[Nuff]

I own both the 20mm f1.7 on e-p1 and 31mm limited on k5. And all I can say that the 20mm doesn't compare, I've owned it for 2 years and the images don't produce the pop the 31mm manges or any of the limited lenses for that matter. It is a good lens, one of the better primes on m43. It's very sharp, but to me I wouldn't say it's appealing or there's something special about it. As a matter of fact I've sold the 20mm + e-p1 a week ago. I've just stopped using it after getting 31mm. Also 31mm is far from small, since it's my largest lens.

[chickenandavocado]

Yikes the FA31 is not over rated, it has a big reputation here but it deserves every bit of it and more. It's hands down the best lens I've ever had the pleasure to use, the best amongst this not-so-shabby group anyway.



Indeed, on film it is fantastic and I can't imagine it losing any magic on FF digital.

great lens pron

you have way too many nice pentax primes

how do you decide what to use and what gets the least usage?

for me i couldnt justify having 15 / 21/ 31/ 40 / 55 / 70 and had to break up my kit as i just ended up using 31 and 15 all the time

[twitch]

great lens pron

you have way too many nice pentax primes

how do you decide what to use and what gets the least usage?

for me i couldnt justify having 15 / 21/ 31/ 40 / 55 / 70 and had to break up my kit as i just ended up using 31 and 15 all the time

I know what you mean, I need to make some hard decisions this year.

[br.davidson]

@Nuff: Thanks for the insight from someone who owns (owned) both lenses. The problem I've had is that I've stopped carrying my entire Pentax kit (K-7 + DA15, DA35, FA50) after getting the GF2 and 20mm. The week I spent with the FA31 was enough to convince me that it's earned its reputation, though.

[Nuff]

I think it's case of different strokes for different folks. I can't really put it into words why, but 31mm appeals to me a lot. For some reason I choose it 60% of the time over the other 4 limited I have and I've to say I like all of them for different reasons. And I pretty much know for what subjects I will use specific lens.

I also had Pana 14mm f2.5 prime and I hated it! I had to do a lot of PS on this photos to even become half decent. I kind of liked Pana 7-14mm, but I just didn't spend enough time on the wide end to justify keeping it. It was useful and fun, just not used frequently enough.

[chickenandavocado]

2 things you ignore. the apsc options will have significantly better high iso performance. the second is DOF possibility. a 31 1.8 is more like a 20 1.2 in m4/3 from this characteristic.
there is also in apsc the option of the Sigma 30 1.4 which by all accounts is a very standout lens at a much lower price

excellent point above

and to put it in FF terms and subject isolation for dof, 20mm f1.7 in m4/3 = 40 f3.4 in FF equivalent, whilst fa31 f1.8 on aps-c ~ approx 47 f 2.8 ...

and if put on an FF camera: fa 31 f1.8 = 31 1.8 whilst the 20 f1.7 = 40 3.4 with a massive black circle

[JoostW]

No-one is going to argue against Zeiss, but what does this mean exactly? In what way is the FA 31 Limited over-rated?

In my opinion the FA 31mm limited is not the most sharp lens wide open. Sure that can be QC, since it was a vietnam assembled piece, not sure. In general i am pleased with my DA limiteds, but was not with the FA 31mm. The CZ screams quality all over. The build quality (japan build and human tested) as well as the IQ wide open.

Bokeh is more subjective, but both lenses perform above par in that department.

Since both lenses are in the same range in prize, i just believe the CZ is the better choice if you dont mind about AF that much.

[rparmar]

In my opinion the FA 31mm limited is not the most sharp lens wide open.

In my opinion, this sort of pixel counting doesn't matter much. Near as I can tell from published figures, the Zeiss wide is sharper than the FA Limited by a small factor in the centre, but is likewise duller at the borders. The overall consistency in detail goes to Pentax. And remember we're comparing f/2 to f/1.8. The Limited gets better even stopped down to f/2 (where testing is generally not done).

But all of this is nitpicking between two excellent levels of optical performance.

Sure that can be QC, since it was a vietnam assembled piece, not sure.

That's basically bias, since no-one has produced any evidence that this results in a poorer lens. I recall that "made in Japan" was once a sign of cheap quality crap, when the dominant ideology was bias against the Japanese (some call this racism). Likewise, assembling a lens in Germany does not necessarily make it better. It's all about the quality of the assembly. You take Zeiss at their word when they say each piece is hand-checked etc. but don't do the same for the Pentax Limiteds. I wonder why this discrepancy?

I look forward to using a 35mm Ziess lens, but wouldn't settle for the Distagon 35mm ZK. It is known to be notably inferior to the Biogon-T 35 ZM or even the C-Biogon 35 ZM, which has the bonus of being very compact. The Distagon ZK is a honking huge monster that does not accord with the form factor most of us are interested in.

[lytrytyr]

You take Zeiss at their word when they say each piece is hand-checked etc. but don't do the same for the Pentax Limiteds. I wonder why this discrepancy?

Because Zeiss provide the customer with legal documentation, a signed inspection report. Pentax don't.

I look forward to using a 35mm Ziess lens, but wouldn't settle for the Distagon 35mm ZK. It is known to be notably inferior to the Biogon-T 35 ZM or even the C-Biogon 35 ZM, which has the bonus of being very compact.

Of course rangefinder lenses are more compact than telecentric SLR lenses.
That's why I never got a 35mm lens for film use on my LX,
using a Summicron on an M2 body instead.
The body with lens occupied the same bag space
that a 35/2 reflex lens would have occupied.

But on what basis do you claim that the ZK is "notably inferior"?

The Distagon ZK is a honking huge monster that does not accord with the form factor most of us are interested in.

The ZK 35/2 is 65x97mm, no wider and not much longer than an FA 31
once you've got an effective APS-C hood arrangement on it.

[rparmar]

Because Zeiss provide the customer with legal documentation, a signed inspection report. Pentax don't.

Good point. Pentax are inane at actually communicating with their customers. They put ASPH glass in lenses and don't tell us. They make focus improvements in firmware and don't tell us. I honestly don't know what their problem is!

Bur, paradoxically, this very fact, along with what I can see and feel for myself regarding the construction of their lenses, lends credence to their claims. We wouldn't expect signed forms from Pentax, so the lack of these does not raise any alarms.

Of course rangefinder lenses are more compact than telecentric SLR lenses.

Of course. But beyond this fact, Zeiss produce larger lenses than are necessary, precisely because they don't prioritise physical size as a design constrain. This is well known. Their rangefinder lenses are bigger than equivalent Leica lenses and ditto on the SLR front. The lens in question is larger than the FA31 Limited even though the latter has aperture circuitry and coupling, auto-focus, and is a tad faster. So, if anything the Zeiss should be smaller.

As a point of fact, I was comparing the C-Biogon 2.8/35mm at 200g and 30mm long to the Biogon-T 2/35mm at 240g and 68mm. The Distagon 2/35mm ZK at 530g and 97mm is too large no matter how you slice it. FWIW, I think the FA 31 Limited is too big as well, out of line with its siblings.

The C- lenses show that Zeiss can produce small glass with a one-stop light penalty. I wish they did so more often.

But on what basis do you claim that the ZK is "notably inferior"?

I am very interested in Zeiss since I like the rendering (similar to Pentax, IMO) and have good memories of their Contax lenses. So I did a fair (some would say "obsessive") amount of reading, even though I cannot afford any such items. I haven't tracked all of this, but recall that the Biogon-T has a flatter field, is sharper in the corners and has less distortion at close focal ranges. The C-Biogon has even nicer bokeh and is said to be "probably the only 35mm Zeiss with no faults". That could have been Erwin Puts, Michael Holve, or someone on the rangefinder forum.

It is now entirely possible to compare all these lenses on the same mirrorless camera. Someone with access to a rental company and the discipline to do so would provide some interesting food for thought, but unfortunately I don't rate the cheerleader-style bloggers who have so far made an attempt.

[lytrytyr]

Bur, paradoxically, this very fact, along with what I can see and feel for myself regarding the construction of their lenses, lends credence to their claims. We wouldn't expect signed forms from Pentax, so the lack of these does not raise any alarms.

They used to put the little gold sticker on their lenses, but no longer do.
I don't have total confidence in the construction of Pentax lenses,
following reports of DA Ltd lenses separating
(a whole thread on the French Pentax forum for the DA21),
and wobbles in the double internal barrel construction of the FA31.

The lens in question is larger than the FA31 Limited even though the latter has aperture circuitry and coupling, auto-focus, and is a tad faster. So, if anything the Zeiss should be smaller.

The ZK35/2 is a lot smaller than the Z* (not ZK) and Samyang 35/1.4 lenses.
It does have aperture circuitry, and a solid manual focus helicoid
does not make a lens smaller than one with screwdrive AF.

The Distagon 2/35mm ZK at 530g and 97mm is too large no matter how you slice it. FWIW, I think the FA 31 Limited is too big as well, out of line with its siblings.

I do appreciate compactness, but in deciding to purchase the ZK35/2,
I found its "excellent" center and "very good" edges at f/2 (using Photozone terminology)
to make it worth the bulk for my own needs.

The C- lenses show that Zeiss can produce small glass with a one-stop light penalty. I wish they did so more often.

For a small 35/2.8, I'm very happy with the DA 35 Ltd.

I am very interested in Zeiss since I like the rendering (similar to Pentax, IMO) and have good memories of their Contax lenses. So I did a fair (some would say "obsessive") amount of reading, even though I cannot afford any such items. I haven't tracked all of this, but recall that the Biogon-T has a flatter field, is sharper in the corners and has less distortion at close focal ranges.

Symmetrical Gauss designs certainly have intrinsic advantages,
but it seems that the size and complications of the Distagon 35/2
have evened out the balance.

It is now entirely possible to compare all these lenses on the same mirrorless camera.

This issue has just arisen on a parallel thread:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/179589-31ltd-v...rsion-1-a.html
However, the short-register rangefinder lenses do require angled sensor wells for optimum performance,
like the Ricoh GXR Leica M mountor.

[rparmar]

I don't have total confidence in the construction of Pentax lenses, following reports of DA Ltd lenses separating
(a whole thread on the French Pentax forum for the DA21),
and wobbles in the double internal barrel construction of the FA31.

Oh please. If you're going to resort to this, I can quote endlessly from Leicaphiles denigrating the poor quality of Zeiss lenses, their sloppy focus rings, poorer build, etc.

Got a bad copy? Send it back. End of story.

And don't expect a cheap consumer lens (DA21) to perform the same as something that costs five or ten times as much. In the meantime the FA Limiteds (the only Pentax lenses I was referring to, not the DA Limiteds) have stood the test of time "quite" well. As in, they rock everything else.

[rparmar]

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/179589-31ltd-v...rsion-1-a.html
However, the short-register rangefinder lenses do require angled sensor wells for optimum performance, like the Ricoh GXR Leica M mountor.

That thread indicates the Pentax lens is superior, which wouldn't surprise me since every knowledgeable M-mount review I've found has noted the inferiority of Voigtlander to Leica. (I have found fewer comparing to Zeiss, but since I prefer Zeiss rendering...)

With my limited practical experience I would be content to say the best ($4K price range) Leica lenses, the Zeiss, and the best of Pentax are in the top class. Only niggles separate them.

But since I much prefer the FA43 and FA77 to the FA31 I'll bow out of a discussion in which I appear to be defending a lens I didn't even bother buying. As soon as someone gifts me a couple grand I'll get back to you on the merits of Zeiss M-mount glass, since I certainly would be buying. In the meantime, I can take the photos I want with what I have.

Which really is what it should all be about. And to patch up some of the damage I have done obsessing, here's a photograph.

[lytrytyr]

Oh please. If you're going to resort to this, I can quote endlessly from Leicaphiles denigrating the poor quality of Zeiss lenses, their sloppy focus rings, poorer build, etc.

Got a bad copy? Send it back. End of story.

And don't expect a cheap consumer lens (DA21) to perform the same as something that costs five or ten times as much.

Regarding the build quality of the modern Zeiss DSLR lenses,
I consider their performance in Lensrental's repair statistics to be a significant indicator.
I've only been using them myself for less than a year,
so get back to me in two decades for a personal assessment.

Apropos Leica, after three decades of hard use,
the focus helicoid of my Summicron 35/2 is a little sloppy.

I have been using Pentax lenses for more than forty years,
and have had excellent experience with M42 and M lenses.
As for the DA Limiteds, I would not describe them as "cheap consumer lenses."
The two I bought each cost about half as much as a Zeiss ZK lens.
Based on the user experiences that I referred to,
and the lack of a commitment on the part of Pentax
comparable to the Zeiss inspection/rejection procedure,
I would estimate my confidence in them (using the DA 15 and DA 35 Macro)
as higher than for a plastic DA lens, but, as I said, not total.

Not sure to what the gratuitous "if you're going to resort to this" is meant to refer.
I am trying to reach objective assessments of quality,
and have no interest in fanboy legends.

[lytrytyr]

That thread indicates the Pentax lens is superior

It indicates that a telecentric SLR lens does better on a "flat" sensor
than a short-register rangefinder lens.
Which is why Leica and Ricoh use special microlenses
in sensors designed to work with rangefinder lenses.