[Theme] Pictorial UV

[Bjørn Rørslett]

The vernacular names in English (UK/US etc.) are little standardised (compared to the Nordic system in which official names and spellings are provided). Marigold thus is used also for other species.

To illustrate the confusion by non-standardised vernacular names, the following excerpt from en.wikipedia.org/wiki/caltha_palustris is presented;

"In the UK, Caltha palustris is known by a variety of vernacular names, varying by geographical region. These include in addition to the most common two, marsh marigold and kingcup, also brave bassinets, crazy Beth, horse blob, May blob, mare blob, boots, water boots, meadow-bright, bullflower, meadow buttercup, water buttercup, soldier's buttons, meadow cowslip, water cowslip, publican's cloak, crowfoot, water dragon, drunkards, water goggles, meadow gowan, water gowan, yellow gowan, goldes, golds, goldings, gools, cow lily, marybuds, and publicans-and-sinners.[5] The common name "marigold" refers to its use in medieval churches at Easter as a tribute to the Virgin Mary, as in "Mary gold". In North America Caltha palustris is sometimes known as cowslip. However, cowslip more often refers to Primula veris, the original plant to go by that name."

I rather prefer Caltha palustris.

[BW]

To be on the safe side I`ll stick to scientific names

[charlie]

Børge, I quite like the colors of your photos, particularly post #127. Which lens are you using for you UV work?

Bjørn, I'm curious to try the white balance method you've mentioned. Using a Baader U filter is it as simple as finding any opaque white teflon/PTFE material and setting W/B off of it?

[BW]

I have the total of one lens for UV. It is a Novoflexar 35 mm f3,5 that Bjørn kindly sold me. The colors are a result of my work on the RAW-file. It comes out more purple-looking, while the yellows come out yellow

[Bjørn Rørslett]

Charlie: any UV-neutral subject will do. White Teflon is a good choice, but be aware that its reflectance usually is non-Lambertian, ie. the angle of incidence comes into play. Bitumen sidewalks tend to be neutral, as well as the kind of expanded grey foam-like padding material used in packing of consumer goods.

Setting the w/b under UV against a single ("UV-white") reference point might not suffice if the software is incapable of handling the skewed ratio red:blue in the RAW file. See examples below (Nikon D3, UV-Nikkor 105, Baader U, studio flash with uncoated Xenon tube). First example using a click-white operation in Aftershot Pro, the second using PhotoNinja. The failed w/b usually is typically manifested in an inability of remove the strong reddish cast of the RAW file.

[charlie]

Thank you for the info. There is quite the difference between Aftershot and Photoninja. The PN version is quite 'natural' looking even though it is a false color image. I've always adjusted the W/B slider by eye to get the most satisfying result on a image by image basis, I am interested in trying this technique in the RAW converters I have on my machine to see the differences. ACR, NX-D, & Capture One.

[Bjørn Rørslett]

In PhotoNinja, a simple "click-white" operation to a UV-neutral target will suffice. However, for other programs, do ensure you have more than one target of different intensity and use curve tool to bring them all to be rendered neutral. ASP will do this quite successfully, but of course with far more efforts than the ease of PhotoNinja. Also every image will need its own fine-tuning, whilst with PhotoNinja you can just paste the settings to other images taken under similar light conditions.

[BW]

Further interpretation of the UV-world. Taraxacum officinale "my style"

[Andrea B.]

Lovely! I like this interpretation.

[Bjørn Rørslett]

Nothing beats a fertilised meadow in May when the dandelions bloom ... an eyesight in any part of the spectrum. Apparently there is no lack of suitable meadows in your part of the country Nice and the depth of field adds to the overall impact as well.

Just a hint: try in IR. Dandelions have many surprises in store.

[BW]

Thanks Andrea and Bjørn! I will tray IR version later. But I have to hurry before the cows comes marching in

[Frank Fremerey]

Børge! Your Billie-the-kid smashes me, esp the super small DOF combined with the super high definition and the convincing expressions. Great models you have there!

[Bjørn Rørslett]

Recent years have seen an invasion of beavers into my neighbourhood, which is situated on the northern perimeter of Oslo, capital of Norway. The return of wildlife isn't surprising and even wolves have been reported from the suburban areas in the last decade.

A small creek nearby now is almost impassable due to all the recently felled logs of Downy Birch, apparently a favourite snack of the local beaver tribe. I combined a birch trunk with spring blooming Marsh Marigold (Caltha palustris) in this snapshot of the riparian ecosystem. Later, upon processing the files, I observed how UV actually made the forage trail left by beavers going back and forth to this log much more visible than in the field. The trail cuts into the frame diagonally from the lower right.

Nikon D3200, internal Baader U (gen.2 Venus filter), Tamron 21 mm f/4.5.

[Bjørn Rørslett]

Schnell's Window (restricted view of sky seen under water due to water's refractive index of 1.33-1.34). Here done in UV using the water surface itself as "lens".

I used an old Nikonos II housing loaded with Fuji negative colour film and the bespoke dome port of a 7.5 mm Fisheye lens adapted for Nikonos, but without any  lens inside, only a Hoya U-360 UV bandpass filter. The lens mount and film gate prevents capturing the entire Schnell's Window (around 120 degrees).

The brighter blobs within the window are probably sun reflecting off the water surface.

[Erik Lund]

Extreme minimalism! Very impressive:)