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UltravioletPhotography

More on petals under high magnification in UV


nfoto

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By the way, the water reservoir/cooler system worked well. The Al block was just lukewarm and plenty of water left after the shoot had completed. So the flowers hardly were impacted and kept from wilting.
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I've been using my granite rock with the drilled hole for water.

The flowers hold up pretty well. However I usually don't make 40 shots of them. "-)

But I'm thinking Al might be a better cooler.

 

QUESTION: Are all surface cells on flower petals considered Conical Cells? We know that Conical Cells are not always conical. But how do we know that these cells we are photographing are Conical Cells?

Thanks.

 

I simply must try this. It is so cool what you are showing us!!!

 

I think maybe my UV-Planar would be good for the effort.

I also have a Schneider-Kreuznach M-Componon 28/4.0 which Klaus very kindly gave me that would be good for this if I could figure out a good way to mount the filters. Can't hold them in front by hand for 40 shots.

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Not all epidermal cells on floral structures are conical cells, far from it. I've seen figures indicating about 80% of flowers have this feature, but to tell the truth, we really don't know yet. Thus, it is a fact that conical cells only may appear on parts of the corolla and hence one really needs UV photography combining wide coverage and high resolution to observe and verify their presence. SEM photomicrographs of course are superb in showing conical cell structures in all their splendour and glory, with far superior resolution than we UV enthusiasts ever can dream of achieving. However, if the SEM sample is taken in a region where there are no such cells, even SEM won't show them.

 

The conical cells clearly are shaped so as to interact with incident light. In order to accomplish this they have 3-D shapes creating reflections (particularly in UV apparently), or act like spectral gratings to create iridescence. The 3-D shape also acts to increase traction, thus the assumption pollinators get a better grip (the 'Velcro' hypothesis). Another assumption is the conical cells alter the 'wettability' of the petals and other floral parts so the flowers are less adversely impacted by rain.

 

For the Achillea ptarmica, conical cells are only seen on the ligulate (ray) flowers. I just commenced shooting Campanula persicifolia, which has a highly UV-reflective corolla, but so far I haven't seen any conical cells here at all. The corolla epidermis of C. persicifolia all comprises flat 2-D surfaced cells which also are much smaller than the conical cells I have documented so far.

 

For the practical shooting: you definitively need to use a filter box to hold your filter. There is no way you can succeed using hand-held filters!

 

Your 28 mm lens could (and should) be reverse-mounted on a bellows or focusing helicoid.

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"I've been using my granite rock with the drilled hole for water.

The flowers hold up pretty well. However I usually don't make 40 shots of them. "-)

But I'm thinking Al might be a better cooler."

 

Consider I'm using multiple 600 W/s studio units at full power and fairly close range (about 20 cm). You can almost fry eggs with that output. Then, repeat 40-50 times with just a few secs interval.

 

I really need to find a better lens for this line of work. The Canon is too little responsive in UV and besides needs to be stopped down to a nominal f/5.6 in order to give adequate sharp images in UV. Needless to say, at 10X we are travelling way inside the domain of diffraction.

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enricosavazzi

[...]

I also have a Schneider-Kreuznach M-Componon 28/4.0 which Klaus very kindly gave me that would be good for this if I could figure out a good way to mount the filters. Can't hold them in front by hand for 40 shots.

[...]

At magnifications above 1x, this lens probably performs better reversed. It also makes sense to place UV filters between lens and camera in this case. In practice, if you have filters in 52 mm diameter mounts, a relatively simple solution is using extension tubes with 52 mm threads at either ends, which lets you place the filter wherever you want along the stack of tubes (I don't think it makes a real difference though where you place the filter, as long as it is not close to the sensor). Old Nikon and Nippon Kogaku extension tubes have 52 mm threads, and other types/brands may also be available with this size of threads.

 

The problem will be to connect the filter mount of the lens (if there is such a thing, otherwise it might be time to epoxy a step-up filter adapter into this end of the lens barrel) to the extension tubes. So-called "reversing rings" can also come in handy.

 

If you already have M42 or other types of extension tubes or bellows, it is probably possible to mix-and-match adapters from eBay to connect all pieces together.

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Bill De Jager

Yes, visit http://www.teleskop-express.de/shop/ which is their online shop. I think the site is in German only, but the pictures are self-explanatory. Besides, German is not that difficult to understand.

 

Just click the British/American flag near the upper right corner and you'll get it in English. Lots of goodies on the site and excellent service.

 

Bjørn, thanks for explaining about the filter boxes. I have not used mine yet, and I was thinking I'd have to use multiple adapters at both ends which would be too bulky. Now I know better. Gee, I just should have tried a step-up ring to see if the thread pitch is compatible!

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