What is everyone doing with their 8mm ZWB1

[colinbm]

What is everyone doing with their 8mm ZWB1

[Andy Perrin]

Nothing. I haven’t received it. Also Jason did not respond to my last email asking about ordering status.

[ulf]

My order is resting at the customs, after the long international journey. I have not seen it yet.

 

It will be interesting to see if customs decide to charge VAT on this shipment a second time.

I bought this ZWB1 via the Tangsinuo AliExpress webshop, where I was charged VAT.

It appears like AliExpress has started charging VAT for EU-destinations.

 

Have you got yours, Col?

[colinbm]

Yes I just got mine today.

I am happy with it, no visible leaks with UVA LEDs.

I will show a very windy but bright sunlight, at 2 seconds, with it alone on the lens & converted to B&W.

 

 

 

[diant]

I bought this ZWB1 via the Tangsinuo AliExpress webshop, where I was charged VAT.

Ulf, tell me please, how could I find Tangsinuo on AliExpress?

[colinbm]

& on ebay too....https://www.ebay.com.au/usr/tangsinuo

[diant]

colinbm, thank you! I've bought yet from tangsinuo on ebay and know his there. I can't find him on Ali.

By the by - you are from Australia! (Australia, Australia, Australia... sound like mantra for me). I'm amateur astronomer and did not see south skies at all! ... Australia ... it seems to me like Paradise for everyone like me... Omega Centauri, Eta Carinae etc... Paradise, really Paradise))

[colinbm]

colinbm, thank you! I've bought yet from tangsinuo on ebay and know his there. I can't find him on Ali.

By the by - you are from Australia! (Australia, Australia, Australia... sound like mantra for me). I'm amateur astronomer and did not see south skies at all! ... Australia ... it seems to me like Paradise for everyone like me... Omega Centauri, Eta Carinae etc... Paradise, really Paradise))

 

But I have never seen North Skies, never seen snow....thank goodness.

I haven't done astronomy....I like my doona too much....

[ulf]

Ulf, tell me please, how could I find Tangsinuo on AliExpress?

https://tangsinuo.aliexpress.com/store/4314008?spm=a2g0o.detail.1000007.1.186c6fc8OgQnqL

[ulf]

Yes I just got mine today.

I am happy with it, no visible leaks with UVA LEDs.

I will show a very windy but bright sunlight, at 2 seconds, with it alone on the lens & converted to B&W.

 

 

 

What lens did you use here?

[colinbm]

Thanks Ulf

I used the Canon 40mm pancake, Not the best in UVA but close to the limit of my camera anyway.

[diant]

https://tangsinuo.al....186c6fc8OgQnqL

Thank you, Ulf. Am I right understand that ZWB1 is phosphate glass (like U-340 and UG-11 are)?

I often saw such glasses (here in Russia) totally spoiled (with degraded surface). It is very interesting, how steady is ZWB1 with time? How good it endures water-cleaning?

And am I right that ZWB1 8mm (6mm, 4mm etc) should be asked from Tangsinuo as a custom-made ones? I see on its store only 2-3mm ZWB1 glasses.

[Stefano]

Yes, ZWB1 glass can show oxidation, and yes, you have to ask Jason from Tangsinuo to make one for you. It is a custom-made thickness, he doesn't normally sell filters that thick.

 

Colin, you may check if your camera can see 310 nm. My Canon EOS M can, and the raw color is green. I checked with a 310 nm bandpass filter and a 310 nm LED.

[colinbm]

Colin, you may check if your camera can see 310 nm. My Canon EOS M can, and the raw color is green. I checked with a 310 nm bandpass filter and a 310 nm LED.

 

Hi Stefano

No it doesn't get much at 310nm, basically good to 340nm.

[colinbm]

I do have have 309 LEDs & filters now, & the 8mm ZWB1 will cut the visible leak too.

So I will check in the next few days.

[Stefano]

Beware that using the Soligor 35 mm f/3.5 lens (1% transmission at 310 nm according to Ulf's data) my camera really struggles at 310 nm. I need something like f/3.5, ISO 3200 and 2 minutes of exposure in sunlight, with a 340 nm leak. But with your 310 nm (or 309 nm) array and a quartz lens you may be able to do something.

[colinbm]

Yes I have the quartz single lens.

[diant]

I checked with a 310 nm bandpass filter and a 310 nm LED.

By the by - 310nm Leds, as even 250-270nm Leds and 365nm leds, even Nichia (276C in my case), all have a bold tail in more long-wave direction (Nichia has no so bold, but yet it has...). I checked it on many my leds, and if 310nm BP filter does not guarantee total blockage UVA and visible - there may be tricks...

I even have a thought to start a new theme on it, for instance something like "UV Leds without long tails - is it possible?".

Meantime I've carried out one experiment and learned that opposite tails (in more short-wave direction) most probably do not exist.

I've took a strong 100W 660nm Led COB and imaged the scene lighting by it with Red-IR block filter - with very good result (without leakage and appreciable shadows from the Led COB).

Such result is suggested also by the physics.

[Stefano]

At 340 nm, my camera sees orange. With the 310 nm LED alone (and ZWB1 on the lens) it sees green-yellow. With the 310 nm filter, it sees green. The only way I can get pure 310 nm with the 310 nm LED is by using that filter, otherwise my camera also sees the long wavelength tail.

[colinbm]

At 340 nm, my camera sees orange. With the 310 nm LED alone (and ZWB1 on the lens) it sees green-yellow. With the 310 nm filter, it sees green. The only way I can get pure 310 nm with the 310 nm LED is by using that filter, otherwise my camera also sees the long wavelength tail.

Yes we'll see what I can get, the 309nm LED is strong at 40w & that is one of the reasons I got the 8mm ZWB1 is to chop the tail off.

[ulf]

The EF40mm is not a specially good lens for this thick filter.

 

Compare that peak with the transmission of the EF 40:

 

When I tried my U-340 4+4mm stack I used my EL Nikkor 80mm, but I guess you wanted something wider for this image.

[dabateman]

I am still waiting for mine. I should ask Jason for a tracking number.

It sort of slipped my mind. This has oddly been a busy month.

[Andrea B.]

Ulf, question please. What is glycerol spaced? Like liquid between two filters? Sounds interesting.

[dabateman]

Ulf, question please. What is glycerol spaced? Like liquid between two filters? Sounds interesting.

 

The refractive index of Ug11 is 1.56.

The refractive index of air is 1.00

The refractive index of water is 1.32

The refractive index of pure glycerol is 1.46

 

Ulf is trying to minimize the index changes to get closer to what the transmission of solid glass would look like.

So its a Zwb1 sandwich.

 

[Andy Perrin]

Andrea, the reflection coefficient at each pair of materials depend on the difference of the refractive index of the two materials. So the closer the refractive indices, the less reflection loss.