[westmill]

I think photozone gave it a fantastic review. Even got the rare green thumbs up.
It seems to peak at a low F4 for cental quality and 5.6 for edge quality which I think is
perfect. Slower lenses are easier to design, so although slow, genraly offer high image
quality. For a fast lens this is as good as they get.

[VisualDarkness]

Yeah, it's like this post I made:

Well, it's good right from the start but maybe sacrifices some top peaks instead. They are praising the Bokeh as unusually good and that's an accomplishment.

A lens that puts everything in the biggest apertures and sacrifices the rest: Leica D Summilux 25mm f/1.4 - Review / Test Report - Analysis

Also consider that 31mm is 4mm shorter than the 35/2.4, without loosing MTF. The 31mm is more comparable to Sigma 30/1.4 and well it's not even a close game: Sigma AF 30mm f/1.4 EX DC (Pentax K) Review / Test Report - Analysis

[Asha]

I came to Pentax and the K-5 rather recently...now I have the kit lens, DA21, FA43 and DA70. The kit lens actually got a decent review, and had some good image quality test results (MTF, chromatic aberration, distortion). However, images shot with that lens consistently disappoint. When I put the FA43 on for the first time, I could see a major improvement overall. The DA70 is also superb, but a less useful FL for me. The DA21 is a super useful FL, but overall is the least good of my primes. Having said that, the center sharpness of the DA21 still beats the kit lens.

So, my point is that the kit lens test results do seem to mislead in terms of overall performance...and if I had used those results as my only indicator, I would have missed out on an amazing lens (FA43).

[vrrattko]

Even if it were true that the FA Ltds were outdated, it would not explain a shift of peak performance of the 31/1.9 in a retest. It would not explain a drop in border performance of the 43/1.9 either. Something is going on with the photozone retests and Klaus does not appear to have the answers himself.

Well, that new review seems to be morec onsistent with the one on LensTip....but somehow I think the both reviewers got something wrong. By just comparing my landscape photos I'm pretty sure that fa43 pulls more detail in corners than fa31, when stopped down. No way that corners in MTF are so low as Photozone suggested....they would be at least equal to those of FA31 from f2.8. Maybe they just tested a faulty lens, i don't know.

[lytrytyr]

However, if lenses like the FA 31/1.8 receive 4/5 then one wonders what lenses will get a rating closer to 5. Maybe a boring macro lens?

You can scan Klaus' reviews to find examples.
The ZF100/2 Makro-Planar (on Nikon D3x), for instance,
which natively isn't quite macro, and is anything but boring.

Summary ratings are always problematic, but I do not think that degrading the FA 31/1.8's rating from 4.5/5 to 4/5 makes sense, if one considers the reputation of the lens with experienced photographers.

Many lenses were downgraded when tested on denser sensors,
which makes sense when they were designed for less demanding media like film.

Maybe other lenses I do not know of have surpassed the 31/1.8 and are more deserving of a 4.5/5 or even 5/5.

The DA 70 gets a "4 to 4.5" on the K5, which I consider to be reasonable based on my own experience with it.

[twitch]

DA70 seems to hold the unofficial mantle of being Pentax's best lens based on technical measurements.

[Class A]

The ZF100/2 Makro-Planar (on Nikon D3x), for instance,
which natively isn't quite macro, and is anything but boring.

A Makro-Planar that isn't a macro...

Many lenses were downgraded when tested on denser sensors, which makes sense when they were designed for less demanding media like film.

You are suggesting that the "denser" sensors outresolve the FA Ltds. They don't, at least not in regions of the image that matter for most photography applications.

The DA 70 gets a "4 to 4.5" on the K5, which I consider to be reasonable based on my own experience with it.

If a DA 70 is rated higher than a 31/1.8 then so be it. For me personally it means that I have to ignore the ratings.

[lytrytyr]

A Makro-Planar that isn't a macro...

There's no doubt that it's a macro lens
(see my sample on https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/36041-zeiss-zk...ml#post1929395),
just not in its native mount without extension.

You are suggesting that the "denser" sensors outresolve the FA Ltds. They don't, at least not in regions of the image that matter for most photography applications.

I am suggesting that it makes sense for Klaus to rate older lenses lower on the K5 than on the K10D,
if those older lenses do not meet the demands of the newer sensor.
I would certainly not like to generalize about which regions of an image a photographer should use.
Some people make portraits, some people make landscapes, . . .

If a DA 70 is rated higher than a 31/1.8 then so be it. For me personally it means that I have to ignore the ratings.

I don't think you have to ignore the ratings.
As others have pointed out, they are just one piece of a mosaic of information
that it is sensible to weigh when you are making a major purchasing decision.
I chose to buy the DA 35 Ltd Macro despite Photozone's rather lukewarm review of it on the K10D.

[Class A]

There's no doubt that it's a macro lens

I didn't dispute that. You did.
Clearly it is a macro lens by design and I just wanted to question the reservation you added about it not being a real macro lens (natively). I was right that a macro lens would have a good chance to get a 5/5 and you confirmed it but saw the need to add some reservation. I didn't get that.

if those older lenses do not meet the demands of the newer sensor.

Yes, "if". Please do not think that a 16MP sensor creates a demand that FA Ltds cannot meet. It is not even close to doing so.

BTW, the FA Ltds weren't sharper on film. They weren't sharper on a K10D either. Yet now they just got worse? Is this Klaus' way of admitting that his way of using the K10D (with its asymmetrical AA filter) produced measuring artefacts which yielded inflated results? Or does it say anywhere on PZ that due to increased sensor resolution, ratings had to be recalibrated? That wouldn't make sense, anyhow.

I would certainly not like to generalize about which regions of an image a photographer should use.

I wrote "most" applications. Which other genre outside landscapes requires high performance corners (which typically sacrifice some centre performance)? Copy work, what else?

I don't think you have to ignore the ratings.

I don't have to.
But I choose to.

[lytrytyr]

Which other genre outside landscapes requires high performance corners (which typically sacrifice some centre performance)? Copy work, what else?

Architecture, group portraits, some kinds of reportage, technical photography, . . .

[Laurentiu Cristofor]

DA70 seems to hold the unofficial mantle of being Pentax's best lens based on technical measurements.

Did you know that the best ranked Pentax lens on dxomark is the DA 35/2.4 lens? Sharper than the DA 70 Limited according to their tests. Unfortunately, they only tested a handful of Pentax lenses, but the results are interesting to check.

[selar]

Did you know that the best ranked Pentax lens on dxomark is the DA 35/2.4 lens

That would make sense, it is the newest lens design in production.

[Blue]

Some people seem to discover the fact that sensors do play a role in the camera output just as much as a lens. The fact is, the 31 & 43 Limiteds are designed for film and are getting hammered on a 16MP sensor by DA Limited lenses designed for digital (DA 35 & DA 40). I expect the same will go for the FA 77 on a K5. The DA 70mm will best it on edge performance.

Photozone downgraded the DA 40 LTD from a recommended status since the did the re-test on the K-5. Of course it is only a 3 year newer design than the FA 31 LTD. However, Photozone gives the FA 31 ltd a thumbs up and recommended status. It is one of the few Pentax lens that currently has the thumbs up from them. The DA 70, DA* 60-250 are the other 2 although the FA 50 says its recommended, it lacks the thumbs up symbol.

[selar]

Wow, photozone is such a powerful site! It can make or break used lens values.

[Rondec]

Photozone downgraded the DA 40 LTD from a recommended status since the did the re-test on the K-5. Of course it is only a 3 year newer design than the FA 31 LTD. However, Photozone gives the FA 31 ltd a thumbs up and recommended status. It is one of the few Pentax lens that currently has the thumbs up from them. The DA 70, DA* 60-250 are the other 2 although the FA 50 says its recommended, it lacks the thumbs up symbol.

It doesn't look to me like they downgraded. It never had "highly recommended" written beside it, I guess because it is only f2.8 and Klaus likes faster lenses. It still gets 4 stars for optical quality and price/performance and 4.5 for mechanical quality. Pretty good in my book if it's the sort of lens you are interested in.

As to other's comments about "older designs" and "designed for film," most of the lenses out there from all lens makers, have their roots in film. The DA 35 f2.4 is a little up date of the FA 35. No one really knows how much coatings have improved over the years, but this is really the biggest difference and while it have some significance, the FA limiteds have a very modern design with fairly new coatings. I think issues in the most recent tests probably have to do more with a poor copy of the lens being tested than anything else.