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08-08-2022, 05:20 AM - 3 Likes   #241
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QuoteOriginally posted by Apas Quote
Well, they might replace just one element with identical one but made with some special glass, like FLD or SLD and that's it
Respectfully, that's a bit naive. If you replace an element with another with different properties, you change the light path. So your lens doesn't work as it did, doesn't focus where it used to, etc. If you change an element for a new one with different optical properties, you have to revisit the whole design. It might be possible to limit the impact of those changes, keep them to a few specific elements, but in most cases it's going to be simpler to just adapt the whole design. you can work with the same size and weight constraints, however, keeping the outer barrel similar.

08-08-2022, 07:13 AM   #242
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QuoteOriginally posted by bdery Quote
Respectfully, that's a bit naive. If you replace an element with another with different properties, you change the light path. So your lens doesn't work as it did, doesn't focus where it used to, etc. If you change an element for a new one with different optical properties, you have to revisit the whole design. It might be possible to limit the impact of those changes, keep them to a few specific elements, but in most cases it's going to be simpler to just adapt the whole design. you can work with the same size and weight constraints, however, keeping the outer barrel similar.
That's what makes this so interesting. How little did they have to change. Hopefully they'll give detailed info on the changes at some point. I suspect it's an excercise in absolute minor changes to make it worthwhile instead of just doing a completely new lens. Just how minor is the question.
08-08-2022, 07:41 AM   #243
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QuoteOriginally posted by house Quote
That's what makes this so interesting. How little did they have to change. Hopefully they'll give detailed info on the changes at some point. I suspect it's an excercise in absolute minor changes to make it worthwhile instead of just doing a completely new lens. Just how minor is the question.
As far as I'm concerned I don't particularly care how major or minor as long as the results are noticeably improved without introducing new negatives. An improved OOC image is important, the changes required to get there not so much. I noticed a recent Tamron lens update leaves it looking and feeling essentially like the original, but the better performance has been noticed by purchasers.
08-08-2022, 08:18 AM - 1 Like   #244
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QuoteOriginally posted by gatorguy Quote
As far as I'm concerned I don't particularly care how major or minor as long as the results are noticeably improved without introducing new negatives.
As a photographer , only the result counts. But some people are also interested in lens designs, they are trying to understand what optical changes have been done on the new version of the 100 macro lens.

08-08-2022, 10:01 AM   #245
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QuoteOriginally posted by Apas Quote
Well, they might replace just one element with identical one but made with some special glass, like FLD or SLD and that's it, fringing may be reduced. But IMHO this particular lens have two other problems: no AF limiter and screwdriver AF. Having these addressed as well, the dfa100 would be much more versatile and would be used as telephoto / long portrait lens (I know that many people using current version that way with some great results, but AF is problematic then) ...
Umm, no. Individual elements are part of a system. Change one and the entire system needs to be redesigned.
This isn't like putting a loud muffler on a car.
I've found over the decades that what makes a macro lens good for macro work makes it less than ideal for portraiture. This is why I have six lenses from 77mm to 105mm, 3 of which are macro lenses.
08-08-2022, 11:06 AM   #246
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QuoteOriginally posted by house Quote
That's what makes this so interesting. How little did they have to change. Hopefully they'll give detailed info on the changes at some point. I suspect it's an excercise in absolute minor changes to make it worthwhile instead of just doing a completely new lens. Just how minor is the question.
On one hand, preserving some of the existing jigs and tooling is economical, but if they need to spend an extra 3 months in R&D to do so, then it stops being a good idea. The cost of a jig is often less than the ost of getting 6 people in a room for an hour to agree on it.

If I was optimizing a lens already globally well regarded, I would not concentrate on reusing existing stuff, but rather on actually improving the lens. That way I might entice existing users to purchase the lens. I might also have the opportunity to include things learned since designing the original lens, to further reduce manufacturing or testing costs.
08-08-2022, 11:48 PM - 1 Like   #247
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One interesting thing is that Tokinas version of this lens got an recent update (less than 3 years ago) and now include two Super Low Dispersion lens elements and two Aspherical lens elements. I do not think they have been included on earlier versions Tokinas 100mm macro.
https://tokinalens.com/product/atx_i_100mm_f2_8_ff_macro/

I wonder if it is the same change that will be introduced on the Pentax lens too? And that the actual lens design was made at least 4-5 years ago by Ricoh, but it is not until now that it made sense for Ricoh to start producing it?
I'm no optical designer, but SLD should improve on chromatic aberration, and the aspherical lens elements may be for correcting the use of SLD elements.

It would not be the first time that Tokina released a Ricoh/Pentax design earlier than Ricoh/Pentax.

08-09-2022, 12:03 AM   #248
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QuoteOriginally posted by Fogel70 Quote
One interesting thing is that Tokinas version of this lens got an recent update (less than 3 years ago) and now include two Super Low Dispersion lens elements and two Aspherical lens elements. I do not think they have been included on earlier versions Tokinas 100mm macro.
https://tokinalens.com/product/atx_i_100mm_f2_8_ff_macro/

I wonder if it is the same change that will be introduced on the Pentax lens too? And that the actual lens design was made at least 4-5 years ago by Ricoh, but it is not until now that it made sense for Ricoh to start producing it?
I'm no optical designer, but SLD should improve on chromatic aberration, and the aspherical lens elements may be for correcting the use of SLD elements.

It would not be the first time that Tokina released a Ricoh/Pentax design earlier than Ricoh/Pentax.
That's certainly interesting. The optical diagram looks identical to the dfa100 but as you mention they claim to have added special glass!

Bdery what's your view on that?
08-09-2022, 12:37 AM   #249
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It may be. Though, remember that the same optical blue print is often labelled differently e.g. Tamron and Pentax version of the 24-70/2.8 (I think that's the one) regarding use of special glass.
08-09-2022, 01:24 AM   #250
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QuoteOriginally posted by thibs Quote
It may be. Though, remember that the same optical blue print is often labelled differently e.g. Tamron and Pentax version of the 24-70/2.8 (I think that's the one) regarding use of special glass.
The labelling differs between the DFA70210 and the Tamron equivalent. Thing is that the DFA100 formula is ancient and it sounds unlikely that they used aspherics and "super ed" in that first version? Similarly it seems unlikely that Tokina just lies about the changes to the new version of the lens. The DFA100 doesn't show any onion rings does it? I mean if they secretly put two asphericals in there it would show right?

It's also interesting if Pentax designed the lens and had it ready for 2019 and then waited to 2022 to announce it for Pentax. They must have had huge stock. It could of course be a different design than the "newish" Tokina but this lens quite an interesting case.

Edit: you were correct about the DFA2470 as well. The Anomalous dispersion asph is just an asph on the Tamron and the XR elements are unlabelled on the Pentax.




Last edited by house; 08-09-2022 at 01:57 AM.
08-09-2022, 02:07 AM - 1 Like   #251
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QuoteOriginally posted by house Quote
The labelling differs between the DFA70210 and the Tamron equivalent. Thing is that the DFA100 formula is ancient and it sounds unlikely that they used aspherics and "super ed" in that first version? Similarly it seems unlikely that Tokina just lies about the changes to the new version of the lens. The DFA100 doesn't show any onion rings does it? I mean if they secretly put two asphericals in there it would show right?

It's also interesting if Pentax designed the lens and had it ready for 2019 and then waited to 2022 to announce it for Pentax. They must have had huge stock. It could of course be a different design than the "newish" Tokina but this lens quite an interesting case.

Edit: you were correct about the DFA2470 as well. The Anomalous dispersion asph is just an asph on the Tamron and the XR elements are unlabelled on the Pentax.



I completely agree with everything. It's just that it is difficult to come to a conclusion, yet.
Very interesting case though, looking forward to a proper conclusion on this.
08-09-2022, 05:14 AM - 3 Likes   #252
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QuoteOriginally posted by house Quote
The optical diagram looks identical to the dfa100 but as you mention they claim to have added special glass!

Bdery what's your view on that?
I don't think anyone can draw actual conclusions based on drawings shown on a public website. I know *I* would never agree to have the details of my own private and complex designs available for all my competitors to see. Those drawings are instructive but not to be taken as fully accurate.

The Tokina has a much wider diameter, for the record, maybe that's just how they built it, maybe that's for a reason.

QuoteOriginally posted by house Quote
it sounds unlikely that they used aspherics and "super ed" in that first version?
Aspherics, absolutely. It's been around for, what, a hundred years?

"Super ED" is just a label. Controlling dispersion has also been of interest for optical designers for quite some time.

Again, you cannot just swap components in a design. If you replace an element by another which does different things with the light paths, then the whole design needs to be revised. Sometimes effects are minimal, sometimes not.

See it this way. If element 3 on the optical path outputs light in a different way, then element 4 isn't getting it where expected, and can't direct it where it should. So element 4 needs to be adapted too, and so on and so forth.
08-09-2022, 05:30 AM   #253
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QuoteOriginally posted by bdery Quote
The Tokina has a much wider diameter, for the record, maybe that's just how they built it, maybe that's for a reason.
The Tokina reminds a lot more of the Pentax F 100/2.8 Macro, the first lens released with this optical formula in 1987. With aperture ring (Nikon version), same type of focus limit switch and a focus scale window as the original Pentax version.
SMC Pentax-F 100mm F2.8 Macro Reviews - F Prime Lenses - Pentax Lens Reviews & Lens Database
08-09-2022, 06:21 AM   #254
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There is a lot of chatter on this thread and I don't have the current DFA 100mm 2.8 macro so I cant really speak to it much but it seems like a very fine lens. Besides the slowish focusing what is it that is missing? I certainly wouldn't expect a different magnification but who knows.
08-09-2022, 07:11 AM   #255
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Are folks trying to figure out how the design of this upcoming lens is different from the current D-FA 100mm WR Macro by comparison of the current lens to what Tokina is advertising for their flavor of the same current lens? What bearing does that have on this?

I think we'll just have to wait and see.
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