[MrclSchprs]

Hello,

I was wondering if Pentax changed lens coatings within the same line of lenses. For example, do all Pentax-M lenses have the same coatings? Or, put differently, will I notice a slight color shift when changing from a 50mm F1.7 to a 35mm F2.0 lens?


I presume the coatings of the original K mount lenses predates the coatings of the Pentax-M lenses. Seems logical as coating technology evolves over time. But I am curious whether or not the coating of the M-line changed over time or changed between focal lengths.

Can anyone shine any light on this?

[bdery]

The answer is yes. coatings have improved incrementally over time, and was not fixed within a given line. For a given lens there are examples of coatings changing (especially in the early days of m42 and K lenses) but mostly a lens model stays the same.

[ChristianRock]

In addition to what @bdery said, some lenses were released as one series, but during the time that another series was the main series. For example, the K 24mm f/2.8 was released during the M era so the coatings look more like M coatings.

Then you have a lens like the K 50mm f/1.2 that spanned during the K and M eras. You can tell which era it is from because the lettering in the lens changed, but the coatings reflections changed dramatically. Yet they are all K series.

Speaking of the 50mm f1.2 design, the A series version of that lens was still being produced and sold during the F era and perhaps even the FA era. Some other manual focus lenses were also still produced and sold within the autofocus era.

And if all that wasn't complicated enough, in a series you could have a bit of variation - I see that in the FA series. Now the M series, which is what most of my lenses are, is quite consistent, at least in terms of what the lens reflections look like (I just checked a few...). But you'd still have a different number of elements from lens to lens, and the decision of which ones to coat and which ones not to coat, will still affect the overall look of that particular lens.

I don't worry too much about these things, if I like a lens I just shoot with it

[mikesbike]

from a 50mm F1.7 to a 35mm F2.0 lens?

The FA 35mm f/2 now comes with the new HD (High Definition) coatings that are much more resistant against lighting conditions causing flare and ghosting, as well as SP easy-to-clean coatings that are potective against smudging. Image clarity and sharpness being improved under many lighting conditions. I've had this lens for many years, having bought it new for 35mm film use, and I now have the newer version as well. Also there is no longer the sometimes blooming effects from lights in night scenes.

This does not make the "F" 50mm f/1.7 a lens without value. On the contrary, it certainly is an outstanding value for sure, and an exceptionally fine performer. Sure you can do better with the latest DFA 50mm f/1.4 the that has the latest coatings- but in addition to its size and weight, have you checked the cost?

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Last edited by mikesbike; 04-11-2023 at 03:00 PM.

[Fogel70]

Both the glass used and coatings have evolved over the years. So for lens models that has been produced for a long time both the glass formula and coating may have changed. Although it may not make a major difference in lens performance.

The changes made may also be for making the coating process more cost efficient and less hazardous. One of the advantages of HD coating is that it is an improved process for applying coating which led to more evenly applied coating for lower variation on produced lens elements, for fewer rejected lens elements. Close to the performance of Aero Bright coating, but much more cost efficient.

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