Summicron50/2 Radioactive?

<p>Being a Large Format photographer I am not very familiar with the Leica world.<br /><br>

I have inherited a 50mm/f-2 Summicron in collapsing LTM screw mount; S/N <em>4164121.</em> It has aLeica UV filter and Leica metal lens cap. In excellent cosmetic condition and working order.<br>

Is this a radioactive lens? <br>

Is it a desirable or collectable item? <br>

What is its approximat value for insurance?</p>

<p>Serial number is inappropriate for the period this lens was produced. Only the earliest were radioactive. I suspect if your lens does not have a strong yellowish colour cast it is not radioactive. Radioactive is not a benefit, and most were not radioactive.<br>

Yes, radioactive or not, it is collectible and desirable, but not extremely valuable.<br>

Value is almost totally on cosmetic and optical condition. It can vary from virtually nothing to whatever people are paying on ebay, as external surfaces are delicate and easily damaged..<br>

You could probably get away with putting $500 on it for insurance, but check the serial number again. I don't think Leica has made over 4 million lenses, although I could be wrong. </p>

<p>The staining of the glass from radioactivity is more a tea brown. <br>

The condition of the front glass totally determines value. The coating is soft (Zeiss had the patent on hard coatings), will scratch or rub off if you clean the lens with ANY pressure. Plus, the glass under that coating is soft flint glass (lead crystal), which also scratches incredibly easily. So many were ruined by cleaning with neckties.</p>

<p>James and John: Thanks for the info. You are correctabout the wrong S/N. Just double checked and the actual number on the lens is 1364121. The front element is prestene with a color cast from coating.</p>

<p>This lens came to me in the mid 1980s in a plastic lens box along with a Leica III-G. The original owner had been a petroleum engineer during the 1950s. He bought the outfit new and took it to Venezuela. At some point he decided that the shutter needed to be adjusted and had the huberus to attempt it himself. The camera came to me in a cigar box with all the parts sorted into little pill bottles.</p>

<p>I had no real idea what I had and sold the outfit, as found and still in the cigar box, at the first camera show I went to in Houston ~1987—for $400. I was a minnow—they were sharks.</p>

<p>Hi Drew - those were manufactured in the 1953-56 era in both LTM (SOOIC) and bayonet (SOOIC-M) mounts. At one time I owned the bayonet version, and it was a fine lens stopped down between f2.8-4. It was originally designed in 1949 using lanthanum glass, redesigned to incorporate Schott glass, and eventually used Crown (Kron - think Summikron) glass by the time commercial production actually began.</p>

See:

 

http://www.sky.sannet.ne.jp/seven-ss/camera/summicron50.htm

 

(in Japanese, but has photos of the different versions)

 

but note also Marcelo's comment at the end of this thread:

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00IUWK

The Thorium Glass Summicrons stop at about 1,050,000. I have two of them, 1 below SN 1M and one at 104xxxxx. I cured

one of yellowing using a UV light, and the second- send to Focalpoint for cure, polish, and recoat.

<p>so it's made in 1956, therefore not radioactive. From what you say about it's history, the coatings might be OK. That alone would make it a little unusual. Therefore worth a bit more, if it's clean. </p>

Radioactive? Like it's going to set off a Geiger

counter? What am I missing out on here?

<p>Craig, lots of lenses used radioactive glass to get the corrections right. Yes measurable on a Geiger counter. The Pentax Takumar 50 f 1.4 was one, Collapsible Summicron another. Obviously they phased out radioactive lenses over time. They go yellowy brown with age, but can be bleached with UV light.</p>

<p>Usually, as in the early Summicrons, the radioactive element was thorium:</p>

<p>http://www.orau.org/ptp/collection/consumer%20products/cameralens.htm</p>

<p>Later they switched to lanthanum, which isn't significantly radioactive, though some lenses contained both:</p>

<p>http://camerapedia.wikia.com/wiki/Radioactive_lenses<br /> <br />Edit: Inevitably, someone has taken a Geiger counter to the Summicron and put it on Youtube:</p>

<p>

<p>One of the comments mentions another innovation by E Leitz, a lead-containing flint glass lens element placed behind the thoriated element to protect the film from radiation!:</p>

<p>http://www.kenrockwell.com/leica/images/50mm-f2-collapsible/patent-2622478.pdf</p>