Hoya U-340 gets the blue out

[dabateman]

 

 

You could also put an UV/IR-Cut filter with proper cut on wavelength on the lens if you happen to have a camera with poor UV-rejection.

 

Yes I think we all should. I am trying to work out the best filter for that purpose. 2017 Cadmium has no fluorescence on a Wratten 2E gel. But 2019 Cadmium seem to see autofluorescence with the 2E. My 2A glows a little as does my Y1.4x and Y 2x filters. But not large amount of glow. I have been trying to look historically in the site posts what maybe the best camera filter option.

One thing I do want to test is a BW 486 first, then a glowy filter to see if there is a difference. The 486, should cut the uv enough, I hope to prevent contrast loss. I can't afford a Badder uvir cut filter yet. So hoping this works.

 

[Cadmium]

Just shows I am getting smarter. Right? :-) Either that or the other way around?

Are you referring to this topic below:

http://www.ultravioletphotography.com/content/index.php/topic/1811-i-want-my-mte/page__hl__%2Bwratten+%2B2e__fromsearch__1

 

First of all, those tests were done for another reason, but do show some fluorescence of the gel, see the edges and even the face of the gel where the light is,

and second point is that those tests were done in ambient light, my last tests were done in darkness, so the fluorescence shows up more.

Wratten 2E is well knows to fluoresce very minimally compared to longpass filters.

Like I have said, put either the gel or the longpass between the UV/IR-Cut filter and the lens, and you will not have fluorescence, that is if you feel you need further specific cutoff of the visible-violet blue.

If you want to use the 2E alone, that should work good also, as long as the torch isn't pointed directly at the lens.

[Cadmium]

You know, based on the B+W graph, I think your barking up the wrong tree by using B+W 486 to block UV for fluorescence photography.

B+W 486 has a 80% transmission at 400nm, and transmits UV all the way down to about 350nm! Yikes! If you don't have one, why bother, save the money, get a Baader UV/IR-Cut for $120, or whatever they are now. Get the unframed (no ring) 50.4mm version, put it in a semi deep 52mm ring, or send it to me and I will do it for you (with a label even! woohoo).

I certainly would not get a 486 for blocking UV, nor would I get one of those to UV stacking either, it seems to be fairly pointless to use that filter for much of anything I can think of.

 

[dabateman]

@Cadmium,

No I was mainly thinking to cut the IR and use the 2A, or something else to cut the UV.

My 58mm 486 is roughly 380nm to 690nm.

http://www.ultravioletphotography.com/content/index.php/topic/2665-sigma-dust-block-filters-bw486-and-my-venus-2-spectra/

 

My 72 leaks into IR a little bit more but not bad.

 

[Cadmium]

You don't need to cut the IR with Nichia 365nm, but if you want to limit the red fluorescence then you can also do that with various BG filter, BG38, BG40, BG39, S8612.

[Cadmium]

Da, I received two new copies of the Amber and Orange UV safety glasses today.

Amber

https://www.fullsour...om/uvex-s0290x/

 

Orange

https://www.fullsour...om/uvex-s0360x/

 

I tested them with Convoy S2+ unfiltered, and the camera sees the same 380nm bright spot through the Orange glasses as I tested before with the copy I sent to John.

So... I like the Amber ones better. Logically, one might assume the Orange glasses might be stronger UV protection,

given the Orange glasses cut off more visual, but they also have a slight leak around 380nm +/-, not sure of the exact band width of the leak,

but I definitely feel that the Amber glasses are technically safer for UV protection.

 

Honeywell/Uvex pdf states:

"UV Protection

Ultraviolet radiation is the most prevalent form of

light harmful to the eyes. Cumulative doses of UV on

unprotected eyes can damage the cornea and lens, and

are a leading cause of cataract formation. For outdoor

and indoor jobs alike, tinted lenses that fully block UVA

and UVB rays should always be worn. All Uvex lenses

filter 99.9% of UV rays. It’s in our name: UV EXcluded."

 

https://www.uvex.us/...5-12-17%20Final

 

However, the Uvex Orange glasses are the only UV safety glasses I have tested that leak the 380nm, so I am not using them, and I recommend the Amber ones instead.

One of the nice things about this design of glasses is they fit over your eye glasses easily when needed.

[dabateman]

Yes tested my Orange 360x glasses today. And they do leak. My leakage is mostly blue mostly likely around 380 to 400nm.

I can also push them to leak with my 370bp15 filter.

I may look into the Amber ones now.

 

I also tested my Convoys. I bought two at the same time, by clicking 2 on Gearbest.

One is amazingly bright. The other is half as bright and leaks little into visible and alot into IR. I see the red dot through most filters. I have not pushed these hard, really not used them much. So looks like you can get a winner and losers with the S2+ units.

 

I think the red dot is a sign that it will not ladt long and the LED is dieing.

 

Interestingly, when I stacked my BW 486 filter on out side of the Y1.4x filter. It glows blue. So you loose the yellow glow but gain a new low contrast blue glow. This is with the convoy pointed at the filter. Looking back at my spectra for the 486. I forgot about my SD15 internal filter. This is 34mm round in plastic holder about 0.2mm to 0.5 mm thick. So I have now taped it into a 37mm to 52mm step up ring and will test this. It has better range of 420nm to 660nm.

[Cadmium]

'Red dot'? You mean like the 'red dot' seen in the top row of this test I did?

http://www.ultraviol...dpost__p__25289

 

380nm is not blue, it is UV (UV-A 320nm-400nm), it is also called violet ( 380nm-450nm), but I don't call it blue.

Not sure how dangerous it is, but I would rather use the Amber glasses which block the 380nm leak.

 

At this point I have experience with many Convoy S2+ Nichia 365nm UV torches, only one did that, it had a weak beam compared to the others, but it went away,

I don't know if it was the battery, or the way I had it all screwed together, but it is the same as the rest now.

I don't know what the situation is with yours, but try unscrewing all the sections, and using a different fresh battery...

You have probably already done all of that.

Make sure the LED in the front is the same LED, get a magnifying glass, and compare the other S2+ LED with the bad one.

 

I think your statement about the red dot is wrong, and I have no idea why you said that, if in fact it is about the 'red dot' I show in my tests (which remember was done with an MTE 303).

Unless of course you have a different LED in that one torch.

You are sure it is an S2+ Nichia 365nm version, and not an S2 UV Cree?

 

486 is worthless for all of this. It doesn't cut UV much, and especially the 365nm range UV that the torch emits.

I think the reason the Baader UV/IR-Cut filter works to prevent GG and other longpass filters from fluorescing, is because it cuts most UV, it may barely have a little UV leak just below 400nm,

but it cuts enough of the 365nm UV to keep the GG from fluorescing, at least that is how is seems to me.

The GG then extends the cut off point to a higher point, like 320nm, 335nm, etc., depending on which GG is used.

But stacking with 486 will not block 365nm much at all, slightly, but mostly just the % of amplitude, not the actual nm.

[dabateman]

Here are some of the Images I took:

 

Camera is Stock Panasonic GM5 using Olympus 60mm F2.8 lens. Aperture was set to F2.8 for all images. I didn't lock in the ISO but the camera set to 12800 for all images below.

 

This is U340 filter on the bad flashlight and No filter on camera (1/8 shutter):

 

This is U340 filter on the bad flashlight and Wratten 2A fitler on camera (1/8 shutter):

 

This is U340 filter on the bad flashlight and BW486 and Y1.4x filters on the camera (1/8 shutter):

 

This is U340 filter on the bad flashlight and BW486 and Y2.0x fitlers on the camera (1/4 shutter):

 

For the last image I rotated the flashlight off the fitler to get a better image of what I call the Red dot.

 

This is a different U340 filter on my other Convoy S2+ flashlight ordered at the exact same time with the 2A filter on the GM5 camera (1/5 shutter):

 

This is the above flashlight with Y1.4x filters on the camera (1/40 shutter):

[Cadmium]

I tested the Zeiss T* UV Filter, and the Hitech Firecrest UV 400 Filter.

Those were both mentioned by Pedro here:

http://www.ultravioletphotography.com/content/index.php/topic/3109-bold-claim-hitech-nd-filters-and-uv-capability/page__view__findpost__p__25416

 

I compared both of those to the Schott KV418, these all seem to cut off UV the same.

Keep in mind that the KV-418 filter and the Zeiss T* UV filter are longpass type transmission,

the Firecrest UV400 is a UV/IR-Cut, bandpass type filter.

 

I will do a formal comparison test of the four filters below and a U-340 filtered Convoy S2+ Nichia.

Baader UV/IR-Cut

Zeiss T* UV

Firecrest UV 400

Schott KV418

So far, they all seem to work the same for 400nm cut off.

[dabateman]

The Firecrest UV400 is a UV/IR cut?

I am surprised by that. I would have guessed it to just cut off the UV. Is it coated like the Baader?

 

Since I got my SD15 internal block filter mounted in a 52mm ring I think I will stick to it. The opening is 33mm circle and I know the range is 410nm to 670nm.

 

My 2A wratten 2 filter obviously leaks UV now. I wonder how much these polyester filters degrade over the years and if that has affected its transmission. I do now see a circle on it from where I have held it up to my camera lens. I just now got a cheap Nikon AF-2 adapter, so no longer need to hand hold it. Probably should have done that years ago, but now they can be found really cheap, used.

[Cadmium]

Da! You are right! I messed up and got the wrong one! Oh well, I like mistakes also.

 

Not the Firecrest UV 400,

https://www.formatt-...ecrest-uv-400nm

 

...but instead the Firecrest UV IR Cut,

https://www.formatt-...crest-uv-ir-cut

 

So, will have to wait a little longer for my formal test, to include one more filter. ;-)

 

 

By the way, here is Digital Loyd's graph of the Zeiss T*

https://diglloyd.com...l-Zeiss-UV.html

[Cadmium]

OK, never mind I get it.