GarageBoy
Well-known
Those Chinese SLRs are cooool
narsuitus
Well-known
kshapero
South Florida Man
What are lanthanum elements?
dmr
Registered Abuser
What are lanthanum elements?
I'm assuming this refers to the older "radioactive" lenses, where they added some rare earth compounds only to have the glass elements yellow with age.
I'm sure most of you have seen this method to "fix" the problem.

mpaniagua
Newby photographer
I'm assuming this refers to the older "radioactive" lenses, where they added some rare earth compounds only to have the glass elements yellow with age.
I'm sure most of you have seen this method to "fix" the problem.![]()
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Well, if it turns yellow, then I won't need a yellow filter for b/w wont I?
David Hughes
David Hughes
What are lanthanum elements?
Hi,
From memory they added Lanthanum Oxide to the glass to improve it a lot. Look it up using a search engine and you'll frighten yourself and re-assure yourself alternatively. From memory, again - so worry - Thorium Oxide was the one to worry about.
It's one of those great leaps forward that several people in different countries discovered, like lens coating.
Regards, David
p.giannakis
Pan Giannakis
Radioactive lenses are safe. I gave one Takumar 50 f/1.4 to one of my friends, physicist in a well know Scottish University to measure it and review it. He concluded that it was safe to use and that the metal camera backs are usually thick enough to stop the radiation from reaching your head or eyes.
I remember reading somewhere that what was a risk to health and safety, were the viewfinder eyepieces in certain cameras that contained thorium. Due to them being very close to the eye, they could pose a risk.
Oddly enough, i never found out which cameras had thorium based eye pieces...
I remember reading somewhere that what was a risk to health and safety, were the viewfinder eyepieces in certain cameras that contained thorium. Due to them being very close to the eye, they could pose a risk.
Oddly enough, i never found out which cameras had thorium based eye pieces...
analoged
Well-known
Thomas78
Well-known
My (second) Ricoh TLS401 with Auto Rikenon 55mm f/1.4
IMG_9320 by Thomas Harwardt, auf Flickr
As I inherited four TLS from a late friend of my parents, now the total number of them is six:
IMG_9322 by Thomas Harwardt, auf Flickr

As I inherited four TLS from a late friend of my parents, now the total number of them is six:

Addy101
Well-known
Thomas78
Well-known
Yokosuka Mike
Abstract Clarity
I would have put this in the Coffee & Camera thread but the cup is empty.
Bessaflex TM with Zeiss Distagon T* 35mm f2 ZS lens (M42 mount)
Bessaflex TM with Zeiss Distagon T* 35mm f2 ZS lens (M42 mount)
DanskDynamit
Well-known
My F and my father's FM

agoglanian
Reconnected.
p.giannakis
Pan Giannakis
Huss
Veteran
Pan, really good product shot of your OM-!
Anyway, this just showed up.
NOS Komrads.
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While it is delightfully solid and rudimentary feeling, I was for some reason expecting it to be bigger..
Anyway, this just showed up.
NOS Komrads.

While it is delightfully solid and rudimentary feeling, I was for some reason expecting it to be bigger..
p.giannakis
Pan Giannakis
While it is delightfully solid and rudimentary feeling, I was for some reason expecting it to be bigger..
That's what i thought too, the later Zenit 19 are massive.
I loved that lens, it has given me great pictures.
Huss
Veteran
That's what i thought too, the later Zenit 19 are massive.
I loved that lens, it has given me great pictures.
I was reading your site and was really glad to have stumbled on your experiences with the Pentax Super Takumar lens on the Zenit. I was about to get one! Glad I dodged that bullet.
ronnies
Well-known
I was reading your site and was really glad to have stumbled on your experiences with the Pentax Super Takumar lens on the Zenit. I was about to get one! Glad I dodged that bullet.
It only affects the Super Multi Coated (or SMC) Takumars which allow full aperture metering on the Sptmatic F. Super Takumars should be ok on the Zenit.
Ronnie
Colin G.
Established

Just got the yellow filter. Looking forward to seeing the results.
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