once cleaned, have you had to clean it again? about how often do you have to do this process? i just got a the tak 50 and I don't want to have to do this all the time.
I have an old canon FL 1.4 50mm lens with a yellow tinge, I put it tinfoil and lef the rear element open, facing the sun on the window ledge today, i will let you all know it it works.
I have one of these lens and put it in the sun on a window sill wrapped in aluminum foil except for the rear element. It took several months, but the yellow is totally gone. It was winter, so the sill was never really hot. This UV lamp trick looks like it's much faster. Whatever the case, I can certainly vouch for the concept of UV light fixing this problem.
Do you happen to know if it matters if you use a florescent tube black light vs a black light bulb? At my local target I was only able to find a 60w black light bulb..
I also have an old M42 50mm f/1.4 S-M-C Takumar with visible yellowing. This method looks safer than the sunlight method. Ive always been concerned that heat from the sun could vaporize some of the lubricants inside the lens, so they end up on the glass surfaces, making the lens hazy.
Followup: I tried this method on the 50mm f/1.4 S-M-C Takumar. The following are some poorly-controlled, unscientific observations:
At the start, the Pentax lens showed 3.0/4.5/5.5 times as much darkening as an old AIS 50mm f/1.4 Nikkor in the R/G/B channels, based on photographing them in front of a computer monitor.
After 2 days of exposure to a 15w Blacklight, the relative darkening was only 1.6x/1.8x/1.6x in the R/G/B channels.
After 8 days, the darkening was only about 1.25 to 1.3 times more than the AIS Nikkor. The Takumar was actually clearer than an old (1960?) 5.8cm f/1.4 Nikkor-S and an old G. Zuiko 5mm f/1.4 lens, according to measurements -- all looked the same to the naked eye.
Excellent, I'll try that on my s-m-c tak 50 1.4. Somehow I prefer your UV lamp method rather than "putting the lens on a south-facing window sill for a month" as suggested in many places :)
How long did it take you to get rid of the yellowing?
Absolutely love this lens, even with the yellow cast. When I shoot B/W it's like a yellow filter :)
once cleaned, have you had to clean it again? about how often do you have to do this process? i just got a the tak 50 and I don't want to have to do this all the time.
ninjavspenguin 1 month ago
hi, is that a UV lamp or a Wood lamp (black light lamp is also called...)? does it have a particular power/watt?
thanks
ugeironIII 7 months ago
Decay of thorium
SuperCrazyStorm1 11 months ago
Hi I see a 1.4 in yahoo auction. It says yellow coating. Is it natural or has problems?
robertlam18 1 year ago
I have an old canon FL 1.4 50mm lens with a yellow tinge, I put it tinfoil and lef the rear element open, facing the sun on the window ledge today, i will let you all know it it works.
robblac 1 year ago
I have one of these lens and put it in the sun on a window sill wrapped in aluminum foil except for the rear element. It took several months, but the yellow is totally gone. It was winter, so the sill was never really hot. This UV lamp trick looks like it's much faster. Whatever the case, I can certainly vouch for the concept of UV light fixing this problem.
arrowcatcher 1 year ago
Thanks for the tip.
Do you happen to know if it matters if you use a florescent tube black light vs a black light bulb? At my local target I was only able to find a 60w black light bulb..
wtnssprgrssn 2 years ago
I also have an old M42 50mm f/1.4 S-M-C Takumar with visible yellowing. This method looks safer than the sunlight method. Ive always been concerned that heat from the sun could vaporize some of the lubricants inside the lens, so they end up on the glass surfaces, making the lens hazy.
uyt384 2 years ago
Followup: I tried this method on the 50mm f/1.4 S-M-C Takumar. The following are some poorly-controlled, unscientific observations:
At the start, the Pentax lens showed 3.0/4.5/5.5 times as much darkening as an old AIS 50mm f/1.4 Nikkor in the R/G/B channels, based on photographing them in front of a computer monitor.
After 2 days of exposure to a 15w Blacklight, the relative darkening was only 1.6x/1.8x/1.6x in the R/G/B channels.
Two days bleached out much of the yellowing.
uyt384 2 years ago
Thanks for the followup! Yeah, it does work. UV light does indeed remove the yellowing.
luketrash 2 years ago
After 8 days, the darkening was only about 1.25 to 1.3 times more than the AIS Nikkor. The Takumar was actually clearer than an old (1960?) 5.8cm f/1.4 Nikkor-S and an old G. Zuiko 5mm f/1.4 lens, according to measurements -- all looked the same to the naked eye.
uyt384 2 years ago
how long should you bath it in the UV a day?
markitymarkiemark 2 years ago
I had the light on 24 hours per day for a week.
luketrash 2 years ago
I did the same to my 50mm f1.4 and although the glass cleared, the image was the same. Great lens!
simonspiers 2 years ago
In my case, the image quality is the same, but I gained about 1.5 stops of speed. Which is really what f1.4 is all about ;-)
luketrash 2 years ago
Excellent, I'll try that on my s-m-c tak 50 1.4. Somehow I prefer your UV lamp method rather than "putting the lens on a south-facing window sill for a month" as suggested in many places :)
How long did it take you to get rid of the yellowing?
Absolutely love this lens, even with the yellow cast. When I shoot B/W it's like a yellow filter :)
Big thanks for the tip!
dupalopez 2 years ago
It took a week for the yellowing to go away. I had the light on 24 hours per day.
luketrash 2 years ago