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Questions about UVIVF

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#1 Fandyus

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Posted 21 July 2021 - 12:44

I read the sticky for it, but has left me rather unsatisfied.
I have two questions.
First one is, do you guys think this looks like a good buy? Furthermore, should I get it with or without the batteries? I heard bad things about offbrand batteries from china.
https://a.aliexpress.com/_mLuw36f
I picked this since I want as much power as possible, and I'm willing to pay up. This seems good, but I'm not sure if it's not too good to be true. I'm not sure AloneFire is a reputable brand.

My second question is, what filter do you guys recommend to get rid of wavelengths of 400nm and shorter? Currently I use a vintage light yellow filter but it fluoresces very strongly and clouds the whole image in orange haze when strong 365nm light is present. I'd like to get something that doesn't fluores but in not sure if I can exactly afford a tiffen filter.

Thanks.

#2 colinbm

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Posted 21 July 2021 - 12:58

The Alonefire is good, I have one & it works fine, I would get their batteries if you don't have any or enough, Amazon is cheaper....
https://www.amazon.c...srs=11498548011

The Zeta UV L41 is a good filter to block 410nm & lower.....
https://www.amazon.c...26872226&sr=8-5

#3 Andy Perrin

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Posted 21 July 2021 - 13:29

It would be interesting to have some tests of the sort Ulf and Colin did for the Nemo (on the spectrum and the power usage and output). For batteries, I think we discussed that the charger matters a lot to the behavior of the batteries as well as the brand of batteries, so maybe you should also think about getting a high quality charger. Ulf previously recommended these chargers:

Quote

I use a MiBoxer C4 Plus
and have an older MiBoxer C4

I think the MiBoxer C4-12 is really nice too
https://www.ebay.com...miboxer+c4+plus


#4 Fandyus

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Posted 21 July 2021 - 16:12

View Postcolinbm, on 21 July 2021 - 12:58, said:

The Alonefire is good, I have one & it works fine, I would get their batteries if you don't have any or enough, Amazon is cheaper....
https://www.amazon.c...srs=11498548011

The Zeta UV L41 is a good filter to block 410nm & lower.....
https://www.amazon.c...26872226&sr=8-5
Thanks for the recommendations, unfortunately the Amazon link would cost a lot more here due to really expensive shipping ($16.57). I have a way cheaper listing for what seems like the same model but it is not branded AloneFire. It uses the same promotional video though, just with music added, probably not that one, seems really sketchy (https://www.aliexpre....acef2e0eD0afoK).
Thanks for the filter recommendation as well.

#5 Fandyus

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Posted 21 July 2021 - 16:14

View PostAndy Perrin, on 21 July 2021 - 13:29, said:

It would be interesting to have some tests of the sort Ulf and Colin did for the Nemo (on the spectrum and the power usage and output). For batteries, I think we discussed that the charger matters a lot to the behavior of the batteries as well as the brand of batteries, so maybe you should also think about getting a high quality charger. Ulf previously recommended these chargers:
Well damn, that's quite an expensive charger. I think I might go and get one from local vendors, they are cheaper but there's still some quality guarantee there.

#6 Fandyus

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Posted 21 July 2021 - 16:26

As for the chargers, I've checked Alza, a local tech vendor and I found two relatively cheap options. They both have different protection mechanisms in place, apparently.
First one is a bit cheaper, has two slots and can only do 18650, it has overheat and overload protection.
https://www.alza.cz/...50-d5278273.htm
The other one is compatible with a multitude of battery types, has only one slot and has overload and short circuit protection.
https://www.alza.cz/...50-d5278273.htm
Which one would you guys say is better? Is short circuit protection important?

#7 Andy Perrin

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Posted 21 July 2021 - 16:50

Probably the most important thing is that the charger is designed with the battery chemistry in mind for the TYPE of battery you are using. Different battery chemistries must be charged in different ways if you want your batteries to last. I think Ulf knows a lot more about this subject than I do.

With regard to the batteries themselves, this guide covers basics:
https://www.makeuseo.../18650-battery/

That guide also recommends a charger:
https://www.amazon.com/dp/B0096U26QQ

Edited by Andy Perrin, 21 July 2021 - 16:54.


#8 Fandyus

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Posted 21 July 2021 - 16:53

I see, perhaps the 18650 specific one could be better then. We'll see if anyone else has something to say.

#9 Stefano

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Posted 21 July 2021 - 17:24

When I need to charge my 18650, I use my bench power supply. I limit the current to 1 A (it is a 2200 mAh cell, but I don't know how old it is and its C rating), and I set the voltage to 4.2 V. Connecting the battery, it first charges it at 1 A (the battery would absorb more current, but it is important to limit it) and after that it absorbs less and less current at 4.2 V (the current never reaches zero, the graph has an horizontal asymptote, you just disconnect the battery after a while or when the current is below a certain value).

I think it is OK doing it for my use. Charging the battery at less than 0.5 C should be safe even if you don't know much about your battery, as it is a slow charge. At that rate, the battery doesn't even get warm. A charger would be useful for me if I get more batteries or if I want to charge them in a specific way.

Ulf knows better than us in this field. I hope that what I do is safe.

#10 Andrea B.

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Posted 21 July 2021 - 18:35

Get a longpass starting at 400 nm or 405 nm to block the UV light if not using a stock camera.
(Usually we use a stock camera for UV-induced Visible Fluorescence,
so in theory there should be an internal UV/IR blocker.
In practice, the efficacy of internal filtration may vary.)

Use some BG glass to block the IR light, if any.
UVIVF is done in the dark, so there should not be any stray, ambient IR light.
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#11 Fandyus

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Posted 21 July 2021 - 23:43

View PostAndrea B., on 21 July 2021 - 18:35, said:

Get a longpass starting at 400 nm or 405 nm to block the UV light if not using a stock camera.
(Usually we use a stock camera for UV-induced Visible Fluorescence,
so in theory there should be an internal UV/IR blocker.
In practice, the efficacy of internal filtration may vary.)

Use some BG glass to block the IR light, if any.
UVIVF is done in the dark, so there should not be any stray, ambient IR light.
Thank you, I know this, however. I use a Canon EOS 6D and obviously I do everything in the dark. Problem is that my 6D very much is able to see 365nm given the exposure is long enough. I also asked this because my issue is with the fact that the light yellow filter I use very much fluoresces under UV, which creates a color cast on the image, washing out the shadows and the blacks. It can be corrected by post processing but it's not ideal.

#12 Andrea B.

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Posted 23 July 2021 - 00:12

Ask Cadmium about longpass filtration which does not fluoresce. A former photographer here was using some kind of K glass to block UV, but I don't recall what kind because he removed all his topics. But somebody will know which K glass was useful.
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#13 Cadmium

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Posted 23 July 2021 - 01:32

Schott KV glass (I think you are thinking about?) has been mentioned often, however it is hard to find these days because it was discontinued. The one that is good is KV-418, it doesn't fluoresce, and it works like a longpass filter.
Search on here for KV-418 and you should find it mentioned in many posts.
Those are made of clear glass with a center colored core made of some sort of plastic. Here is a link, I am guessing this place is out of the KV-418, but shows a graph.
https://www.itos.de/...lter/kv-filter/

My favorite UV suppression filter is the Zeiss T* UV filter. It doesn't fluoresce, and cuts above 400nm. You can install any other GG (for example) longpass filter between the T* and the lens to further define the cutoff nm point., but the T* will work alone also.
The Zeiss T* UV filter is readily available at many camera stores:
https://www.bhphotov...arch=yes&sts=ma

You may still need to stack some BG glass (such as S8612, BG40, etc.) with the T* to cut off any high red and/or IR.
If you are using a stock camera then I recommend a Zeiss T* UV filter to block any transmission below 400nm, because stock cameras usually have some UV sensitivity.

Edited by Cadmium, 23 July 2021 - 01:46.


#14 UlfW

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Posted 23 July 2021 - 01:42

The Tiffen Haze filters do not have fluorescence either.
They have a similar cut-off transmission and designations as the Wratten filters.
I posted about them here: https://www.ultravio...dpost__p__39580
Sometimes you can find them at different Amazon-sites to reasonable prices.

I expect that the the Zeiss T* filters have a higher quality with less flare and better optical quality than the Tiffen filters, but it is normally also more expensive.

Edited by UlfW, 23 July 2021 - 01:42.

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#15 colinbm

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Posted 23 July 2021 - 02:30

View PostUlfW, on 23 July 2021 - 01:42, said:

I expect that the the Zeiss T* filters have a higher quality with less flare and better optical quality than the Tiffen filters, but it is normally also more expensive.

Ulf, I have a Zeiss T* filter & it is very good, when you get it & open the box, it looks so good, that you won't want to touch it or use it.... :cool:

I mentioned the Zeta UV L41, it is also very good, but a lot cheaper, & if you bought one, I am sure you will be impressed :smile:

#16 UlfW

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Posted 23 July 2021 - 08:28

Here I think I can get both types at about the same price. The Zeta filter is also quite expensive.
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#17 Andrea B.

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Posted 23 July 2021 - 19:46

Cadmium, thanks for the reference to KV-418 glass. That is what I was trying to recall. I know that Schott discontinued it, but perhaps there is a Chinese version which would be cheap and good for Fandyus to try out? I have not looked.

Thanks also to Cadmium and Ulf for remarks about the Zeiss T* UV cutter. I didn't know about that one.

I was thinking that I also will try to get a UV cutter for certain scenarios. Actually I might have a few UV cutters laying around from the olden days when we kept them on lenses for protection. But I prolly do not have one which cuts around 400 nm.
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#18 Cadmium

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Posted 23 July 2021 - 23:57

The reason I would use the T* is because it is easy to find, and relatively less expensive than the KV.
If you can find a KV then you will probably be spending several hundred $ for one. You can ask ITOS if they even have the KV-418 still available.
Probably people from here have already wiped out their previous stock of those. You might find one somewhere else, but why not just get the T*, much easier, already in a ring, no do it your self.
I can't find my Tiffen haze filters (as Ulf suggested), and I don't think I have tested or compared those yet.

#19 JMC

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Posted 24 July 2021 - 13:57

Another vote for the T* filters. Good cut off just about 400nm and low fluorescence (and available in many sizes).

KV-418 was the 'go to' filter for this in the past but is essentially unavailable now.

Fandyus, I've measured the responses of lots of cameras over the years, and looked at the transmission spectra of the internal filters. I can pretty much guarantee the 6D will be able to see the 365nm light even will all the manufacturer filters still present inside, and that it'll need a good cutoff filter on the lens.
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