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03-06-2018, 12:26 AM   #3076
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QuoteOriginally posted by FantasticMrFox Quote
My SMC-A 50 f/1.7 doesn't caaare.
The wisdom of age?

03-06-2018, 02:52 AM - 1 Like   #3077
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QuoteOriginally posted by ffking Quote
The wisdom of age?
Nope, my DA 50 f/1.8 doesn't care either. Must be something else
03-06-2018, 06:42 AM - 1 Like   #3078
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Photozone tests of the 31 ltd @ 10 MP
Max. resolution at ƒ4 2345 lw/ph. (Line widths per pixel hight) or how many distinct lines can the lens and sensor reproduce.



At 16 MP. 2596


The increase is about 250 lwph based on 6 more MP. That's about a 14% increase.

At 10 MP you have 243.5 lw/ph per MP.
At 16 MO you have 162.5 lw/ph per MP

So one thing that is happening is the law of diminishing returns. 50% more pixels... 15% more resolution.

How is it on Nikon with more modern glass. I use Nikon because they use similar sensors.

Well how about this guy.. released in 2010.


At 16 MP Nikkor AF-S 24mm f/1.4 G ED = 2883 lw/ph
At 24 MP Nikkor AF-S 24mm f/1.4 G ED = 3704 lw/ph (tested on the D7200) Nikkor AF-S 24mm f/1.8 G ED (DX) - Review / Test Report - Analysis


50% more MP, 28% improvement which is close to the expected ratio of pixel lines to actual resolution.... twice as much as the 31 ltd. Modern glass vs. film era glass.

Th point that most people have lots of resolution with what they have for what they do, just means this isn't the lens for them. But there will be people who want the extra resolution. Whether or not the same kinds of results will be evident from any of the coming Pentax gear remains to be seen. But at least Pentax is acknowledging there is better than what they are releasing. Although, the Nikon is a $2000 lens. Pentax's foray into high end glass is really a pretty bold gamble given their market share.

The interesting thing right now, is the numbers suggest (even if they can't definitely confirm) I could get more resolution out of a D7200 and 24mm, than I could out of a K-1 and any current 35mm Pentax out there. Hopefully the "new spec" Pentax lenses will address that.

But for those of us who don't print larger than 16 x 20, or who view most off our images on electronic devices. on a regular basis, it's just not an important issue.

Last edited by normhead; 03-06-2018 at 08:31 AM.
03-06-2018, 07:40 AM - 1 Like   #3079
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QuoteOriginally posted by normhead Quote
Pentax's foray into high end glass is really a pretty bold gamble given their market share.
Once again, this sort of supports the idea that they've licenced the design to Tokina - that would potentially provide quite a bit extra revenue to offset development costs

03-06-2018, 08:03 AM - 1 Like   #3080
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QuoteOriginally posted by ffking Quote
Once again, this sort of supports the idea that they've licenced the design to Tokina - that would potentially provide quite a bit extra revenue to offset development costs
Now with this new era of 1st party cooperation, maybe we can see some of the holes filled in the Pentax wide angle lineup...like a 16-35 f4, 14mm prime, 24mm prime, and 35mm prime. Its already super exciting to have full HSS support for studio strobes in the near future.
03-06-2018, 11:57 AM   #3081
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QuoteOriginally posted by normhead Quote
Pentax's foray into high end glass is really a pretty bold gamble given their market share.
Always the story of "how expensive lenses draw customer to a brand".

Canon, Nikon, Sony, sell boatload of cheap entry camera because people think "well, i ca go to Full Frame and that expensive lenses if i progress, huh".

There is zero rational in this thinking, only emotions.

But that's what draw customers to a brand
03-06-2018, 12:39 PM - 1 Like   #3082
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QuoteOriginally posted by normhead Quote
Photozone tests of the 31 ltd @ 10 MP.
Are you sure this test can be taken seriously?
03-06-2018, 01:41 PM   #3083
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QuoteOriginally posted by kjames5 Quote
As an Imaging Ambassador for Ricoh Pentax USA, I'm currently testing the new K-1 MkII, and they also sent me the new 50mm F1.4 DFA*. Here are 2 images to take a peek at, saved at 8 X 12, 300 dpi, and Level 10 JPG. These are Unsharpened, FYI. (NOTE, they appear unnaturally dark on the PF website, and the color is off too, sorry).

Attached are the exposure data for each image, a sunrise at Bryce Canyon on March 1, and an arch in the Grand Staircase Escalante on February 28.

Both were shot with the K-1 Mk II, and I'll post more images taken with that, soon.

Kerrick James
Nice images. I guess the big thing that stands out to me is the flare resistance in the first image. The DA *55 would have flared a bunch more than that...

03-06-2018, 02:40 PM   #3084
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QuoteOriginally posted by kjames5 Quote
(NOTE, they appear unnaturally dark on the PF website, and the color is off too, sorry).
A bit OT here, but I suppose you are working in ProPhoto RGB colour space. The images you posted are untagged so they are rendered in sRGB. If you assign a ProPhoto RGB profile they look much nicer and less dark.
03-07-2018, 08:12 AM   #3085
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QuoteOriginally posted by Pål Jensen Quote
Are you sure this test can be taken seriously?
Given that this is the website that originally trashed my DA 18-135, and then watched every other website including this one join in the charge, I don't take them very seriously.

The problem being there are no other websites I take more seriously.

Which is why I said
QuoteOriginally posted by normhead Quote
is the numbers suggest (even if they can't definitely confirm)
. This is a case of too little information. But I have to say, the fact that camera manufacturers release lw/ph numbers based on the lens designs, not actual performance and that there is no standard test lab where these kinds of things can be confirmed. I'd argue that at the moment it's the best we have.

That being said, I've always been suspicious of the 16 MP 31ltd. test. I just can't prove it's wrong. Sometimes you go with what you know. What put me on to this was Kenspo's statement about needing modern glass for modern sensors. As a good spokesman for the brand, I've been trying to unpack that. Pentax isn't going to say the limiteds suck, and they don't. Their rendering is fantastic.But if you need really high res, maybe they aren't the correct choice.

I'm just trying to make sense of the old "Lenses for the way people take pictures, not for the test charts" as opposed to the new "modern glass for modern sensors" The only way that makes sense to me is if they are going for both rendering and test charts, as if they might not be mutually exclusive as the old motto would suggest.

I don't know what the DFA 28-105 would test as on the charts, but compare to my 7 or 8 other non DA+ zooms, it's the sharpest, it has 3d rendering, and overall, it renders better than even my beloved 18-135. Personally I think Pentax has turned a page, and it will be good for those who can afford it. The big question now is , will the clearly heavy investment in development of probably pretty slow selling lenses, kill the company, before they see the fruits of their labours?

I wish the first wasn't a 50. And I wish they could show me, it's similar to the Nikon 24, in terms of giving APS-c better resolution than I can currently get on my K-1. And also confirm what the resolution will be like on the K-1. The camera industry habit of releasing the specs the lens was designed to rather than measurements of actual lenses as at photozone is really irritating.

It's like someone coming to clean the snow your drive, calculating how many cubic feet of snow there are, reading the stats on how much snow the snow blower can throw and hour. Working for an hour and claiming according to spec, your driveway is clean, when it's like to be less than 2/3 done.

I'm the kind of guy that says, "If I pay you to clean my driveway, clean my driveway. I don't care how much cubic feet of snow there is, I don't care how many cubic feet an hour your snow blower is rated for, I'm paying you to clean the driveway. You're not done until it's clean."

Last edited by normhead; 03-07-2018 at 10:06 AM.
03-07-2018, 09:44 AM   #3086
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I suspect some of these tests are done with AF. The AF system cannot discriminate between 2347 and 3211 l/mm.
03-07-2018, 09:54 AM   #3087
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Photozone/Optical Limits tests are done AFAIK with manual focus and several attempts (I remember reading how they found even manual focus to be somewhat imprecise).
The results are not comparable between systems (also due to the different processing applied). And Klaus doesn't seems to have any plans for resuming K-mount tests
03-07-2018, 10:02 AM   #3088
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I've long found it a little concerning that the camera used is relevant to the results obtained - it does tend to favour newer lenses, as they are usually tested on the most up to date camera at the time of testing
03-07-2018, 10:03 AM   #3089
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The tests are not written in scientific terms. It would be written like 3200 +/-50 if it were. That tells you something. In other words they never measured their measuring.
03-07-2018, 10:13 AM   #3090
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QuoteOriginally posted by ffking Quote
I've long found it a little concerning that the camera used is relevant to the results obtained - it does tend to favour newer lenses, as they are usually tested on the most up to date camera at the time of testing
No kidding, lw/ph should be a neutral cross platform measurement. The differences from site to site and the evolution of testing methods over the years, with changes in the software used for evaluation etc. make it all worthless.

For example Imaging resources changed their lighting on test subjects a few years ago. Results before the change are not directly comparable to results after the lighting change. There just is no reliable test site. Part of that is sample deviation, part of that is different people interpreting the test standards different ways.

All you can do is look for clues. The above posted material is speculation based on perhaps faulty data. I personally think Klaus dropped his 31 ltd. after he tested it at 10 MP before he test it on the K-5. But Can't prove that.

Yet, I still prefer speculation based on data that might be faulty compared to speculation based on no data at all. "I like this lens better" could be based on so many different things, it's kind of a last resort if I can't find anything else.

Based on the clues I'm expecting a big price, a huge resolution increase, and a more modern interpretation of whatever formula Pentax uses to compromise between absolute sharpness and other rendering properties.

Last edited by normhead; 03-07-2018 at 10:24 AM.
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