Showing posts with label 375nm. Show all posts
Showing posts with label 375nm. Show all posts

Sunday, May 6, 2012

[UV] filters for recording deep(er) reflected UV for peak 375nm, 365nm, 350nm, 325nm

Here a comparison of the false UV colors to expect using the Baader-U white balance setting when using specific short wave filters for deeper reflected UV recording with the effective [*] peaks: 375nm, 365nm, 350nm, 325nm. It includes that new Jupiter-U filter of mine.

[click on image to see a larger one]

The UV images here also uses my standardized false UV color normal + high intensity palette:





top left: Baader-U (effective peak approx. 375nm), top right: Jupiter-U (effective peak approx. 365nm)
bottom left: filter stack I (effective peak approx 350nm), bottom right: filter stack II (effective peak approx. 325nm)
[ignore quality issues please, these latter three are experimental versions]

Interesting to note, that the red channel looses on intensity when the wavelength gets shorter, the green channel stays about constant, the blue channel declines first, then later on (325nm) recovers slightly.

Note that the exposure of these 4 images are not the same; I tried to get about equal exposed results.

[*]In that context "effective" means what the combination of filter, lens, sensor results in (for a given light source: sun / Xenon in that case) as a peak wavelength for that combination (lens is a flat transmitting quartz fluorite lens, Cerco 94mm in that case) as per my simulation system.

So, now the question arises of course, if such deep UV explorations is only for the the priviledged owners of a quartz fluorite lens. Well, have a look at that following test result using a common 35mm lens and the same filter sequence as above.



Of course there are differences, especially in exposure, but in principle, it seems doable. Don't get too excited, please, the exposure difference is a massive one.

I will reveal more about these experimental filters of mine here later, once they have proven their usefulness and when acceptable photographic quality has been achieved.

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

Wednesday, September 26, 2007

Dive into the wonders of the Mexican Zinnia

Today I would like to invite you to a journey into the wonders of the Mexican Zinnia, which is one of my favorites for UV shooting, since it has so much to offer.

Equipment used was two Macro Nikkors 35+19mm, a modified Olympus variable extention tube and a 375nm UV LED light. All shots were done at ISO400 to capture the faint fluorescence, thus the higher amount of visible noise.

So this was the one from a previous session...[click on image yields a larger version].



Now let's dive in...



and deeper...



Now let's switch modes from "visible and fluorescence" to "UV and UV induced visible fluorescence":



and deeper...



and deeper...



and deeper....reaching about 14x magnification on CCD, on screen ca 160x...



So this wonderful little flower has it all, a nice visible appearance, a sharp UV pattern, fluorescent petals, pollen and stems (even in different color!)...

Lenses used were Macro Nikkor 35mm+19mm on a modified Olympus variable extention tube + RMS mount adaptor. UV LED 375nm. Camera used was the Olympus E-510.


Stay tuned, more will follow on that subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos