Question about older lens coatings.

Discussion in 'Nikon' started by coryammerman, May 22, 2014.

  1. This is just for curiosity's sake, and my Google skills are failing me with this, so I thought I'd ask here.
    I was wondering if anyone had any info about the coatings Nikon used prior to the introduction of NIC in '74 (if my research is correct). My reason for asking is that whilst gazing lovingly at my camera collection (just kidding, I was bored while feeding the baby) I noticed a bit of a trend in the colors of light reflected by the front elements. It's my understanding that this is because of the lens coatings. If this is incorrect, please feel free to enlighten me. Anyway my three oldest lenses, as best I can tell from Roland Vink's site (50/1.4 S, 35/3.8 S, and 105/2.5 P), all have reflections with a yellow/orange tint (see picture below).The next two in age (28/3.5 H, and 50/2 H) both have a purple-ish tint. It seems that there was a change of some sort in the mid 60's. Another bit of curiosity,my AI lenses (all of which should have NIC) all reflect light with the same blue/green tint, with the exception of my 50/1.4 which appears more similar to the yellow/orange of the oldest lenses. This seems at odds with my readings that say all AI lenses and later got the NIC coatings untill 2000 when they came out with SIC.
    Like I said before, this is just for curiosity's sake. I'm not sitting here obsessing about which is better than the other or anything. Slow news day I guess.
    00cbHQ-548487584.jpg
     
  2. very cool collection, btw...
    I believe that the color of light reflection does in fact reflect which kind of coating was used, but others who know for sure will chime in.
     
  3. The original coatings on lenses, from the 1940s, is blueish purple. This is a single coating (mono coating) and is vaccuum applied magnesium flurite if my memory is correct. Multicoating didn't really get going until the 1970s. I mostly only collect uncoated lenses (pre-WW2) but do have a few single coated lenses from the 1940s, mostly Leica plus one Zeiss Tessar (on a Rolleiflex.)
    Kent in SD
     
  4. Admittedly, modern MC tend to be blue-green (if seen from the right angles). But the true difference between MC and single-coating is transmission/reflections. Just compare your Ai and pre-Ai versions of 50/1.4. OTOH, the pre-Ai S.C. version has reddish-purple multi-coating.
    The Series E prime lenses have magenta/purple single-coatings like your 50/2 H.
     
  5. As I remember, all pre-Ai Nikkors had either an amber or blue single coating. In fact I believe that some lenses had an amber coating on the front and a blue coating on the rear, or vice-versa. To be honest I got rid of all my pre-Ai lenses years ago except for two - a 50mm f/2 and a 35mm f/2.8 PC-Nikkor - and I now can't recall the rest exactly. I do remember that the 105mm f/2.5 Nikkor Q had an amber front element while the 35mm f/2 Nikkor O was blue in front.
    I can't even remember now if the first Nikkor-C coatings were supposed to be NIC, or just plain multi-coating. It certainly gave the reflections of Nikon's lenses a more psychedelic and rainbow-like look from then on - cool man!
    The whole point of NIC (Nikon Integrated Coating), as I understand it, was to complement and compensate for any natural glass tint with a coating that transmitted more of the opposite colour of light. In other words the multi-coating applied was intended to cancel out any slight colouration of the glass used. For example: If the native glass had a greenish tint, then a coating was applied that transmitted more magenta. The idea being to standardise Nikon's lens range to a more "neutral" light transmission quality. I'm not convinced this was actually achieved in practise, but the new NIC multi-coating was certainly a big improvement over the old blue/amber single coatings as far as reducing flare and improving contrast.
    Having said that, I have two samples of 35mm f/2 Ai Nikkor, one of which (an earlier version) exhibits a distinctly green-looking coating on its front element, and a later version where the front element is decidedly blue. So YMMV.
    Edit: The apparent colour of single AR coatings is due to the thickness of the coating, not the material used, which nearly always used to be Magnesium Fluoride - a material that's a real pig to evaporate evenly BTW. There may also have been some reaction between the glass surface and the fluoride coating, whereby the coating was partially absorbed by softer glasses, but I have no evidence for this theory.
     
  6. @Rodeo Joe I especially signed up to respond to your answer, because most parts are so totally wrong and mistaken...
    "multi-coating applied was intended to cancel out any slight colouration of the glass used" is complete nonsense, the light reflected is because of the coating thickness
    don't believe me but check; http://rick_oleson.tripod.com/index-166.html
    and "softer glass" absorbing coating... really? come on man...
    ow yes; magnesium fluoride (which has a refractive index of 1.38) because itโ€™s relatively cheap, easy to apply, and gives a hard scratch resistant surface. http://www.canonrumors.com/tech-articles/all-about-lens-coatings/
    actually ALL the info you provide here is incorrect....
     

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