[lukelbd]

I'm looking to get a fast, cheap, autofocus 50mm prime for portraits and such, and can't decide between the first, second, and third generation of AF 50mm pentax lenses (I didn't even know the F-series existed before I began researching this; this article I found on the subject is interesting).

I initially was set on the 50mm/1.4 for which I have already found several used deals at $225-250. But I know from photozone and several user reviews that it gets rather soft wide open and increases slowly to its peak sharpness at f/5.6; but of course, this kind of lens will be used very much at wide apertures! I've begun to rule out the 50mm/1.8 because it's slightly slower, pretty much the same price (the used market for this lens is a lot less variable because it is a more recent model), and the bokeh/chromab according to pentaxforums is not as good -- but I'm open to hearing your opinion. Now the 50mm/1.7 seems perfect, but it's pretty rare and I don't know where to find any relevant evaluations of its performance. However, I have read many subjective reviews on pentaxforums claiming it to be tack sharp even wide open, which is a very exciting prospect!

What do you think? And does anyone on here have experience with the elusive F 50/1.7?

PS: I also noticed that a Pentax F 50mm f/1.4 exists, but I'm under the impression that it's about the same optics as the FA 50mm f/1.4 -- correct me if I'm wrong. It also seems to be more rare than the f/1.7.

[jimby]

Get the FA 50mm F1.4. Dreamy and a little soft wide open and tack sharp starting at F2. You have the most versatility with this lens. Sometimes you want dreamy.

[Boker]

The FA 50 1.4 can still be had new and KEH usually has both the 1.7 and 1.4 in stock and some go threw the buy-sell trade section of this site.

[lukelbd]

Well I just found this thread: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/81528-fa50mm-f...mm-f1-7-a.html

And I see now that there is an FA version of the f/1.7 (but I'm assured now that the F and FA are optically exactly the same, and mechanically just a matter of preference). The f/1.7 seems to be significantly sharper than the f/1.4 -- so I guess the only advantage of the f/1.4 is that half-stop, which I consider pretty insignificant.

[jimby]

Sharpness is not everything. The FA 50mm F1.4 is sharp enough though. The bokeh is really good, and that extra half stop comes in handy.

Shot at 50mm f1.4.


100% detail at F1.4.

[Docrwm]

The 1.4 and 1.7 have different designs with the 1.7's front element significantly more recesed thereby giving it a permanent hood. The 1.4 benefits significantly from a hood because of its exposed front element. If you get a 1.4 you really must use a hood to get the most out of it.

[EarlVonTapia]

Sharpness is not everything. The FA 50mm F1.4 is sharp enough though. The bokeh is really good, and that extra half stop comes in handy.

Shot at 50mm f1.4.

WOW




Is that a Houndstooth blazer?

[frank]

Whoever says FA50/1.4 is soft wide open should try it on the new K5IIs. It's tack sharp even wide open, at least my copy is

[DSims]

My FA50/1.7 was slightly better than my F50/1.7, and my F50/1.4 was a little better than both of them. This is also the overall consensus amongst other Pentaxians, if you thoroughly read the comments and reviews.

However, the FA43 is significantly better than all of them, if it's within your budget. I sold all my AF 50's after I bought it.

The A50/1.7 is actually your best value here, if you don't need AF. I haven't used the DA50/1.8, so I can't comment on it.


But none of the AF 50's is tack sharp wide open - not even the DA*55 is, and it's by far the best of the bunch (but it sure comes close, being tack sharp around f/1.6 or 1.8!).

(incidentally, my K-5 IIs creates sharper photos from most of my lenses, but it doesn't produce miracles)

[pinholecam]

To me this is a myth.
Partly propagated because the F50/1.7 was in the past much cheaper than the recent FA50/1.4 price.
So many gave it high praises.
I've tried all the A and M 50s.
With a deep hood, they were all so close to be splitting hairs.

I find that the FA50/1.4 is not soft wide open.
Often its either lack of contrast (no hood or challenging condition) or poor focus due to shallow DOF.
Unfortunately for the latter, I personally find that the AF is not precise enough to be tack accurate most of the time.
Manually focus with time or on LVAF or LFMF, the FA50/1.4 is certain pretty sharp wide open.

[snake]

To me this is a myth.
Partly propagated because the F50/1.7 was in the past much cheaper than the recent FA50/1.4 price.
So many gave it high praises.
I've tried all the A and M 50s.
With a deep hood, they were all so close to be splitting hairs.

I find that the FA50/1.4 is not soft wide open.
Often its either lack of contrast (no hood or challenging condition) or poor focus due to shallow DOF.
Unfortunately for the latter, I personally find that the AF is not precise enough to be tack accurate most of the time.
Manually focus with time or on LVAF or LFMF, the FA50/1.4 is certain pretty sharp wide open.

I have the f50 1.7 and tried the fa50 1.4. I prefer the 1.7 due to being sharp wide open and insanely sharp at f2.2 It's also my fastest and most accurate focusing lens, in all conditions.

You raise the point that the 1.4 gets slammed only because it's more expensive than the 1.7. I can assure you that for the prices the 1.7 versions go for here, one could easily jump to the 1.4, even as new.

You are dead on about the point about the lens hood- I found, as written in the reviews, that the 1.4 benefits hugely from a hood. It's not up to the aggressive sharpness of the 1.7, but they're not far off. Colors and contrast mostly improve.

Where the 1.7 gets me is that it's sharp from wide open, without fuss. I don't use it with a hood, which preserves the compactness. The front element is recessed, so it looks as if no hood is truly needed, though I've used one just to see and saw no difference. For my money, the 1.7, with its faster focusing, lack of a need for a hood, and compact dimensions without the hood do it for me.

However, it's in a range that I rarely use, but for concert shoots, when I am on the stage with the performers, it becomes invaluable.

[creampuff]

Whoever says FA50/1.4 is soft wide open should try it on the new K5IIs. It's tack sharp even wide open, at least my copy is

+1.
Most lenses of mine see a definite improvement with the K-5IIs.
A little off topic but the 50mm lens that is uber sharp even at f/1.4 is... wait for it... the Sigma 50mm f/1.4 HSM. The center sharpness is just astounding...

The Pentax 50mm Lens Thread - Page 3

[creampuff]

To me this is a myth.
Partly propagated because the F50/1.7 was in the past much cheaper than the recent FA50/1.4 price.
So many gave it high praises.
I've tried all the A and M 50s.
With a deep hood, they were all so close to be splitting hairs.

I find that the FA50/1.4 is not soft wide open.
Often its either lack of contrast (no hood or challenging condition) or poor focus due to shallow DOF.
Unfortunately for the latter, I personally find that the AF is not precise enough to be tack accurate most of the time.
Manually focus with time or on LVAF or LFMF, the FA50/1.4 is certain pretty sharp wide open.

So true. Owned a few copies of the FA 50mm f/1.4 and have to say that the lens delivers good performance particularly with a deep hood. I actually prefer the f/1.4 to the f/1.7, particularly where bokeh is concerned.

[jimby]

WOW

Is that a Houndstooth blazer?

Why, yes it is.

And I always use a lens hood on the FA 50mm F1.4.

[lukelbd]

Well after more research I've only reinforced what I initially thought -- which is that the f/1.7 lens is sharper than the f/1.4 lens.

I'm not sure how so many people in this thread find the FA/1.4 to be better than the FA/1.7, but would urge posters to speak objectively rather than defensively and subjectively. Given the comparisons I found in the thread I linked above, and given the reviews I've found of the optics of the FA/1.4, I don't see how it would be possible that the FA/1.4 is "sharper." The photo posted above only reinforces this -- I see a failed attempt to compensate for very poor sharpness with software and terrible purple fringing. Also, lens hoods may increase contrast (which if post-processed is a non-issue), but certainly not sharpness.

And here are the reviews I found:
Pentax SMC-FA 50mm f/1.4 - Review / Lab Test Report - Analysis & Verdict
Pentax smc FA 50mm 1:1.4 review: Digital Photography Review

You'll notice that the reviews are perfectly consistent with each other. I know some people are going to have a problem with this, but I find it hard to believe after thousands of lens reviews that either dpreview or photozone are fundamentally screwing up their sharpness tests.

My FA50/1.7 was slightly better than my F50/1.7, and my F50/1.4 was a little better than both of them. This is also the overall consensus amongst other Pentaxians, if you thoroughly read the comments and reviews.

I had thought the F versions were the same optically as the FA; this is incorrect?

+1.
Most lenses of mine see a definite improvement with the K-5IIs.
A little off topic but the 50mm lens that is uber sharp even at f/1.4 is... wait for it... the Sigma 50mm f/1.4 HSM. The center sharpness is just astounding...

The Pentax 50mm Lens Thread - Page 3

Yep, I've read the reviews of the Sigma 50mm. However for me, one of the biggest points of having a prime lens, aside from being fast and sharp, is that it should be small!