Modified UV flash or UV torch for UVIVF

[Jody Barends]

Hi all. I am trying to figure out the best lighting solution for UVIVF photography involving small reptiles. In my testing, I managed to capture some neat fluorescence in a chameleon illuminated using a Lightfe UV301D torch. This torch has a "black filter lens" but I have no idea what material it is and as you can see in the attached image there is plenty of blue so it probably isn't a very good filter. The picture was taken at ISO400, F20, and a 1 second shutter speed. Now 1 second is fine for a slow moving and relatively calm lizard like a chameleon but for other critters I am gonna have a tough time trying to make them sit still for a long exposure. 

 

I was thinking that a modified UV flash might be better because it might be able to "freeze" motion like a regular flash would? But I have no idea about the differences in exposure times between using a flash and using a torch. Secondly, would one fire of from a UV flash produce enough UV light? I am assuming a flash is more powerful than a torch. 

 

Would it be better to go for a modified flash, either premade like the Kolari Vision multispectral flash or DIY with a yongnuo or godox and some filters, or would it be better to get a powerful torch like a Convoy or Nemo with filters. There's also things like the Adaptalux UV but I don't know if those are powerful enough for animals bigger than insects. Any advice and recommendations would be appreciated.

 

On an unrelated note, does anyone know if Uviroptics is still available as a source of filters? Their page is empty on ebay.

 

 

[Andy Perrin]

I haven’t seen Cadmium (UVIRoptics) around in a while…I hope he’s doing ok. 
 

I haven’t tried a flash for fluorescence before but I suspect you are right that it will work better for animals that may move. 

37 minutes ago, Jody Barends said:

and as you can see in the attached image there is plenty of blue so it probably isn't a very good filter

That actually does not follow. Most fluorescence tends to be blue, and I think that’s what you are seeing. You can verify by adding extra filtration to the torch, but I don’t think it will get rid of the blue. I often adjust white balance to reduce the amount of blue because otherwise it drowns everything else out. You could also put a filter on the camera that will reduce some of the blue I guess. 

[Jody Barends]

Thanks Andy. Maybe I was misinterpreting the blue. But I do still want an option for shorter exposure times so I would be keen to hear from anyone who has a UV flash

[ulf]

I have been experimenting a lot with flashes for UV.

 

There is a a big difference between the UV-output of different flash models, not only due to their visual flash power.

Many modern flashes have a high guide number based on a tight zoomed in setting, that is not actually useful for determining the power.

Almost all flashes need some kind of modification to output UV. You need output filtering only for UVIVF.

 

My favourite flash for UV is the Godox AD200. It is four times as powerful as the old Canon 199A

https://www.ultravioletphotography.com/content/index.php?/topic/3242-intensity-comparison-between-canon-199a-and-godox-ad200/#comment-27115

 

The 199A is reasonably easy to modify for UV and you could get a sheet of ZWB1 roughly tape on to test and see if that is a usable solution for your needs.

https://www.aliexpress.com/item/4000835518056.html

 

I guess the best way to use such a flash for UVIVF is on full power and if the image is to dark increase the ISO.

As I have not tried UVIVF myself yet I do not know.

 

I prepared a few of the flash heads to my AD200 for different purposes:

https://www.ultravioletphotography.com/content/index.php?/topic/5542-godox-ad200-speedlite-head-mod-for-uvivf/#comment-58691

 

If you are interested in trying a 199A, (or a few), I have some (5?) that I bought before I found out about the AD200.

One of them is roughly modified for testing, the others untouched, but in good working order.

I can part with most of them for a juste price, less than I bought them for.

If if you are interested, please message me privately.

 

A warning, when buying old flashes there is always a big risk that thy are not working as the internal photo-flash capacitor will die if not charged now and then, at least every second year. I bought a few that turned out to be dead.

 

 

[StephanN]

I've modified a few Yongnuo YN-560 IV flashes, by removing the front glass and using some filter glass as uv-filter. There is a youtube-video out there somewhere describing the procedure.

 

NOTE: be careful, there may be some charge in the capacitor, so either modify a brand-new unit which you've never fired, or fire the flash manually until it won't fire anymore, or whatever are the usual precautions @ulf can surely explain better.

 

Main motivation for me was the fact that they were quite cheap (around 50 € new), and have an internal receiver for a remote trigger, so one can fire as many flashes as required. (Truth be told, I had bought them earlier for some fun with high-speed photography)

 

I can't tell you the exact emission,  but for uv-only (with filter on the lens), and uvivf they worked well, though for fluorescence better use 2 units. It also depends whether you want something portable for wildlife or something solid for indoor work. If the former, you'll ned the most powerful source you can find, perhaps the really big uv-torches

[Jody Barends]

47 minutes ago, StephanN said:

I've modified a few Yongnuo YN-560 IV flashes, by removing the front glass and using some filter glass as uv-filter. There is a youtube-video out there somewhere describing the procedure.

 

NOTE: be careful, there may be some charge in the capacitor, so either modify a brand-new unit which you've never fired, or fire the flash manually until it won't fire anymore, or whatever are the usual precautions @ulf can surely explain better.

 

Main motivation for me was the fact that they were quite cheap (around 50 € new), and have an internal receiver for a remote trigger, so one can fire as many flashes as required. (Truth be told, I had bought them earlier for some fun with high-speed photography)

 

I can't tell you the exact emission,  but for uv-only (with filter on the lens), and uvivf they worked well, though for fluorescence better use 2 units. It also depends whether you want something portable for wildlife or something solid for indoor work. If the former, you'll ned the most powerful source you can find, perhaps the really big uv-torches

Thanks Stephan. In your experience with the Yongnuo, would you say it allows for short exposure times?

[StephanN]

2 hours ago, Jody Barends said:

Thanks Stephan. In your experience with the Yongnuo, would you say it allows for short exposure times?

 

You're welcome.

 

Well, if we're talking plain UV, easily (for example the photos in this thread, btw, I used YN560-III, but -IV is probably similar in performance)

 

As soon as we move to UVF, it all comes down to how strong the fluorescence is. Using special dyes, the flash is easily strong enough, but with bio-luminescence I can't honestly say. Perhaps one of the other members has done a comparison of more flashes?

 

A quick search for Yongnuo here yields these topics, perhaps there's more info buried deeper - just make sure not to "delve too greedily and too deeply" :

 

https://www.ultravioletphotography.com/content/index.php?/topic/4000-filter-options-for-yongnuo-yn660-flash-uvivf/#comment-37314

 

https://www.ultravioletphotography.com/content/index.php?/topic/5406-schlumbergera-truncata-zygocactus/#comment-56597

 

https://www.ultravioletphotography.com/content/index.php?/topic/5163-huntsman-spider/#comment-53774

 

https://www.ultravioletphotography.com/content/index.php?/topic/5011-avocado-uvivf/#comment-51730

 

https://www.ultravioletphotography.com/content/index.php?/topic/4144-my-first-uvivf/#comment-39269

 

[ulf]

3 hours ago, Jody Barends said:

Thanks Stephan. In your experience with the Yongnuo, would you say it allows for short exposure times?

All modern flashes work like this:

With a fully charged capacitor they ignite the flash tube and start draining the energy from the capacitor. After some time the current path to the tube is switched off. That can either be after a fixed time if the flash have manual power levels or automatic, even by the camera when enough light have been detected for a good exposure.

 

This means that to reach very short flash times the flash is turned off very quickly emitting little light energy.

For UV and UVIVF of biological matter very much light might be needed, especially if you also have stopped down for a bigger DOF.

However even a full power discharge is normally rather fast, maybe less than 2ms (1/500s).

If you need a lot of light fast a bigger flash or several smaller might be a solution.

 

For me the flash illumination time have never been a problem, but I have found that for my style of UV-Macro I need much flash power.

At ISO 100 and extension for 1x magnification with the lens at f/11 two modified Godox AD200 are not quite enough.

Most speedlite type of "powerful" flashes store ca about 50Ws of energy. An AD200 store 200Ws.

 

I think it is a really good idea to test a cheap flash first to see if it is powerful enough for your needs.

If not then you have not wasted that much money and learned something.

The possibility to remote control a flash is very nice and some of them recharge very fast from a full blast. 

 

A very important thing to realise is also that the distance between flash and motif is extremely important. If you double the distance the illumination drops to a 1/4.

 

[Jody Barends]

9 minutes ago, ulf said:

All modern flashes work like this:

With a fully charged capacitor they ignite the flash tube and start draining the energy from the capacitor. After some time the current path to the tube is switched off. That can either be after a fixed time if the flash have manual power levels or automatic, even by the camera when enough light have been detected for a good exposure.

 

This means that to reach very short flash times the flash is turned off very quickly emitting little light energy.

For UV and UVIVF of biological matter very much light might be needed, especially if you also have stopped down for a bigger DOF.

However even a full power discharge is normally rather fast, maybe less than 2ms (1/500s).

If you need a lot of light fast a bigger flash or several smaller might be a solution.

 

For me the flash illumination time have never been a problem, but I have found that for my style of UV-Macro I need much flash power.

At ISO 100 and extension for 1x magnification with the lens at f/11 two modified Godox AD200 are not quite enough.

Most speedlite type of "powerful" flashes store ca about 50Ws of energy. An AD200 store 200Ws.

 

I think it is a really good idea to test a cheap flash first to see if it is powerful enough for your needs.

If not then you have not wasted that much money and learned something.

The possibility to remote control a flash is very nice and some of them recharge very fast from a full blast. 

 

A very important thing to realise is also that the distance between flash and motif is extremely important. If you double the distance the illumination drops to a 1/4.

 

Very informative Ulf, thank you. Given my budget, I am unable to acquire multiple units of flashes and filters and the impression I am getting from my searches is that just one is unlikely to be enough to do what I want it to do. Might be better off with torches.

[dancingcat]

You might try the Kolari flash, but make sure you can return it if it doesn’t work.  I’ve had more luck with it without the UV cup and on full power, but I’m using it as a strobe on long exposures and not as a motion-stopper.  Have a chat with the Kolari folks before you buy is my recommendation.

[KaJashey]

I have the adaptalux With two UV arms and two visible light arms. I haven't done too much UVIF yet. The UV arms are well filtered but I don't know how much power they really have especially when spread over a larger object. I've only done small things (12mm) in UVIF so far.

 

Using the visible arms for normal macro I struggle getting much fill against daylight. I have two extra bright arms on the way. 

 

The adaptatlux people seem pretty positive but it's been an expensive adventure for me.

 

Don Komarechka has a video on modding a cheap flash. 

 

He then adds an expensive IR filter.I wonder if that could be done cheaper. I don't think he uses the flash on things with eyes but on plants.

 

[cazza132]

Some cool UVIVF markings on the chameleon!

 

I do prefer to use UV led torches for UVIVF as the exposure time is much shorter enabling faster image acquisition with focus stacking.  Note that high power UV led torches loose brightness and you may have to lengthen exposures during a focus stack to compensate.

 

I have two Youngno YN560-IV that I modified myself and built 77mm filter adaptors using the slot on flash diffusers and a 82-77 step down rings. I can mount 77mm filters on the end. With this setup to illuminate the subject with ISO100 and f8 aperture, I find I'm using a long exposure (approx 2 minutes), flashes set to full power and firing 5 - 6 times. The flashes require a 10-15s recharge time between firings.  This can make focus stacking very time consuming.

 

For a moving target, such as the chameleon, flashes would be better, but you will require full power, f8 or wider aperture and higher ISO - say ISO800 for a single firing.

[ulf]

1 hour ago, cazza132 said:

The flashes require a 10-15s recharge time between firings.  This can make focus stacking very time consuming.

 

For a moving target, such as the chameleon, flashes would be better, but you will require full power, f8 or wider aperture and higher ISO - say ISO800 for a single firing.

Some more powerful flashes recharge much faster, but they are expensive.

My Godox AD200 do a full power recharge in 2s.

19 hours ago, KaJashey said:

He then adds an expensive IR filter.I wonder if that could be done cheaper. I don't think he uses the flash on things with eyes but on plants.

That extreme filtering is only needed if you do UVIIF and are looking for weak UVIIF with a FS-modified camera.

A cheaper way to filter is to use a thick Chinese UV-Pass filter a 3mm thick rectangular ZWB1 or ZWB2 could be cut to fit the front of the flash 

https://www.aliexpress.com/item/4000404340542.html

Or a stack of two circular filters can be used temporarily and then ready for reuse elsewhere:

https://www.aliexpress.com/item/4001191819104