DXO test some Pentax Lenses

Picked up on these tests by DXO on the 15mm, 21mm, 70mm & 40mm lenses.

link

I have the 21mm and 70mm lenses and am more than happy with them.

Best regards

I must say that I am very surprised to see the rather negative comments on the 15 and 21mm. Both seem to me to be exceptionally sharp on my K5 and I do not recall photozone complaining about their resolution. Maybe one should not take these lab tests too seriously - after all the 18-135 was slated by photozone and yet the other forum is full of people singing its praises.

I agree - the DXO 'scores' do seem odd when compared to other tests (eg. the 40 produced high and even resolution from wide open in the Photozone test) and user feedback. I have the 15, 21 and 70 and have been very happy with the images produced by all three.

I'm taking a days holiday tomorrow to test my new DA 21mm Ltd in good light(fingers crossed), hopefully I'll be able to post some real-life images to prove the DXO scores wrong

I wonder if some of the testing is a bit careless. There is a sentence which reads:
The link here goes to the DA 15mm review, not the 14mm.

The test results are only as good as the person doing the test, and if the camera used has an issue, such as back focussing the results will all be skewed. I'm not saying that is the case but it is odd the results differ so much to other test results. However test results are not everything unless taking pictures of test charts is your thing!

In the 70mm test is the strange statement:

The lens is what it is therefore that is a somewhat naive comment. Surely a larger aperture = a larger lens so it's no longer a pancake! I never thought of f2.4 being slow in any event.

John

DxO lens tests are known to be a bit strange and Gary likes
to have a dig at Pentax every now and then

I would just ignore them

I've thought I'd have a quick look at the 21mm review but when I saw in the 'Lens Use Case Scores' it had the 21mm down as 'not applicable' for a travel lens I think I'm going to just ignore the reviews

As a user of the Pentax brand owning multiple bodies and a large range of Pentax lenses including two in the DXO test, I fail to see it as a dig. For sure, Pentax fan boys won't like the results from DXO unless it the one about the K5 sensor where it was the best print on a web page.

I am, as I said, happy with my 21mm and 70mm yet you don't seem to accept others point of view or findings.

We could introduce a forum rule where nothing negative about Pentax can be mentioned or posted and you can be in charge of retribution to the unfaithful or those wandering from the chosen path.

I keep an open mind Algi and use whatever equipment I see fit for purpose and hence use more than two systems. There is no harm in discussing any points or reviews of Pentax equipment. If one is a sole Pentax user who is also blinkered and deaf then so be it. Long live the fan boys. Where would the photographic community be without them.

21mm K7







Best regards

It's all a bit too clinical for me, if it was 'DXO Photography' doing a review I might take a bit more notice, I like to see a few photos taken with the lens and not just graphs and numbers.

I suppose if you are happy with your glass then these results aren't very important.

There are no tested lenses form Pentax that score well. I'm not going to lose any sleep over it though. I personally think these test are given a little too much credence as the real world use of these lenses is rather removed from the testing environment.

What tends to get ignored in reviews is that lenses have a character and are intended for particular applications. Unfortunately, even the lens makers don't really come forwards and explain what that application might be for a particular lens.

So, a portrait lens might be softer wide open and critically sharp when stopped down. A macro lens we assume is critically sharp from the start and also has a flat field for copying purposes. An architecture lens should be as near rectilinear as possible. And so on.

My 18-135mm, for example, has high MTF20 scores and lower MTF50 scores, and sure enough it has wiry, contrasty detail, but a macro lens it isn't. If you read some tests you wouldn't buy it, but if you are aware of its characteristics it might suite you very well.

The 70mm Limited is a lovely portrait lens, just the right length and with beautiful rendering. I'm not too concerned about how it reproduces test charts....

I think the results (for the 15mm) are fairly predictable. The lens suffers in edge quality at f4 and slightly less so at f5.6. The centre is always sharp though, and at f8 the sharpness evens out across the frame. Fortunately f8 is a very reasonable aperture to use with such a lens! All the other reviews have taken this into account, and given credit for the small size of the lens, and it's lovely contrast and colours, and referred to real life shooting, but DXO seems to have more of a rigid test procedure.

They are right about the CA of the DA15mm - easily removed but a bit disappointing to have it there in a prime.

My problem is that the DXO assessment doesn't seem to reflect either my experience of the lenses I have or the testing/user feedback I have seen for all the lenses.

For example, they complain about the resolution of the DA15, yet in my experience it is brutally sharp when stopped down (probably even sharper than the DA12-24, which is always praised for this characteristic) - a fact widely observed by both users and reviewers. With the DA40 they complain about lack of sharpness wide open - and yet this is directly contradicted by Photozone test results and by photos I have seen and by user feedback. I don't think you have to be a Pentax fanboy to wonder how DXO came to their conclusions?

But of course the bottom line is that mille19 and Jon are right - the test results only give you some idea about how a lens will perform in real life. The DA21 is a case in point - for a prime it generally gets lukewarm reviews. Vignetting, distortion, softness wide open are all problems. However, despite these failings, in practice it does produce very nice images.

It's not about proving measured values wrong. The results are the product of testing with specialist equipment. It's more about the final image and the image quality perceived.

I can take most lenses in my collection and specifically shoot an ideal subject and get the best from the lens and that is what it is all about. Knowing your glass well enough to use it at it's best.

At the time I bought the 21mm, it was a gift for some one. I was impressed enough to buy another. Have I been disappointed with it - not in any way. It's a cracking street optic with a FOV of a 31mm. Would I like it faster - no as I have other faster glass to shoot in the dark, something a rarely do.

Best regards

There are loads of threads on the other forum and also on Zeiss
forums criticising DXO's lens testing. This one is current about the
DA40 f/2.8 LTD link
It seems the DXO tests contradict Photozones and SLRGears tests.

Maybe if it had had Nikon stamped on it it would have done
better

Gary the two 21mm photos you posted look fine