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UltravioletPhotography

In the spotlight


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A few week ago I played around checking focus shift in UV for a few lenses.

As I did that indoors with a Baader U on the lens, I used one of my Convoy S2 UV-flashlights for illumination.

The exposure times with the flashlight was quite short and made me realise how powerful the Convoy is.

 

Today for the first time I brought the Convoy with me, to use as focusing aid when changing filters.

It worked very well and I was amazed how much brighter the Convoy is at close range compared to the bright sunshine.

In the scene below I used a stack of S8612, 2mm and U-360, 2mm on an El-Nikkor 80/5.6 metal version.

 

Exposure times:

Sun only: 15s, Sun + Convoy: 1/2s

 

I held the lamp rather close, 5-10cm.

 

post-150-0-80162000-1533662166.jpg

 

post-150-0-15440200-1533662154.jpg

 

post-150-0-61103600-1533660557.jpg

 

It was some movement of the flowers due to a slight wind.

This can be seen as a slight yellow halo around the edges of the flower petals.

 

Due to the very different illumination, the raw processing in rather different.

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Yes, indeed! The Convoy 2+ has strong emission and based on using equivalent LEDs on their own, I think the reflector concentrating the beam has much to do with the very high irradiance achieved at close range.
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The Convoy also helps to bring out details such as the pollen grains in the last photo. Very nice!

 

One small problem I've had using a 365 nm UV-LED flashlight to supplement sunlight is that it creates a color cast - usually yellow. So you must be careful to evenly illuminate the subject with the UV-LED flashlight or you can get some strange patchy false colours.

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One small problem I've had using a 365 nm UV-LED flashlight to supplement sunlight is that it creates a color cast - usually yellow. So you must be careful to evenly illuminate the subject with the UV-LED flashlight or you can get some strange patchy false colours.

And weird shadows! Like when I tried this (see last photo):

http://www.ultraviol...__fromsearch__1

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