Tag Archives: pentax

Radioactive Lenses

I read this article in Petapixel about old radioactive lenses and I realized I have one of them!! So I gave it a try with a portable geiger counter I bought in Japan a couple of years ago.
I’m not an expert on the matter, anyway the normal safe level is 0.05μSv/h and the lens was 5.00μSv/h It’s not dangerous, but it was cool to see that indeed they made these lenses with some radioactive elements.

Based on this question posted on the website of the Health Physics Society, the element used was thorium to increase the index of refraction of the lenses. Based on the answer the use is safe and in their own words:

…the dose rate near the viewfinder of an old Pentax camera of mine (Super Takumar lens) is roughly 100 microrad per hour—approximately ten times background. In other words, looking through the viewfinder of this camera for one minute results in the same dose that I receive every ten minutes when not using it. I would have to hold this camera up to my eye for several million hours to exceed the threshold dose for cataracts…

I’m happy with this lens, in fact the optics of Takumar lenses is great! I use it with an adapter for Nikon to shot video and they work great.
Remember that the world is radioactive and it’s natural to live in a radioactive environment, as far as we don’t surpass certain limits. Anyway if you have a Takumar lens or any other old lenses that you feel afraid to use due their radioactive nature, please send them to me I will be more than happy to keep them safe :)

Check the video bellow to see it in action:

Super Takumar 55mm Pentax lens

The Takumar is the name of a wonderful lens, that the previously Asahi Optical and now Pentax, gave to its lenses.

I bought one for 3000 yen ($33) in a shop in Akihabara (Techno district of Tokyo) that sells junk stuff. The glass is in perfect conditions and the big aperture plus the good ISO performance of the Pentax K-X makes a good combination for nocturne urban photography.

manubrio

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Pentax K-X review

Pentax really shocked me this time. I’m really happy with this camera, it’s amazing, indeed. I would have never imagined that for such a cheap price I could have such a great camera. Of course it has bad things too, but almost none of those “bad” things have a direct impact to the final results, that, by the way, is the most important thing! :)

This is not a pro camera, it’s an entry level one. But to be honest, you can have the same performance as many pro equipments. This camera has really full set of options, a big manual to read and a really huge menu to configure almost anything. BUT the great thing is that Pentax K-X has options for people that don’t know anything about photography as well. It’s possible to use it in automatic and never enter in the menu. This is a great thing and a big challenge at the same time: “How to make a camera that will make a pro feel comfortable and an amateur feel that an DSRL is not hard to use.”

Before introducing the details, here you have a quick description.

Good: Pentax K-X is good for night photography, it has a wonderful ISO competitive with high end pro cameras. It’s fast to focus, is light and easy to carry. It has a nice design, it takes the advantage of doing video with a DSRL, it’s compatible with almost all Pentax lenses, even the very old ones. It’s completely configurable and, at the same time, extremely easy to use. It’s good for pro and amateur. It has a really good price!!

Bad: It’s noisy, the plastic is good, strong but cheap. The menu design is ugly but at least really functional. It lacks of video and HDMI output.

Pentax k-x

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