50mm Hamamatsu Quartz fluorite lens vs D.O. Industries enlarger lens for reflected UV photography II

Today again about comparing a quartz fluorite lens with a conventional, but UV capable D.O. Industries enlarger lens. I have done a similar comparison previously here. I'm using a beautiful yellow/red Phalaenopsis flower, for that as well as my "work horse" UV filter, the Baader-U filter. Lenses used are a Hamamatsu f3.5/50mm quartz fluorite lens as well as a 4.5/50mm D.O. Industries enlarger lens. Light source was an UV enhanced Xenon flash. All shots done at f8.

[click on image to see a larger one]

Visible light image for comparison:
 

1) Quartz Fluorite lens: "standard" UV image using Baader-U filter:
 

2) Enlarger lens: "standard" UV image using Baader-U filter:
 

UV - VIS differential:
 

It gets pretty obvious that this very affordable D.O. Industries enlarger lens reaches quite close to the quartz fluorite lens, yet can't quite beat it in terms of sharpness + contrast. But it is astonishingly close. Also its focus shift is relatively small, as the differential image clearly shows. Quite a nice lens!

I have written about that enlarger lens before HERE


Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

D.O. Industries 50mm old enlarger lens: reflected UV ultraviolet photography

I was digging through boxes, when some older, but new in box D.O. Industries f4.5/50mm enlarger lens fell into my hands. Well, I was curious to see how it would perform in UV, so I took a few shots in the Hermannshof park with it, using my "work horse" UV filter that never let me alone, the Baader-U filter. How nice that this lens has a 40.5mm  filter thread, as not all enlarger lenses have that. A simple short M42 focusing helicoid served as a focusing aid and as it has a Leica thread mount (M39), so simple M39-M42 ring was all needed to make it fit. All shots were done at f8 in evening last sunlight with not much UV left to use.

[click on image to see a larger one]

Rudbeckia hirta, wild form from Illinois:


same, but closer:


Rudbeckia fulgida:
 

Quite impressive performance for a most likely simple Cooke triplet 3e/3g lens. Oh and I forgot to mention, is has no (or barely any) focus shift. Here is its transmission graph versus my usual reference lenses, which reaveals how well this lens transmits UV:

 

More research and testing needs to be done, but it could form the basis of a comparably cheap UV photography system; we'll see...

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos