UG2A Just for me

[Cadmium]

Oh no, Andrea, you misinterpreted my topic, sorry, I am not announcing UG2A. I don't sell it.

I am only getting some for myself, and for Ulf and Bob, who I have been discussing UG2A with, on and off, for months now. It was Ulf who first started talking about this with me.

I am not selling anything to them, it is group thing, just sharing the cost of the glass.

I just wanted to make it a public 'discussion' about the UG2A glass type, because I was excited about it, and I feel it is interesting, and I have never seen anyone mention or discuss it before, except privately,

as I have previously done with you, Ulf, and Bob.

So I am sorry if that sounded like an announcement about selling it.

It seemed like an interesting topic of discussion to me, that was my only intention, just like any other filter(s), but something entirely new to me.

Please delete that topic. It was not an announcement of a any product. I am never here to sell anything, only to share and learn.

So if this glass type looks interesting to anyone, or not, please post. I would be interested to hear anyone's thoughts and ideas.

Thank you. :)

 

 

[bobfriedman]

i want one.

[Cadmium]

Ha ha, you want the 8mm carousel mod too, Bob! :D But I already knew you wanted one of these.

(I think I may have messed up my 8mm carousel, or at least that project is on the back burner for the moment...which, by the way, is also something I don't sell)

When Ulf first talked to me about UG2A I didn't have much interest because it was like a 'watered down' version of UG1,

but then it started to make sense, and now I can't wait to try it out.

Has anyone?

It looks pretty interesting to me now.

I would like to have some that is 1mm or maybe 1.5mm also, but going to start with 2mm, seems to be the best for an extended UG1 1mm use.

[bobfriedman]

i still want one.

[Cadmium]

You wanted two of these.

I only have enough for Ulf and you, and me. By the way, I don't sell it, just to make that clear, but I am very excited about trying it out. :)

I never even thought it was available before, I thought it was one of the older out of production glass types, the UG2A is newer I think, I think I had it mixed up with UG3 which I think is no longer made.

[ulf]

I became interested in investigating how small additions of blue visual into UV worked.

Last summer I got an UG1, 1mm and used it stacked with my S8612, 2mm.

I really liked the difference in the image and see that stack as a complement to my Baader U.

See my images at post#40

http://www.ultravioletphotography.com/content/index.php/topic/2543-my-first-uv-photograph/page__st__40

 

When I played around with the 2017 Schott excel filter-calculator, I discovered that the UG2A stacked with my S8612 would get me 5nm further into the blue area, compared to the UG1, 1mm.

 

I hoped that this stack would get me some interesting images and started to convince Steve to get some material.

I'm glad that it eventually worked. ;)

 

I'm very excited and hope to have the filter when the flowers emerge here. :) :) :)

[Cadmium]

Ulf, Thanks again for bringing this glass type to our attention. It looks very interesting.

Yes, I think the difference between UG1 1mm thick and UG2A 2mm thick is about 5nm.

It looks like UG1 1mm crosses the 1E-03 line at about 420nm, and UG2A 2mm crosses the 1E-03 line at about 425nm.

 

(please note that with the new Schott program the Linear graph nm increments are labeled differently from the Diabatic graph, which can throw you off at first if you are not used to it,

but I have lined up the nm on top and bottom graphs, for better direct visual reference)

 

[Cadmium]

Here is a comparison between the UG1 1mm + S8612 2mm stack, and the UG2A 2mm + S8612 2mm stack.

 

(please note that with the new Schott program the Linear graph nm increments are labeled differently from the Diabatic graph, which can throw you off at first if you are not used to it,

but I have lined up the nm on top and bottom graphs, for better direct visual reference)

[Andrea B.]

---

I GIVE UP!!! Tread carefully, very carefully.

---

 

Ulf: I became interested in investigating how small additions of blue visual into UV worked.

 

If you restrict the bandwidth of a filter or stack to between about 375-400 nm with no leakage over 400nm into the violet, then you'll still get the blue look.

Two things:

• Remember that it is primarily violet which is "leaking" just over 400 nm. The violet gets recorded into the blue channels usually.
  
• The usual click-white balance step will often remove a lot of the blue look, so perhaps do not use that when processing your blue look UV files?
  

[Cadmium]

Thank you Andrea, but don't ever give up. :)

What do you think about the UG2A, useful maybe? I guess we will find out when Ulf gets to test it.

Ulf will be testing the stacked use, he has done a very nice job with the other UV+Blue+Green stacks he has used.

Bob will probably mostly be testing the dual band use, because he is famous for his IR and dual band IR comparisons.

 

I did a few more graphs to help me think about UG2A.

First, I want to reiterate that UG2A is almost identical to UG1, but UG2A is 3 times as thick for the same transmission.

So in other words:

UG1 0.33mm = UG2A 1mm

UG1 0.66mm = UG2A 2mm

UG1 1mm = UG2A 3mm

UG1 2mm = UG2A 6mm

 

So if you were to use UG1 at a thin enough thickness, then you could use that in place of the UG2A in most situations,

however anything under 1mm gets very delicate to make and care for, I have a few various filters that are 0.75mm thick,

but I don't like to use anything under 1mm thick, and I prefer 2mm thickness for durability when possible.

Thicknesses between 1mm and 2mm are good too, and often are best or needed for some stacks.

Keeping in mind that a glued stack of UG2A 0.75mm and S8612 2mm (for example) would not be fragile like a 0.75 single filter would be.

So, These graphs are just to help me think.

 

 

 

 

[Cadmium]

More graphs ideas...

Other than the last graph idea example at the bottom, these are all based on the idea of a UV+Blue+Green+Red mix.

Starting with the UV+Blue+Green+Red UG5 based stack (UG5 1mm + S8612 1.5mm):

 

These following ideas are all hypothetical, and stretch the limits of the glass thinness. I am not sure these would be practical to make.

Now compare that to this UV+Blue+Green+Red UG2A based stack (UG2A 0.33mm + S8612 1.5mm):

 

Now be aware that the UG2A 0.33mm thickness used above is most likely physically problematic to manufacture, and would certainly need to be glued to the S8612 to maintain any strength.

So, here is another similar idea using UG2A 0.5mm + BG40 3mm instead, 0.5mm would be slightly easier to make, but still very hard to make.

 

While I was at it, I plotted this idea using UG1 0.33mm + S8612 1.75mm (again, this is extremely thin glass, not sure practically feasible):

[ulf]

(please note that with the new Schott program the Linear graph nm increments are labeled differently from the Diabatic graph, which can throw you off at first if you are not used to it,

 

 

You can adjust the wavelength range in these diagrams by right-clicking on the wavelength numbers below the graph and selecting "Format Axis..."

[Cadmium]

Thanks for the tip Ulf. I will try that next time.

I still use the 2012 version usually, because it has all my extra manually entered data in it for other glass, but not the UG2A,

so I used the 2017 for this because it has the UG2A in it.