Has anyone besides me noticed how little information there is available on some of the specialty coatings used by Pentax? The SMC coating is also limited and apparently had undergone numerous revisions since the early 70s. Some rumors say it was originally designed at the request of Japanese police for traffic cameras.

The Ghostless Coating was announced in 1992 and is considered a milestone for Pentax. It was apparently 1st used in 1997 on the the FA 43mm ltd and all subsequent limited lenses as well as certain * lenses. However, besides the LTD lenses, the other lens it was used on is unclear.

SP Coating The front surface of the optics is treated with the Pentax-original Super Protect (SP) coating. Applying a special fluorine compound to the lens surface through a vapor deposition process, this coating effectively repels dust, water and grease, making it easy to wipe off annoying stains such as fingerprints and cosmetic marks.

The Aero Bright Coating enhances image-description performance by effectively reducing reflections over a wider wavelength range. Compared to conventional multi-coatings, this new coating greatly improves light transmittance in the lens, while drastically reducing flare and ghost images that deteriorate image quality. It is an original lens coating using a silica aerogel with uniform porous structure as a base material to produce clear high-quality images by assuring and outstanding anti-reflection performance over a broad range of wavelengths. It is currently used on internal elements of the DA* 55mm for improved light transmission and reduced flaring and ghosting. Apparently the DA* 60-250mm also has the A.B. It is used on the new 645D lenses as well.

Update as of 2012:

Pentax released a new coating called the HD coating, which offers better reflectance (i.e. less ghosting/flare) compared to SMC, and it is more durable than Aero Bright and thus suitable for use on the front element as well as other elements.

	SMC	HD	Aero Bright
Reflectance	-	+	++
Durability	+	+	-
Cost	++	+	-

That is all I've turned up on these. However, Pentax has been close to the vest on Coatings all the way back to the 50s. This info is from Pentax Imaging, Dimitrov and Pentax press releases.

[Blue]

Is this the Aero Bright Patent or SMC

United States Patent: 8199404

Abstract An anti-reflection coating comprising first to seventh layers formed on a substrate in this order, the first layer being an alumina-based layer, the seventh layer being a porous, silica-based layer, and each of the first to seventh layers having predetermined refractive index and optical thickness in a wavelength range of 400-700 nm.

Inventors: Yamada; Kazuhiro (Saitama, JP), Nakayama; Hiroyuki (Tokyo, JP), Suzuki; Mineta (Saitama, JP) Assignee: Pentax Ricoh Imaging Company, Ltd. (Tokyo, JP)
Appl. No.: 12/342,128 Filed: December 23, 2008

Is the the Aero or is it HD (High Definition) Patent

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fn...ntax&RS=pentax

Abstract An anti-reflection coating comprising a mesoporous silica coating composed of mesoporous silica nano-particles formed on a substrate or a dense coating formed on the substrate, the mesoporous silica coating having a refractive index of more than 1.10 and 1.35 or less.

Imai; Hiroaki (Kanagawa, JP), Nakayama; Hiroyuki (Tokyo, JP), Shiokawa; Takanobu (Kanagawa, JP), Yamada; Kazuhiro (Saitama, JP), Suzuki; Mineta (Saitama, JP) Assignee: Keio University (Tokyo, JP)
Pentax Ricoh Imaging Company, Ltd. (Tokyo, JP)
Appl. No.: 12/393,333 Filed: February 26, 2009

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Last edited by Blue; 09-16-2012 at 06:19 PM.

[Blue]

"Compared with conventional multi-layer coatings, the new multi-layer HD Coating, exclusively developed by PENTAX, offers much improved light transmittance and a much lower refractive index. Because it minimizes reflections, it delivers sharp, clear images free of flare and ghost images, even under demanding lighting conditions such as backlight. This coating assures optical performance almost equal to Aero Bright Coating, another PENTAX-exclusive lens coating process made possible by advanced nanotechnology and applied to higher-class lenses."

More Pentax news at: Pentax Announces 8 New Products and Lens Coating - Pentax Camera News & Rumors - PentaxForums.com

[monochrome]

From Asahi Optical Historical Club

"As I already wrote, Asahi didn’t invent the multicoating, since they bought patents from Optical Coatings Laboratories Inc. (OCLI), based in California. The merit of Asahi Opt. Co. was to understand the importance of anti-reflective coating, looking for the proper technology, developing their own industrial process and put it into production at acceptable costs. That marked a turning point in the evolution of photographic optics, allowing the development of modern ultrawide-angle and wide-range zoom lenses. With the growing popularity of zoom lenses and their ever-increasing focal length extension (needing more and more elements), multicoating became almost as necessary as glass in order to obtain quality optics."

Also, there were Ghostless (coated) Pentax filters, usually UV and Skylight.

[Blue]

From Asahi Optical Historical Club

"As I already wrote, Asahi didn’t invent the multicoating, since they bought patents from Optical Coatings Laboratories Inc. (OCLI), based in California. The merit of Asahi Opt. Co. was to understand the importance of anti-reflective coating, looking for the proper technology, developing their own industrial process and put it into production at acceptable costs. That marked a turning point in the evolution of photographic optics, allowing the development of modern ultrawide-angle and wide-range zoom lenses. With the growing popularity of zoom lenses and their ever-increasing focal length extension (needing more and more elements), multicoating became almost as necessary as glass in order to obtain quality optics."

Also, there were Ghostless (coated) Pentax filters, usually UV and Skylight.

The filters were different than the later Ghostless Coating that was developed for street cameras in the early 90s. It was first used in 135 format lens, the FA 43mm LTD. This thread has focused mostly on the coatings newer than the SMC. However, Asahi Optical was the first to start using multicoatings on production lenses.

That said, there is not much available on the coating(s) used on the Takumars, Auto-Taks and Super Taks.

[Alizarine]

The FA 28-105, f3.2-4.5 has the ghostless coating.

Which 28-105? The one with powerzoom or the newer ones?

BTW, the DA*55 and DA* 60-250 both have Aero Bright, but how about the DA*50-135?

[Blue]

They are both nano technology. I would assume there are enough differences to deal with patent issues. Nikon calls their Nano Crystal Coat.

Nikon's exclusive Nano Crystal Coat nearly eliminates the ghosting and flare seen with some wide-angle lenses for improved clarity and contrast. Impressive on both FX- and DX-format cameras,

I have seen also Nikon (Crystal Clear Coat) and Canon (Sub Wavelength Coating) which are also nano tech coatings.

[Blue]

The announced PENTAX D FA 645 90mm HDmacro lens apparently couples both the HD Coating and the Aerobright Coating. This lens was announced in Dec 2012.

This lens is treated with HD Coating*, a newly developed, high grade multi-layer lens coating , which offers higher light transmittance with reduced reflection, to deliver sharp, clear images free of flare and ghosting, even under demanding lighting conditions such as backlight. By coupling this coating with the PENTAX-exclusive, high grade Aero Bright Coating,** this lens optimizes light transmittance while minimizing refraction.

[Kerrowdown]

Interesting read this thread, didn't realise the was quite such a variance in all the coatings.

[wombat2go]

That said, there is not much available on the coating(s) used on the Takumars, Auto-Taks and Super Taks.

Here is a little from an Asahi Pentax lens catalog 06101, I think from 1961.

[Blue]

Here is a little from an Asahi Pentax lens catalog 06101, I think from 1961.

Thanks Wombat. That is more likely from the early 70s though, perhaps 1971 since that is when Asahi Optical unveiled the S-M-C.

[wombat2go]

971 since that is when Asahi Optical unveiled the S-M-C.

You are correct, as confirmed by Herbert Keppler page 95

[Giklab]

Here is a little from an Asahi Pentax lens catalog 06101, I think from 1961.

I have a magazine from 1974 where a similar comparison is made. A picture of a woman and a building with flare and one without. The difference is stunning.

Also stunning is that they thought nobody would notice how the perspective is ever-so-slightly not identical, enough to have the sun covered by the girl.

[mingkoy]

what do you think my is the coating of my pentax 50mm 1.4 ??

JUST CURIOUS

thanks

[MSM]

what do you think my is the coating of my pentax 50mm 1.4 ??

JUST CURIOUS

thanks

@mingkoy: Which 50 mm/1.4? Pentax has made a few over the years. The type of coating is often in the name of the lens such as the 'Pentax SMC FA 50 mm f/1.4'

mark

[Blue]

what do you think my is the coating of my pentax 50mm 1.4 ??

JUST CURIOUS

thanks

Based on what your profile says, you have an SMC 50/1.4 so that means it has the SMC coating. The Super Tak 50/1.4 had different coatings. There are no 50/1.4 with the Ghostless , Aero or HD coatings, at least yet.