Knog Qudos action video light - First impressions, considerations, and tips

The first real-world test of the pole-knog tray + light has been done finally. Conditions were far from optimal, so we can see how good it handles it´s function in low visibility dives.

The test was conducted with the gopro 3 silver, recording at 1980x1020, 30 fps, medium view mode. The dive site chosen was River Popa, the stern of a cargo ship that broke off after it collided with the walls of cape Espichel, in Sesimbra, Portugal, around 15 years ago. The average depth during the dive was 20 meters, with a bottom time of 35 minutes on air, and the visibility was around 5-6 meters, with alot of suspension near the bottom.

First of all, this tray setup, as highlighted in the qudos instruction sheet, is not recommended for scuba diving, as the closeness of the light source to the lens will cause alot of backscatter ( basically it lights up suspension particles in front of the lens, as we will see ), reducing the quality of the shots. This first run confirms this, even shooting in medium view. Knog recommends the qudos to be used in a dedicated dive tray.

Fiddling loosely with the lights three modes, we found that action mode, the brightest one, can be used to light up large overhead enviroments, like caves, or the inside of the ship´s hull. But even in it´s low settings, it causes either to "burn in" the subject in the image ( like a fish ), or light up backscatter in a panoramic shot. Perhaps this can be mitigated if the light source is moved further away from the lens ( knog recommends 50 cm! ), but this set-up is about being practicle, not optimal.

The second mode, spot mode, perhaps is more usefull for macro or night diving, as the light beam only illuminates a subject, and not the surroundings. As the beam is narrower, it causes less backscatter.

The third mode, ambient mode, is what perhaps seems to be the most usefull. The light intensity is just right to shoot close subjects, and even some more distant shots, and it´s a good compromise in relation to other modes, as it saves battery and provides good overall lighting.

Battery life was as expected, lasting the hole dive always on, sometimes in the maximum setting, but mostly with the ambient light setting. By the end of the dive, the battery indicator signaled low battery, but the light didn´t fade, and i thought it could carry on a bit more. As a primary light source, i can´t recommend it, as i think the user has to be conservative and turn off the light after shooting, or it risks running out of battery by the end of the dive. Anyway, the user will need to recharge or replace the battery after every dive, or be extremely conservative on it´s use. On the positive side, as it´s charged by usb, a power bank might help in recharging the battery.

Perhaps Knog could provide a bigger capacity battery on the future.

On the next time, we will change the position of the qudos on the tray, placing it on the right side of the tray, with a little hacking, to put it a bit more away from the lens, in hope it will reduce backscatter.

Stay tuned.

Atlantic Diver

Unboxing the Knog Qudos action video light

As an amateur underwater videographer, i have to deal with the loss of colours when i do my shootings. The deeper i go, the more blueish/greenish my recording becomes – more water to absorve the energy from the lightwaves, making less available lightwave spectrum. There are ways to compensate this, with filters, using the cameras white balance, or lights.

When i dive, i usually take my gopro 3 silver with me, for some casual shooting of whatever i can see down the water column. I like to keep things simple, and i don´t need professional level filmings, just some decent and neat ones.

Depending on the water turbidity and available sunlight, the gopro fairs relatively well up to around 5-8 meters, with even the possibility of some colour correction in post-production ( i use the gopro studio ). But the small size of the sensor on this type of cameras becomes the limiting factor for capturing light – the sensor just doesn´t have enough size to capture the lightwaves in low light situations, independently the sensor quality and technology. I used a polar pro red filter with the gopro, and the colour in the filmings improved dramacticly – well, at least until i reached 10-15 meters. Unfortunately i broke the filter when i dove in the caribbean sea a while back, so i searched for other solutions.

Enter rhe Knog Qudos. What the heck is a knog, you might ask? Knog is an Australian company, founded in 2003, wich specializes in video lights and bicycle acessories. Qudos is an small form-factor, multi-purpose action video light designed for divers, or nocturnal surfers / riders. It can be fitted to action cameras compatible with gopro mounts, or the coldshoe of dslr´s.

Here are the specifications :

• OUTPUT : 70 – 400 lumens
• DIMENSIONS : 31x70x40mm
• WEIGHT : 150 gr
• MATERIALS : die cast + CNC machined aluminium heat sink and and optical grade lens;
• LEDS: 3 XB-D CREE LEDS.
• BATTERY SPEC: 3-7V 1000mAh 3.7Wh. Replaceable USB Rechargeable Lithium Polymer battery.
• CHARGE TIME: 5-6 Hours
• CONSTANT CURRENT DRIVE TECHNOLOGY: prevents video flicker;
• WATERPROOF : up to 40 meters.

Ligh Modes	Beam angle	Lumens (High/low modes)	Runtime
Action Sports	Wide	High : 400	70 minutes
		Low : 225	1 hour and 30 minutes
Target Spot	Near	High : 175	1 hour and 50 minutes
		Low : 100	2 hours and 40 minutes
Ambient	Ultra wide	High : 270	1 hour and 10 minutes
		Low : 70	4 hours and 30 minutes

Pricing : can range from 80 to 100 euros.

So let´s get this bad boy out of it´s cage.

 

First, the packaging : it comes with a metal sheet case, cool, but too thin, it kinks real easy. The case has a lid that´s on the back. Very nice, with a premium look to it.

 

The acessories included inside : action Camera Mount Bracket and Hardware, Cold Shoe/Tripod Adaptor (for use with DSLR cameras), USB Recharge Cable, two silicone anti-vibration pads, two stickers, a quick reference card, and a spare o-ring.

 

 

The 3 Leds : all three are one when in action sport mode; only the bottom one in target mode; and the top two in ambient mode.

Opening the plastic backdoor gives acess to the battery. The door is not very tough, but the locking mechanism is tight, and won´t open accidently. Below the locking mechanism there are 4 led lights, The first 3 from the left indicate what is the current light mode selecter. Each light mode has 2 colours to indicate high ( green ) and low ( blue ). The forth led is the battery charge level.

Unlocking the backdoor.

 The battery is removable, and charged via usb or charger. It has indicator light on the battery, so you now when it´s fully charged..

 

This is the setup i´ll be testing the light : a SP pole and the qudos. Simple, and portable. I made a small modification so the camera won´t scratch the side of the light, and also keep it in place - i cut the small silicone anti-vibration in half, and put it between the two.

Next article, i´ll post in-water testing with this setup.

Thanks for the attention.

Atlantic Diver

About the call of the deep

Mermaids have been part of sailors mythology and folklore for a very long time, as far as ancient babylon. These beautiful creatures, half-woman and half-fish, are often associated with bad luck and misfortune. They lured sailors off course and into rocky shoals, to their demise.

The deep waters have always fascinated scuba divers, and non-divers. Most of the non-divers question a scuba diver about how deep they have been underwater. The challenge of depth has led scuba diver to break world records, and to some failed attempts ( some even fatal ).

I view depth as the scuba diver´s mermaid. It calls him, trying to lead him astray from his dive plan, luring him to his demise.

Depth should not be a goal to achieve in scuba diving, but rather an important part of the equation when planning a dive. Scuba divers don´t dive deep because they can, but because there is something below 18 meters that´s the real objective – a reef, a wreck, deep water fish, etc. Most fun can be had in shallower dives :

• they are colourfull, because you have a broader lightwave spectrum availabe – less water for them to travel and get absorved;
• most sealife resides in shallow water, as most of them feed on plankton or soft corals, wich needs light to thrive;
• it´s less stressfull for the divers – they are less focalised in the NDL and air consumption, and acess to the surface takes less time in case of an emergency;
• it´s safer and there is less nitrogen absorved by the body, so there is less risk for decompression sickness;
• it´s warmer – the more closer to the surface, the less chance to hit a thermocline, and a diver can wear less thermal protection.

It´s not that there is no fun in deeper dives, they just requires more risk manegement by the diver, so they avoid accidents, such as :

• running out of air ( the deeper one goes, the more air he consumes );
• running into deco limits;
• decompression sickness.

There are no reason in doing a deep dive to do something or see something that can´t be done in shallower depths. The main reasons for doing deep dives are :

• there are certain types of fish, corals or kelp that can only be seen at deeper depths;
• waves, weather, fishing, and other negative factors tend to affect less the underwater ambient;
• underwater mountains, pinnacles, and walls usually present themselves at deeper depths;
• wrecks are usually found, and are probably less damaged, at deeper depth.
• drift dives are usually done at depth, because currents lose intensity or cease at shallow waters;

To safely do deep dives, a scuba diver must seek training, and develop skills and confort underwater. Deep dives start at the advance adventure course, which certifies divers up to 30 meters, and after, the deep dive specialty that certifies a diver up to 40 meters of depth, the limit for recreational diving. Nitrox Specialty course is also a must, as it essencialy increases both safety and bottom times. Peak performance boyancy diver specialty, can also help develop an important skill for deeper dives.

Scuba diving at night

You can scuba dive in virtually any type of sea conditions, if provided training and safety. Since wreck diving ( wich i covered previously ), to drift diving, deep diving, altitude diving ( such as lakes in mountains ), cavern diving - among a few others - one important requirement for them is day light, or sight of day light. But marine life doesn´t stop at night, fish actually kind of work by shifts – diurnal, crepuscular, and nocturnal – so divers would miss out on alot of underwater action. Thus, the night dive was invented. Most of the divers who start diving at night will probably do it for the challenge, some for curiosity, and others by advice of it´s instructor. But no matter the motive, one can expect a different experience :

• to our senses, it feels like floating in space, and our attention becomes focalized in what the light beam illuminates, with colors and life popping out better than daytime;
  
  
• the underwater life changes significantly at night, from coral reefs - static reefs during daytime come alive, with tendrils and feed tubes, to fish that change behaviour or come out only at night ( most diurnal fish become lethargic, and sleep, nocturnal fish come out to hunt );

Nocturnal fish usually dont swim as fast as diurnal fish, tend to be more solitary and shy, and during the day are found hiding in caves or under overhangs. They also tend to be carnivores ( Diurnal fish are often herbivores or omnivores ).

It also can provide some good opportunities for some amazing underwater photos and videos, as there is no intrusive natural light in the shots – the subject is illuminated by the divers light setup. Heres an example of this :

One can try night diving by doing the adventure diver course, after the open water course. Later, the diver can take the correspondent specialty course. With the help of an instructor, a diver learns about the required equipment, how to function with primary and backup lights, navigate under low visibility, how to communicate via light and hand signals, and how to handle general skills in darkness.

Besides wreck diving, this is also one of my favorite type of dives. I think its both rewarding, and relaxating, and i highly recommend to try it – 10 out of 10.

Dont fear the darkness, embrace it. :)

Atlantic Diver

10 tips for diving safely

1. Dive within your own limits. It´s not only about what your certified to do, but also in your own personal physical/psychological limits, experience in dives, and skill confort underwater;
   
   
2. Most diving accidents happen by poor judgment. Good judgment comes from training, continued education, and experience. Experience comes from dealing with different scenarios and situations, and reflected practice;
   
   
3. Always be conservative as possible in the decisions you make. Put safety above fun ( but never forget to enjoy the dives );
   
   
4. Prefere diving with support from local dive centers or a dive pro – they provide the tools that the diver needs to manage it´s own risk, such as :
    
   • knowledge about local diving conditions;
   • a general dive plan for the spot;
   • logitics as equipment, transportation, food and hidration;
   • complience for local law regarding diving;
   • emergency plans and equipment.
   
   
5. Keep a good physical and mental form, or at least adpot healthier habits. Don´t dive ill or tired – there is no fun in doing so;
   
   
6. Dive with well maintained equipment, it´s your life support when your under there. You can replace equiment, but no your life;
   
   
7. If you feel something is not right during a dive, stop what your doing, take long and slow breaths. When your more calm, find the source of the problem, think of an solution and then make act on it. If you can´t find what´s wrong, keep calm and signal your buddy or dive guide. Any diver can abort, or end a dive at any time;
   
   
8. Take time during some dives to practice a skill. Make sure you tell your intentions to the dive guide or buddy as they can help you. Remember, practice makes perfection;
   
   
9. Get dive insurance, they are relatively cheap and come in handy if something goes south of the border. This is even more important if someone dives abroad; 
    
10. Take the rescue diver course. It will change the way you dive.

Atlantic Diver

I kissed a propeller and i liked it...

Some say that supertition comes from the belief in supernatural causality, that by doing something A, causes B without any related connection. We sometimes do it to avoid bad things, like avoiding crossing a black cat, or bring good luck. Passed down through our culture, folklore or religion, everyone knows some type of it. Sailors also have supertitions, and probably scuba divers do to.

When i was diving the SS thistlegorm in the red sea, i was told that kissing the trailing edge of it´s propeller would bring good luck. Hmmm....yep seems legit, so i did it....and i still havent won the lottery ( although i did have some fine dives that week ). My buddy also did the same - reluctantly i might add, as he wasn´t very keen on removing his regulator at 28 meters of depth - but also without any effect. We did have some laughs afterwards - we did in fact kiss the Thistlgorms bottom....
Oh well, i guess i´ll try on other wrecked ship propellers. Who knows, i might really bring me luck...

I wonder if there are other kind of scuba supertitions....

So pucker up....

Atlantic diver

Why i think wreck diving is awesome - part I

The MV Dori wreck ( formely known as liberty ship Edwin L. Drake )

It´s not the Thistlegorm, but this ship participated in the invasion of Normandy in 1944, as a troop carrier. Later converted into a cargo ship, this 800 meter ship sank around 1964,in São Miguel island, in the Azores. It lies on a sandy bottom, around 25 meters of depth. Although the sea hasn´t been kind to this little giant, you can still see big hull sections, the propeller, and the engine. The most damaged part is the bow section.