[ChristianRock]

FWIW, comparing a bunch of opinions from untrained testers without any standard testing protocol to a similar handful of tests from some other testers is not statistically valid. Considering how the differences in construction might affect you is where you might focus.

I appreciate reading the opinions of others and the time they spent to share them, but relying on the numerical representation? I know better.

I agree that the rating number doesn't mean much. Especially since there's some "reviewers" that have some pet peeve and just go and give a "No" recommendation to a lens and a bad score. Like some "reviewer" gave a no recommendation based on perceiving that the lens was overpriced, while implying he perhaps never even owned the lens. Then the same "reviewer" goes to the worst film-era kit lenses and gives a recommendation and a good review. Obviously there's some trolling going on with the ratings.

But reading through the reviews is far more informative. It allows people to say how they use the lens, what they like and don't like about it and you can decide if it applies to you and your style of shooting. To be honest, I rely far more on this real-world experience and on picture samples than on MTF tests and professional reviews - though I do look at those. But - here's an example - recently real-world users and sample pictures helped me decide to buy the SMC DA*16-50 instead of the Tamron 17-50 which I could have had for almost half the price, or the Sigma 17-50 that I also found cheaper than the Pentax lens. But I like the pictures of the Pentax lens a lot more and I'm so happy I did this. It's also why I just bought a K-3 instead of going for a K-70 at about the same price (both used of course...) - though on paper the K-70 has newer and better features and in theory, better image quality. But a better build and user experience seems to make K-3 users that have similar styles of shooting as me, a bit more satisfied.

tldr; don't put too much faith in the ratings... read people's real world experiences.

"I have an HD DA 21mm on order. I’m curious why this lens has a higher rating in the review section than the older version." Maybe it was suggested by Ricoh/Pentax that the HD coating is better than the SMC before. And people will believe that and certainly when "reviewers" (amateur and professional) state that it is better in various kind of ways, less ghosting, less flare and so on. But it could be that they were just lucky to take a picture with all of those assumed qualities and that it in fact was just luck and some knowledge of how to take a picture. Nothing to do with the lens and its coatings. The new HD coating is a selling point but I honestly doubt that it has such an impact on a picture as the manufacturer and others want me to believe.

[BigMackCam]

"I have an HD DA 21mm on order. I’m curious why this lens has a higher rating in the review section than the older version." Maybe it was suggested by Ricoh/Pentax that the HD coating is better than the SMC before. And people will believe that and certainly when "reviewers" (amateur and professional) state that it is better in various kind of ways, less ghosting, less flare and so on. But it could be that they were just lucky to take a picture with all of those assumed qualities and that it in fact was just luck and some knowledge of how to take a picture. Nothing to do with the lens and its coatings. The new HD coating is a selling point but I honestly doubt that it has such an impact on a picture as the manufacturer and others want me to believe.

DxOMark isn't affiliated to Ricoh, so it's neutral in the SMC vs HD debate... and it doesn't rely on "luck and some knowledge of how to take a picture" when testing lenses, but rather a well-established methodology which - though not without its critics - is nonetheless consistently applied, and removes the elements of chance and optimistic marketing you allude to. The folks there know a thing or two about a thing or two, and they had this to say about the HD DA21:

"Compared with its smc predecessor, the HD version performs very similarly as you might expect, but there are some improvements. From the initial aperture to f5.6, the new HD coated lens has slightly better uniformity, although from f8 through to f22 the two remain alike. Although peak sharpness and transmission remains unchanged, the new HD coating technology, which, according to the company shuns the conventional vacuum evaporation process, appears to improve peripheral illumination while also lowering lateral chromatic aberration.

Pentax HD DA 21mm F3.2 AL Limited on Pentax K-3 versus Pentax smc DA 21mm F3.2 AL Limited on Pentax K-3 - Side by side lens comparison - DxOMark 2014-01-13 16-10-49

Between the initial aperture and f5.6, the HD version has higher sharpness and better uniformity than the original smc model.

With lens compactness being a real selling point these days the popularity of Pentax’s tiny ‘pancake’ primes continues unabated. The smc 21mm f3.2 AL Limited was a well-liked model and the new HD version, with its improved coatings, has brought subtle but welcome enhancements to image quality. If you already own the smc version there seems little real reason to upgrade, but if you were thinking of picking one up for the first time, the small premium of around $50 appears to be a small price to pay for the benefits."

I haven't personally tested both the SMC and HD versions under controlled conditions with the necessary equipment and software. DxOMark has, so - in the absence of my own comparable tests - I choose to accept their findings in good faith. Of course, they're reporting test-bench differences, and real-world shooting probably won't highlight the stated improvements so readily. What might be apparent to some users, though, are the differences summarised by @luftluss in an earlier post.

I've never used the SMC version, but I will say that the HD DA21 is my favourite of all the DA Limited primes. It's a cracking little lens

[Apet-Sure]

that is how the US automakers used to make the big money in long ago years

I'm amused at how many car makers use the phrase 'all-new 2020' in their commercials. If these models are 'all-new', then last year's models must have been terrible; not a single thing worth carrying forward.

Hello BigMackCam, "I haven't personally tested both the SMC and HD versions under controlled conditions with the necessary equipment and software. DxOMark has, so - in the absence of my own comparable tests - I choose to accept their findings in good faith." I understand that position you take, but these reviews or tests are worthless in my opinion. The only thing that is important is how one experiences in this case the DA 21mm. And there are a lot of camera's you can attach this lens to, but the results you get are they really because of the lens being better, or has it to do with the camera the lens is attached to. I do not believe in these tests because it is just a snapshot (pardon the pun). The only thing that counts for me is how I experience the lens (or camera) and if the outcome is what I saw when taking the picture. You experience the 21mm a cracking lens, I did not know how fast to return it. With all those reviews it is a personal experience with a combination of lens, camera and a certain photographer that gives a result, but as I am not that certain photographer, with my camera and the same lens the result can be very different.

[normhead]

Hello BigMackCam, "I haven't personally tested both the SMC and HD versions under controlled conditions with the necessary equipment and software. DxOMark has, so - in the absence of my own comparable tests - I choose to accept their findings in good faith." I understand that position you take, but these reviews or tests are worthless in my opinion. The only thing that is important is how one experiences in this case the DA 21mm. And there are a lot of camera's you can attach this lens to, but the results you get are they really because of the lens being better, or has it to do with the camera the lens is attached to. I do not believe in these tests because it is just a snapshot (pardon the pun). The only thing that counts for me is how I experience the lens (or camera) and if the outcome is what I saw when taking the picture. You experience the 21mm a cracking lens, I did not know how fast to return it. With all those reviews it is a personal experience with a combination of lens, camera and a certain photographer that gives a result, but as I am not that certain photographer, with my camera and the same lens the result can be very different.

There is simply no review that is likely to emulate your shooting style, work flow, post processing etc.
I see very little difference between my lower priced lens and some higher one. I generally to and go with the most current lens, although current Pentax pricing is shooting that out of the water.

My own testing has show that most people don't prefer the sharpest best rated review lens. With 6 or 7 lenses comparing images, no lens has ever scored more that a 30% following. Whatever lens you choose, the odds are against you that you choose these that's best for your purposes if you cant work with them first.

MY own advice would be select you lens because it's the highest priced copy of the FL you need to cover, and send it back if you don't like how it renders. The IMHO any lens in a given FL is good. You just have to remember, older lenses from the film era are not corrected for purple fringing. My DA* 60-250 is better than my F70-210. I suspect the DFA* 70-200 would be better than my DA*60-250.

Things are not as complicated as people make them out to be.

[AgentL]

I generally prefer lenses that are less perfected, when they have some character to them. A cheap kit lens with deficiencies, for example, most likely doesn't have anything which could be called character, but the older SMC Limiteds are often said to have it.

[BigMackCam]

I understand that position you take, but these reviews or tests are worthless in my opinion.

... and yet, like me, you've posted lens reviews on PentaxForums for others to read... which leads me to wonder why your lens reviews (or mine) might be worthy of attention and those of DxOMark and others are worthless.

The only thing that is important is how one experiences in this case the DA 21mm.

I agree that it's our individual experience of a lens that ultimately matters, and reviews can't take our subjective assessments into account. However, well-defined and controlled bench tests from reputable review sites ("reputable" being the key word here) can measure what a lens is technically capable of, and this can help to inform a buying decision. Such measurements are no guarantee that we'll like a particular lens, but if our own results don't broadly match those of the reviews in terms of basic performance, we might reasonably suspect that we bought a dud or perhaps we're doing something wrong (e.g. using the wrong AF mode for our use case, or the wrong aperture for our required depth of field), or not doing something at all (e.g. correct AF fine adjustment). That in itself is useful.

And there are a lot of camera's you can attach this lens to, but the results you get are they really because of the lens being better, or has it to do with the camera the lens is attached to.

If you look at DxOMark's comparison of the SMC and HD DA21, they used the K-3 for both. Actually, they performed the same tests using a variety of Pentax bodies with both lenses, and provided the data for all of them. The results in every case showed the HD performing slightly better in certain respects, though the differences are such that any benefit should be marginal and largely subjective in most situations.

I realise some reviewers use opaque, questionable or inconsistent approaches in testing, but not all review sites are made equal. Some really are worthy of our consideration, and where lenses are concerned I find DxOMark to be a pretty dependable resource, so far as it goes. There are several others of note, and in my experience it's best to look at a number of them to aggregate findings and filter any anomalies due to errors, sample variation etc.

I do not believe in these tests because it is just a snapshot (pardon the pun). The only thing that counts for me is how I experience the lens (or camera) and if the outcome is what I saw when taking the picture. You experience the 21mm a cracking lens, I did not know how fast to return it. With all those reviews it is a personal experience with a combination of lens, camera and a certain photographer that gives a result, but as I am not that certain photographer, with my camera and the same lens the result can be very different.

Again, I'll say that not all review sites and not all reviews are made equal. Personally, I consider aggregated and filtered findings from multiple reputable sources to be a fairly reliable starting point when choosing lenses... and whilst I have neither the equipment and software nor the inclination to repeat their controlled test-bench measurements, my real-world shooting experience of lenses I've bought (the HD DA21 included) has generally matched review findings. Still, some of those lenses - despite performing as the reviews suggested - aren't favourites of mine due to one or more aspects the reviews didn't pick up on, or simply my own tolerances or rendering tastes... which proves your point that it's the way we each experience a lens that matters most.

If your experience with a specific lens is such that the technical performance aspects don't appear to match the majority of reputable review findings, there comes a point where you have to seriously consider why that might be, rather than concluding all reviews are worthless and/or that model of lens isn't very good