60mm f3.5 C mount UV lenses on eBay

[lonesome_dave]

Thanks Lou, it does look very much like the Sirchie KSS100a. You got a good deal.

 

A Sirchie catalog from 2012 specifies the following for the KSS100b:

Focal Length- 60mm
Aperture- f/3.5 - f/32
Lens construction- 4 element quartz
Spectral waveband- 230-280nm
Geometric Distortion- <0.1% in corners
Vignetting- <22% in corners
Minimum focus distance- <4 inches

 

As Andy and others have said years ago in this thread it does have CA, focus shift, & flare issues particularly in the visible & IR. It was designed to mainly be used only at 254nm so I presume those were not really problems for it's intended application.

 

[Lou Jost]

The specs seem nearly identical. And yes, as a pure quartz lens, it will only be really sharp with monochromatic light. I don't think the exact wavelength will be too important, though. There may be less field flatness at wavelengths outside the designated range of 230-300nm, but that often can be fixed by stacking.

 

I don't think my version was designed specifically for 254nm, since the coatings were designed to give peak transmission at 230nm and 300nm.