[biz-engineer]

I don't know either but a reviewer shooting the DFA21 on K-1 and some Sony body noted that the lens shot on Sony showed less dispersion. Now that could either be software corrections or a different sensor stack.

Sony camera sensors make all lenses sharper due to the layer of micro lenses that is on top of the CFA layer. Pentax K1 uses previous generation sensor CFA top layers from the original A7 and D800E/D810, generates less false colors / moiré patterns, but also deliver 20% to 30% less micro-contrast, because wider pixel aperture acts as low pass filter. So if you look at lens tests on ephotozine performed with the K1 or K1II, all test charts max out at 3000LP/PH, while the same (Tamron) lenses tested on Sony A7RIII (next gen CFA layer) test charts rise up to 4500 LP/PH. You get the same sharpness from the K1 via sharpening radius < 1 pixel to boost pixel to pixel contrast. If you look at the DFA*85 1.4, the resolution chart is almost flat at 3000LP/PH up to about f/16, that's because the K1 sensor limits how much micro-contrast from the lens converts into image sharpness.

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Last edited by biz-engineer; 09-21-2022 at 10:50 AM.

[repaap]

Sharpness is over rated. Besides those sony images and also video image does look too sharp. People end up using mist filters to bring it down in their videos..

[Serkevan]

Sharpness is over rated. Besides those sony images and also video image does look too sharp. People end up using mist filters to bring it down in their videos..

It definitely is. Beyond a certain point, it's "sharp enough". And nowadays, even cheap-ish zooms are comfortably at that point. Back then, many trans-standard zooms were much more of a compromise.

[DagT]

Do you know of any such examples? I don't.

Certainly. After working as a patent attorney for almost 30 years :-)
A patent can end up with anything from nothing to a whole class of products, Depending on how smart the solution was and how the granted patent claims are phrased.

[Kunzite]

Certainly. After working as a patent attorney for almost 30 years :-)

Let me rephrase that. Do you know of any such examples, that is, more than one of the possible implementation examples from an optical design related patent being implemented, that is, made into actual lenses people can buy?

You are talking generically; I don't, and you shouldn't. Clearly you're right in the general sense, but here it's about Pentax.

[DagT]

Let me rephrase that. Do you know of any such examples, that is, more than one of the possible implementation examples from an optical design related patent being implemented, that is, made into actual lenses people can buy?

You are talking generically; I don't, and you shouldn't. Clearly you're right in the general sense, but here it's about Pentax.

Why do you think there can be only one product per patent? Why limit the case to Pentax? They have obviously licenced form others throught the years.

If they did something revolutionary, like the first zoom lens (U.S. Patent 696,788) why would they only use it in one lens? If they found something that may work in different lenses, why limit it? The patent claims do not limit the protection to only one of the solutions.

Don't you think the old fish-eye patent US3515462A has been used for more than one lens?

[Rondec]

I thought the whole point of the numerous examples was simply to provide protection from other brands using the same optical formula in a lens. Often some of the examples are unlikely to happen -- they require a shorter registration distance or have really odd aperture/focal length combinations.

[DagT]

I thought the whole point of the numerous examples was simply to provide protection from other brands using the same optical formula in a lens. Often some of the examples are unlikely to happen -- they require a shorter registration distance or have really odd aperture/focal length combinations.

Both may happen. Every patent has degrees of preferred embodiments, and examples that you use to widen the area around the patent stopping others from getting too close. You use the specification to publish what you don't want others to patent and the claims to stop others from making similar products. Of course the scope of the latter will often decrease during the prosecution, maybe ending up with the preferred embodiment while the surround area is maintained.

If your patent also covers embodiments that you don't intend to use you can licence them to someone else, possibly trading patents.

If you find a solution that, for example, can simplify internal focussing for a certain type of lenses of course you may want to use that several lenses. The examples in the patent are not limiting, you may choose to use patented solution in lenses that have not been suggest. You may even for strategic reasons omit mentioning a lens that you intend to produce.

This is why I don't really consider patents as a prediction of future lenses.

---------- Post added 22-09-22 at 14:01 ----------

Just for fun, here's a machine translation of the independent claim. Sadly, thay have not applied for a patent outside Japan, which could indicate a low interest in the idea. It seems that the most important aspect of the patent application is how they move two focussing lens groups. I think this can be used in many different lenses.

[Claim 1]
Sequentially from the object side, comprise an object side lens group, an aperture
diaphragm, and an image side lens group, and, [ an object side lens group ]
Sequentially from the object side, have the 1st lens group of the object side, and
the 2nd lens group of the object side, and, [ an image side lens group ] Sequentially
from the object side, the *** 1 lens group of positive refracting power, and the
image side intermediate lens group, Comprise an image side last lens group and the
variable power from a short focal length end to a long focal length end is faced, The
interval of the 1st lens group of the object side, and the 2nd lens group of the
object side, the interval of *** 1 lens group and the image side intermediate lens
group, And the interval of the image side intermediate lens group and the image side
last lens group changes, and, [ at least one copy of the 2nd lens group of the object
side ] Have the object side focussing-lens group which moves to optical axis
direction at the time of the focus to a short distance from infinite distance, and, [
at least one copy of the image side intermediate lens group ] The variable power
optical system characterized by what it has the image side focussing-lens group which
moves to optical axis direction at the time of the focus to a short distance from
infinite distance, and the object side focussing-lens group and the image side
focussing-lens group move to optical axis direction by each other different locus at
the time of the focus to a short distance from infinite distance.

[reh321]

Sharpness is over rated. Besides those sony images and also video image does look too sharp. People end up using mist filters to bring it down in their videos..

Perhaps for landscapes and wedding pictures. For the ‘remembrances’ I take, there can never be enough true sharpness.

[Kunzite]

Why do you think there can be only one product per patent? Why limit the case to Pentax? They have obviously licenced form others throught the years.

Why limit the case to lenses? Why limit the case to patents? Why limit the case to, well, anything, including this Universe?

This is about the expectations we can draw from a Pentax lens patent, and as I said I'm not aware of more than one of the possible implementation examples being actually implemented.
Every single time, the people saying "they'll do this, and this, and that - because that's what the patent says" were wrong.

[repaap]

Perhaps for landscapes and wedding pictures. For the ‘remembrances’ I take, there can never be enough true sharpness.

Yeah, it is nice to have. but if one is talking about these modern lenses, like DFA*85 or DFA 21 limited having 'just 3500' what ever sharpness. and some lenses having 4550 or what not. It is not actually something someone would have to worry about. All of this grade lenses (talking about DFA 24-90/4 should it happen some day or not) will be good enough in terms of sharpness. They are designed for digital sensors. Even some old designs can cut it. And there sharpness is not the only merit, especially FA limiteds or so.. but even most recent DFA and DFA * and DFA limited lenses are designed to please the eye. -my main reason to keep shooting and buying Pentax even if I use other brands for my work too(mainly for video/hybrid)

[pres589]

It seemed like the D-FA 28-105 cut the mustard in regards to general IQ including sharpness. I've never used one but I've seen lots of sample shots that made it seem like a very good all-arounder. If this 28-90 f4 can act the same, hopefully through the entire zoom range*, then it's a winner. When's the last time Pentax put their name on an optically weak lens? The days of putting a lens like the DA 50-200, just to get something out on the market, seems dead and gone a long time ago. I can't imagine worrying about general sharpness of this lens.

* - I know that this a tall order and is in the eye of the beholder. I've got faith in Pentax on this.

[DagT]

Why limit the case to lenses? Why limit the case to patents? Why limit the case to, well, anything, including this Universe?

This is about the expectations we can draw from a Pentax lens patent, and as I said I'm not aware of more than one of the possible implementation examples being actually implemented.
Every single time, the people saying "they'll do this, and this, and that - because that's what the patent says" were wrong.

OK, so this is some kind of expectation based on the latest patents. That is kind of vague. What if they had found something really smart this time?

As you can see above the patent relates to a lens where they move two internal focussing lens groups in a certain way. Why cannot this be used for more than one lens? There is nothing in the rest of the claim that makes this limit.

Du you think the first patent on internal focussing only was used in one lens? Actually, as they havent filed outside Japan I doubt that it will be used at all.

[Kunzite]

OK, so this is some kind of expectation based on the latest patents. That is kind of vague. What if they had found something really smart this time?

As you can see above the patent relates to a lens where they move two internal focussing lens groups in a certain way. Why cannot this be used for more than one lens? There is nothing in the rest of the claim that makes this limit.

Du you think the first patent on internal focussing only was used in one lens? Actually, as they havent filed outside Japan I doubt that it will be used at all.

Yes, it's about sites and people getting too enthusiastic and say stuff like "Pentax is preparing a bunch of lenses!". Happens about every single time we find out about such a patent.

No, it won't be different this time either. Please pay attention to what I'm saying, it's not "they'll never use this patent again" - but rather "no, they're not preparing a 24-70 and an 18-300 and a micro 4/3 lens..."

I hope it's clear now and we can leave this subject behind.

[biz-engineer]

I hope it's clear now and we can leave this subject behind.

I think I left the subject behind right from the start