[jbondo]

Due to low penetrating power of the radiation it's perfectly safe to use for standard camera usage. About the only things you would not want to do are:
- Convert one to a telescope eyepiece and use it with your eye directly at the lens for long periods of time.
- Smash glass and ingest / inhale particles.

You will get more radiation by watching your TV or being in front of your computer monitor than what you will get from this lens.

True if your TV was manufactured before 1970. Not so much with modern CRT's / Panels.

Long wave UV lights

These compact ones do a fine job of clearing yellowing after a few weeks of exposure. UV Compact light

[lightbox]

You can find UV bulbs at aquarium supply stores, but at a premium (due to being hobbyist specialty items).

[clackers]

Lee, I kept mine beside my aquarium and look what happened!

[Digitalis]

Lee, I kept mine beside my aquarium and look what happened!

...you know "blinky" is a common mascot in hospital radiology and nuclear medicine centers.

[Schraubstock]

Stay away from such lenses.
All pictures taken with any of these lenses will be radioactive and must be stored under either a concrete or lead sarcophagus

[bigdavephoto]

Due to low penetrating power of the radiation it's perfectly safe to use for standard camera usage. About the only things you would not want to do are:
- Convert one to a telescope eyepiece and use it with your eye directly at the lens for long periods of time.
- Smash glass and ingest / inhale particles.


True if your TV was manufactured before 1970. Not so much with modern CRT's / Panels.


These compact ones do a fine job of clearing yellowing after a few weeks of exposure. UV Compact light

I was thinking about what I said and I should have said, You will get more radiation from a long distance plane ride.


Check with a garden supply house. UV bulbs are used for growing plants indoors.

[goatsNdonkey]

Why buy one of those lenses and then try to get the yellow out of it? It has a built in yellow filter for shooting B&W film!

[Digitalis]

It has a built in yellow filter for shooting B&W film!

on film deep Red filters are better filters for darkening skies in landscapes. Orange/Yellow is better for portraiture, though I know some photographers that use strong magenta filters for portraits.

On digital using coloured filters can be detrimental to image quality as they may have a conflicting band pass with the CFA.

[Lee Malta]

Many Thanks for the Advice I will keep the lens Now for sure i need a good prime Lens.
I thought it was just a case of the Usual Youtube Experts sorry paid sales people for Nikon an Canon doing there thing again.
And how is the Nuclear Disposal Business going Mark Jerling )))

---------- Post added 12-07-16 at 11:13 PM ----------

Due to low penetrating power of the radiation it's perfectly safe to use for standard camera usage. About the only things you would not want to do are:
- Convert one to a telescope eyepiece and use it with your eye directly at the lens for long periods of time.
- Smash glass and ingest / inhale particles.


True if your TV was manufactured before 1970. Not so much with modern CRT's / Panels.


These compact ones do a fine job of clearing yellowing after a few weeks of exposure. UV Compact light

I take it that the Yellowing is with age then and not a coating thing

---------- Post added 12-07-16 at 11:16 PM ----------

Stay away from such lenses.
All pictures taken with any of these lenses will be radioactive and must be stored under either a concrete or lead sarcophagus

so i will need to Bunker my Laptop an K-3 when not in use ? Just ordered a Bio Hazard suit from e-bay ;-)

[Not a Number]

I take it that the Yellowing is with age then and not a coating thing

Technical Tip: Radiation Processing for Glass Coloration / Discoloration | STERIS AST
http://onlinelibrary.wiley.com/doi/10.1111/j.1151-2916.1955.tb14568.x/abstract
http://franklin.chem.colostate.edu/glassguy/irradiation.html

[Lee Malta]

Technical Tip: Radiation Processing for Glass Coloration / Discoloration | STERIS AST
Formation of Color Centers in Glasses Exposed to Gamma Radiation - KREIDL - 1955 - Journal of the American Ceramic Society - Wiley Online Library
Activation of color centers in Glass

Thanks Looking at what you linked now )))

[Not a Number]

Thoriated Camera Lens (ca. 1970s)

Measurements have indicated that the exposure rate at a depth of 10 cm in the body of an individual carrying a camera containing 0.36 uCi of thorium would be approximately 0.01 mrem/hr. Based on this value, NUREG-1717 calculated that a serious photographer might receive an annual exposure of 2 mrem. This assumed that the photographer carried the camera 30 days per year and for 6 hours per day. They also estimated an exposure of 0.7 mrem per year for an average photographer. If the camera lens contained the maximum permitted concentration of thorium (30%), NUREG-1717 estimated that the aforementioned annual doses could triple.

Exposure Limits
International Commission on Radiological Protection (ICRP) Limits:

2) The annual limits to the lens of the eye, to the skin, and to the extremities, which are:

A lens dose equivalent of 15 rems (0.15 Sv)
A shallow-dose equivalent of 50 rems (0.50 Sv) to the skin or to any extremity.

Note:
2 mrems = 0.002 rems
0.7 mrems = 0.0007 rems

X-Ray Imaging: The Fallacy of the "Day in the Sun" Comparison, 2/28/00

When the "day in the sun" analogy is meant to compare x-ray exposure to exposure by one day of natural background radiation, the comparison is still mistaken, even though natural background radiation has access to the body's internal organs. The reality:

At sea-level, the typical dose from natural background (excluding the dose from inhaled radon/thoron) is about 0.1 rem per year. It is a little higher at higher altitudes (e.g., the comparable annual dose in Denver is about 0.12 rem).

At sea-level, the natural background dose per 24 hours is 0.1 rem divided by 365 days, or 0.000274 rem per day (274 micro-rems/day). This refers to average INTERNAL organ-dose (not the surface or skin dose), and it refers to the WHOLE body. Approximately 20% of the 0.1 rem comes from radioactive potassium-40 which is in every cell. The dominant share of the 0.1 rem comes from external radiation. Below, we will approximate that none of the 0.1 rem is from internal potassium-40.

A reasonable APPROXIMATION is that average internal organ-dose is about one-half of the surface dose. So the surface dose from natural background radiation is about 0.000274 rem times 2, or 0.000548 rem per day, on the average, at any place on the body.

By comparison, what are the surface doses from common x-ray procedures? X-ray doses are rarely measured. The figures below, from limited samples, may be typical. Doses are much higher at some facilities than at others, according to limited surveys. First, we multiply the surface dose from x-rays by 0.33, because we will use the approximation that the typical x-ray procedure exposes just one-third of the body. Then we divide the product by 0.000548 rem (the whole-body surface dose per day, from NATURAL background radiation). The resulting ratio reflects approximately how many times riskier the x-ray procedure is, than one day of exposure to natural background radiation.

Routine chest x-ray, per image: About 0.01 rem * 0.33 = 0.0033 rem. Ratio = 6.
Many other routine exams, per image: About 0.3 rem * 0.33 = 0.099 rem. Ratio = 181.
CT scan, per exam: About 4.0 rem * 0.33 = 1.32 rem. Ratio = 2,409.
Fluoroscopy, per minute: 2 rems * 0.33 = 0.66 rem. Ratio for a minute of FLU = 1,204.

[Lee Malta]

Just Found This on Just Scored an SMC Takumar 55mm F1.8!: Pentax SLR Talk Forum: Digital Photography Review
I bought a new Spotmatic back in about 1965 with one of them. At the time, I couldn't afford the 50mm f1.4. That proved to be a blessing as the 55mm f1.8 does not use thorium treated glass and therefore does not suffer from yellowing with age as the 50mm f1.4 does.

[Not a Number]

Yellowing of the lens is not really an issue since it is easily reversible. Exposure to sunlight or even from one of the "Party" UV light bulbs you can buy just about anywhere have shown to work.

[Bui]

I see plenty of them on ebay.fr, sold from France for around 15 euros plus 6 euros postage costs. Just search for "ikea jansjo"

Thank you, thanks to your advice I tried to look around and found one used sold by a lady for 8e, not on ebay but leboncoin, I guess that's is as good as I could get