My friends helped me to measure radioactivity of my lenses. I had some yellowish lenses, and had an assumptions that some of them are possibly radioactive. However, I did not know until this time if it’s true.

These are the results of our measurments. We have been written down only the maximum values.

I am not able to disclose information about the person who conducted the measurments, the place, and even the device name.

background front el. ( μSv/h) rear el. ( μSv/h)
Asahi Pentax Super-Takumar 353.5 0.08 0.08
Asahi S-M-C Super-Takumar 1353.5 0.086 0.08
Carl Zeiss Jena Flektogon 352.4 0.098 0.083
Carl Zeiss Jena Biometar 802.8 0.1 0.091
Fuji Fujinon 283.5 0.091 0.086
Helios(KMZ) 40-2 851.5 0.062 0.089
Industar Industar-61 (i-61) (FED-3 lenses, lanthanum optics) 552.8 0.085 0.085
Mamiya AUTO Mamiya/Sekor (DTL series) (identified thorium-232) 501.8 0.24 1.164
Mamiya AUTO Mamiya/Sekor 551.4 0.09 0.09
Mamiya Mamiya-Sekor E 501.7 0.056 0.056
Pentacon MC auto 501.8 0.14 0.13
Zenit MC Zenitar-M2.816 Fisheye 162.8 0.095 0.075

Apparently, Mamiya/Sekor 55mm which is reported to be radioactive[1] is not active according to our measurments. May be there been different 55mm f1.4 lenses in production?

The only really dangerous lenses we found in my collection were Mamiya/Sekor 50mm f1.8 which came with my Mamiya 1000 DTL. It’s also yellow. The device could identify the radioactive element, which is, no wonder notorious Thorium-232.

When measuring Helios 85mm, the radiation level went lower than the background, when the device got closer to the glass: that’s because it’s built from solid metal, and it filters background radiation at it’s front part which has small hood. These lenses are also a bit yellow.

What was surprising, that lenses from the FED-3 camera, officially promoted as lenses with lanthanum optics, seem to have no dangerous level of radiation.

We have also measured the Mamiya-1000 DTL viewfinder, and FED-3 viewfinder, they are clean and safe to use.

Another test we conducted - we were trying to get the device notice the radiation when the thoriated lenses were on the camera. We could not detect radiation by moving the device sensor arond the lenses, near m42 mount, everywhere around the camera. It seems that the metal parts filter radiation well, and even those lenses are safe to use.


I may update this information here

#radioactive_lenses #radioactive #radiation #thorium #lanthanum #thorium-232 #camera #viewfinder #m42 #mamiya #carl_zeiss #carl-zeiss #jena #asahi #pentax #super-takumar #takumar #fuji #fujinon #helios #industar #fed #fed-3 #mamiya_1000dtl #zenit #zenitar #pentacon

բնօրինակ սփիւռքում(եւ մեկնաբանութիւննե՞ր)

I have accidentally found film photos i have made of these kids and maize in Shoushi, Artsakh. First I did film photos, then to make sure, i have them, the digital one. Then, I had an impression, that film photos have been spoiled and have had published only the digital version. The third photo was made with canon 450d, pentacon 28mm lenses on a crop sensor. I have already published it somewhere on this or my Armenian language stream, I believe. The first two photos are on black and white film, Kodak CFT (which is not a film for photography, but for the medical purposes), and Mamiya-ZE2 with 50mm lenses, and that camera, unfortunately, leaked light.

#photo #shoushi #artsakh #kids #maize #comparison #film #diigtal #mamiya #mamiya-ze2 #kodak-cft #kodak_cft #mamiya_ze2 #light_leak #leak #black_and_white #scan #canoscan_9000f_mark_ii #28mm #50mm #2013 #city #street

բնօրինակ սփիւռքում(եւ մեկնաբանութիւննե՞ր)

This test proved to me several things. First, c.1956 Rolleiflex Twin Lens Reflex cameras can keep up with modern photographic equipment. Let me put this another way; I’m blown away by the fact that a 50 year old single coated lens camera can produce large prints that show as much fine resolution and detail as the best modern multicoated lens that I currently own. Both Rolleiflex tested at 96 lines per mm against the USAF Resolution test chart. This equals the newer Zeiss Planar optics in the Hasselblad. Both Rolleiflex controlled flare better than the 500CM too. In practical use, a photographer would be very hard pressed to tell the difference between images taken with c.1956 Rolleiflex and the latest greatest mulitcoated wonder-camera. In oh so many ways, this was a staggering realization.

My tried and true Mamiya 7 travel companion came shining through. I had assumed its optics were slightly less contrasty than the Hasselblads 80mm CT* Planar. With the possible exception of its interchangable film backs, I no longer feel that I’m missing something now that I sold the beautiful 500CM. While Mamiya has made consistantly fine camera equipment, I somehow believed that the Hasselblad was a sharper, more constrasty solution. In this test, the Mamiya 7 is the hands down winner on all accounts. On this day, there was none better. But there were these two little 50 year old cameras that gave the young pups on the block a good run for their money. I knew there was a reason I needed to give Rolleiflex twin lens reflex a third try. I’m glad I did.

#mamiya #rolleiflex #optics #camera #test

բնօրինակ սփիւռքում(եւ մեկնաբանութիւննե՞ր)

the Mamiya lenses are rated as being just about the sharpest lenses ever made for a 120 camera. The Pentacon lenses, on the other hand, even the CZJ multifoated ones, are adequate at best, and awful at worst(in the case of a lot of the Russian lenses). That’s optical quality. When you look at mechanical quality, you are comparing one of the best examples of Japanese design and engineering, to one the eastern bloc’s best examples of design and engineering.

#lenses #mamiya #pentacon #photography #design #engineering

բնօրինակ սփիւռքում(եւ մեկնաբանութիւննե՞ր)

@{Մուլտիվակ Multivac* ;} @{imandes (իմանդէս) ;} #կրեածիվ֊դասակարգ #սեղան #ժամանց #խցիկ #մամիյա #քենոն #գնու #ջիփիէլ #ջիջիլ #օփենմոկո #կոբո #ռիչարդ֊դոկինզ #երեկոյ #վիքիմեդիա #թեյ #զրոյց #լուսանկար #նկար #հաւէս #creative-class #table #tea #evening #work #camera #mamiya #canon #gnu #gpl #openmoko #kobo #richard-dawkins #talk #evening #photo

բնօրինակ սփիւռքում(եւ մեկնաբանութիւննե՞ր)