[aslyfox]

Yes, thanks for the link, but... I'd expect much less difference between DA ltd and HD DA due to DA lenses already being coated for use on digital cameras. My initial post is with regards to FA ltd re-coating for full frame digital.

I was responding to this part of the post I quoted:

maybe a HD vs SMC DA 21mm review or something like that.
. . .

Read more at: HD-or Aerobright coated FA Limited Primes - PentaxForums.com

I did note that the in depth review was only discussing DA limiteds in the post I first cited it in

since the FA limiteds only come in SMC how could any one find a review of the difference with HD coating

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Last edited by aslyfox; 02-26-2020 at 12:35 PM.

[stevebrot]

I'm not aware of the FA Limited primes demonstrating problems with reflection between the sensor and rear element.

To be honest, the reflection "issue" is pretty hard to demonstrate unless there is an unambiguous large hot zone in image. Usually, such would present simply as low contrast. I have one lens that definitely does the reflection thing (wide flat rear element and 60s era coatings), but surprisingly, my other vintage lenses do not. (Makes me wonder about the 8-element ST 50/1.4.)

Something to read with my evening glass or two of wine

Better bring out the large glasses and make it Port.


Steve

[stevebrot]

I linked to the " In Depth Review " comparing all of the HD and SMC DA primes in Response no. 4

here is the link once again

HD vs. SMC Pentax Limited Primes Review - Introduction | PentaxForums.com Reviews

...and here is the text from the "4. What's New" section of the review...

The HD coating promises to do a better job of suppressing flare and ghosting while increasing overall contrast in images. The photo below shows the difference in reflectance and light transmission of uncoated glass, SMC-coated glass, and HD-coated glass. The jump from no coatings to SMC needs no explanation. But if you look closely at the pair of coated lenses, you will notice that the PENTAX logo on the far right (seen through the HD-coated lens) does not have a yellow color cast, so the white and red colors are more true-to-life.

Note: The point above concerning color cast is due to the transmission characteristics of the HD vs. the SMC coatings which is readily apparent in the spectral graphs provided on the Ricoh Web site in regards to HD tech. http://www.ricoh-imaging.co.jp/english/products/lens/technology/hd_coating/


...and from "7. Aberrations and Flare", the only part of the review that mentions CA...

Fringing (also known as chromatic aberrations) is not prevalent on the Limited lenses, be that the SMC versions or the HD versions, even in areas containing brightly-lit edges. We tried hard to provoke fringing and only got coma rather than chromatic aberrations in the shots below.

Apparently one cannot improve on what is not there.


Steve

[BigMackCam]

The star Pentax glass that is aerobright coated definitely render differenlty from HD glass. Not saying that HD is not good, but HD does not render like aerobright IMO.

How are you able to compare one with the other, and how would you describe the difference?

With respect, I don't see how it's possible to assess rendering differences without direct comparison between two copies of exactly the same lens but with different coatings, on the same camera and for the same shot. If comparing two different lenses with different coatings, it's highly likely there'd be rendering differences regardless of the coatings. I'm not saying Aero Bright isn't fantastic - I've no doubt it is. I just don't understand how any of us can currently assess the rendering difference it makes.

With SMC vs HD, it was easy to do such comparisons, using respective versions of the DA Limiteds - and now, with the SMC vs HD FA35/2, for example...

If so after so many years of having the FA ltd for sale, sales rate must be very low.

I don't know what the sales rate is. Low but steady, would be my guess, much like the SMC FA35/2 (only just replaced by the new HD version) and SMC FA50/1.4 (still going strong)...

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Last edited by BigMackCam; 02-26-2020 at 01:20 PM.

[BigMackCam]

FAO BigMackCam

I too have read that HD coatings reduces CA in several different places can't remember where exactly, maybe a HD vs SMC DA 21mm review or something like that.

If the OP or or anyone else is able to provide me with a source that definitively states and/or demonstrates that HD coatings reduce CA, I'd be grateful. Although doubtful, I remain open-minded and ready to be convinced... but I think it's worth pushing for such verification, as someone will read this thread in the future and might believe the reduced CA claim without evidence - then they tell someone else, the chain of possible misinformation gets bigger and bigger, and before long it becomes legend

All I know is my HD DA15 and 20-40 Limited give the most accurate, contrasty and saturated colours out of every lens I have owned and that is reason alone to just love 'em :-)

Oh and the sun flare resistance too...
.
So very critical to a landscape photographer

I really like my HD lenses too. I'm not sure I could identify when or where where the coatings have prevented issues I might have experienced with SMC versions, but I love the rendering of the HD lenses I own. I'd be quite happy to see this coating on any future lens, regardless of price

[biz-engineer]

How are you able to compare one with the other, and how would you describe the difference?

I can recognize from images an aerobright coated lens from hd coated lens, when I check the exif it just confirm what I thought the lens would be almost every time.
You could take the same photo with HD lens, and Star lens at the same aperture and FL, and you'll see truer colors from the Star lens (aerobright coated), and I'm not talking about sharpness and corner sharpness I'm only referring to color rendering.

---------- Post added 26-02-20 at 21:41 ----------

If the OP or or anyone else is able to provide me with a source that definitively states and/or demonstrates that HD coatings reduce CA

I can't tell for the sole reason that I'm don't know the difference between each kind of aberration (please excuse my ignorance) , as long as my software can correct it automatically I'm fine with that. What I know if when I printed photos and forgot to correct CA before sending the file(s) to the lab, I've bitten my fingers when I received and looked at the pricey print(s).

[luftfluss]

I really like my HD lenses too. I'm not sure I could identify when or where where the coatings have prevented issues I might have experienced with SMC versions, but I love the rendering of the HD lenses I own. I'd be quite happy to see this coating on any future lens, regardless of price

The one substantive (IMO) improvement I've noticed wrt HD vs SMC DA Limiteds is that my HD 21 Ltd has much less of an issue with the infamous "green blob" that can sometimes be provoked on the SMC 21. I've owned all of the SMC & HD DA Ltd lenses.

[JensE]

I linked to the " In Depth Review " comparing all of the HD and SMC DA primes in Response no. 4

here is the link once again

HD vs. SMC Pentax Limited Primes Review - Introduction | PentaxForums.com Reviews

And, on fringing: "There is no visible difference between the performance of the HD and the SMC variants." The review however didn't find the right subject to test for PF.

[BigMackCam]

I can recognize from images an aerobright coated lens from hd coated lens, when I check the exif it just confirm what I thought the lens would be almost every time.
You could take the same photo with HD lens, and Star lens at the same aperture and FL, and you'll see truer colors from the Star lens (aerobright coated), and I'm not talking about sharpness and corner sharpness I'm only referring to color rendering.

Interesting... and impressive - both the Aero Bright's colour accuracy, and your ability to consistently identify it. So it's a pretty significant difference, then? Can I ask, how does it manifest - is it an overall colour shift (e.g. warmer, cooler), differences in specific hues (e.g. reds, blues and/or greens more accurate), contrast (e.g. more accurate balance of tones, less under/over-saturation), etc.? And, from your earlier post, you infer it's a significant enough difference that you'd buy a $1,000 prime with Aero Bright coatings, but not with HD?

Honestly, I'm a little lost on the "truer colours" bit, given the dependence on a one-size-fits-all colour profile for in-camera JPEG processing (where Pentax colour reproduction typically has quite magenta-like reds, for example), and one or more profiles in post-processing software for raw files. Is it, perhaps, just a happy coincidence that the Aero Bright coated lens(es) work so nicely with the profiles used (since I can't imagine those profiles were originally created using the more recent Aero Bright lenses)? And for raw, does the ability to profile any camera-plus-lens combo for near-perfect colour accuracy make this difference of negligible importance?

Anyway, this feels like a rabbit hole we're diving into. What really matters, when all's said and done, is that - for whatever reasons and the evidence and/or perceptions and/or personal reasons behind it - you prefer Aero Bright coatings, and you're a paying customer with money in his hands for new lenses. Ricoh, take note!

I can't tell for the sole reason that I'm don't know the difference between each kind of aberration (please excuse my ignorance) , as long as my software can correct it automatically I'm fine with that. What I know if when I printed photos and forgot to correct CA before sending the file(s) to the lab, I've bitten my fingers when I received and looked at the pricey print(s).

You misunderstand, or I've explained myself poorly. I'm with you completely in not liking CA and having to correct for it (or forgetting to do so ). I'm just trying to obtain a source - official or otherwise - that claims HD coatings reduce CA, as discussed earlier. My reasons are two-fold: (1) I'm genuinely interested by that possibility and would love to read up on it, and (2) if it's merely hearsay, rumour, an "old wive's tale", false memory or assumption rather than the manufacturer's claim, I'd rather establish that here so that misinformation doesn't spread

[stevebrot]

I can recognize from images an aerobright coated lens from hd coated lens, when I check the exif it just confirm what I thought the lens would be almost every time.
You could take the same photo with HD lens, and Star lens at the same aperture and FL, and you'll see truer colors from the Star lens (aerobright coated), and I'm not talking about sharpness and corner sharpness I'm only referring to color rendering.

I am only aware of one Aerobright II coated lens in the current lineup. Are you saying that you can always pick out photos done with the DA* 55/1.4?

Correction: I am now aware of two lenses with Aero Bright II coatings in the Pentax lineup and neither is the DA* 55/1.4.


Steve

[stevebrot]

And, on fringing: "There is no visible difference between the performance of the HD and the SMC variants." The review however didn't find the right subject to test for PF.

Out of curiosity, what would you have used?


Steve

(...am pretty sure I know who wrote the review and while no one's credentials are unassailable theirs is pretty close...)

[aslyfox]

I am only aware of one Aerobright II coated lens in the current lineup. Are you saying that you can always pick out photos done with the DA* 55/1.4?

Steve

according to this old thread

by twilhelm

From the Ricoh/Pentax documentation, only two lenses I could find have Aero Bright II, the D FA*70-200 and the new D FA*50 1.4, both being star lenses. Even the original Aero Bright coating seemed to only be used on star lenses. Likely part of the price difference?

Read more at: Aero Bright Coating II - PentaxForums.com

Description:
The HD PENTAX-D FA* 70-200mm F2.8 ED DC AW telephoto zoom lens was announced at the CP+ tradeshow in February, 2015 preceding the announcement of the K-1 Pentax 24x36mm full-frame DSLR. Together with the HD Pentax 150-450mm extreme telephoto zoom lens these are the first Pentax lenses to cover the 24x36 mm full-frame format since the D FA 100mm F2.8 WR lens, which was introduced back in 2009.

While this lens is designed for the 24x36mm full-frame format it can also be used on cameras with the APS-C sensor format. With a respectable maximum aperture of F2.8 and rounded diaphragm blades for smooth Bokeh this zoom can be used as a portrait lens in addition to its more traditional use for sports, wild life and distant landscapes.

This lens is pro-grade as indicated by its star designation and also by its feature list:
* All-weather protection (AW)
* HD coating
* SP coating of the front element
* Aerobright II nano-coating of the inner elements
* Four super-low dispersion elements, two ED elements and two super ED elements with properties like flourite elements
* Enhanced Quick-shift function via a three-way switch on the barrel
* Focus limiter
* Tripod mount

The lens hood has the for Pentax traditional removable piece that allows for easy adjustment of an attached polarizing filter.

The lens has a built-in DC type autofocus motor and no provision for screw drive autofocus. Autofocus is thus not possible with the K100D/K110D and *istD series cameras. Autofocus is not available with film cameras

Read more at: HD Pentax-D FA* 70-200mm F2.8 ED DC AW Reviews - D FA Zoom Lenses - Pentax Lens Reviews & Lens Database

Coating HD Coating
Aero Bright Coating II
SP (Super Protect) Coating

Read more at: HD Pentax-D FA* 50mm F1.4 SDM AW Review - Specifications | PentaxForums.com Reviews

I also found this:

Ricoh's new Aero Bright II lens coating

Ricoh also announced a significant update to their Aero Bright lens-coating technology. Aero Bright is Ricoh's version of nano-particle coating, a technology that's had a big impact on lens flare over the last few years. Manufacturers tend to be pretty tight-lipped about the specifics, but we do know that there are various flavors of nano-structure coatings for camera lenses. They all basically attempt to provide a more gradual transition of refractive index at air/glass boundaries. It's the abrupt change in refractive index that produces reflections; no index change, no reflection, big, abrupt index change, lots of reflection. If you can make the refractive index change gradually instead of abruptly, you can dramatically reduce the reflections. . . .

https://www.imaging-resource.com/news/2015/03/23/in-progress-ricoh-reveals-p...-coming-soon-t

[stevebrot]

I think it's worth pushing for such verification, as someone will read this thread in the future and might believe the reduced CA claim without evidence - then they tell someone else, the chain of possible misinformation gets bigger and bigger, and before long it becomes legend

Hold the presses! I found proof (sort of)...

Harvard Makes Nanosurface That Fixes Chromatic Aberration in Lenses

Of course, it is the headline that is misleading, but it might explain how such a rumor might have gotten started. This is was returned about half-way down the page when I did a search on "lens coating chromatic aberration". At the top was a Q/A answer indicating emphatically, "no".


Steve

[stevebrot]

Read more at: HD Pentax-D FA* 70-200mm F2.8 ED DC AW Reviews - D FA Zoom Lenses - Pentax Lens Reviews & Lens Database

Read more at: HD Pentax-D FA* 50mm F1.4 SDM AW Review - Specifications | PentaxForums.com Reviews

Read more at: HD PENTAX-D FA?70-200mmF2.8ED DC AW / Telephoto Lenses / K-mount Lenses / Lenses / Products | RICOH IMAGING

Read more at: HD PENTAX-D FA? 50mmF1.4 SDM AW / Telephoto Lenses / K-mount Lenses / Lenses / Products | RICOH IMAGING

Nothing like pointing to a primary source, eh? I confused the original aero bright with the aero bright II and did not dig deep enough. My bad. I corrected the other post.

I still remain skeptical of the claim of being able to pick out photos taken with an aero bright II lens, but that is just me.


Steve

[aslyfox]

. . . I confused the original aero bright with the aero bright II and did not dig deep enough. . . .

Steve

I think we all have done that

one of my favorite memories of being in Court arguing a motion was the Judge asking why both I and the opposing counsel were saying the same appellate court decision was decisive authority

I explained -

" opposing counsel is quoting from the Appellate Court's recitation of the reasoning of the lower court

I am citing to the overruling of that reasoning by the Appellate Court"

the Judge was not thrilled by the opposing counsel's mistake