[UV] Transmittance of the Minolta TC f4 135mm Triplet Lens

I tested some bellows lens heads the other day and the (expected) surprise was, how well that older and overlooked Minolta TC f4/135mm bellows lens head performed (teal and pink line), nearly identical to the Noflexar 35mm (red line; only about 0.2 stops less at 365nm). [I'm not sure if later made models may have the same good transmittance, as the coating may have been changed]

[click on image to see a larger one]



Here now a quick photographic test of that lens, which shows quite some focus shift in UV, the triplet lens design it is.



The micro structure that gets visible on the left petals looks promising, so quite a useful lens I have to say. Btw. it also comes mounted on a focusing helicoid for Minolta mount, sold under the same name, but the lens head can be unscrewed as it has a Leica thread mount (M39 x 26tpi) which is the standard enlarger lens mount.

Outside tests will have to be performed to see if it is free of hotspots, how free of flare it is etc.

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] Transmittance of some Bellows Lens Heads

I conducted a test today to measure the UV transmittance of some older manual bellows lens heads I have here.

Be reminded that this is only a test of the suitable UV transmittance, not of other important parameters for UV photography (sharpness, contrast, freedom of flare or hotspots etc.)



Of course the well known Novoflex Noflexar 35mm has been used as a reference, as it stands out as a very well UV transmitting lens. The (expected) surprise was, how well that older and overlooked Minolta TC f4/135mm perfomed, nearly identical to the Noflexar (only about 0.2 stops less at 365nm).

I will show its photographic performance in a separate test later.

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,VIS,IR] Staeble Lineogon f3.5 / 35mm wide angle lens for reflected UV

Here some test results using the Staeble Lineogon 3.5/35mm lens for reflected UV photography, as well as for IR after having done some successful transmittance tests as shown here on my BLOG

VIS:


UV:


VIS-UV differential:


IR:


VIS-IR differential:


UV-IR differential:


[please ignore the shadow image in the last three images caused by ND+IR stacked filters, this is unrelated to the lens performance]

In summary one could say that the lens performs quite well; there is some focus shift, but rather small. No wonder actually, since Stable was the subcontractor of Novoflex, so the Noflexar 3.5/35mm and the Lineogon 3.5/35mm share the same optics based on my research. The mechanics are different though, as the Lineogon has a quite smaller barrel and also lacks the close-up focusing mechanism teh Noflexar is so famous for. It also has a M39 thread mount, but not a Leica register, as it once was made for the Braun PAXETTE camera, having a 44.0mm register.


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] Tested transmittance of eight 35mm wide angle lenses for reflected UV

I conducted a test today to measure the UV transmittance of some older manual focus lenses I had sitting around, all f = 35mm and all having either M39mm or M42mm thread mount, so may easily be adapted onto modern DSLR's, if their back focal length fits the camera register.

Be reminded that this is only a test of the suitable UV transmittance, not of other important parameters for UV photography (sharpness, contrast, freedom of flare or hotspots etc.)



Of course the well known Novoflex Noflexar 35mm stands out as a very well transmitting lens and it is actually not a surprise that the Staeble Lineogon does about equally well - it is the same optics inside as Novoflex subcontracted to the German company Staeble to design their optics, which my own research concluded. Be reminded that the Lineogon was made for the PAXETTE camera with M39 thread mount, but for a 44mm register (so is NOT Leica compatible, but helps to adapt as it allows for 15mm more space).


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