Tuesday, January 4, 2011

Wide angle lenses for UV?

Here today a wide angle test I made with some wide angles I had around (all Nikon mount except the Lithagon)

1) Nikkor E 2.8/28mm
2) Nikkor-H 3.5/28mm
3) Tokina RMC 2.8/28mm
4) Tokina RMC 2.8/24mm
5) Enna Lithagon 3.5/28mm
6) Noflexar 3.5/35mm

The green vertical line indicates the 365nm wavelength and in that box one can find the transmission at 365nm as the rightmost value. Remember that 12.5% equals -3EV, 25% equals -2EV, 50% eq. -1EV

The 24mm lens is used to show how harder it is to get some useful UV transmission when the focal length and complexity of the lens design increases.

The blue line indicates the transmission of a typical Noflexar 35mm for comparison, about 63% at 365nm. A very good lens for UV which hardly shows any focus shift!

[click on image to see a larger one]

Remark: this test only shows the transmission of a lens, it does not say anything about sharpness, contrast, flare resistance, freedom of hotspots etc. which has to be evaluated additionally through photographic tests before a lens may turn out useful for UV photography!

[P.S.: that green line (Lithagon 28mm) shows the typical effect of "lens yellowing" which results in some loss in transmission of shorter wavelengths]

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