How efficient is a Sun Lotion for UV protection?

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Shooting a person in visible light or in UV can provide striking differences. A Sun lotion really attenuates a lot of UV., as documented by these improvised (and hand-held) captures of a young fair-skinned girl at an alpine resort.

 

 

 

I used my D70 with the UV-Nikkor 105 mm f/4.5 lens and Hoya U-360 stacked with B+W BG-38 for the UV capture.