c-mount lenses for reflected UV photography

Today about a find I made a while ago, when I wondered if those usually small c-mount lenses (originally used for video and cine) would be suitable for reflected UV photography. And indeed out of the many I have for normal photography, just a few turned out to be useful. I'm using a yellow/red Phalaenopsis flower for that and my "work horse" UV filter, the Baader-U filter. Light source was an UV enhanced Xenon flash. All shots were done at f8 and are presented side-a-side for easier comparison.

[click on image to see a larger one]

50mm - Visible and UV image using Baader-U filter (approx. 320-395nm, effective peak approx. 375nm):
 

40mm - Visible and UV image using Baader-U filter (approx. 320-395nm, effective peak approx. 375nm):
 

40mm w. 1.4x Barlow lens - Visible and UV image using Baader-U filter (approx. 320-395nm, effective peak approx. 375nm):
 

That 50mm lens has 1.0% focus shift, whereas the 40mm (w/o) Barlow has 0.5%, with Barlow 1.0%. Of course those lenses do not reach that deep into UV, but seemingly deep enough to make them a suitable alternative and a small and lightweight one!


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

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

Quartz fluorite lens vs Komuranon enlarger lens for reflected UV photography

Today about comparing a quartz fluorite lens with a conventional, but UV capable enlarger lens. I'm using a beautiful flower, Eucharis × grandiflora, also called Amazon Lily, for that as well as my "work horse" UV filter, the Baader-U filter and a Hamamatsu f3.5/50mm quartz fluorite lens as well as a 3.5/50mm 6e/4g enlarger lens, a Komuranon-S 3.5/50mm. Light source was an UV enhanced Xenon flash.

[click on image to see a larger one]

1) Quartz Fluorite lens:
visible light image:
 

"standard" UV image using Baader-U filter:
 

UV - VIS differential:
 

2) Enlarger lens:
visible light image:
 

"standard" UV image using Baader-U filter:
 

UV - VIS differential:
 

This flower does not have a very prominent UV pattern, nor does it reach very deep into UV, so this comparison here is limited to the range down to about 370nm, bare that in mind. The quartz fluorite lens is the much sharper one and also has quite less focus shift, but still this enlarger lens seems to be useful, at least as a beginners lens for reflected UV photography.

Here the transmission chart of this KOMURANON enlarger lens, as compared to my "standard" comparison lenses which reveals that it transmits UV quite similar to a Noflexar 35mm to about 335-340nm.
 

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

[UV] STEINHEIL lenses for UV

As I was testing (again) lenses for UV photography, so I ran a few more spectrometric tests now on STEINHEIL lenses, which might be of interest. These are all M42 thread mount taking lenses in silver aluminum barrel.

[click on image to see a larger one]

UV transmission graph:


In terms of UV transmission, all are quite good (except the Culminar) but all exhibit focus shift.

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