My first decent reflected UV photo

[Doug A]

After the original full spectrum camera died, I tried the unmodified Olympus E30. It required 60 second exposures at ISO 1600 and F8 with the Kyoei 35 clone and ZWB1/BG39 filter stack in full sun. The wind caused some slight motion blur. Not acceptable results.

 

Tried a different non converted camera. My original Pentax *ist DS 6mp cd sensor camera. It is much more sensitive to UV. ISO 800, F8, at 15 seconds. This was taken indoors with sunlight thru a large glass window. Same lens and filters. This was almost overexposed.

 

The Pentax couldn't set in camera WB. Not sure if it is out of range or the illumination was too low. Set the camera as close as possible, then did the rest of the adjustment to the Raw file in Photoshop 11.

 

Would like opinions on white balance and the image.

 

Thanks,

Doug A

 

The replacement FS converted camera is still a few weeks away.

[Andy Perrin]

Taking it through a glass window is not a very good idea in general. Your photo is very nice though. Hope you get a converted camera soon!

 

Photoshop is incapable of setting a UV white balance properly. This one still has some remaining red in it.

 

The image is nice and sharp.

[Doug A]

Taking it through a glass window is not a very good idea in general. Your photo is very nice though. Hope you get a converted camera soon!

 

Photoshop is incapable of setting a UV white balance properly. This one still has some remaining red in it.

 

The image is nice and sharp.

 

Thanks. Also thought it looked a little brownish red. Will try other editing programs, when time allows. Knew the window would reduce UV, but Andrea B had luck with old window glass. Gave it a try. I can live with longer time exposures if it stops wind motion. This is my first sharp UV photo.

 

Kolari has the camera now. They should finish conversion and it will arrive in a few weeks. It is an upgrade from the previous camera.

 

Thanks for the feedback,

Doug A

[Andrea B.]

Yes, you are on the right track. You have clearly captured a known floral UV-signature.

 

In window light you might only be recording between 375-400 nm (guessing), but most floral signatures are reasonably constant between, say, about 350-400 nm. (That's an armchair estimate only.) In standardized UV false color white balance (not a hard requirement here unless you are posting in the botanical section) there should be no pink/magenta/orange tones, whether dark or light.

 

You might want to try Dark Table, a free download. You open the file in DT, make a white balance only and export it as a TIF which can then be further edited in any other photo app you have. I have not tested convertibility in Adobe Camera Raw for at least a year now, but before that it was never entirely satisfactory for raw UV files in white balance or in demosaicing.

 

Also you can download a free Pentax converter -- probably some Silky Pix thing -- to make a white balance only before moving the exported TIF to another app.

 

If you already know this stuff, kindly ignore.