Various metals in UV-B

[lukaszgryglicki]

Various metals in UV-B.

Made with:

- camera: Mono Fuji GFX 50R.

- lens: Universe Kogaku Optics (UKO) UV5035BK 50/3.5 UV lens.

- filters: 2 x Invisible Vision 308nm + Hoya U-340 4 mm thick.

 

Lens at f=11 or f=16.

Exposure: 40s or 50s.

ISO: 400.

Light - full sunlight around 2:30 PM.

 

Note that glass sphere is totally opaque and looks like other metal spheres.

 

Full resolution files here: https://teststats.cncf.io/backups/metals/

[colinbm]

Terrific !
That Silicon sphere could be Escher's Magic Eye 

[lukaszgryglicki]

I was actually expecting silver to become darker, but no. Then I decided to try all my metals.

Also most of them are 1kg, this is why they differ by size, 1kg ones are: Si, Cu, Ti, Ag, Tungsten is 3kg and WC-Co is one pound.

Then metal boxes are either 5cm or 1 inch or 1 cm.

 

[dabateman]

Wow thank you.

You have so many different metals there. 

Is you silver oxidized? 

With the shinny reflections its hard to tell, but with glass next to it, it does look dark.

Too bad uv polarizers are insanely expensive.  That would help with the reflections.

[lukaszgryglicki]

Silver is a bit oxidized, but rather slightly, it's shiny in visible ligh and in UV too.

 

[StephanN]

Very nice

[Stefano]

Nice element collection! If you will get filters for UV TriColour, one of your subjects should be this. Some metals (like silver) should become yellow or colored in general. Glass too will look yellow to orange.

 

Also, I too like the reflection from the silicon sphere in the first photo, with the other spheres and your hand. I find it artistic.

[lukaszgryglicki]

I have filters, will do next time, UV-B, UV-A, Vis & IR in mono and then will stack them.

 

[Stefano]

If you use this lens, the refocused images will have different magnifications. Those made at longer wavelengths will have a slightly narrower field of view, so to properly stack them you will need to crop and zoom-in the images made at shorter wavelengths. I can do it for you if you need.

 

Also, if you have a PTFE target it is a good idea to place it in the picture as a white reference.

[lukaszgryglicki]

Well, I was thinking about how not to equalize each shot, so they will balance all to gray, but then different spheres/cubes shoudl show the difference. But different field of view will also be a problem.

 

EDIT: I don't have PTFE, but how would I use it, if all 4 images would be monochrome anyway?

 

 

[Stefano]

An ideal white object reflects 100% of every light wavelength, and PTFE is close to that. If you expose your images so that the PTFE target appears with the same lightness in all of them, then whatever color comes out of your subject (like metals, glass, flowers, etc.) will be the "right" color, since a white object (white in a broad sense) appears white in that combined image.

 

You could also get a gray target, this is useful as you don't have to underexpose your photos to avoid overexposing it (in UV especially, things are dark).

[lukaszgryglicki]

Ohhh, ok, makes sense. Only if PTFE is still "white" aound 315nm.

 

[Stefano]

It has almost constant reflectivity down to UVC: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=13871

[Stefano]

Actually, looking at the raw data, it peaks at 310 nm: https://www.thorlabs.com/images/tabimages/PMR10_PTFE_reflectance.xlsx

[Unscenerie]

Glass looking opaque?

This takes my breath away!

[Stefano]

Like this?

 

Anyway, most glass objects are black or very dark at 310 nm. My SvBony lens is actually mostly transparent.

 

Taking photos of normal camera lenses would be fun.

[colinbm]

@Stefano
I like the song & the girl, but what is the connection ?

[Stefano]

The title of the song, from Unscenerie's post. It has nothing to do with the topic, just a play of words.

[Bill De Jager]

Wow!  Those are really cool.  Great idea and excellent execution.

[lukaszgryglicki]

Good idea to photograph lenses and filters .... I will do this next, I expect most of them to be opaque.

 

[Fandyus]

I didn't know hands could look even more rubbery than they do in normal UV pictures, guess I was wrong. Interesting.

[otoien]

On 5/28/2023 at 11:46 AM, lukaszgryglicki said:

Good idea to photograph lenses and filters .... I will do this next, I expect most of them to be opaque.

I did a quick test with ASI678MC with Cassarit 50mm f/2.8 and ZWB1+QB39 filter today on a Nikkor 50mm f/2 Pre-AI at an outdoor location sitting on a transparent case. At first I thought I had transmission, but tilting the lens a little more found that it was all UV reflections in the coating of the lens surfaces acting like a mirror that projects a fisheye-like image.

 

[lukaszgryglicki]

I did a similar tests with 2 lenses (with my 2 x IV308 + HU340 + UKO 50/3.5 UV lens):

- UV-Nikkor (I've photographed it - you can see through it - 4 first images - 3 are from behind the lens - 2 wide open and one stopped down, 1 is from the front).

- Nikkor 80/1.4 AI-S - looks like a mirror made from black glass - you can see me, my camera and tripon in the reflection (last 2 images).

Thera are also 2 glasses and a normal UV/protection filter.

 

 

[Stefano]

The UV protection filter being transparent in UVB is quite hilarious.

[lukaszgryglicki]

Yeah that is a surprise, isn't it?