[RobA_Oz]

You'll be able to generate it, Rob, just choose your scene. It's like sunflare in any lens - shoot the right scene and it'll be there!

What serious testers would do is measure CA in a RAW file for the same scene and compare it across brands, but that's beyond DPR. Quite frankly, they know their audience is not up to scientific rigour and fairness, it's all about page views and click-throughs to sponsored Amazon products.

From all other accounts, I know it’d be there in the right circumstances, and I have shot a few contre-jour photos just to test it, but I have to say it hasn’t been so prominent that I noticed it, clackers. I guess I just don’t take the right sort of photos.

But, yes: I agree it’s unfair that DPR essentially discriminated against this very fine lens, by comparison with its treatment of others.

---------- Post added 3rd May 2019 at 03:17 PM ----------

I’ve had mine since the very first day and though I’m not a very good photographer I know enough to know I’ve never seen LoCA with my copy. I even fooled around with chain link fences.

The innocent explanation is an institutional case of Confirmation Bias. The malevolent explanation is intentional Othering to bond their members. Pentax is the ‘Other” brand that unites everyone else as NOT-Pentax; IOW not the Other. The technique of forming a large group out of competing interest groups by Othering a single universally-demeaned Identity group was pioneered by Saul Alinsky in Rules for Redicals.

I like Alinsky’s Rules that say “never allow your group outside of its field of expertise” and “always attack your enemy outside their field of expertise”, or words to that effect. We seem to be dealing with those situations here. Most professions base their rules of conduct on the former. Sun Tszu would have appreciated both sentiments.

I guess I’m a natural Other.

---

Last edited by RobA_Oz; 05-02-2019 at 10:18 PM.

[Wheatfield]

Three days with my copy, and I still haven’t seen what they’re talking about.

I think you will have to work really, really hard if you want to. If you look at their test, it is pretty obvious that they worked a lot harder with the Pentax lens than they do with those from other companies to get their results.

[gazonk]

My DA70 shows pretty strong LoCA on some occasions. I can’t remember that it has ever ruined any important shot, though. Instead, the lens is a real gem that delivers stunning sharpness even at large apertures and beautiful OOF rendering :-)

[RobA_Oz]

I think you will have to work really, really hard if you want to. If you look at their test, it is pretty obvious that they worked a lot harder with the Pentax lens than they do with those from other companies to get their results.

Come on. I’ve retired. I don’t do that stuff any more...

[beholder3]

Any imperfections can be highlighted at will.

LoCA require very strong black/white contrasts or light reflexions like silver metal surfaces in the sun.

But then you have to take authors opinions into account:
That is the Sigma 50 Art (Barney Brittons view on this is: "The Sigma 50mm F1.4 actually does not have significant LoCA; all but absent "):

https://www.cameralabs.com/wp-content/uploads/reviews/Sigma_50mm_f1-4_DG_HSM...loCA_79058.jpg
and this as well
https://c2.staticflickr.com/4/3856/14400872360_203e736c81_b.jpg
also see clacker's sample files above:
https://www.pentaxforums.com/forums/attachments/16-pentax-news-rumors/450243...ns-capture.jpg
and
https://www.pentaxforums.com/forums/attachments/16-pentax-news-rumors/450244...ns-capture.jpg

So the above is not significant.

And by contrast this here "is Noticeable LoCA at wide/medium apertures" and "Second, there's the pesky issue of longitudinal chromatic aberration, which - where you see it - is pretty hard to ignore":
https://www.dpreview.com/files/p/articles/1148307569/CA/F1p4_ACR.jpeg

That is SCIENZE. Um. Or so. Mumble.

[Rondec]

I just studied e photozine's comments on both the Sigma Art 50 and the Pentax DFA *50. They do indicate a bit more chromatic aberration with the Pentax than with the Sigma -- about a quarter pixel on the edges with the Sigma and around half a pixel to three quarters of a pixel on the edges (depending on the aperture). This certainly doesn't seem to be a deal breaker.

On the other hand, what is more important is that the Pentax kills the Sigma at wide apertures when it comes to border performance. The Pentax up to f4 seems to have significantly better performance than the Sigma. To me, this is the sort of thing that is important to mention. 'x' lens will give significantly better border sharpness between f1.4 and f4 but, has .25 more pixels of CA. Part of the problem here is that DP Review while "scientific" doesn't shoot test charts and put numbers on things. I'm not a big fan of test charts, but they certainly do let you know how lenses will perform at given apertures and can allow comparison of lens performance in a way that real world images can't particularly do.

This is why real review sites like photozone/optical limits and ephotozine actually shoot test charts as well as real world scenes and post the results of both.

[Wheatfield]

I just studied e photozine's comments on both the Sigma Art 50 and the Pentax DFA *50. They do indicate a bit more chromatic aberration with the Pentax than with the Sigma -- about a quarter pixel on the edges with the Sigma and around half a pixel to three quarters of a pixel on the edges (depending on the aperture). This certainly doesn't seem to be a deal breaker.

On the other hand, what is more important is that the Pentax kills the Sigma at wide apertures when it comes to border performance. The Pentax up to f4 seems to have significantly better performance than the Sigma. To me, this is the sort of thing that is important to mention. 'x' lens will give significantly better border sharpness between f1.4 and f4 but, has .25 more pixels of CA. Part of the problem here is that DP Review while "scientific" doesn't shoot test charts and put numbers on things. I'm not a big fan of test charts, but they certainly do let you know how lenses will perform at given apertures and can allow comparison of lens performance in a way that real world images can't particularly do.

This is why real review sites like photozone/optical limits and ephotozine actually shoot test charts as well as real world scenes and post the results of both.

Edge performance wide open is one of those things that is difficult to accomplish without throwing major money at the lens. Pentax fast 50s have always had decent edge performance at wide apertures, but the D FA 50 is head and shoulders above anything I’ve seen before.
I’ve always bought fast standard lenses because I wanted better low light focusing, I always accepted that I was getting at best an f/2.8 lens with a 2 stop brighter screen. The D FA* 50 gives me a very usable f/1.4 rather than an OK in the center but make sure the edges are supposed to be out of focus because they will be anyway.

Looking at the DPR samples, for the most part the types of pictures they took to show that they could torture some chromatic aberrations out of the lens would be better served, or at least not hurt, by shooting at a somewhat smaller aperture where the problem is gone anyway.

[normhead]

I just studied e photozine's comments on both the Sigma Art 50 and the Pentax DFA *50. They do indicate a bit more chromatic aberration with the Pentax than with the Sigma -- about a quarter pixel on the edges with the Sigma and around half a pixel to three quarters of a pixel on the edges (depending on the aperture). This certainly doesn't seem to be a deal breaker.

On the other hand, what is more important is that the Pentax kills the Sigma at wide apertures when it comes to border performance. The Pentax up to f4 seems to have significantly better performance than the Sigma. To me, this is the sort of thing that is important to mention. 'x' lens will give significantly better border sharpness between f1.4 and f4 but, has .25 more pixels of CA. Part of the problem here is that DP Review while "scientific" doesn't shoot test charts and put numbers on things. I'm not a big fan of test charts, but they certainly do let you know how lenses will perform at given apertures and can allow comparison of lens performance in a way that real world images can't particularly do.

This is why real review sites like photozone/optical limits and ephotozine actually shoot test charts as well as real world scenes and post the results of both.

I've always deferred to Klaus at photozone on CA, when he says CA is only really noticeable over 0.7 pixels. I've never found lenses rated for that kind of CA to cause problems.

[c.a.m]

I am not planning to acquire the D FA* 50/1.4, so I'm not affected directly by DPReview's treatment of the lens. However, I go to that site occasionally, and was interested to hear what they say about the lens.

To its credit, the piece covers a number of important aspects and presents positive and negative comments, and the authors have responded to numerous comments from readers. However, I find the review to be largely subjective and absent of some key details. Furthermore, it's easy to spot snide shots against Pentax.

• The review mentions that the tactile pattern on the focus ring is "not quite as comfortable as the ribbed design common to many other lenses." No other specific lenses are indicated, and the review doesn't explain how the author finds the ring less comfortable. It's not apparent whether the 'comfort' factor was specific to one person's preference or was a general conclusion of several testers. (Edit: At DPR, one commentator has remarked that the focus ring offers excellent purchase for gloved fingers while wet or icy. It's unlikely that the DPR review tested the lens under various environmental conditions.)

• The review emphasizes the weight of the lens, but inconsistently and absent of any comparison standard. To put the weight "into perspective," a comparison is made only to the combined weight of two unrelated Canon lenses, which are not mentioned elsewhere in the review. The Pentax is called a "fairly weighty lens" and "heavy and bulky, even by modern 50mm F1.4 lens standards." On the contrary, another statement concludes that "the [lens] is one of a generation of heavy, expensive standard prime lenses...".

• Concerning the focusing action, the review states that focusing is "not quite as discreet as some other modern optics." None of the others are named, nor is it clear whether the focusing noise is really a problem in real-world use. The review should have explained the criteria or standard; an objective test would have included sound intensity measurements.

• A concluding positive point says that the lens has a "superb build", but the review provides no discussion or evidence to support that conclusion. It's not clear what DPReview uses as criteria to assess the build quality of a lens, nor is it apparent that the reviewers have any credentials to do such an assessment.

A couple of points seem to be shots at Pentax. In one paragraph, the review attempts to draw a similarity between the Pentax lens and the Tokina Opera 50/1.4. It's not obvious why this comparison is necessary, and it seems to be a speculation, perhaps aimed at implicitly questioning the inherent quality of the Pentax lens.

In my opinion, the last sentence of the review is another shot that's neither pertinent to the review nor realistic: "For many reasons -- not least, let's be honest, the paucity of options for full-frame Pentax photographers -- the FA* 50mm F1.4 should be on every Pentaxian's wishlist."

On the positive side, the review does present several points that a prospective buyer should research further by using the DPR review as a cue to potential issues. For example, the weight of the lens might be a factor, so one could decide whether 910 g is too heavy for them. Compared to a 500mm f/4 lens, the Pentax lens is lightweight; compared to a FA 43mm Limited, it's a monster!


- Craig

[normhead]

DPR always says the same thing... don't buy Pentax.
Why do forum discussions not ever change anyone's minds? - PentaxForums.com

And nothing is ever going to change that. They aren't smart enough to understand their obvious confirmation bias.

[Wheatfield]

• Concerning the focusing action, the review states that focusing is "not quite as discreet as some other modern optics." None of the others are named, nor is it clear whether the focusing noise is really a problem in real-world use. The review should have explained the criteria or standard; an objective test would have included sound intensity measurements.

I admit my hearing is not what it once was, but the D FA* 50/1.4’s focusing is pretty much silent. To me this is just another example of DPR leaving their integrity in the parkade in the name of driving a hit piece against a non advertising company.
It is also yet another example of DPR’s lack of standards or criteria.

[RGlasel]

Redicals

Deliberate misspelling?

I can only comment based on a non-blind comparison of posted images, but there is something about the resolution, contrast and bokeh of the DFA 50 that visibly distinguishes it from the DA 55 and FA 43, at apertures wider than f2.8. Whether that is enough to make it the best in its class (or best value) isn't for me to say, but you can't completely replicate the DFA 50 with other K-mount lenses.

---------- Post added 05-03-19 at 01:13 PM ----------

They aren't smart enough to understand their obvious confirmation bias.

They don't care. DPR reviewers get paid to perform self-gratification, without any accountability. It's a great gig, for those who can get it.

[monochrome]

I think I’m going to head on over for a little Friday afternoon reading. I badly need a sardonic chuckle after this week.


Aaaaaand I’m back. 20 minutes.

89 is the highest B it is possible to get.

[lukulele]

I ventured over for the first time in three+ years to see the KP review and started on the comments first. I left after ten or twelve comments. It’s like social media projectile vomiting. I never read the review.

[reh321]

I ventured over for the first time in three+ years to see the KP review and started on the comments first. I left after ten or twelve comments. It’s like social media projectile vomiting. I never read the review.

That's too bad. I thought their Final Words

The improvements on the 'Function Dial' and incredible high ISO performance make the KP one of the best Pentax cameras, period. The slightly higher price and different ergonomics don't make it the better choice over the K-3 II for every shooter, but Pentax fans looking for the right camera to go with their favorite prime (35mm Macro anyone?) may have found it with the KP.

were very accurate.
Pentax KP Review: Digital Photography Review