i buy scuba blue ;)

[Cadmium]

Eka was using a stock D40 with UG1, perhaps the stock D40 makes the red center work with UG1. Was there any post processing for the Stock D40/UG1 shot?

Birna had some older shots like that, some were done on film, I don't know if any of hers were done with digital. Here is one example of Birna's:

https://fineartamerica.com/featured/dandelion-in-uv-light-bjorn-rorslettscience-photo-library.html

I have tried to simulate that look using a UG5 stack before (UG5 1.5mm-2mm + S8612 2mm, or U-330 instead of UG5, AKA 'Bee Vision' stack),

post processed via channel mixer. Example:

[ins13]

Evgeniya,

thank you very much! I really,really like your photos of dandelion with ПС11 and IR-cut filter. the center of the dandelion is warm shades and "pistils" are blue. nice and informative.. It is wonderful !!!

Yes photo with ПС11 3mm + S8612 1mm is the best. But I do not have filters need thickness for similar images. While I can do only this(

 

by the way now I am exploring opportunities ПС11+IR-cut filter for landscape and urban shooting, as it well "sees" and UV and IR and do photos without noticeable focus shift on my lens, unlike the UV+weak IR-cut filter

 

Yes, my photograph of dandelions with UG1 was shot by unmodified Nikon d40. This camera perfectly works in the invisible spectrum from hands because its IR-blocking filter is very leaky. And now I'm looking for and looking for the opportunity to take such pictures on a modified camera. Your pictures are very similar to what I'm looking for. Thank you for them!

 

Cadmium,

the processing was done. But it was so long ago, I don't remember. Surely the red color of the center was corrected programmatically. But I like it here not only the red center. but the overall ratio of color and brightness. the leaves are almost white like in IR photos and vivid the center of flower as in UV photo and deep blue pistils against the background of a warm color of center. i like it

Birna's pictures are beautiful! I already wrote that i am admirer and try to emulate....

I like your version of dandelion with UG5 1.5 mm-2mm + S8612 2mm.

[Cadmium]

Eka, have you noticed any difference in chromatic aberration around the edges of your shots with the results of your Russian glass tack and your Lee #729 stack?

Do you see any chromatic aberration difference between the two stacks when using wider angle lenses?

[ins13]

Steve, I didn't notice it. But I didn't look too closely. I will make comparative pictures in a few days and show here

[Cadmium]

Eka, Thanks. I don't have all those same glass types you have.

It would be good to 'clear up' that point of comparison.

Keeping in mind that such CA can come from the lens, not the filters, especially when used out of visual range, and when used for a combination of visual and out or visual range.

Thank you.

[dabateman]

Cadmium, does Yann have you worried about CA in Lee vs glass?

I do wonder about that as well. I haven't looked for it either, but depending on the wide angle lens used, we may see an effect. I am not sure though.

[ulf]

Keeping in mind that such CA can come from the lens, not the filters, especially when used out of visual rang, and when used for a combination of visual and out or visual range.

 

This I think is mainly correct. For very thick filters and stacks made of materials with a big dispersion https://en.wikipedia.org/wiki/Dispersion_(optics), in combination with very wide lenses there might be some CA added.

I have no idea if it ever would be significant at all as most of our lenses are only designed for VIS and likely have CA for a combination of visual and out or visual range.

[Andrea B.]

A comment for Eka about the UV and IR reflectivity of the dandelion, a Taraxaxum species. Your question about the dandelion's IR appearance is a good one!

 

First, remember that UV/IR false colours are misleading and should not be used to judge the reflectivity or absorption of either UV or IR. False colours are an artifact of our camera's Bayer filter, the white balance algorithm, the converter app and more. It takes only a small nudge of the "color wheel" to move one false colour to another.

 

To better judge absorption/reflection of a particular subject in UV or IR photos, you must make a monochrome photo of the subject and include a black and white standard to properly set the black/white points of the histogram. (I'm being very brief here.) Then you have omitted the false color variable which can confuse the determination of reflective/absorbing areas in a particular waveband. But another caution - at best, a monochrome photo gives us only an indication of absorption/reflectivity which should then be confirmed spectrometrically if the result is to be scientifically meaningful. This is because the conversion of a photo's raw data (whether monochrome or color) includes the application of a curve and tone scaling which may stretch the histogram, change the lights/darks and change the contrast.

 

 

The reproductive parts of a flower often show a UV or IR reflectivity which differs from the flower's rays or petals. More so in UV than in IR. But we do have some examples of different IR reflectivities of different parts within a flower. (Taraxacum, Gazania). It would not surprise me if the dandelion's stigmas were a bit darker in IR. But I don't think you can determine that with false color photos. :)

 

Here is a Taraxacum which has stigmas partially IR-dark when seen with the B+W 092 IR-pass. Although please note that this is not an official monochrome photo! Nevertheless the false colour is quite low, so I'll use it since I don't have a mono with this filter.

https://www.ultravio...&attach_id=1491

 

Here is a Taraxacum which has stigmas which are IR-light when seen with the B+W 093 IR-pass. It's a mono photo.

https://www.ultravio...&attach_id=8909

 

Now I've become very curious about dandelions in IR and must go out and look for one!!! :lol: