Tag Archives: video lights

DivePro G18 Plus video lights review

I managed to get hold of a pair of DivePro G18 Plus samples last week to use for my wide angle video hereby my thoughts on this product that I believe could be interesting for many video shooters.

Construction and technical data: solid anodised aluminium smoothly finished. Jaunt has decided to expose the battery that screws into the light head as oppose to house the battery itself into the light a more conventional design. The light features a Cree CXB3590 LED with a color temperature of 5000K and a CRI of 92 with declared output of 18,000 Lumens and a 95 degree beam angle. The battery delivers 14.4V with a total capacity of 6800 mAh giving an autonomy of 52 minutes at full power of 105 minutes at half power. The technical specifications of Creed LED give full details of the light used https://www.cree.com/led-components/media/documents/ds-CXB3590.pdf

When you look at page 14 performance group EB you see 15000 lumens nominal per bin, take into account that the array has an efficiency of 120% so this gives you the nominal lumens. In terms of viewing angle the nominal beam in air is 115 degrees and this in water gives you 100 degrees according to my calculations am not sure how Jaunt worked out 95 degrees. Looking at page 10 you can see that even at CRI=90 there is a spike in the navy blue colour this is most likely to show in water when combined with close up lenses as blue fringing and should be completely irrelevant at wide angle.

The provided chargers delivery only 1A with a declared charging time of 8 hours that frankly is totally unacceptable for a video light.

I recommend getting a spare battery the code is DivePro B06. The light has a color indication for the charge level around the switch button that is simple and effective at the same time although you don’t get your residual time in minutes as you do from some other products.

Ergonomics: the light feels very much like a torch and when attached to the included ball mount is very bottom heavy. The fresh water weight is 350 grams and becomes 370 grams with the mount. The light feels very well built, smooth and rugged.

Dry weight of the G18 Plus
Weight in fresh water

The light switch system allows for 100% 50% and any intensity from 1% to full power however this is slightly difficult to use, there is also an SOS feature. Generally the light feels well designed with few small niggles, the ball attachment is quite long this is not an issue except the light is already heavy on the bottom whilst the attachment to the arm is in the front part this creates a significant torque especially on land. Use of a bespoke underwater float is advised. Another minor issue of the ball mount is that it is not actually 1” but 2.65 cm. 1mm may seem little but it does bring the clamp off balance making it easier to loose grip. I recommend changing the o-rings with normal buna rings to reduce the size and improve grip if you use Ultralight, Inon or Nauticam arm systems. Another small issue of the switch system is that at rest on land the button may hit the floor. Previous version of the light switch on immediately at button press now Jaunt has changed the logic of the switch on to a long 2 second press to avoid accidentally switching on the light.

Video with the old switch mode

As the light overheats outside water this will prevent LED burnout. I had the latest version of the light, other copies on the market may still have the old logic check carefully yours.

Torch shape of the G16 Plus

Field test: Testing the light in a tank confirms the beam angle and the battery life as per specification more detailed testing is only possible in the pool.

I tested the lights in a pool with a 5 meters deep end. Pools have controlled conditions to check how the lights fall off and what is the real life coverage of the lights for your lens. It is not possible to provide a real test of the geometry of a light in the sea unless you know exactly the dimensions of what you are shooting and you have flat surfaces. I have some diving end of April in the Mediterranean will provide an update later on open water performance especially in terms of color rendering that I have not checked in the pool.

Beam angle: I took a series of stills at 80, 100, 150 from the axis of the lights using arms 28” long to which you need to add the length of the tray to determine where the light beams will meet.

As expected at 80 cm you see two separate circles of light, this become an elliptical shape at 100 cm and fill the frame at 125 cm with small fall off at the edges.

Dark Shadow as the lights are too close to the pool wall to merge the beams.

This pool shot gives an idea of the coverage only the edges are dark and the light is very nicely distributed. I have removed the reflections of the lights on the wall as they are distracting. 

1 Meter distance from the WWL-1 shot (1.15cm from light axis)

In order to understand the light falloff I ran the stills into a monitor equipped with false colour you can see the results here the lights are in my opinion very convincing and still deliver at 1.5 meters distance although you may need to pump up the ISO.

False colour shows good distribution of the beam across the frame. Note this is a 4:3 shot the 16:9 crop is the red frame

I would think that with this angle of coverage a distance of 30” between the two lights is ideal with my rig this means two 8” segments however this may create ergonomic issues so I settled at 5 + 8 this gives an arm length of 21” and with the GH5 26” from centre. Considering a WWL-1 set up with the front of the lens 6” ahead this means shooting distances up to 1 meters from the front of the lens covering a frame width of around 3.5×2.0 m that is a huge surface.

After the pool test I noticed a number of scratches in the paint clearly the coating is not the same quality of more expensive lights.

Conclusion

Overall the lights have great performance in terms of power, beam distribution and are very well built with excellent autonomy. Issues to note and suggested remediation:

  1. The chargers that come with the lights are inadequate. A 2A charger would be better and would halve the charge time without damaging the battery pack, here some links for  third party 16.8V/2A chargers:
    1. UK https://amzn.to/2YPyg4G
    2. US https://amzn.to/2HZEJoK
    3. Germany https://amzn.to/2I2hN83
  2. The clamp position creates an issue of pitch in water obviously if you manage to have some floatation system for the individual light this is no longer a problem.
  3. The light intensity adjustment is not effective and you can’t really tell if the two lights are set the same. Obviously this is only an issue if you need less than 9000 lumens for example for close shots. There is no easy solution to this problem other than controlling the two lights simultaneously.

Considering the price point and the quality this light competes with the Gates GT14 and the Keldan 8X and when it comes to power, CRI, autonomy and price beats them both in terms of durability and ergonomics they appear to be a level down but they are also less expensive.

Jaunt is setting up relationships with distributors in major markets and in UK there is already one so everybody should be able to get a set of lights. Depending on location, duties and import regulations the price will change but generally I have seen it remain competitive.

Choosing a video light for your Underwater Video Rig

I thought of writing a brief article about video lights.

In the last years LED lights have become incredibly cost effective and there are many products on sale that look promising and cheap.

A special mention goes to the GoPro a very cost effective option for underwater video plagued by poor performance in low light. The GoPro market seem to have injected new life into the video light marketplace and of course calls for products that are not expensive in line with the typical profile of the GoPro user.

There are many examples of footage with what you would consider powerful lights that actually do not look that bright or even nice, why is that?

Lights are now measured in Lumens which is the SI unit of measure of luminous flux a light is said to emit one lumen if it emits one candela over a solid angle of one steradian. This sounds all very complicated and not very helpful so let’s try to make some sense of this.

Usually when we go an buy a light we are given three key pieces of information:

  1. Lumens – this in a way is considered the power of the light*
  2. Beam angle – this is the maximum horizontal beam that the light can cover – note this does not relate with solid angles but is merely a 2D view
  3. Color – this represent how white is the light, a good light should not exceed 6500K which is what is considered a day light white

*we will see that this is actually incorrect

Let’s have a look at a typical best buy the Archon Video Light W38VR, this light is declared to have the following:

  1. 1400 Lumens
  2. 120 degrees beam angle
  3. 5000K temperature

Looking at the specifications this looks like a very warm (5000K) wide beam light and very powerful so how comes that with a subject at one meter or 3 feet distance this light seems to have no effect on a bright day?

The reason is that lumens are not a real indication of the amount of light that hits the subject but just the total light emitted which includes the light that illuminates the water between us and the subject that we actually are not interest at all in illuminating.

If you had to do a video production in studio you would be looking at intensity of 1000 lux where a lux is measured in lumens/m2. The lux is the density of light that hits a flat surface at a given distance.

With a few calculations we see that the Archon light because of the very wide beam is effective at two feet and produces around 1200 Lux which is great however at 3 feet this drops to 550 Lux which is not that great.

Many times when comparing the new cheaper lights to expensive lights like Sola or Fix  despite the less nominal lumens declared the sola or fix seem brighter at the same distance.

So let’s evaluate the lux produced by a Sola 1200 a light much more expensive than the Archon with only a 60 degrees beam.

At two feet the sola produces around 4000 Lux which would nearly tan a fish, at 3 feet it still produces nearly 1800 Lux dropping to the studio value of 1000 Lux at a distance of 4 feet or 1.2 meters. This is because the illumination is in a smaller and narrower beam and is like the light was more dense.

Of course this has the disbenefit of a narrower beam so we need to step away from the subject in order to cover it properly, this diagram gives an idea

Typical Wide Angle Light Set up
Typical Wide Angle Light Set up

The two set of lines contain the video lights beams, we can see that those beams cross and them keep as combined angle of coverage the same beam of the lights themselves, that is the ideal spot for our lights as there are no shadows there.

Another consideration is the angle of coverage that we need for our camera lens to follow the lights, two 60 degrees beam lights actually cover a 100 degrees diagonal lens or 90 degrees horizontal lens typical of a 18mm lens. The GoPro and all compact cameras with a 100 degree lens fall in this group.

Another consideration to be done is that due to the light angle of coverage there is a minimum distance to be kept if we want to avoid our subject to be in the shade, this minimum distance depends on the light beam and the distance between them.

Once you get closer than one foot it is not necessary anymore to point the lights forward as the amount of water is limited and the lights can be pointed directly at the subject like in this example

Monopod front Macro Light Position
Monopod front Macro Light Position

So assuming we want to be at a distance of one foot or 30cm how far do the lights need to be?

For a 60 degrees beam the lights need to be 36 cm away or around 12 inches. For a light like the Archon with 120 degrees beam the distance between the arms needs to be 1 meters or 40″. Considering a tray is around 30 cm or 12″ this means you need arms at least 13″ in order to cover something at one foot and to cover a subject at 2 feet you need two meters distance that means again 33″ worth of arms.

What happens if you only have the tray with the lights on and your subject is at 3 feet with two very wide video lights of 120 degrees beam?

  • You illuminate already after 3″ from the camera
  • The two lights emit 550 Lux that combined are not such a small output

The net result is that a lot of the water in front of the subject is illuminated and this creates backscatter where all the silt in the water gets reflection and ultimately deteriorates the quality of the footage.

If you ever wonder why underwater photographers that shoot super wide have two 16″ arm segments this is why the want to avoid backscatter with their 110 degrees strobes and still be around one foot distance with their fisheye lens.

So what are the conclusions that we can draw:

  1. A wide beam light is only good if you have long arms, the wider the beam the longer the arms otherwise the beams just light up the particles in front of the subject producing backscatter
  2. Lumens are not a real indication of the effectiveness of the light per se but need to be taken into account with the beam angle and a lux calculation needs to be performed you want to aim for 1000 lux at the distance of choice
  3. Light beams need to be evaluated together with the camera lens horizontal field of coverage 60-80 degree beam angles are adequate for most of the video rigs out there and more is only justified for fisheye type of lens not commonly used in video

I hope you find this information useful and get in touch if you want to discuss, the subject is not that simple!