[Wheatfield]

I guess he could have used a Sony or some othe mirrorless, but then we'd have complaints about the adapter alignment or something else.

Is there a Sony to KAF4 adapter? Last I heard, there wasn't.
I expect that there would be fewer cases of having to explain away bad testing results if the same body was used throughout.
It takes away one major and unavoidable variable that really renders any tests rather moot..

[tibbitts]

Is there a Sony to KAF4 adapter? Last I heard, there wasn't.
I expect that there would be fewer cases of having to explain away bad testing results if the same body was used throughout.
It takes away one major and unavoidable variable that really renders any tests rather moot..

The only adapters I know of are manual and I don't have this model lens or a Sony camera or adapter to know if enough functionality would be retained to do a test at f4 (I'm guessing not at any other aperture for sure.) So if there are no adapters, how do you propose to test these lenses on the same body? If it can't be done, it isn't fair to be critical of the author for not doing it.

[Wheatfield]

The only adapters I know of are manual and I don't have this model lens or a Sony camera or adapter to know if enough functionality would be retained to do a test at f4 (I'm guessing not at any other aperture for sure.) So if there are no adapters, how do you propose to test these lenses on the same body? If it can't be done, it isn't fair to be critical of the author for not doing it.

Is it more fair to give someone a pass on a meaningless test?
“If it can’t be done”, it isn’t fair to come up with a false simulation and try to pass it off as some sort of science.
I’m all for having faith and all that, but let’s not be pretending it’s science.

[Digitalis]

Copy variation.

[bdery]

Not quite : this diagram shows that basically the magnets and the black pieces do add up to non stabilized lens.

Good point, I had forgotten about the SR system in the Tamron version.

[house]

Is it more fair to give someone a pass on a meaningless test?
“If it can’t be done”, it isn’t fair to come up with a false simulation and try to pass it off as some sort of science.
I’m all for having faith and all that, but let’s not be pretending it’s science.

I don't know if any reviewers pretending they are doing science. It would be foolish.

[Wheatfield]

I don't know if any reviewers pretending they are doing science. It would be foolish.

Agreed, but it is also foolish to give much credence to their results if they are not following established scientific methodology.

---------- Post added Mar 30th, 2020 at 10:58 AM ----------

Thankfully, there are very few use cases - and users - who need something closer to (technical) perfection. Most (perhaps all?) mid-to-high-end lenses from any brand are more than capable enough for the majority of amateur and professional applications. There would seem to be quite a few folks who want near-perfection "just because"... and they're allowed to want that, of course, even if the vast majority don't need it.



I'd say the D FA*50/1.4 falls into that bracket, though it's only the first in a line of such lenses that will take some time to flesh out. Until then, Pentax may not be the best choice for the tiny proportion of users who actually need technical perfection (you may be one of the rare few?), or those who simply want it even if they don't need it...

I’ll just point out that the D FA* 50/1.4 offers high level technical performance combined with high level aesthetic performance.

[WorksAsIntended]

Agreed, but it is also foolish to give much credence to their results if they are not following established scientific methodology.

---------- Post added Mar 30th, 2020 at 10:58 AM ----------



I’ll just point out that the D FA* 50/1.4 offers high level technical performance combined with high level aesthetic performance.

As others do. The Sony Zeiss 50 1.4 and the RF 50 1.2 by Canon as well as the 50 1.8 Z by Nikon all deliver very nice looking bokeh transition and high sharpness and contrast.
I love my DFA 50, it is a great lense and a true new generation lense.

[normhead]

As others do. The Sony Zeiss 50 1.4 and the RF 50 1.2 by Canon as well as the 50 1.8 Z by Nikon all deliver very nice looking bokeh transition and high sharpness and contrast.
I love my DFA 50, it is a great lense and a true new generation lense.

The comparisons I've seen the DFA* 50 looks better, but I'd be happy to have my mind changed.

[bdery]

I don't know if any reviewers pretending they are doing science. It would be foolish.

"Doing science" is a pretty vague concept.

Agreed, but it is also foolish to give much credence to their results if they are not following established scientific methodology.

Applying the scientific method is easier to demonstrate, indeed.

When reviewing, I try to be methodical, transparent, use a repeatable list of test and testing conditions, control my variables, make hypothesis but let the data speak and avoid, as much as possible, bias.

[normhead]

"Doing science" is a pretty vague concept."

Doing science is a very expensive concept. Charities and trusts don't give money to science as it applies to cameras, neither do camera companies or camera buyers. They have more important fish to fry.

When reviewing, I try to be methodical, transparent, use a repeatable list of test and testing conditions, control my variables, make hypothesis but let the data speak and avoid, as much as possible, bias.

Many reviewers don't seem to understand. I don't care what the competition is like, I'm not buying the competition. All I want to understand are the ins and outs of using the lens.

[house]

"Doing science" is a pretty vague concept.



Applying the scientific method is easier to demonstrate, indeed.

When reviewing, I try to be methodical, transparent, use a repeatable list of test and testing conditions, control my variables, make hypothesis but let the data speak and avoid, as much as possible, bias.

imho. you'd have to, at a minimum, determine and spell out your margin of error and tolerances to qualify as "doing science". Even in the loose meaning of the term. Naturally reviewers should try their best to arrive at solid conclusions. Some do better than others.

[normhead]

imho. you'd have to, at a minimum, determine and spell out your margin of error and tolerances to qualify as "doing science". Even in the loose meaning of the term. Naturally reviewers should try their best to arrive at solid conclusions. Some do better than others.

You can't run a standard deviation analysis on a sample of one. Lensrentals would probably be the only ones who could do this.

I tend to be of the opinion that every lens has a use. I don't want to know if the lens is "good or bad". I want to know how I would make optimum use of the lens. For what use does it's design make it compelling. My FAJ is not that good, but it's super light weight. Even though it pretty much sucks optically, I used it extensively when a friend was cottage hunting. We'd go to 3 or 4 cottages a day, the GPS and FAJ-18-135 provide excellent 1920 x 1080 images so when we sat down afterwards we knew what we were looking at. It's far from my best lens, but on those days, coupled with the K-1 it was king. I've grown to be of the opinion, there are no really bad lenses, (a least not manufactured in the last 10 years, maybe 20) just lenses people don't need for the way they shoot. I would still recommend the FAJ for anyone doing what I was doing. A terrible lens, but it was up to that particular task, and there would have been no benefit to using a better lens. And I paid $100 CAD for it. I don't have a big investment in it so I don't mind if it sits on the shelf, 362 days a year.


My only question about the Pentax 70-210 would be is it sharp enough to support the 1.4 TC at the long end? My 60-250 is. I expect that from all my long lenses. The problem with being too soft in the long end is, you can't extend it with a TC and get more than you'd get just enlarging the image. The things I care about most are often never adressed.

[Wheatfield]

"Doing science" is a pretty vague concept.



Applying the scientific method is easier to demonstrate, indeed.

When reviewing, I try to be methodical, transparent, use a repeatable list of test and testing conditions, control my variables, make hypothesis but let the data speak and avoid, as much as possible, bias.

Doing Science is as accurate a term as is required, as long as one is willing to put fixed definitions to words.
The thing with doing science is that it implies scientific methods, and that means when comparing two things, only one variable gets changed at a time.
Even then, it’s hard.
When I compared the FA50/1.4 to the D FA*50/1.4 I missed focus on one of the lenses by a couple of millimetres. Normally I’m pretty good about this stuff, I’ve been doing science since I was 13.
Anyway, I was off by enough to render an absolutely direct comparison impossible, and so results needed to be somewhat extrapolated. It didn’t take away from the fact the new lens was a couple of football fields better than the old one, the results were good enough for that, but I would have liked to have done better.

When someone is comparing, for example, a Tamron 70-210/4 On a Nikon to a similar Pentax 70-210 on a Pentax, there is no “doing science” going on, there is just some dude in his backyard playing with cameras, and a lot of make believe. It’s the very definition of “fake news”.

[WorksAsIntended]

Doing Science is as accurate a term as is required, as long as one is willing to put fixed definitions to words.
The thing with doing science is that it implies scientific methods, and that means when comparing two things, only one variable gets changed at a time.
Even then, it’s hard.
When I compared the FA50/1.4 to the D FA*50/1.4 I missed focus on one of the lenses by a couple of millimetres. Normally I’m pretty good about this stuff, I’ve been doing science since I was 13.
Anyway, I was off by enough to render an absolutely direct comparison impossible, and so results needed to be somewhat extrapolated. It didn’t take away from the fact the new lens was a couple of football fields better than the old one, the results were good enough for that, but I would have liked to have done better.

When someone is comparing, for example, a Tamron 70-210/4 On a Nikon to a similar Pentax 70-210 on a Pentax, there is no “doing science” going on, there is just some dude in his backyard playing with cameras, and a lot of make believe. It’s the very definition of “fake news”.

I agree on the last paragraph. But there is a lot of other ways of doing science than isolation of parameters, it is just not possible in too many cases. It is just a matter of which conclusion is drawn.