5cm f/2 Nikkor - haze or separation?

[Dante_Stella]

How does separation manifest on the 5cm f/2 Nikkor? Is it generally rainbow-colored, or can it be milky and splotchy?

Given the block diagram, I assume that if it is behind the aperture and bows toward the front, it is separation - and that if it is in front of the aperture and bows to the front, it is surface haze?

Thanks!
Dante

 

[raid]

Hi Dante,
I am no expert on anything related to lenses.
In the past thirty years or so of using RF lenses, I have never touched any rainbow colored lens glass. If lenses looked having haze in them, I sent them out for a clean-up, and I received them back much cleaner looking. I assumed always that rainbow colored implies glass separation.

 

[Dante_Stella]

I know that rainbow discoloration definitely a separation. I have seen a hazy type of cement degradation on some newer lenses that had bad cement used in manufacturing, but I am never sure quite what to think on older optics.

D

 

[Highway 61]

Given the block diagram, I assume that if it is behind the aperture and bows toward the front, it is separation - and that if it is in front of the aperture and bows to the front, it is surface haze?

Separation cannot affect uncemented elements.

That said, the lens diagram shows that either the group located in front of the aperture or the group located behind it are cemented. Only the front element isn't cemented to any other.

By the way that's why some nasty Summar fans still pretend that the extraordinary Sonnar 5cm f/2 created by Zeiss in 1936 is nothing better than "a Cooke triplet". 😀

Link to the diagram

(Source : Ken R., on this page 😉)

Separation in this lens usually looks like some milky veiling precisely located at the periphery of the affected group - no rainbow. I have seen separation in two of such lenses of mine. Both were affected at the group located in front of the aperture (3 cemented elements). I was almost certain that the separation was between the two elements cemented on their flat surfaces (elements #3 and #4). Both lenses were of the late black version. Both still performed beautifully. Only one could exhibit an excess of flare on some occasions, as expected from a lens having some separation.

 

[Mackinaw]

This may or may not help you with your problem, but several years back I bought an old Nikon M with a 50/2.0 Nikkor that was so cloudy you literally couldn’t see through the lens. I figured it was haze caused by out-gassing, probably on the elements nearest the aperture. I sent the camera and lens off to Stephen Gandy’s repair tech for a CLA and the lens came back looking brand new. The milkiness I saw when I bought the lens was totally gone.

Jim B.

 

[ZivcoPhoto]

Several years ago I bought a very late production (black ring) 50mm nikkor F2 with haze but otherwise perfect glass
DAG was able to clean everything. LTM version

 

[Highway 61]

I took my lenses apart - this is not difficult with the late black Nikkor-H 5cm f/2 - and could not clean the milky veiling which was at the periphery of the cemented triplet. It was separation, with well defined edges. Not haze.

Looks like there are many kinds of separation all depending on the glue used to cement the elements, and the type of coatings the elements have received before getting cemented. There is the Carl Zeiss "rainbow". And the "golden droplets" a large amount of late black Nikkor-S 5cm f/1.4 in Nikon RF mount suffer from (around the edges of the rear group).

I have seen separation growing quite fast in a professional Sony DV video camera zoom made in the 2000's... Suddenly, one milky stain at the periphery of the elements located inside the zoom... then another one... then another one... after a few weeks the whole thing got separated. But the optical performances of the zoom weren't affected.