Dallmeyer 50mm f/0.8 #713810 8-14 Microns Multilayer Coated Lens REF:I3915

[Miranda]

Can anyone help, I've stumbled across this lens on eBay, I've tried to find out more information using online catalogues but have drawn a blank so far. The seller knows nothing as came as a job lot with a thermal camera. Any information would be gratefully received

 

[Ian Grant]

Welcome to APUG

It's a highly specialised lens for some kind of industrial use, it will be useless for conventional use. I have a 75mm f1.9 Dallmeyer that barely covers 35mm, mine's an oscilliscope lens. It's coatings indicate it's designed for something special, as you've indicated possibly thermal imaging.

I've quite a few adverts for Dallmeyer lenses but it's not listed. You'd need to look up lenses for thermal imaging.

Ian

 

[Ian Grant]

Interesting a quick search shows thermal imaging lenses with similar blue coatings.

Ian

 

[AgX]

What may this "8-14 Microns" refer too?

 

[mr rusty]

What may this "8-14 Microns" refer too?

wavelength of light in the infra red section. Quick google shows humans emit infra red radiation at around 10 microns, so slap bang in the middle of this range. I think you have found what this lens was intended for.

 

[Ian Grant]

The OP is the seller "mirandute" I think

Ian

 

[Miranda]

Nope genuine buyer, but can see why you thought that! I'll be honest I don't know much about lenses but this caught my eye as I know Dallmeyer Lens are collectable. I'm after a IR lens for a "project" but can't find anything technical about the lens. As it's almost certainly a IR lens I'm curious as to the lens material as glass is no good for this field of work, possibility of Germanium which explain the opaque lens.

Thanks for your help so far, I just wish to learn more about this lens, technical specs and year of manufacturer, several lenses like this have appeared on ebay from £500 to £30,000, none detail much information on the lens other then stamped markings.

 

[Ian Grant]

That lens is highly specialised, Applied Photography, Focal Press, says that the 8-14 microns transmission band is used for thermal imaging of bodies too cool to emit near infra red. There's 3 other ranges 1.4 -1.9, 2.0 - 2.6 and 1.9 - 4.3 microns

0.3 - 1.38 microns covers the UV and visible light range as well as photographic infrared.

This lens isn't for film use it would have been used with some type photo cathode amplification device. Lenses like this are still made around the world and you can get a camera and lens for less than the asking price of this particular lens, it'll be digital though.

Pentax made a Nocta, ifra-red film camera,

Ian

 

[16:9]

Sorry to be late to the party: 11-year thread-bump alert . . . however your lens is/was part of Dallmeyer's Infrared range, comprising Germanium triplets in 35mm, 50mm and 75mm focal lengths – all f0.8, and all made in the late 1970s. The 50mm is the most common. They were Whitworth-threaded for attachment to pyroelectric cameras. Although only designed to project an image circle of 18mm diameter, the 75mm will probably cover M43. For more information, please see Delta Lenses.