A new UV-Pass, NIR Blocking Filter

[rfcurry]

EDITOR'S NOTE:  UVP supports a one-time new product announcement.

UVP is non-monetized and has no monetary association with anyone or any company.

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I would like to announce the presentation of a new NIR blocking filter - UVROptics NIR-Block. You can see some of the statistics for it at https://uvroptics.com/index.php?NIRBlocking.
Although I ran a modest characterization using a Hitachi U-1500, I thank Ulf for offering to undertake a more advanced characterization. Both my split-beam spectrophotometer and Ulf's array spectrophotometer can only go down to OD3, however Ulf has a routine to extrapolate to OD5. 

I use an Opteka R72 to test NIR blocking on my filters. The images below are from a Lumix GF1 full-spectrum, CZJ 50/3.5, ISO 400, f11. The illumination is sunlight through floor-to-ceiling double-pane windows on a cloudy day.

Image1 - NIR-Block, 1/800s.

Image2 - R72 over NIR-Block, 10s.

Image3 - R72 over NIR-Block, 25s.

 

 

 

 

 

 

 

We are offering the NIR-Block in 52mm diameter and 3mm thickness. I prefer a 3mm over a 2mm in this filter because the slight loss in the UV for the 3mm is more than compensated for by the additional NIR blocking.

Below are comparisons of the NIR-Block and the S8612. The attached images show the differences between 2mm and 3mm in both SS8612 and NIR-Block. The Schott programming is taking care of any interpolation between 3 and 2mm. I  tested the NIR-Block twice at 3mm on the spectrophotometer.
 

 

 

I look forward to your response to this new offering for those who like to stack
We also have a new ionic UV-Pass filter on our website.

Thank you.
Regards,

Reed

 

[dabateman]

Isn't 1% transmission at 710nm too much for a ZWB2 filter?

Also I am not sure this would sufficiently block the IR leakage from a UG11/U340/zwb1 filter.

Can you show some dandelions with this IR blocker and any of the typical UV filters.

Thanks Reed for creating something new. I hope it does work out and has less oxidation problems than S8612. 

[rfcurry]

Dave,

 

I think I'm the only person on the block who is eager to see dandelions appearing on his lawn! Alas, no fleurs yet. 
You wrote:
"Isn't 1% transmission at 710nm too much for a ZWB2 filter?"
I agree in theory; however, life is always confounding theory.

The R72 is already transmitting IR at 700nm. If you look at the real-life example shown above, with the R72 over the NIR-Block, you will see that at 25 seconds exposure, there is zero IR leak. This bumblebee should not fly!!!

 

I do have some U and Z type UV-pass filters that I could test. Could you suggest a subject other than a dandelion? (I miss the dandelions...)

 

regards,

Reed

[photoni]

Looks good

I calculated that with your filter there are 13 diaphragms of difference between 1/800 "and 25"

(your file below is 13 levels out of 255 = ~ 5% of IR)

good for your ionic filter

maybe too red for UG5

[rfcurry]

Thank you, Antonio.

I used a handy calculator - https://imaginatorium.org/stuff/stops.htm - and came out with 14.33 stops.  Either way, 13 or 14, it provides plenty of NIR blocking, imo.

 

What NIR blocker do you stack UG5 with? It seems that 5mm thickness of UG5 would be necessary to get rid of most of it's visible leak; but I have never used UG5, so the real-life application may be far easier than the theoretical. 

Thanks again.

[Andrea B.]

EDITOR'S NOTE:  UVP supports a one-time new product announcement.

UVP is non-monetized and has no monetary association with anyone or any company.

[Andrea B.]

What NIR blocker do you stack UG5 with? It seems that 5mm thickness of UG5 would be necessary to get rid of most of it's visible leak; but I have never used UG5, so the real-life application may be far easier than the theoretical. 

 

Reed, we usually use UG5 as a UV+Blue+Green filter and do not want to block the Visible passage. The resulting photograph, after white balancing the false colours, is a kind of representation of the colours bees can detect. A typical IR-blocker is used with UG5.

 

[rfcurry]

Thanks, Andrea. I guess I haven't been following that technology. I have a couple raw slabs of UG5 that I picked up years ago, but I have never fashioned them into anything. I wonder why I bought them? 

Anyway, thanks, Antonio's comment about UG5 makes sense in that light. 

 

[rfcurry]

I just had some feedback from the first user of the NIR-Block. Nate Wrote:
 

Quote

Thanks Reed, I've been playing with the filter today, and going to work perfect for my needs. I use a 1.25 Antilia Venus for uv, but it leaked a bit of IR, but goes lower than the baader. So with your nir cut, it blocks all ir, couldn't force it with 10 sec. Much sharper than my faulty S8612 I had, 

                                                                                                        Thanks

It feels really good to get such positive feedback. Thanks, Nate for taking the time. 

[Andy Perrin]

Looks really neat! I will probably get some.

[Nate]

On 4/15/2022 at 7:41 AM, rfcurry said:

(I miss the dandelions...)

I had a few pop up, figured I'd snap a couple before I cut the grass, Too windy to get a proper pic but used my new filter blend of Antilia/UVROptics NIR-Block, and EL Nikkor 80

[colinbm]

Looks real good Nate.

[Nate]

Thanks @colinbm It was nice to get out and take some pics again, says it's spring here, but not quite yet.

[rfcurry]

Ulf came through again with his characterization of a filter. Below is the UVROptics NIR-Blocking filter at a 3mm thickness, compared to the Schott S8612 @ 2mm. The flat peak of the NIR-Block is interesting. Obviously, the S8612 has less transmission in the UV than the NIR-Block. I've been saying for many years that the S8612 is not the best UV-pass/NIR-block filter available.

 

The chart above is internal transmission, the usual for the Schott program. The chart below shows the actual transmission of the NIR-Block. Ulf only measured from 309nm to 800nm.

Thank you, Ulf!!!

[colinbm]

Thanks Reed & Ulf
I need old sol.....

[Andy Perrin]

Yep, looks like you’ve nicely improved on S8612 there, Reed. Thanks Ulf!

[ulf]

On 5/12/2022 at 4:55 AM, rfcurry said:

Ulf came through again with his characterization of a filter. Below is the UVROptics NIR-Blocking filter at a 3mm thickness, compared to the Schott S8612 @ 2mm. The flat peak of the NIR-Block is interesting. Obviously, the S8612 has less transmission in the UV than the NIR-Block. I've been saying for many years that the S8612 is not the best UV-pass/NIR-block filter available.

 

Ulf only measured from 309nm to 800nm.

 

I actually measured from 210nm to 1015nm.

Below 309nm the data was limited by the measurement setup to OD3

Above 800nm the data was limited by the measurement setup to  a bit below OD4 and above 950nm the noise became more dominant.

 

In the post process I selected to truncate the data I sent to Reed to within 309-800nm, where the graph still is nice and smooth..

 

The filter's IR rejection is similar to the BG40, 2mm, but has a better UV-pass.

In some situation this rejection is enough, but for some stack combinations and illumination situations the rejection will not be enough to avoid IR-leakage.

 

A 2mm thick filter of Reeds new material might give exiting controlled IR-leakage in some stacks for some creative images, mixing UV and IR

[lukaszgryglicki]

Can you paste a photo of that filter? Is it a big bluish tint - a bit less than S8612? I just wonder how it looks in visible light. Another story - any photos made just with this filter outside - like landscape, then maybe some portrait? I guess auto white balance will be too blue to use it as a "hot mirror" on a converted camera? I mean, say, I have a BB/FS camera (considering my GFX 50R) and then use this filer to revert it to normal visible photography usage (UV is usually too weak to do any change when there is full visible spectrum next to it). Will photos be "almost" normal or just blue-tinted?

 

[Andy Perrin]

Lukas, even S8612 is not very good for visual photography. This will be worse. ;-)

 

Quote

(UV is usually too weak to do any change when there is full visible spectrum next to it). Will photos be "almost" normal or just blue-tinted?

Heh. UV is more than enough to screw up a visible photo with haze and bad color rendering.  It's true the majority of the light will be visible, but that doesn't mean it's the spectrum of visible light you want...

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For most cameras (not all), BG38 2mm or the Kolari UVIR cut version 2 are the best solutions we know for visual photos.

[Nate]

Just tried auto WB with mine, looked fine, but it's cloudy and rainy. I also haven't shot visible in a while, so not sure what you'd want in the colors.

[Andy Perrin]

Nate, can you also try with S8612? If that looks good to you too, under the same conditions, then we may just have different standards...

[Nate]

@Andy PerrinI ended up ruining my S8612 for not being sharp

[JMC]

Can I ask something. In the graphs shared above there is a difference in the the IR blocking of the two filters (at 700nm for instance there is a big difference). But the two filters are different thicknesses. If the S-8612 thickness was reduced so that the behaviour was similar the new filter in the 700-750nm region, what effect would that have on the UV transmission of the S-8612?

 

It's a genuine question, but I don't want to derail this thread, so Mods please remove if you prefer.

[Andy Perrin]

Actually, I noticed the red end is much higher than S8612 here, so maybe that's why it's doing ok on a cloudy day without much UV. You'd expect extra hazy photos in sun, I would think, and the white balance would have to shift things the other way to reduce the blues. 

[lukaszgryglicki]

On 5/14/2022 at 3:39 PM, Andy Perrin said:

Lukas, even S8612 is not very good for visual photography. This will be worse. ;-)

 

Heh. UV is more than enough to screw up a visible photo with haze and bad color rendering.  It's true the majority of the light will be visible, but that doesn't mean it's the spectrum of visible light you want...

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For most cameras (not all), BG38 2mm or the Kolari UVIR cut version 2 are the best solutions we know for visual photos.

I have S8612 and it is awful for "normal" photos - it cuts too much red. I believe this new filter will cut less red so it should actually be OK. I want to cut IR and not cut visible, again, I'm OK with passing UV - even if photos would be more "hazy" -that's OK. 

Hmm - different question - are there any camera conversions just for UV + vis but no IR? I saw conversions to BB/FS, Only-IR (many variants), only-UV - but never seen UV+Vis...