[GibbyTheMole]

So... I have two pristine nifty 50s. A Pentax-A 50 / 1.7, and a Pentax-M 50 / 1.4. Both are cracking good lenses, and I can't see a difference in the IQ. I usually end up using the "A" so I can shoot in Av mode if I want. I'm thinking about selling the M-1.4, but I dunno...

Is there ever an instance where that extra half-stop is a make-or-break thing? The DOF is already razor-thin at f1.7 with loads of creamy bokeh. I would think at 1.4, the DOF would almost be too narrow.

Thoughts?

[jatrax]

No difference for me. If you cannot tell the difference keep the A and sell M.

I have F 50 f/1.4 and F 50 f/1.7. Why? Just because. I honestly do not see any difference. But the design is very different with the 1.7 having a more recessed front element. I'll keep both, but I certainly do not NEED both.

[VisualDarkness]

If you don't need it, you don't need it.

[yusuf]

So... I have two pristine nifty 50s. A Pentax-A 50 / 1.7, and a Pentax-M 50 / 1.4. Both are cracking good lenses, and I can't see a difference in the IQ. I usually end up using the "A" so I can shoot in Av mode if I want. I'm thinking about selling the M-1.4, but I dunno...

Is there ever an instance where that extra half-stop is a make-or-break thing? The DOF is already razor-thin at f1.7 with loads of creamy bokeh. I would think at 1.4, the DOF would almost be too narrow.

Thoughts?

I doubt if you get razor-thin DoF at 50 f1.7 unless you are shooting a small test object. Anyway, I personally found that the 50/1.7 has busier bokeh compared to 50/1.4.

[8540tomg]

Rather like comparing apples and oranges.

Both are great lenses - keep them both.

If you are like me you will regret selling either one.

Tom G

[Kozlok]

The obvious answer is to keep both AND buy an A50/1.4. Might as well pick up an old Takumar 50 while you're at it.

[ismaelg]

I was in the exact same situation a while ago with the A50/1.7 and the M50/1.4
I ended up selling the 1.4. The A setting was the main reason. IQ wise, I prefer the 1.7 just a hint more, but a simple lens hood in the 1.4 would most likely even them out.
I later bought the F50/1.7 for the AF and those are my two favorite lenses.

Thanks,

[robthebloke]

I'd sell the 1.7, get a da50 f1.8, and keep the 1.4 for special occasions (until you can replace it with an fa77!).

The 1.4 has a certain amount of pixie dust for full open portraits that I've only seen bettered by the fa 77. It's not easy to make it shine in that role, but when it does, it's amazing (mind you, the same can be said of the fa77, where you are normally shooting at f4+). I'm surprised you can't see a difference between the two though, at f2.8 the bokeh from the 1.4 is so much smoother than the 1.7 imo (always remember to stop down lenses when comparing bokeh - comparing lenses wide open will skew the results in favour of the worst performer).

Personally, I tend to think:

Fa77 > 1.4 > da1.8 > 1.7

However, I find the da 50 to be the most usable of the lot (the fa is a little too long on apsc in my opinion - but amazing when conditions are right). Some people whine about the da50 being soft, although tbh, on my k5 it's just as sharp as my fa77. There may be a difference on the k3, or maybe some sample variation, so ymmv.

---------- Post added 08-02-14 at 12:52 AM ----------

Fwiw, the 1.4 comes into its own in low light portraits, especially in night clubs. Yeah you could take a flash, but that loses the ambience imo.

[GibbyTheMole]

Eh... I'll probably hang onto both of them for now. They're not big money lenses, anyway.

[Not a Number]

I have both an A f1.7 and an A f1.4. I thought about selling the f1.7 but after reading the manual for the Pentax Auto Bellows A they do not recommend the f1.4 and f1.2 50mm lenses for macro work. It probably doesn't matter because of the crop factor but I may as well keep the f1.7.

[stevebrot]

Is there ever an instance where that extra half-stop is a make-or-break thing? The DOF is already razor-thin at f1.7 with loads of creamy bokeh. I would think at 1.4, the DOF would almost be too narrow.

I dunno. You own both lenses and should be in the position to tell. Probably the biggest thing in favor of the M 50/1.4 is its build quality relative to the A 50/1.7. If your A 50/1.7 does not already suffer from a damaged aperture mechanism (mine does), it will most assuredly develop the problem due to poor choice of materials. This is not an issue unless you want full usability with a body lacking the "A" contacts.

I'd sell the 1.7, get a da50 f1.8

I guess it depends on how the A 50/1.7 is being used. Mine spends most of its time on my Super Program film SLR. I own both lenses and am also not so sure that the DA 50/1.8 is a step up in quality or usability on Super Program or on the K-3*. At this point, it is highly likely that I will sell the DA 50/1.8.

BTW...my assessment of pixie dust for the lenses I own goes like this:

FA 77/1.8 >> KMZ Helios 44M 58/2 with everything else being pretty much lacking of the glittery stuff.


Steve

* An assessment of the DA 50/1.8 on the Super Program will be done at some point. I just have not gotten around to it.

[GibbyTheMole]

Probably the biggest thing in favor of the M 50/1.4 is its build quality relative to the A 50/1.7. If your A 50/1.7 does not already suffer from a damaged aperture mechanism (mine does), it will most assuredly develop the problem due to poor choice of materials. This is not an issue unless you want full usability with a body lacking the "A" contacts.

Not an issue, since I leave it in 'A" & use it exclusively on a DSLR.

KMZ Helios 44M 58/2

I may pick one of these up. The unique bokeh looks intriguing. Plus, I kinda have a thing for old Russian lenses.

[gaweidert]

I have several 50/55mm primes accumulated over the years. All manual focus. My 55mm F1.8 SMC screw mount lens is downright awesome. I have a 50mm F1.4 F lens that is also very good. Even my Ricoh 50mm f.20 Rikenon P lens rates right up there too. This lens is almost a pancake lens it is so thin. Love them all. I have not tested my Mamiya Sekor 50mm screw mount lens as of yet,

I am being greedy and keeping all of them.

[jatrax]

If your A 50/1.7 does not already suffer from a damaged aperture mechanism (mine does), it will most assuredly develop the problem due to poor choice of materials. This is not an issue unless you want full usability with a body lacking the "A" contacts.

First I've heard of this, but by a coincidence I've just come into possession of an A 50 f/1.7 that has something wrong with the aperture ring. The ring only moves between f/5.6 and f/11. Is there a way to get it to move to 'A'? I only have digital bodies so manual aperture is not an issue. I'll keep it if I can get it to 'A'. It came free with some other stuff so I'm not out either way, just hate to see gear not able to be used.

[stevebrot]

First I've heard of this, but by a coincidence I've just come into possession of an A 50 f/1.7 that has something wrong with the aperture ring. The ring only moves between f/5.6 and f/11. Is there a way to get it to move to 'A'? I only have digital bodies so manual aperture is not an issue. I'll keep it if I can get it to 'A'. It came free with some other stuff so I'm not out either way, just hate to see gear not able to be used.

It is a very common problem with the A 50/1.7 and evidence of just how inexperienced the camera makers were when they first started adding plastic to their lens construction.

There is a description somewhere on this site detailing how to resolve the jam. I think it may have been posted by just1moredave. The short description is that a plastic part in the click-stop mechanism becomes brittle with age, breaks off and jams the works. The fix involves disassembly of the rear of the lens and repair of the broken mechanism.


Steve

---------- Post added 08-02-14 at 05:44 PM ----------

Found it!

https://www.pentaxforums.com/forums/114-maintenance-repair-articles/88051-pen...ng-repair.html

Note the several pages of discussion following. The risk of lost parts is significant.


Steve