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Yellow Lenses?


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#1 Adrian Correia

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Posted 09 October 2006 - 03:50 PM

I recently bought (about two weeks ago) a set of Canon K35 lenses from a retired DP in Florida. I got a 14mm (I believe this is EOS glass) in a PL mount and a complete set of K35s (18, 24, 35, 55, 85) in BNCR mount. I sent them to a friend in Los Angeles to be inspected and remounted to PL mounts. The lenses are in excellent shape, but the 35mm and 55mm have a "yellow tint" (the techs term not mine) to the image.

My question to the members of this forum is....what is that yellow tint? What could it be? Is it correctable? I was told that it is a slight shift in warmth to the yellow side. Could I match these with the rest of the lenses in the set with some simple color correction? Any advice would be greatly appreciated. The man I bought these from also has another set of K35s - should I try and exchange the 35mm and 55mm for the corresponding lenses in that set? Thanks!
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#2 Joe Gioielli

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Posted 10 October 2006 - 03:56 PM

Try leaving it in direct sunlight, I've heard that helps.

Joe
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#3 Stephen Williams

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Posted 10 October 2006 - 04:21 PM

I recently bought (about two weeks ago) a set of Canon K35 lenses from a retired DP in Florida. I got a 14mm (I believe this is EOS glass) in a PL mount and a complete set of K35s (18, 24, 35, 55, 85) in BNCR mount. I sent them to a friend in Los Angeles to be inspected and remounted to PL mounts. The lenses are in excellent shape, but the 35mm and 55mm have a "yellow tint" (the techs term not mine) to the image.

My question to the members of this forum is....what is that yellow tint? What could it be? Is it correctable? I was told that it is a slight shift in warmth to the yellow side. Could I match these with the rest of the lenses in the set with some simple color correction? Any advice would be greatly appreciated. The man I bought these from also has another set of K35s - should I try and exchange the 35mm and 55mm for the corresponding lenses in that set? Thanks!


Hi,

Not wanting to to repeat myself:-

"Possibly radioactive coatings/elements. Cooke series II 75mm are usually very yellow as well as many older Nikon still lenses I own.!
It's quite likely that the 35 & 55 of the other set will be the same.
Color correction will fix the problem. The latest lens sets match in color perfectly but that was not the case 30 years ago!"

Have you looked at the other 35 & 55 lenses from the other set?

Stephen
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#4 Adrian Correia

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Posted 10 October 2006 - 05:13 PM

Stephen - sorry! No disrespect intended! I diid see the answer you had given. I was just trying to compile as many theories or possibilities as possible to try and nail down the reason. The seller of the lenses is on vacation in Seattle and will be back this week, so I will have some idea then. I have asked him to send those two lenses to my tech in California and then he will be able to do side by side tests. We shall see. I have actually directed my tech to your answer....hopefully things will work out, but I will keep you abreast of the situation. I may do some 35mm tests when I get the set....
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#5 Chris Keth

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Posted 10 October 2006 - 08:09 PM

Hi,

Not wanting to to repeat myself:-

"Possibly radioactive coatings/elements. Cooke series II 75mm are usually very yellow as well as many older Nikon still lenses I own.!
It's quite likely that the 35 & 55 of the other set will be the same.
Color correction will fix the problem. The latest lens sets match in color perfectly but that was not the case 30 years ago!"

Have you looked at the other 35 & 55 lenses from the other set?

Stephen



This is often the case with old lenses, I have found. the materials used were mildly radioactive and over time have either just "aged" however those materials age or have began to decay and yellowed. I have an old angenieux zoom that is, I figured out, equivalent to between a Y10 and a Y15 color correction filter (yeah, really that yellow!) in color cast. Average for all lenses, I heard somewhere, is the effect of a Y05.
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#6 Bill Totolo

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Posted 10 October 2006 - 11:30 PM

A lot of older lenses develop a color bias over time.

A tip that was passed down to me is:
Isolate yourself and the lenses in a darkroom and shoot a scorpion (or any powerful, focusable source of light) through one end of your lens, fit a toilet paper roll over the narrow end (mount side) and use a color temperature meter to gage the color temp coming out of the lens. Now do this for all lenses in a specific line of lenses and correct the aberrant lenses to what the norm is by using gels fitted on the rear element.
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