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12-25-2017, 02:55 PM   #31
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I think the real problem with modern lenses is their mechanical construction, with their breathtakingly floppy barrels. I'd like to buy a DFA50 Macro but know there's no point. It doesn't matter how brilliant an optical design is if the elements can be rearranged randomly by gravity.

12-25-2017, 03:06 PM   #32
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QuoteOriginally posted by tibbitts Quote
I think the real problem with modern lenses is their mechanical construction, with their breathtakingly floppy barrels. I'd like to buy a DFA50 Macro but know there's no point. It doesn't matter how brilliant an optical design is if the elements can be rearranged randomly by gravity.
I think the somewhat-loose design is quite common (and, in some cases, necessary) with AF lenses... especially low-to-mid-price zooms. But it certainly doesn't affect all modern lenses. None of my HD DA Limiteds feel sloppy, nor does my D-FA100 Macro or DA*60-250...
12-25-2017, 03:41 PM   #33
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QuoteOriginally posted by BigMackCam Quote
I think the somewhat-loose design is quite common (and, in some cases, necessary) with AF lenses... especially low-to-mid-price zooms. But it certainly doesn't affect all modern lenses. None of my HD DA Limiteds feel sloppy, nor does my D-FA100 Macro or DA*60-250...
I don't have this issue with some lenses either, including the 60-250, but I never had this issue with previous generations ('80s) of consumer-level zooms. That's the only reason I attribute it to "modern lenses." I've seen the same problem from other manufacturers so I don't mean to blame Pentax alone, but I think there's just no excuse for this and in every case I know of it DOES visibly affect resolution. There's really no way it can't. I don't believe it should be "necessary" with any lens, and those that have the problem should be redesigned to prevent it.
12-25-2017, 04:10 PM   #34
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QuoteOriginally posted by tibbitts Quote
I don't have this issue with some lenses either, including the 60-250, but I never had this issue with previous generations ('80s) of consumer-level zooms. That's the only reason I attribute it to "modern lenses." I've seen the same problem from other manufacturers so I don't mean to blame Pentax alone, but I think there's just no excuse for this and in every case I know of it DOES visibly affect resolution. There's really no way it can't. I don't believe it should be "necessary" with any lens, and those that have the problem should be redesigned to prevent it.
No, I completely get what you're saying, and I didn't think you were aiming it at Pentax. I too have some modern lenses with a rather "relaxed" feel (!), and I'm not keen on it. From memory, though, it tends to be on consumer-level models - but I agree, it should be possible to avoid it...

12-25-2017, 04:52 PM - 1 Like   #35
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QuoteOriginally posted by BigMackCam Quote
I think the somewhat-loose design is quite common (and, in some cases, necessary) with AF lenses... especially low-to-mid-price zooms. But it certainly doesn't affect all modern lenses. None of my HD DA Limiteds feel sloppy, nor does my D-FA100 Macro or DA*60-250...
I have wondered whether the requirement of fast AF seriously complicates the lens designer's job and makes it especially hard to also optimize sharpness, bokeh, and other aspects of rendering.

Fast AF in a large aperture lens requires creating some special small group of small elements inside the lens that can send the lens from minimum focus distance to infinity without much movement of that light-weight focusing group. That requirement would seem the force the designer to add more elements and create a rather loose internal mechanism designed more to be quick than to be good.

Any correlation between lots of elements and loss of traditional rendering might not be the fault of the element count. It could be the fault of fast AF that causes both higher element counts and strange rendering (and loosey-goosey mechanical designs).
12-26-2017, 06:52 AM - 1 Like   #36
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People want stiff lenses and fast AF. So I guess they are hoping for AF motors the size of ceiling fans.

It's sad people can't just sit back and try and understand why things are built the way they are.

You may have a problem with a lens, you might want to analyze the trade offs before you decide you can't live with it. The FA 50 macro has a lock that locks the barrel. Invest in one, get on with your life.
12-26-2017, 06:59 AM   #37
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QuoteOriginally posted by normhead Quote
People want stiff lenses and fast AF. So I guess they are hoping for AF motors the size of ceiling fans.

It's sad people can't just sit back and try and understand why things are built the way they are.

You may have a problem with a lens, you might want to analyze the trade offs before you decide you can't live with it. The FA 50 macro has a lock that locks the barrel. Invest in one, get on with your life.
Whilst I agree with the basic sentiment of what you're saying, Norm, the engineering is possible. My Sony Zeiss 24-70 f/2.8 SSM is rock solid and smooth in both zoom and focusing, with just the right amount of resistance and damping, and no sloppiness in the barrel or controls - and it's no bigger than any other 24-70 f/2.8 lens I've seen. Not cheap, admittedly, but not crazy expensive in its class...
12-26-2017, 07:22 AM   #38
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Not cheap is a huge trade off.

On B&H it's no longer available and it's selling used for $1349

Pentax D FA 24-70, new $1000.

Does the Pentax 24-70 drift?

Is that what it costs to tighten up the lens ? $350 and that's used? So I'm guessing the new difference would be at least $500. For my use I think Pentax made the right choice, although both are too expensive for my taste. I'll deal with lens drift (if in fact there is any in the Pentax) and keep the $500 thank you very much.

12-26-2017, 07:39 AM - 1 Like   #39
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Mike, I'm really, really sorry about this, but I have to say it.

@OP:
On the internet, every idiot can pose as an expert - and even write "convincing" articles.
Don't get fooled. They're sure of themselves and even make up some sort of "proofs" but that doesn't make them knowledgeable. IIRC, the same guy was blaming a modern lens design for "flattening" the nose of a nice Asian lady... surely, that was the lens and not how she looked IRL

IMHO if we're getting lenses more optimized for test charts than a pleasing rendition is because that's what the customers are expecting / how they're "evaluating" a "good" lens (i.e. numerical reviews). Not because it would be impossible to design a modern lens with pleasing rendition.
But I'm sure Pentax will beautifully combine these two in their D FA* primes.
12-26-2017, 07:44 AM   #40
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QuoteOriginally posted by normhead Quote
Not cheap is a huge trade off.

On B&H it's no longer available and it's selling used for $1349

Pentax D FA 24-70, new $1000.

Does the Pentax 24-70 drift?

Is that what it costs to tighten up the lens ? $350 and that's used? So I'm guessing the new difference would be at least $500. For my use I think Pentax made the right choice, although both are too expensive for my taste. I'll deal with lens drift (if in fact there is any in the Pentax) and keep the $500 thank you very much.
Well, there's arguably more than just tight build for that extra $350-$500... optically, for example. That Sony lens is by far the best AF lens I own.

Frankly, I can live with a relatively loose mechanism on lenses, even if I don't like it. I may prefer the feeling of my Sony Zeiss lens, but - with the exception of several DA16-85 consumer zooms I tried and returned due to an image that visibly and alarmingly moved in the viewfinder during focusing - a loose build has yet to cause me any problems.

My point was, you don't need an AF motor the size of a ceiling fan with a tightly constructed lens. It would seem, though, there *is* a price to pay

Last edited by BigMackCam; 12-26-2017 at 07:50 AM.
12-26-2017, 12:34 PM   #41
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All this talk of loose, sloppy lenses reminds me of the Nikkor 80-200 from about 35-40 years ago. If you pointed it down it would crash to the end of the zoom as if spring loaded. I don't recall ever seeing one of those that wasn't a loose, sloppy mess.

And it was a stout, robust thing, designed as a high end zoom when zooms were still pretty new, with no autofocus to excuse the sloppiness.

The only Pentax lens I've ever seen remotely that bad was a Takumar-A 70-210, and it was an inexpensive consumer-grade lens.

So I think there is a technology element there as well -- people just didn't understand how a particular technology was going to age, so they either dramatically overbuilt it or took a guess on longevity that was not always right, depending somewhat on the lens' intended market...

-Eric
12-26-2017, 12:53 PM - 1 Like   #42
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QuoteOriginally posted by photoptimist Quote
I have wondered whether the requirement of fast AF seriously complicates the lens designer's job and makes it especially hard to also optimize sharpness, bokeh, and other aspects of rendering.
You'd have to think it does to some extent considering the breathtaking manual lenses companies like Samyang and Irix have put out in recent years.
12-26-2017, 03:01 PM - 1 Like   #43
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I don't really know what people are talking about. Generally speaking you get what you pay for. The FA 200 macro is still one of the best macro lenses available with amazing creamy rendering. But the DFA 70-200, while being sharper than the DA *200 wide open, has really nice rendering of out of focus areas as well.

At the same time, if you take a 50mm f2 lens from the past, it may have "interesting" bokeh, but its overall rendering won't be anything to write home about.

Even today, modern lenses range from 18-135 territory (which is fine, but nothing amazing) to 12,000 dollar Leica primes. Obviously there is a lot of distance between those.

That said, I think most folks judge photos based on lighting, composition and subject and less on rendering of a particular lens. The lenses that stand out most to me, that I can recognize right off without looking at exif, are those like the Soligor which are pretty rough, in my opinion, but I guess some people love them.

Last edited by Rondec; 12-26-2017 at 07:19 PM.
12-27-2017, 01:57 AM - 2 Likes   #44
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QuoteOriginally posted by photoptimist Quote
As others have noted lens element count means almost nothing in terms of lens quality or rendering -- there's good and bad lenses of every element count.
...
What's especially amusing is that lead glass is called "crystal" because it was actually used to imitate natural rock crystal and gemstones -- lead crystal is a fake knock-off of the natural material!

To me, lenses with character are wonderful but they are anything but natural. They actually impose the imperfections of their optical designs on the image. It's actually the clinical lens that creates the most objective and true image. Yet lenses with character are wonderful artistic tools.
You're spot on with all your points. But one...
Even the most advanced multicoating is not 100% effective. Each glass-to-air surface reflects back (instead of refracting and letting through) at least 7% of the incoming light. IIRC any uncoated element reflects as much as 30%. That's why for long time the glass-to-air surfaces were kept to a minimum, and the Planar (which actually predates other common designs like the Cooke triplet and the Tessar) was practically abandoned until the vacuum coating process was invented.
So the actual number of elements makes a difference, albeit not as relevant as in the past, even with modern multicoated objectives.
The author of the blog referenced by the OP presents a couple of concepts I wholeheartedly concur with (I love SOME vintage lenses), then he tries to conceptualize... covering everything with a whole load of BS.
Of course he knows about optical glass as much as I know about rocket science.
The choice of different types of optical glass is so wide nowadays, and so specialized, that really makes no sense to differentiate "crystal" from "normal" optical glass, based on lead content.
Excluding a few specialized optics possibly made for photography outside the visible spectrum, the only true crystal (quartz) lens I remember is a variant of the Struss portrait lens. Struss was the first Oscar award winner for motion picture photography, and earlier he devised a soft focus lens, aspheric and hand ground/polished, that was either made from optical glass or transparent quartz. The price of both was very high, with the same money you could buy three Ford model T!

If you dig through the pile of BS, you find some truth, though. Old low-elements optics often give pictures that are more "rounded". He is right about that, if you convert to grayscale there is a wider, richer spectrum of grays, especially visible at the two ends, deep shadows and strong highlights.

As I already mentioned a "proper" soft focus lens, I'm going to explain why it's naive to compare a lens to a computer.
You don't need a super clinic lens to capture the maximum of information, that could eventually be degraded/enhanced/morphed/whatever afterwards by an algorithm. It is the sensor that does it. All lenses provide the same amount of data. It's the quality of that data that is not the same.
Interpolation, or if you prefer fabricating pseudo sharpness in a slightly blurry image is almost as difficult as faking the exact sharpness-meets-halo of a true soft focus lens.
I'm sure there are bitmap wizards who can work with plug-ins and layers, plus a considerable amount of time, and get almost there... but it's not photography anymore, at least not the kind of photography I like. It gets pretty close to graphic art.
The day this kind of process is made as simple as a couple of clicks and available to everyone, it would be the programmer who makes most of the esthetic choices, not the photographer.

I like vintage optics, I really do, and because I do I also know that generalizing a judgment, either good or bad, makes no sense at all. I often shoot in manual focus, the pleasure of using a smooth, well built object with pleasant ergonomics have a positive impact on the quality of the pictures. Though build quality is secondary, if optical quality is not at the same level.
To be more precise, a vintage lens that is purchased with the intention to use it as a picture-taking tool has to give something that a reasonably priced modern zoom can't offer. Other way it's a collector item.
I'm fine with it, but I'm aware that the scope is different.
I own a large number of vintage lenses (BTW, most of them are linked to my signature, so whoever got curious can check my tastes) and I really treasure a few of them, but since the beginning I always tried to have a reasonable answer to the question "why I want to buy it?"
Of the many, many lenses I could mount on the K-1 that sits on the table in front of me while I'm writing these lines, very few were hoarded just for the sake of it. I tried to always have a reason. There can be many.
One is economical. I can't have the A Star 1.8/135mm, I'll buy a cheaper alternative!
Another one is affection, or historical interest. I thought that the last designs by a genius like Bertele should have been good enough, so I purchased the Schacht 2.8/35mm.
Then there is the pleasure of handling (and using!) a well made example of opto-mechanic, but the main reason is the hope, that with time becomes an educated guess, of finding a new paintbrush, or a new color for the palette, that would in some way help me develop my own humble way of painting with the camera.
There is no way a software algorithm could create the bubble bokeh of a Trioplan out of a far, out of focus highlight. Maybe one day it will, but I'm not holding my breath.
The same way, at a much subtle level, a simple design could help getting a fuller grayscale gradation, and a single coated, or even uncoated lens could get even further preventing "burning" the extreme highlights.

In the end, it's up to our own individual taste, with the caveat that when differences get subtler, the response of the casual viewer could differ from that of an educated eye... but all this has been already written, over and over



QuoteOriginally posted by Rondec Quote
I think most folks judge photos based on lighting, composition and subject and less on rendering of a particular lens. The lenses that stand out most to me, that I can recognize right off without looking at exif, are those like the Soligor which are pretty rough, in my opinion, but I guess some people love them.
Of course you are right. In most pictures the choice of the lens is barely noticeable (if at all possible). In a few cases the particular lens "makes" the shot.
Regarding Soligor, I think it would be useful if you specified which lens you are referring to.
There are Soligors and Soligors... at that time, the worst of the worst were the Korean lenses, by almost unanimous consensus. I wouldn't use the name Soligor as an example of horrible optics. Maybe at the very end they rebranded some terrible Samyang... the same brand of a terrific 35mm I really treasure, and of a 24mm that I just bought with high expectations (with the hope it won't come decentered).
Things can change a lot over the years...
Back to Soligor, a few primes I own are quite good (the best are made by either Kino or Tokina). I have no zooms though.

EDIT
Re: flimsy AF construction.
I'm sure there are others more versed in optics who could go much deeper. I'm just reminding the readers that there are optical designs that are quite impervious to mis-spacing.
Move the central element of a simple Cooke triplet : you get a soft focus lens!
Change the distance of the two halves of a Plasmat, and you've only changed the conjugate the lens was optimized for (read: it will be better at infinity or at close range).
I suspect Pentax and other lens makers have considered the wobbliness of some AF lenses when they designed the relative optics.
Not sure if decentering can be easily compensated for. I'm totally ignorant in that regard

Cheers

Paolo

Last edited by cyberjunkie; 12-27-2017 at 03:56 AM.
12-27-2017, 04:42 AM   #45
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I think you have to revise those numbers, at 30% reflectance that is a mirror. AFAIK it's more like 5% for uncoated glass - much less with modern multi-coating, but take it with a grain of salt.
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