/1.4, FA 50/1.4) all evidence is that they are the same optically and should have similar vignette, ca/fringing, and resolution allowing for sample variation. If there is any huge difference, it might be when compared to their f/1.7 stablemates.


Steve

He compared the F to the DFA and they surely not share much of the same formula.

[stevebrot]

Unless you use the general rule that older primes are usually good (at least the ones from the big camera manufacturers) while the zooms are typically bad?

It depends on the lenses for both cases and also what one means by "older". That said it is a pretty safe bet that almost any zoom made prior to the mid-to-late 1970s will likely disappoint and that zoom quality, even to the present, remains spotty at lower price points. There is at least one current model Pentax zoom that I won't buy nor recommend.


Steve

[stevebrot]

The 70-210 A is remarkably good

I concur. In many ways it is a standout performer in its zoom range.


Steve

[pschlute]

They are soft, very soft I would say. A professional photographer once told me that they are all designed for film camera's and that it is a problem to adjust digital camera's, that is the sensors, to that old glass

When I do dog portraits, my go-to lens is a near 30 year old film era portrait lens, the FA* 85mm f1.4.

What do you think ?...........

[aslyfox]

sample images, with EXIF data included would help, but good glass is always good glass...

admittedly I am no expert

but I am very satisfied with my " legacy " primes

[Kerrowdown]

Is old glass really that good on DSLR

Well my "Ladies" are still producing perfectly acceptable results... well no clients found fault so far.

[kernos]

No one defined old so let me take a shot. So for purposes of discussion, I'm saying that old is before 1990. Given that I'd say good old lenses can be better than modern glass because of aesthetic effect that has only a passing relationship to sharpness. If you look at British TV period pieces like Downton Abbey, there is also an atmosphere. Its not particularly sharp, but it has an effect. So here's a wide open shot at 1.2 from a 50 year old lens. It is not sharp. You might not like it, but it does have an atmosphere that transcends a recording of reality. That's the main people folks use old lenses, for that spark of something different.

[MossyRocks]

When I do dog portraits, my go-to lens is a near 30 year old film era portrait lens, the FA* 85mm f1.4.

Those * lenses are in a whole different class but if showing off what those exceptional legacy lenses can do I offer up a sample of the SMC A* 400mm f/2.8 ED [IF] can do when pointed up:

[Apet-Sure]

I'll throw a couple ideas into the mix not mentioned so far:

1. Some 'old' glass does not report its focal length to the camera. If SR is turned on and not set to the lens' focal length, the camera may be introducing blurriness by moving the sensor in an inappropriate way for the lens that is mounted.

2. One issue that came up with the introduction of digital sensors was that their surface was more reflective than film emulsion. The sensors could reflect light back onto the rear element of the lens, impairing image quality. Modern lenses have an anti-reflective coating on the rear element to deal with this. Some (most?) film era lenses do not.

I got my M50/f1.7 lens when I bought an ME Super back in the day. (One of the best 'kit' lenses ever!) Is it sharp? You judge:
K10D with M50/f1.7 on short extension tube. This... - Apet-Sure's Album: Nature-K10D - PentaxForums.com

[aslyfox]

I'll throw a couple ideas into the mix not mentioned so far:

1. Some 'old' glass does not report its focal length to the camera. If SR is turned on and not set to the lens' focal length, the camera may be introducing blurriness by moving the sensor in an inappropriate way for the lens that is mounted. . . .

if you are using an zoom lens and have to set the SR setting manually, what you select is what is reported in the EXIF data