Originally posted by ManuH OK but how is SMC defined? I mean all Pentax lenses are designed smc and we know that some lenses have special coatings like aero bright on the *smc* Pentax DA* 55mm f/1.4 SDM. I'm sure the smc formula was improved since it was first introduced. The DA 15mm and 35mm seem to resist flare better than the 21mm and 40mm for example. So smc is just a generic name. I would believe that all modern lenses are multicoated, the Tamron 18-250mm sure is as it is reasonably flare resistant (for a zoom). And it would make no sense economically to make this lens with Pentax coatings when the Tamron works just as well.
Actually, there have been some Pentax lenses produced without SMC coating. It is defined and patented as Super-Multi Coating. The few budget lens produced without it still got non smc multi-coating. Ghostless coating is another coating added to the rear element and is applied to certain lenses. All Ltd lenses have it. The SP Super Protect is added to the front coating to reduce dirt smears etc. The Aero Bright is the newest of the bunch and there is next to no information about it except it is used in the DA* 55 and DA* 60-250mm.
SMC is a 7-layer process.
About Super-Multi Coating (SMC)
Edit: Here is a list of non-smc k-mount primes and zooms compiments of dimitrov.
http://kmp.bdimitrov.de/lenses/primes/_non-SMC/index.html http://kmp.bdimitrov.de/lenses/zooms/_non-SMC/index.html
Asahi Optical/Pentax were always pushing the envelope on coating development. The Coatings on the Takumar was evolving and there were changes to the coatings during the production span of some of the Super Taks as well as optical changes in some cases. Likewise, the SMC was improved between 1971 into the last decade several times. How much was serious improvements and how much was to renew patents only Pentax knows. They have been very secretive about there coatings. I have an ongoing thread to post information as it comes available.
These milestone quotes are from the Asahi Optical Historical Club.
Quote: 1971 - Super-Multi-Coating
World's first multi-layer anti-reflective coating on consumer lenses. This patented technology made possible high-quality wide-range zoom lenses.
All competitors owe Asahi Opt. Co. this technological breakthrough.
Quote: 1992 - Ghostless Coating
World's first and unique anti-reflective coating allowing no flare at all in daylight and negligible flare in nighttime shots with direct light entering the lens. It is employed on some critical elements in FA* and Limited series lenses.
http://www.aohc.it/milestone.htm
Last edited by Blue; 09-16-2011 at 08:06 PM.