So I recently decided to modify a cheap cree light I've had for a while to make the 'Perfect' light painting torch. I've got many torches but I was after something that could paint up dark spaces super evenly and show all the details super clearly.
I spent some time nerding out and really thinking about what makes the perfect 'Light painting' torch.
Beam
A torch with a nice soft floody beam will nicely light up a space very evenly, but won't travel far so won't reach to the end of a long tunnel. A focused throwy torch will easily light up a long tunnel, but leaves streaky light as the hotspot of the light is harsh and can make painting evenly tricky.
This leads me onto focusable lights like the trusty Led Lenser P7.2. A very versatile torch and great for painting as it can be both zoomed in for long tunnels and zoomed out for nice soft even lighting. A great torch no doubt, but not very bright at 320 Lumens and the tint isn't brilliant either. Also using AAA batteries isn't the best power source IMO. The only downside of a focus-able torch is that it wastes a lot of lumens through lens inefficiencies compared to a fixed focus torch.
Lumens
I think something around 500 Lumens is probably enough for most uses. You could almost argue that a lower output light is better for painting as you have to take a longer exposure photo. This gives you more time to carefully paint an area meaning that the spread of light can created more evenly with no burnt out bits. Trying to paint evenly over 5 seconds is going to be much harder than doing it over 45 seconds.
Tint and CRI
Ever used a cheapy cree torch and noticed how everything is a horrible blue tint?
That's because they use a cheapy LED with a very low CRI rating, so it casts a blue tint on everything rather than showing the true colour of an object.
A 'Hi-CRI' torch solves this as the light spectrum has a wider range of colours so brings out the true colours of whatever your lighting up.
A light with a nice tint and CRI rating (Colour Rendition Index) can really make colours pop out and bring out some lovely detail.
CRI is measured in percentage, and anything 85 CRI and above is considered 'Hi-CRI'. Your standard Chinese cree light or Lenser will be something around 60-70 CRI. An old Incandescent light bulb torch has a CRI of 100, so LED technology hasn't quite caught up with them yet.
When it comes to the tint of a torch, it can either be Blue, White or Yellow. A warmer slightly yellow tint tends to produce a nicer image, but this is a personally preference thing.
The last thing is battery source. It has to be Lithium 18650 as this has the best power density of any commonly available battery at the moment.
Knowing all this I decided that the ideal torch would have to be:
Focus-able
Hi-CRI (90+)
Uses 18650 Batteries
around 500 Lumens
A warmish tint of around 4500K to 4000K.
It's very hard to find a torch like this for sale, as there isn't really any HI-CRI focus-able torches on the market, so I would clearly have to make my own.
Here is my old light in bits. The LED was an old nasty one with blue tint and it wasn't very bright (around 250 Lumens?) It was zoomable, but a bit rough and stiff so need a bit of cleaning up.
So the simple solution was to buy a new LED and a better driver board to provide more power. More power equals more Lumens. Luckily you can buy these pre-soldered onto a board that virtually drop straight in the torch bodies.
I settled for a Nichia 219C LED at 4000K tint. It had a CRI of 93, so ideal.
The new driver board put out 3 amps of power, so should be enough for a bit more output.
All of this came to about £6 from a kaidomain.com. Not bad!
While I was waiting for the parts to arrive I decided to bling up the body of the torch and add some personal touches, because I clearly had nothing better to do!
Using a Dremel I removed the black anodized finish back to the aluminium and polished it till it was shiny.
Finally after almost 3 weeks my new LED parts arrived. I soldered the new parts in and added some thermal paste to dissipate the extra heat that it would be generated. I have access to a laser engraver through work, so decided to Laser engrave it too.
I dub thee 'The Painter'.
The final product
This is my the tint compared to my Led Lenser M7 (which has a pretty blue tint)
Led Lenser M7
'The Painter'
And a test paint at Coulsdon Deep Shelter
It was a lot of work for what some people may seem as a very small improvement, but I'm pretty happy with it!
Most importantly though, its shiny!
