Auto Rikenon 55 f1.4

[antico]

The lens


1#


2#

[scsambrook]

Those shots look very pleasing - please let's see some more ! Especially taken in low light . . .

[nrparsons]

Beautiful blossom shots! They remind me why I love this lens so much: rich, vibrant color and soft, velvety bokeh. I need to get mine out again. I haven't used it in several years, and don't have a good reason why not.

[antico]

Radioactivity? I'm selling my Rikenon because of that, but I'm trying to enjoy it while I have it. I bought it for the camera, a Ricoh TLS 401. I have a Pentax 50 f1.2, great lens, I think that technically it's better than the Rikenon, but the Rikenon is more fun to use, distinctive bokeh and some vigneting makes it special.

[jamaeolus]

I also have a 55 1.4 and it is one of my favorite normal lenses. Not as pretty a copy as the one you have (a bit worn) glass is very good though and its operation is still as new. As far as radioactivity from lenses go, I really don't think its anything to spend a lot of time worrying about. If you kept it close by your side non stop for years, maybe, but the way most of these lenses get used its not a threat. Even a tea tin will be plenty to stop it from being dangerous in your den. I have quite a few that are allegedly radioactive and I recycle my wifes tea tins for them. Toss in a dessicant pouch and long term safe storage is excellent.

from camerapedia:

Radiation LevelsEdit
Typical radiation levels can approach 10 mR/hr as measured at the lens element's surface, decreasing substantially with distance; at a distance of 3 ft. (.9 m.) the radiation level is difficult to detect over typical background levels. For reference, a typical chest x-ray consists of about about 10 mR, a round-trip cross country airline flight exposes a passenger to 5 mR, and a full set of dental x-rays exposes the patient to 10 mR to 40mR.

Most smaller lenses with thorium elements are not very dangerous. However, thorium eyepieces are dangerous. They can give a very large alpha and beta particle dose to the cornea of the eye, causing cataracts and other problems. Normally these particles are stopped by skin, but the surface of the eye is quickly damaged by them, and at close range, the dose can be very high.


He also has a list of Kodak lenses he has measured as radioactive and a huge list of others reported to be radioactive.

Here is a shot from my canon 60d with the rikenon resize only no adjustments:


and a 100% crop:

[antico]

Thank you for the information jamaeolus. It's good to know that the radioactivity on this lens is not something that's going to kill me from one day to another, but I'm going to sell it anyway, the will pay it well for being f1.4. 100% crops from this lens wide open are something really interesting.

[dimitrygo]

@antico
Can you please provide a picture of the rear part of your lens with the rear element extended?

[antico]

[dimitrygo]

Thank you. This is what I had hoped to see based on its serial number. It's quite rare version with completely flat rear element.
Other versions have slightly convex rear element although most people don't recognize the difference.

[Attila]

[antico]

Thank you Attila.

dimitrygo, thank you for the information. I didn't know it was a rarer version, but the flat rear element was something that caught my attention, never seen any lens like it before. The construction of this flat element was possible thanks to the use of thorium?

[luisalegria]

This is quite a common lens.
Its been supplied under many brands; it was a premium "kit" lens for several SLR makers.

The most common US brand for it is probably Sears because they sold tons of rebranded Ricohs.
But IIRC you will also find this under all the brands used for Cosina cameras and even as a Yashica.
I have one as "Exaktar" made for the Exakta Twin TL (Cosina made, Exakta Real mount) and another "Exaktar" in M42 for the later version of the Exakta Twin TL. There are lots of others.

[Oldhand]

[dimitrygo]