Well, I like ionic stacks more because they usually have better blocking and look cooler in my opinion, but I never used a dichroic broadband UV-pass filter, so I can't say this by experience.

EdmundOpticsCamera

The only real life situation that I know of where natural IR is big issue for a Baader is when taking UV photos under nighttime conditions. We have had several examples on the board of dubious nighttime “UV” photos that were probably IR contaminated. I found it is best to use extra S8612 (1.5+1.75mm) to fully block IR at night.

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If you have full control over the lighting, a 2mm S8612 filter only and illuminating your subject with filtered 365nm light, also is my favorite. For a UV/visible look.

Every UV-pass solution has its pros and cons for UV-peak, IR-leak, sharpness, transmission ("speed"), dichroic effects or not, reflections or not, speed or not, vignetting or not, flare or not. You get the drift. So just pick something and learn how to use it really well.

Opticssurplus

LOCA is used in an optical bonding process where the air gap between the touch display and cover lens is filled. This adhesive is cured using UV light instead ...

With more than 25 years of experience and subsidiaries in the USA, Japan, South Korea and the UK as well as offices in Europe and Asia, IDS Imaging Development ...

None of these filters last forever. Coatings, dichroic or otherwise, get scratched no matter how "hard" they are claimed to be. Glass oxidizes, chips and cracks. AR coatings wear off. Glued stacks develop weird spots (drying out?). And so forth. I've had everyone of those things happen in my filter set.

I find that a good way to test for leaks is to use a halogen bulb so the UV to visible/IR ratio is very much skewed towards the latter and then doing a long exposure, as I mentioned I did. Would that work with the new Baader U?

To make it a bit more clear what kind of question I'm asking. I really like the QB39+ZWB2 combination that I have recently acquired. It's affordable, doesn't leak (or at least so far I have not discovered any leaks, even when I used a halogen bulb for illumination with long exposures), and it passes light one stop better than QB39+ZWB1 which I used before. These are my reasons, which are yours? Do you like stacks or do you prefer the convenience of a Baader U Venus? Or do you use something else entirely?

As a regular filter, doing the UV photography that others would be able to do. The Baader venus is still my favorite. It has a certain contrast that none of my other filters have.

I have seen faint leakage effects with my Baader U at a few occasions where the S8612/U-360, 2mm stack performed perfectly.

Narrow bandpass filters, like a 340/10 or UVB-bandpass filters are only available as dichroic filters. They are not terribile, but can have the disadvatages discussed above (such as color shifts at the edges with wide-angle lenses). As long as they don't leak, I like them.

For other work (landscapes or street, for example) I'll use the SEU (formerly StraightEdgeU) or a U-360 stack (either DIY or LuvU2). Both the SEU and a thick-enough U-360 + S8612 stack are very very good about not having IR-leak unless forced beyond anything reasonable.

The "old" gen.1 had too much IR leakage, which I for one quickly found out once full-spectrum cameras became the normal tool for UV photography. With earlier cameras such as Nikon D40 or D70, I used these unconverted since they had weak internal UV-filtration combined with sensible attenuation of IR. Baader responed with an improved Gen.2 version that had much better IR blocking. I have at present 3 of them of various ages and cannot detect much of a difference now.

Infrared heat process in the glass industry · Medium-wave infrared radiation is optimal for the absorption of glass. · Gold reflector on the emitters directs ...

The question, as Birna implied, is how much IR blocking you really need for everyday use. In sunshine the Baader will be fine, and under artificial UV one can choose the light source to not have too much IR.

you should get a Foldscope, it is inexpensive but the magnification is 140x and the resolution is 2u. The 'deluxe' version (explorer kit) has ...

LaserOptics

YM Lee · 2021 — Efficient Extreme Ultraviolet Mirror Design describes an approach to designing EUV mirrors with reduced computational time and memory requirements, providing a ...

I also have a U360/S8612 stack which performs well enough, and I used to have a UG11/S8612 stack on a lens which I no longer have. If I ever do photography below 340 nm, none of these will be suitable.

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I have seen faint leakage effects with my Baader U at a few occasions where the S8612/U-360, 2mm stack performed perfectly.

There was an older version that had a slight leak, the 1-1/4 inch one maybe from the older stock, but the 2" is the latest & good.

1) it is a dichroic filter and thus suffers from ring artifacts with wider-angle optics (FOV 40 degrees or greater;) and

by M Daimon · 2002 · Cited by 151 — The refractive indices of synthetic calcium fluoride for 69 wavelengths from 138 nm in the deep ultraviolet to 2326 nm in the near infrared were measured by ...

But I also love my 313bp25 filter stacked with U330WB80 improved. That UVB is also my favorite. Then I do the 254bp25 because I can. So would be interesting to merge all three in my next series of images.

I still use an old AndreaU for a bit of violet pass which I really like in non-white-balanced UV fotos. (The newer AU is different.)

Yaw, pitch, and roll rotations.

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All these filters leak if pushed hard enough; it is just a matter of degree. The leak in the Baader is most noticeable if you are shooting in light that has an unfavorable IR/UV ratio or if there are bright IR sources in the frame. It is most noticeable somewhere beyond 800 nm. I know less about the other stacks, but I would expect analogous findings. The main disadvantages of the Baader are not so much leakage as:

Right angle prisms are generally used to bend image paths or redirect light at 90°. This produces a left handed image and depending on the orientation of the prism, the image may be inverted or reverted. Right angle prisms can also be used in combination for image/beam displacement

My standars choice is the Baader U. It can be remounted to 52mm filter threads in various manner. Because it is slightly smaller than 52mm filters it is much easier to insert into adapters etc. to give a rear filtration solution. This reduced the dichroic side effects to a large extent so even on my 21mm lenses /FX camera there is little chromatic unevenness.

Lens EdmundOptics

Might be a bit of a bold question, as I know that there are a lot of experimentators in here who are always looking for the next exotic thing that they can make by stacking different filters or such. But what is your favorite UV-pass solution, and why?

2021630 — In this video, I'll explain the reason for the inverse numerical relationship between f-numbers and the aperture.

Imagingoptics

I prefer U-360 to any other U type filter glass. You can get glued together versions of that stack, but then you loose the versatility and experimental value of the two filters.

Opticsbuyers Guide

very large fresnel lenses I am interested in your capacity to design and manufacture a very large diameter 1 5 - 2m diameter fresnel lenses If you are able ...

U-360 can also be used for dualband IR, and S8612 2mm can be used for various other stacks such as UV+Blue+Green ('bee vision').

It's wide range of magnifying glasses include, magnifying glass with light, eclipse glasses, kids magnifying glasses, dome magnifiers, reading magnifiers, hand ...

The first UV filter I bought was the Baader u venus filter, as I wanted to buy one filter that I knew would be good for UV. That was 2008 or 2009.

I've recently realized that simply saying a certain UV-pass filter is, for example, "OD3.5 or better" is not quite enough to know. A lot depends on just how much of the filter's bandpass is OD3.5 and how much is not. If the filter only hits OD3.5 in a couple of narrow places, then there's not too much to worry about. If the OD3.5 is broader, then you might need to be more careful and supply extra UV illumination. I learned this lesson on my goofy mirrored Edmund 340BP10 which is said to be OD4 or better. However, there is too much OD4 and not enough "better". IR gets through this one more than I like. I'm about to give up on that expensive mess.

I find that a good way to test for leaks is to use a halogen bulb so the UV to visible/IR ratio is very much skewed towards the latter and then doing a long exposure, as I mentioned I did. Would that work with the new Baader U?

BaaderU is my choice for close work. The filter is fast and sharp and puts the documentary floral signatures at a nice 350 nm peak. You can force IR thru it under some conditions. It is easily scratched. It's not quite wide enough so vignetting occurs. (Rear mounting is solution for that.)