A friend has shown me his Nikkor 35mm f/1.4 Non-AI and the glass has a very strong yellow colour cast when you look though it. Is the yellow colouration normal ? What is the cause for the colour cast ? Could it have been manufactured that way, Is it a factory fault, or has the lens aged causing the colouration ?
Hmmm... Depending on how old this lens is. It looks like the glass may be tarnished from polishing or age.
This is a good thing, by the way... It's sort of how lens-coating was discovered. Some bright mathematician discovered that a tarnished lens allowed more light through than a new lens with no sheen on the elements.
You might want to do a more thorough visual inspection to make sure no fungus has begun to grow. Hold the lens up to the light, with the diaphragm open, and look through it at the edges of the front and back... If you see things that look like dirt, the lens may be infiltrated already.
Lens coatings are also used to compensate for a lenses defficienct in one colour, so the yellow tint may be for this as well.
Thanks Frankie for your input. This lens was probably manufactured around 1970-1973. The was boxed lens was boxed hadn't been used, and was lying in a shop that cleared out old Nikon stuff. It was stored in in a case called a bubble case (more of a plastic capsule).
The 35mm f/1.4 were the first Nikkor lenses to leave the Nikon factory already multi-coated. I am doubtful whether the multi-coating of that era is similar to the Nikon Integrated Coating (NIC) which was introduced sometime in 1977.
There is no fungus in the lens.
I have seen a Nikkor 15mm f/5.6 Q-DC, of probably the same era, and it too has the yellow colouration (though to a lesser extent).
I have this lens, it is my favorite one. Mine is a very late AIS version and when I look at the front element, I can see clearly two tints... purple and green... no yellow.
You are correct that this was the first Nikkor that was multicoated, and the optical formula is said to be the same, (although the cosmetics have changed over the years). There is a chance that the coatings have degraded from long term storage in less than optimum conditions, or that Nikon has "tweaked" the coating process over time since the introduction.
I guess the only good test would be the shooting of some good slide film, and check the results on a neutral light table.
Thanks all. The reflections of the coatings of this lens exhibit purple and green colours (as noted by f8bthere). JRP you too are correct in stating that some of the early Nikkors had a yellowish coating. Howwever, what I am maintaining is that when I mount the lens to a camera and look through the viewfinder, I see a distinct yellow cast. When I remove the lens from the camera and view through the lens on a light-table (like a loupe), the yellow cast is still there ?
For what it's worth, all of my AI-Nikkors (28, 50, 55-Micro, 135 and 80-200 zoom) have a distinct GREEN tint to them when observed from the front. From the back, it looks more like a MAGENTA cast. Opposite colours, in fact. The effect disappears when you look through it.
I've seen plenty of expensive binoculars with what looks like a vivid RED coating, which also disappears once you actually look through them. The pre-multicoating Karl-Zeiss Tessar on my Rolleiflex-T has a distinct BLUE, but I'm delighted with the 6x6 slides it produces. My Mamiya C330 lenses (55, 80 and 180-Super) all have the same kind of YELLOW tinge to them, so far invisible on Ektachromes.
I also remember handling an old pre-AI 50mm Nikkor (f-2, I think) recently and it did look kind of YELLOW. If you have no fungus growing on it, I wouldn't worry too much.
So, we have RED, GREEN, BLUE, YELLOW and MAGENTA. Anybody got a CYAN-coated lens?
Thanks Merlin. You are talking of the reflections of the coatings, and I have already acknowledged that this lens has coating reflections of purple, green, and blue colours. My question though, is not about the colour of the reflections, but of the visible yellow cast when looking through the lens (having nothing to do with the colours of the reflections caused by the lens coatings).
Hmmm... good point. I'm holding an old Karl-Zeiss UV Rollei filter in my hand right now, and it does indeed have a faint yellow tinge to it, I'd guestimate it at a bit less than a 5Y filter.
Question: have you had a chance to try your lens out with a roll of slide film yet? It would be interesting to see if you notice any colour shift.
Years ago, before Kodak got their act together with the newer Ektachrome films, it used to be the case that you'd get blue shadows. A lot of serious slide photogs (this is back in the late 70s) used to put a 5 or 10 yellow filter on their lenses to correct for it. I wonder if this was the thinking behind the yellow coating?
You are right about the bluish Ektachrome of the Seventies and Eighties. I double whether Nikon would tailor the colour cast of this Nikkor to suit Ektachrome. Also note that Kodachrome has been around for ages, and has always been neutral in it's colour balance.
If you can see the Yellow cast looking through the lens, it's most likely damaged. It's possible the plastics in the lens (I'm sure there's some plastic in there) has begun to break down. This is similar to the "car-windshield-dirt dilemma" which comes from the breakdown and release of gasses in the plastic of the dashboard.
Was there a filter left on the lens? Because the filter could have been back-coated, where the back facing the lens may have been coated with the colour gelatin... And the gel can decintegrated and deposit on the front element.
It's possible the cement in the elements themselves is deteriorating. Yes, there is plastic in the barrel of nearly every Nikkor except the very earliest models which looked like Summicrons..
Either way, a yellow tint of the elements is not a good thing. All this being said one could theoretically experiment with a blue filter (like the ones sold with the "litespan" scanning backs) to correct this problem in the lens...At the expense of ISO...