Jump to content
UltravioletPhotography

Laminated filter glass (AKA glued)


Cadmium

Recommended Posts

I understand the point of stacking the filter glasses, but I wonder whether the glasses actually need to be glued in order to gain the benefit of reducing reflection losses. As long as the two pieces are physically in contact with each other, would that give the same benefit (without the benefit of structural integrity of course)?
Link to comment
As well as possible fungal growth in the "space" between the glass. And if not firmly fitted in the filter holder, any motion may result in eventual scratching or mars.
Link to comment

Here is an example of Newton's rings, which happens when the filter glass is touching, no adhesive, no air gap.

When the glass is laminated (glued), or when the glass is air gaped, there are no Newton's rings.

How much the Newton's rings will show up in photos shot through the touching stack would be something you would have to test, It may or may not show up in different situations.

An air gap, is essentially the same thing as two filters screwed together (with perhaps less of a gap than two filters).

As Andrea says, other problems can arise on the glass surfaces inside an air gap.

With air gaps it is probably best to use two separate filters screwed together, that way any problem can be easily removed whenever needed.

 

Example of Newton's rings (Schott UG11 + S8612 touching, no adhesive or air gap).

post-87-0-27147900-1488086829.jpg

Link to comment

What adhesive?

 

Clark, Please understand, I won't say the specific optical adhesive I used for the lamination shown in the photo at top.

I mostly wanted to show an up close pic of what the general idea looks like.

Link to comment
Cool. I learned two new things from this thread: "Newton's Rings", and adhesives are special/secret (industry IP I suppose). I wonder if Newton's rings decrease filter(s) performance, i.e., if I stack filters on a light source (instead of a camera) will the rings/interference decrease the performance (transmission/passbands/other) of the stack? For example - stacking a UV-pass and a IR absorber on a hot-shoe flash.
Link to comment
Well, they certainly affect light transmission in PRINCIPLE, but whether there is any practical difference, I guess you would have to test. I mean, the Newton's rings are essentially the same phenomenon used in our dichroic filters and AR coatings, except it's just one layer instead of many.
Link to comment

Cool. I learned two new things from this thread: "Newton's Rings", and adhesives are special/secret (industry IP I suppose). I wonder if Newton's rings decrease filter(s) performance, i.e., if I stack filters on a light source (instead of a camera) will the rings/interference decrease the performance (transmission/passbands/other) of the stack? For example - stacking a UV-pass and a IR absorber on a hot-shoe flash.

 

Mark, There is nothing secret about optical adhesives, there are many, some are more suited for different applications, such as transmitting UV.

I just wanted to show what it looked like. I feel you are expecting something more from me here?

 

As far as flash filters, I have tried them both ways, touching, air gaped, and laminated, and I don't see any difference, exposure time and photo appearance is the same.

It can be nice to have the flash filters separate, so that if you want to use one without the other then they can be used that way, but they can be laminated for ease of use.

Link to comment
I'm not looking for anything more, regarding adhesives (to me, its all just glue). Its good to know stacking filters doesn't affect transmission - as I've been using a UV-pass/IR-block stack for a while now (good to know I haven't been working with an impaired filter config). Thanks for the info.
Link to comment
Hmmmmm......do the Newton's Rings show up in the photo? I can think of interesting and weird possibilities for, shall we say, non-traditional photographs. :lol: :lol: :lol:
Link to comment

Hmmmmm......do the Newton's Rings show up in the photo? I can think of interesting and weird possibilities for, shall we say, non-traditional photographs. :lol: :lol: :lol:

 

Andrea, I thought so, I did a test at one time which showed some irregularities, but when I tried it the other night I didn't get it to show up.

Give it a try if you get a chance. One of your S8612 filters stacked in a frame/ring with one of your U-glass filters.

You will need a deeper frame/ring maybe/probably, depending on each glass thickness and frame/ring.

The rings will show visual (as above) with any two thicknesses. So the stack doesn't need to be 'UV-0nly correct', I say this because it might be easier to stack two thinner filters into the same frame.

Link to comment
Would you need to go to a very high F-number maybe? The same circumstances that make sensor dust visible would probably make the Newton rings most prominent?
Link to comment

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...