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In the spotlight

UV Camera
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#1 UlfW

    Ulf W

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  • Location: Sweden, Malmö

Posted 07 August 2018 - 17:27

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.

Attached Image: _MG_9766 full.jpg

Attached Image: _MG_9767 full.jpg

Attached Image: _MG_9767 crop.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.

Edited by UlfW, 08 August 2018 - 12:59.

Ulf Wilhelmson
Curious and trying to see the invisible.

#2 Pedro J. Aphalo

    Pedro J. Aphalo

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  • Location: Helsinki, Finland

Posted 08 August 2018 - 07:06

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.