[acoufap]

It would be nice to have list of those. I'm shopping at the moment and it's desired feature.

I cannot deliver a list but an experience.

As far as I can see Capture One Pro doesn‘t support local CA adjustment. The tool only supports automatic modes.

I recently had an image with every kind of CA colors you can imagine red, cyan, blue and maybe a bit yellow. It was made using DA55-300PLM plus DA TC1.4x.

You won‘t believe it but I tried to remove it with different software.

The only one that did it satisfactory was Apple Aperture 3 that offers 2 sliders for red-cyan and blue-yellow correction. I guess you know how good manual usage of these from your own experience ...

Other software I tried were Capture One Pro, Apple Photos, Adobe Bridge CS4 ACR, Raw Therapee and Affinity Photo - none of those did as well. Maybe Raw Therapee could do as well but this software needs a lot of know how about how it works and the user interface is (at least for me) difficult for occational users like me. I use it only for PSR images.

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Last edited by acoufap; 03-28-2020 at 06:50 AM.

[Paul the Sunman]

That's why I suspect they had a misaligned lens,

Pentax Distributors: "Hey Boss, we have a request for an inspection copy of the DFA 70-210 from Font-of-all-knowledge.com". Boss: "Great. Go into the store room and find the most de-centred copy we have to send them. And if you can't find a de-centred one, pick any and drop it from head height. Then send it off to them straight away; we want to see those MTF charts out as soon as possible."

Is that what really happens? It would seem so, given the regularity of the "they had a bad copy" mantra here on PF. As someone with a cupboard full of Pentax lenses and not one dud, I find it strains credulity that these review sites cop the bad copies so often. Indeed, surely distributors should test any lens before sending it for review, just to be safe.

[normhead]

Pentax Distributors: "Hey Boss, we have a request for an inspection copy of the DFA 70-210 from Font-of-all-knowledge.com". Boss: "Great. Go into the store room and find the most de-centred copy we have to send them. And if you can't find a de-centred one, pick any and drop it from head height. Then send it off to them straight away; we want to see those MTF charts out as soon as possible."

Is that what really happens? It would seem so, given the regularity of the "they had a bad copy" mantra here on PF. As someone with a cupboard full of Pentax lenses and not one dud, I find it strains credulity that these review sites cop the bad copies so often. Indeed, surely distributors should test any lens before sending it for review, just to be safe.

Two lenses is exponentially better than 1 for testa, doubling the amount of information and therefore reliability, so starting to build a consensus. If bdery and Digitalis came to the same conclusion I think we could call it a wrap. The score is 2-0 for the Tamron, but it's only the fourth inning.

If it were baseball, you'd say "With the score two nothing and 4 innings left to play, my team still has chance to win." Those of us who follow sports know you can't just run to a betting site and place a bet because one team has a lead, and claim you're going to win your bet. You'd be wrong good portion of the time.

I'd be more worried about making an error in judgement based on too small a sample than giving Pentax a break by suggesting bad copies caused the problem.You look at the tests, the images etc. you make an informed decision.

But honestly, everyone trashed my 18-135 and I love the lens, so I give no credibility to any of these clowns. They know what their measurements tell them. That has no correlation with whether or not people might like the lens. It's a public service that they publish their results, it's on the people who read the results that think a lens is unsatisfactory because of them if they judge a lens to be unsatisfactory because of them.

What's worse, people who suggest it might be a bad copy, or people who suggest Pentax is building an inferior lens based on two copies?

In my opinion, when users results are contradicted by the internet sites, the user is always right from their perspective.
The sites run their tests, but clearly, in the case of the 18-135 and many other lenses, their tests are often irrelevant to the users.

I know people have a hard time with this but, the only test that matters is whether or not you like the images.
The test charts don't predict how popular a lens will be.
Price/performance costs.
Affordability counts.
Handling an ease of use count.
Overall rendering counts.
My issue is not with those who are enamoured or dismissive of test scores.
My problem is with people who look at these scores and try and draw conclusions about the utility of the lens from them.
My experience is that when I look at test site scores, then look at the images I like, I'd caution against posting anything negative about a lens because of test scores. You still have to try out the lens. Given the generally positive reviews the lens had, a few people jumping on resolution and CA scores who haven't used the lens is frightening.

My own polls have suggested most people can't tell the difference between reduced size K-3 and k-1 images, and yet people want me to believe they would be affected by the difference between the Tamron and Pentax versions of this focal length. When you're ready to run blind test if DFA*70-200 and DFA 70-210 images @ ƒ5.6 to see who can tell the difference let me know. I'll be interested.

Sorry if I'm dismissive, but I go with blind testing with polls of usually 75 or more respondents. In blind tests, people don't think what they think they think, and they don't know what they think they know. My 18-135 received far worse reviews, on tester rating it 1.5 out of 5. Yet it's one of my most used lenses. Why would I have any faith at all in the meaning of their tests? Keep an open mind, you may find something you like despite the meaningless rumination of test numbers.

A bit of balance please.

Incredible we'd be criticized for being prudent by someone who appears to be so impulsive.

As for the test scores, as published, a lot of people are happy with a lot worse even if the current test scores hold up.

[tibbitts]

I don't have this lens, but from owning many lenses and from unscientifically testing many others, substantial variation in quality seems to still be widespread across the industry. I've encountered so many truly poor lenses that sometimes I wonder if I'm too picky now and rejecting ones I shouldn't. It's like I'm looking for problems now where I didn't used to. I don't put a lot of weight into whether other people are "happy" with a lens, although when specific comments are truly overwhelming in a large sample size (purple fringing on the Tamron 70-300 would be a good example), my experience has usually corresponded with the majority. On the other hand, I think most people don't test lenses very thoroughly, and some lenses skate by on reputation alone. I guess if you have a decent sample size where the exact same behavior occurs, then you might draw some conclusions from that as to what you're likely to experience.

It's very frustrating as a consumer to not be able to utilze reviews the same way we can with many products, where the liklihood of the product we buy performing similarly to the review seems much more likely than with even mid-to-high-end lenses.

[RGlasel]

It's very frustrating as a consumer to not be able to utilze reviews the same way we can with many products, where the liklihood of the product we buy performing similarly to the review seems much more likely than with even mid-to-high-end lenses.

If we were experts at toasting bread and had our personal preferences as to whether the bread was evenly toasted, toasted in a grid pattern, or held firm longer under the pressure of a butter knife, we would have the same issues with published reviews of toasters.

From what I know of industrial manufacturing, there is no way for Tamron to downgrade its quality control for Pentax branded versions of the 70-210, but equipment goes out of adjustment over time. Initial copies of a new product will be more carefully screened, so if a reviewer is working with a Beaujolais Nouveau Tamron lens and a Vin de le Mois Pentax lens, it is more likely that the Tamron will get a higher score.

[tibbitts]

If we were experts at toasting bread and had our personal preferences as to whether the bread was evenly toasted, toasted in a grid pattern, or held firm longer under the pressure of a butter knife, we would have the same issues with published reviews of toasters.

From what I know of industrial manufacturing, there is no way for Tamron to downgrade its quality control for Pentax branded versions of the 70-210, but equipment goes out of adjustment over time. Initial copies of a new product will be more carefully screened, so if a reviewer is working with a Beaujolais Nouveau Tamron lens and a Vin de le Mois Pentax lens, it is more likely that the Tamron will get a higher score.

I wonder if that's the case - if we took ten toasters,would we be able to tell as much difference in their output (whether we cared as much or not) as we seem to be able to with ten lenses, all of the same models.

I don't believe Tamron would downgrade quality control, although as has been pointed out, at least the design has to be somewhat different without vibrtion compensation, even assuming the lenses are othewise identical. So two different designs could have different quality control implications.

[stevebrot]

Are we still assuming it's the same lens manufactured in the same facilities except for coatings and finishing?

Does Tamron assemble in Vietnam?


Steve

[stevebrot]

Is that what really happens? It would seem so, given the regularity of the "they had a bad copy" mantra here on PF. As someone with a cupboard full of Pentax lenses and not one dud, I find it strains credulity that these review sites cop the bad copies so often. Indeed, surely distributors should test any lens before sending it for review, just to be safe.

Lens Rentals | Blog...Fun with Field of Focus II: Copy-to-Copy Variation

A lot depends on how close one is looking for faults.


Steve

[RGlasel]

Does Tamron assemble in Vietnam?

Yes, someone else on this forum did a search and discovered that the Tamron factory is less than 40 kms from the Pentax factory.

Until @bdery in Quebec City is finished his review, I am disregarding all and any external reviews. This is the Age of Disinformation, where the free things in life are worth less than what you pay for them.

[mee]

absolutely dissapointing imatest results compared to same optical desigh Tamron 70-210/4. I compared ephotozine reviews of these two lenses and results are much worse for Pentax

Yes their Tamron version on a D810 is muuuuuch sharper at 210mm... several stops sharper. I was expecting more similar results out of each than what I see on the charts.


That said, it really doesn't matter as the Tamron version doesn't mount to a Pentax camera. And the Pentax version, in actual photos, looks fantastic at least to me. But I relent all are welcome to form their own viewpoint.

Yet I do wonder why the differences? Poor copy of the Pentax variant? Different settings? Accidentally had 5 UV filters on the front of the Pentax for the imatest? haha

[clackers]

If a reviewer finds they can't replicate the published MTF results, especially in symmetry, they have to understand they've got a dud copy. Real reviewers will have Imatest software or similar, if they can't be bothered paying for and using it, they're not real testers, they're being amateurs. That's most 'testers' on the web, by the way, the standard of science, journalism and even their photography skills can be appalling. I saw that Angry Photographer guy in a video taking portraits of a chick in daytime with a Fuji MF, and for some reason the dumb so-and-so was letting his ISO automatically go up to 12,800 or whatever, he was real Uncle Bob level during the shoot, that was being filmed by Jason Lanier's team.

[house]

don't they always say not to compare mtf across systems?

All recent Pentax lenses have what looks like lopped off performance Very even but not as high peaks.

Wether this is testing methodology, lens design or something else I don't know.

[RobA_Oz]

Ever since I’ve had my copy of this lens, I’ve been looking carefully for CA, and I did find some. One click in Camera Raw, and it was gone. So, it’s there, but so far not an issue for me.

I didn’t buy it expecting it to be better than the D FA*70-200, or even my FA*80-200. For the purpose (lighter weight for travel and track-walking) it’s so far exceeding my expectations.

Anecdotally, the AF is quick and seemingly accurate (Cameraville’s test backed that up). I haven’t yet had time to compare sharpness against the FA*80-200, let alone my friend David’s D FA*70-200, and our collective present circumstances may prevent that for a while.

I’ll put up some images in the relevant thread when I’ve done with my present tinkering.

[Rondec]

Sandy Hancock has posted photos that seem to perform better. I'm still thinking copy variation, although every lens has strong points and weak points and it seems that the long end is the weaker side of things, even for the non-K mount version tested by ephotozine.

[clackers]

don't they always say not to compare mtf across systems?

All recent Pentax lenses have what looks like lopped off performance Very even but not as high peaks.

Wether this is testing methodology, lens design or something else I don't know.

You can't beat the MTF curve, it's the calculated maximium and is independent of the camera or the photographer or the subject. An optical testing bench will use lasers to verify problems with a real specimen. How to Measure MTF - Optikos