8 replies to this topic

[Cadmium]

Asahi Pentax Ultra-Achromatic-Takumar 300mm f5.6

I saw this on eBay, a bit expensive, and I think Jonathan said those aren't the best for some reason, I forget
https://www.ebay.com...9?ul_noapp=true

[JMC]

Yes I saw that one too. Very over priced, so good luck to them. They are optimised for Vis and IR, not UV like the 85mm one. I seem to recall they have glass element(s) rather than just quartz and calcium fluoride.

[Cadmium]

Jonathan, Yeah, thanks.

[dabateman]

Yes just a slow IR lens. One was up for $2000 just a couple months ago. This one is a bit much.

[Andrea B.]

Given that IR photos can be made with so many non-specialized lenses, this 300/5.6 UAT is simply a Pentax collector's item, IMHO.

BTW, I saw a lot of 35/3.5 lenses on Ebay recently. Nothing too special though, mostly in the Lentar, Telesar, Kaligar type brands. Also saw a 35/3.5 Spiratone enlarger. I have one and like it. (Adapters are always needed for enlarger lenses so that could be an additional expense for some.)

[Andy Perrin]

Andrea B., on 25 November 2020 - 17:49, said:

BTW, I saw a lot of 35/3.5 lenses on Ebay recently. Nothing too special though, mostly in the Lentar, Telesar, Kaligar type brands. Also saw a 35/3.5 Spiratone enlarger. I have one and like it. (Adapters are always needed for enlarger lenses so that could be an additional expense for some.)

Hmmm. I inherited many lenses from my grandma and I think I saw one of those in the mix. What kind of adapter is needed for a Sony?

[Andy Broomé]

Andy Perrin, on 25 November 2020 - 23:29, said:

Hmmm. I inherited many lenses from my grandma and I think I saw one of those in the mix. What kind of adapter is needed for a Sony?

Enlargers have no helicoid, so all that is normally required for a Sony is an M42 helicoid and slim M42-NEX adaptor ring. Some enlargers are in M39 mount, so an M39-M42 ring is required in those instances.

[Alaun]

Actually it has also some fluorite elements and is not bad for UV
malva

[JMC]

Yes, the 300mm 5.6 had 2 fluorite and 3 glass elements (just checked the manual). It was designed to be a vis-IR unlike the 85mm one. The manual quotes it as being optimised for use between 400 and 800nm. Not hugely surprised it can be used in the UV, but that wasn't what it was designed for.