[photoptimist]

"Men of genius do not excel in any profession because they labor in it, but they labor in it because they excel."

W. Hazlitt

---------- Post added 01-11-19 at 10:57 AM ----------




Thanks for proving my point photoptimist. The DA21 as you pointed out followed the same basic optical design as the M20 to create a small compact wide angle lens.

Is everyone now going to deny that the DA40 ƒ2.8 LTD was modeled after the M40 ƒ2.8?

All lenses share a small number "basic optical designs" but that does not mean that making a new lens modeled after an old lens is easy and cheap.

The cost of "updating" the FAs would be small if the only change was an update to the coatings. Adding an electronic aperture might not be too expensive although it would probably entail redesigning some aspects of almost all of the parts from the aperture to the mount.

Adding in-lens focus motors to some smaller lenses might not be too expensive as long as AF speed can be slow. But AF on some larger lenses or fast AF on any lens would be require a ground-up redesign for internal focusing. Adding WR might also force a ground-up redesign to reduce how much of the optical assembly has to move.

Reducing CA/PF or vignetting is not a tweak on a basic optical design, it is an entirely new design. Although a low-resolution drawing of one lens might look similar to that of another lens, the exact dimensions will be entirely different for every element, spacer, and moving part and that will need engineering work.

People think they are asking for easy minor updates, but much of what they want would require an entirely new lens design even if it seems similar to the old design.

[Trickortreat]

Probably going into their calculations is that many APS-C enthusiasts who buy the DAs, like me, are cheap. Or frugal.

Somebody should break it to them that it isnt true. Look at Fuji for exalmpe. They sell crop stuff at premium price because *gasp* people just want smaller and lighter an are prepared to pay premium for it.

[c.a.m]

Edit: I was typing while @photoptimist was posting above. I think we're thinking along the same lines. Systems engineering backgrounds?


The notion of "tweaking" or updating a lens design might suggest that it's a relatively easy task.

However, systems that are tightly integrated -- such as optical lenses -- have been designed so that all components contribute to the design objectives and technical requirements precisely. For lenses, design objectives would include focal length, aperture, optical performance (quantitative and qualitative), physical dimensions, mass, balance, electrical power, operating temperature limits, autofocus speed and tolerances (e.g., focus throw, gears), manual focus haptics, among others. The lens system includes the optical elements and their coatings, structural elements, lubricants, mechanical components, fasteners, electrical and electronic elements and assemblies, and others. There are many trade-offs amongst these objectives and design choices, and the designer also must work within specified financial cost constraints.

In this type of tightly integrated system, "tweaking" one design objective can perturb many design elements, depending on the extent of the system design 'trade space'. It's more reasonable to think of a "re-design" that would reset all of the design objectives and requirements while encompassing modern materials and methodologies. The designer would then start from the ground up, so to speak.

Of course, a new lens might be based on certain key design objectives of an existing one -- a designer might wish to achieve a similar physical size or mass, focal length, or widest aperture, for example. But it's not a simple matter of doing minor adjustments to, say, a previous optical formula or to insert a new autofocus motor or gear train, or wedge in environmental seals.

[ThorSanchez]

Somebody should break it to them that it isnt true. Look at Fuji for exalmpe. They sell crop stuff at premium price because *gasp* people just want smaller and lighter an are prepared to pay premium for it.

Fuji people might want to pay a premium! I think there are at least a few of us here at Pentax Forums instead of Fuji Forums because we liked the idea of sub-$1000 prosumer bodies and DA limiteds that are $300-500 used (or less - I was patient and got the 15 and the 40 LTDs for less than $500 total).

I looked a number a months ago, and if I sold all my Pentax stuff I'd have just enough to get a good Fuji body and maybe two lenses. It would set me back five years.

[clackers]

Nope. 85mm beats the 50mm as bokeh machine. And 50mm is too narrow or not long enough for night photography. And there is a true need for fast aperture for night photography due longer exposures prone to more dark current noise or shorter exposure requiring high ISO, scene being at infinity DoF isn't a concern, and wide aperture helps a lot in the exposure time/ISO equation. The reason why 50mm was popular in SLR day was that 50mm is close to actual distance between lens mount and film plane, making the design of fast 50 cheap enough for using delivery as kit lens. While 50mm makes it easier to reach the best possible optical performance, the 50mm FL in combination of wide aperture itself isn't that useful. The DFA*50 is luxury lens, like luxury cars, it's a pleasure to own and fun to use, but there are other cars that are better designed for usefulness.

If you look at one of the Pentax interviews they confirm the 50mm was the most desired, so they rearranged their priorities.

The fifty isn't the heart of brands' prime systems hust because it's easiest, on FF it's the most useful.

Canon have just one prime for their EOS-R. Guess what it is?

[Kunzite]

Fuji people might want to pay a premium, while Pentax people might not even want to pay a fair price. That's how hype works.

---------- Post added 11-01-19 at 07:22 PM ----------

Canon have just one prime for their EOS-R. Guess what it is?

Yes, interesting how the Canon's is most acclaimed, while Pentax... "why have they done that and not something different?".

It's always "why not something different?" with Pentax. It excuses people from putting money where their mouth is; after all, why would you buy something, when you wanted something else?

[Rondec]

All lenses share a small number "basic optical designs" but that does not mean that making a new lens modeled after an old lens is easy and cheap.

The cost of "updating" the FAs would be small if the only change was an update to the coatings. Adding an electronic aperture might not be too expensive although it would probably entail redesigning some aspects of almost all of the parts from the aperture to the mount.

Adding in-lens focus motors to some smaller lenses might not be too expensive as long as AF speed can be slow. But AF on some larger lenses or fast AF on any lens would be require a ground-up redesign for internal focusing. Adding WR might also force a ground-up redesign to reduce how much of the optical assembly has to move.

Reducing CA/PF or vignetting is not a tweak on a basic optical design, it is an entirely new design. Although a low-resolution drawing of one lens might look similar to that of another lens, the exact dimensions will be entirely different for every element, spacer, and moving part and that will need engineering work.

People think they are asking for easy minor updates, but much of what they want would require an entirely new lens design even if it seems similar to the old design.

Very much so. I do think the HD modifications to the DA limiteds were much more along the tweak variety. New coatings and rounded aperture blades.

The thing is that in general the issue isn't the optical formula that is difficult to come up with -- that's done with computer modeling. It is figuring out how to get everything to work perfectly together with a camera's auto focus module and then figuring out the manufacturing processes necessary to build high quality lenses without a lot of duds.

[Mistral75]

(...)

Canon have just one prime for their EOS-R. Guess what it is?

The RF 35mm f/1.8 IS STM Macro?

[y0chang]

An HD re-release of the FA limited line would be nice. The FA limiteds only really have one major weakness and that is flare control. And right now the limiteds are still under production, the plastic-era FA would require a whole new production line since the molds, lens components, and electronics and such are long long gone, Its not like they can just turn on a line that made 20 to 30 year old lenses on and say start it back up again.

[clackers]

The RF 35mm f/1.8 IS STM Macro?

They do have that as well as their 50mm f1.2, Mistral, thanks for the correction.

It's Nikon who only have a fast fifty, an eccentric 58mm f0.95.

Neither company have started with an 85mm, but like Pentax I'm sure will add one.

[y0chang]

it seems Pentax has the resources right now to only do one lens at a time, and no matter which choice they make, it will make one group unhappy. I think that the 70-300 makes the most sense since it will cater to the largest group of folks. Crop users want something that resolves better than the 55-300mm and the full frame users have no modern zoom lens in that range unless you want to spend 1500 for a f2.8 lens combined with a 300mm f4.

[repaap]

Well regardless, 50 mm is the one and only normal lens for all enthusiastick photographers. More so on FF. 85 already is special purpose lens. So is 35 mm.

---------- Post added 01-11-19 at 20:46 ----------

it seems Pentax has the resources right now to only do one lens at a time, and no matter which choice they make, it will make one group unhappy. I think that the 70-300 makes the most sense since it will cater to the largest group of folks. Crop users want something that resolves better than the 55-300mm and the full frame users have no modern zoom lens in that range unless you want to spend 1500 for a f2.8 lens combined with a 300mm f4.

Yes, new 70-300 prosumer lens makes a lot of sense.

[Rico]

All lenses share a small number "basic optical designs" but that does not mean that making a new lens modeled after an old lens is easy and cheap.

The cost of "updating" the FAs would be small if the only change was an update to the coatings. Adding an electronic aperture might not be too expensive although it would probably entail redesigning some aspects of almost all of the parts from the aperture to the mount.

Adding in-lens focus motors to some smaller lenses might not be too expensive as long as AF speed can be slow. But AF on some larger lenses or fast AF on any lens would be require a ground-up redesign for internal focusing. Adding WR might also force a ground-up redesign to reduce how much of the optical assembly has to move.

Reducing CA/PF or vignetting is not a tweak on a basic optical design, it is an entirely new design. Although a low-resolution drawing of one lens might look similar to that of another lens, the exact dimensions will be entirely different for every element, spacer, and moving part and that will need engineering work.

People think they are asking for easy minor updates, but much of what they want would require an entirely new lens design even if it seems similar to the old design.

Your last sentence really sums up the crux to the discussion on this topic. What I am asking for and what half a dozen or more people the last day and half are claiming can not be done have nothing to do with what I have said. Everything they are saying silent motors fixing purple fringing etc etc etc etc have nothing to do with what I have suggested.

It is pretty clear when Pentax became fully engaged in the digital age they set in motion a plan to create 3 lenses the DA LTD 21 40 and 70 that clearly were modeled after the FA LTD's build, form factor and concept. Pentax removed the aperture ring and added Quickshift to the design. The DA LTD's were designed specifically for APS-C which is the singular reason they didn't just do the same thing to the FA LTD's because at the time Pentax was not interested in FF.

Now that we have FF digital going on 3 years Ricoh/Pentax should release DFA LTD's with QuickShift and without aperture rings. It would be nice for some simple WR like an O-ring flange at least. Adding WR would most likely even dampen the "noise" to the mechanical aspect of the screw drive mechanism. But somehow PF users think this can not be done without somehow drastically altering the FA LTD's even though the production of the DA LTD's contradicts everything they are claiming can not be done. i.e. removing the aperture ring and adding Quickshift.

Once I knew Ricoh/Pentax was going to produce a FF body I didn't buy any more DA lenses. This comes back to what I said earlier that Pentax should consolidate some of the DA LTD line to cover FF most especially the DA21 which would fill that Ultra Wide angle spot for FF instead of creating an entirely separate UWA FF lens as the lens roadmap has indicated.

[Mistral75]

They do have that as well as their 50mm f1.2, Mistral, thanks for the correction.

It's Nikon who only have a fast fifty, an eccentric 58mm f0.95.

Neither company have started with an 85mm, but like Pentax I'm sure will add one.

You're more than welcome.

As for Z mount prime lenses Nikon have a 35mm f/1.8 and a 50mm f/1.8 available for purchase, a manual focus 58mm f/0.95 at prototype stage, a 24mm f/1.8 and an 85mm f/1.8 on their roadmap for 2019 and a 20mm f/1.8 and a 50mm f/1.2 on their roadmap for 2020.

So three fifty-ish lenses, of which one available, versus one roadmapped 85mm.

[Rico]

Edit: I was typing while @photoptimist was posting above. I think we're thinking along the same lines. Systems engineering backgrounds?


The notion of "tweaking" or updating a lens design might suggest that it's a relatively easy task.

However, systems that are tightly integrated -- such as optical lenses -- have been designed so that all components contribute to the design objectives and technical requirements precisely. For lenses, design objectives would include focal length, aperture, optical performance (quantitative and qualitative), physical dimensions, mass, balance, electrical power, operating temperature limits, autofocus speed and tolerances (e.g., focus throw, gears), manual focus haptics, among others. The lens system includes the optical elements and their coatings, structural elements, lubricants, mechanical components, fasteners, electrical and electronic elements and assemblies, and others. There are many trade-offs amongst these objectives and design choices, and the designer also must work within specified financial cost constraints.

In this type of tightly integrated system, "tweaking" one design objective can perturb many design elements, depending on the extent of the system design 'trade space'. It's more reasonable to think of a "re-design" that would reset all of the design objectives and requirements while encompassing modern materials and methodologies. The designer would then start from the ground up, so to speak.

Of course, a new lens might be based on certain key design objectives of an existing one -- a designer might wish to achieve a similar physical size or mass, focal length, or widest aperture, for example. But it's not a simple matter of doing minor adjustments to, say, a previous optical formula or to insert a new autofocus motor or gear train, or wedge in environmental seals.

Ok so you focused in on my use of the word "tweak". Mistrial posted links to the optical design of the DA21 and M20. The difference between the two is the DA 21 takes the 8 element 8 group design fo the M20 making it an 8 element 5 group design. Looks like a "tweak" to me. It doesn't look like some complete overhaul that drastically changes the design to say the 10 element 9 group of the A and FA 20mm ƒ2.8 or even the 12 element 10 Group design of the K 20 ƒ4.