[WorksAsIntended]

I never said there is nothing they do. I was just curious what they actually precisly promise to do and did not read up the claims before.

I can agree that certain things may be better with specific coatings, esp if you got specific wavelenght ca issues which in some cases also influences micro contrast.

On this level I can totally agree.

@MickeyBugs: It is rather easy, just use a single layer of hairspray and measure the correspnding wavelenghts in an angle giving those results. It even works with water. The amount reflected is highly depended on angle and polarisation, even ignoring a lot of other parameters. Those graphs are obviously not at 0rad, as this would mean 100% transmission rate in traditional optics and at least 0% reflection rate in quantum optics (which not necessarily means 100% transmission). So which angle did they measure?
@Kunzite: I originally asked how coating is supposed to work and got answers that obviously lacked by scientific background.

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Last edited by BigMackCam; 01-17-2020 at 04:44 PM. Reason: Edited for member's benefit (see my previous post)

[RobA_Oz]

I never said there is nothing they do. I was just curious what they actually precisly promise to do and did not read up the claims before.

I can agree that certain things may be better with specific coatings, esp if you got specific wavelenght ca issues which in some cases also influences micro contrast.

On this level I can totally agree.

@MickeyBugs: It is rather easy, just use a single layer of hairspray and measure the correspnding wavelenghts in an angle giving those results. It even works with water. The amount reflected is highly depended on angle and polarisation, even ignoring a lot of other parameters. Those graphs are obviously not at 0rad, as this would mean 100% transmission rate in traditional optics and at least 0% reflection rate in quantum optics (which not necessarily means 100% transmission). So which angle did they measure?
@Kunzite: I originally asked how coating is supposed to work and got answers that obviously lacked by scientific background.

Without knowing which studies you referred to, it’s difficult to know what you find unconvincing about this. It is, of course, accepted by most users, that modern multi-coated systems considerably reduce flare, at the very least. Chromatic aberration, as I understand it, is caused by the medium, rather than the interface, so I’m at a loss to see how that can be a coatings issue – happy to read further, though.

[reh321]

I never said there is nothing they do. I was just curious what they actually precisly promise to do and did not read up the claims before.

I can agree that certain things may be better with specific coatings, esp if you got specific wavelenght ca issues which in some cases also influences micro contrast.

On this level I can totally agree.

@MickeyBugs: It is rather easy, just use a single layer of hairspray and measure the correspnding wavelenghts in an angle giving those results. It even works with water. The amount reflected is highly depended on angle and polarisation, even ignoring a lot of other parameters. Those graphs are obviously not at 0rad, as this would mean 100% transmission rate in traditional optics and at least 0% reflection rate in quantum optics (which not necessarily means 100% transmission). So which angle did they measure?
@Kunzite: I originally asked how coating is supposed to work and got answers that obviously lacked by scientific background.

As an undergraduate, I majored in Mathematics and minored in Physics, including a course entitled “Intermediate Optics”. Personally, I can handle the calculations involved in calculating how coatings work, but like many here, I do not care. I have seen Pentax lenses at work, and that is enough for me. This is very simple. If you do care, see what, if anything, has been written on the subject.

[BigMackCam]

One more time, everyone - let's move on from this... please.

Help me help you?

[clackers]

One more time, everyone - let's move on from this... please.

Help me help you?

Aye.

[Rondec]

I never said there is nothing they do. I was just curious what they actually precisly promise to do and did not read up the claims before.

I can agree that certain things may be better with specific coatings, esp if you got specific wavelenght ca issues which in some cases also influences micro contrast.

On this level I can totally agree.

@MickeyBugs: It is rather easy, just use a single layer of hairspray and measure the correspnding wavelenghts in an angle giving those results. It even works with water. The amount reflected is highly depended on angle and polarisation, even ignoring a lot of other parameters. Those graphs are obviously not at 0rad, as this would mean 100% transmission rate in traditional optics and at least 0% reflection rate in quantum optics (which not necessarily means 100% transmission). So which angle did they measure?
@Kunzite: I originally asked how coating is supposed to work and got answers that obviously lacked by scientific background.

Not to drag this conversation out, but PF did do a comparison of the DA limiteds (which have the already good SMC coating) with the limiteds after the HD coating was applied. HD vs. SMC Pentax Limited Primes Review - Aberrations and Flare | PentaxForums.com Reviews

The differences weren't huge, but they are definitely visible with regard to flare and contrast. The only lens that they preferred the older lens to was the DA 15, where the rounding of the aperture blades dampened the sharpness of the starbursts it gives and it is already really flare resistant.

I understand that a lot of this seems like advertising speak, but I do think that improved coatings helps produce better images in high contrast situations with strong light sources. There are plenty of other situations where you probably could use uncoated lenses and be fine, but that's what I see.

[WorksAsIntended]

I agree that it helps image quality, no argueing about that.

---------- Post added 01-18-20 at 04:33 AM ----------

Without knowing which studies you referred to, it’s difficult to know what you find unconvincing about this. It is, of course, accepted by most users, that modern multi-coated systems considerably reduce flare, at the very least. Chromatic aberration, as I understand it, is caused by the medium, rather than the interface, so I’m at a loss to see how that can be a coatings issue – happy to read further, though.

Not about the coatings used in specific, as this diacussion should be over, but a general thought on that:
By utilizing resonances around specific frequencys of light you can kind of easily build a material having glass like behaviour but anormal dispersion. This means the index of refrection increases with decreasing frequency, working agai st ca caused by normal dispersion.
The second option is to try to eliminate the ca colours for very specific angles. This way you can get rid of ca in focus plane by removing the specific frequency light very slightly out of focus. This way however you remove specific frequencys and change colors slightly.

[Rondec]

My impression is the only way to get rid of LoCA in lenses with fast apertures is to use apochromatic elements. I'm not sure how much lens coatings affects it one way or the other (although it certainly doesn't hurt).

[Mistral75]

(...)
Not about the coatings used in specific, as this diacussion should be over, but a general thought on that:
By utilizing resonances around specific frequencys of light you can kind of easily build a material having glass like behaviour but anormal dispersion. This means the index of refrection increases with decreasing frequency, working agai st ca caused by normal dispersion.
The second option is to try to eliminate the ca colours for very specific angles. This way you can get rid of ca in focus plane by removing the specific frequency light very slightly out of focus. This way however you remove specific frequencys and change colors slightly.

Not abnormal (anormal in German) but anomalous (anomal in German, without 'r'). You wrote you have a Ph. D. in quantum optics?

[WorksAsIntended]

I did, not about dispersion though. Sorry that my english is not up to your level.

[house]

There has been some suggestions, by no means scientific or even reliable, that HD coating actually makes purple fringing more apparent. Perhaps the price to pay for other improvements.

Imaging Reasource made these tests where you can see a bit of improvement in flare resistance.

Farewell to flare? Pentax’s HD Limited lens lineup gets a real-world test

[WorksAsIntended]

Completly possible too.

[Mistral75]

I did, not about dispersion though. Sorry that my english is not up to your level.

That's not the point. You are living in Germany and the same distinction (abnormal or anormal vs. anomal, with 'r' vs. without) exists in German, as explained in my former post.

Your erroneously employing the (more common but here inappropriate) word anormal instead of the appropriate anomal (German) / anomalous (English) is odd for a Ph. D. in quantum optics, that's all.

[WorksAsIntended]

You are write about that. Sorry for mixing those up, there however is no indication in physics which one is the right one as both are derived from the same word meaning the same.
Still, you are right of course.

[Mistral75]

From asahi man concerning the HD Pentax-D FA★ 85mm f/1.4 compared to the HD Pentax-D FA★ 50mm f/1.4 SDM AW:

Same fine sharpness, same superb coating, better and softer bokeh and a little pricey 😊😊

And a very slow and small production run, to keep the high quality.

Source: Pentax SLR Talk Forum | Digital Photography Review