PRIMARY CANISTER DIVE LIGHT, WHY DO I EVEN NEED ONE?


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I am currently having a little trouble with my dive light as it flooded a few weeks back. I got a replacement battery, but it’s still not working quite as it used to, leading me to think it may be time to get a new one. So I’ve been asking myself what am I looking for in a Primary canister dive light?

Why do you need to use a primary canister dive light?

According to the DIR method, they stated it like this :

The kind of dive light one uses usually depends on the environment in which one dives and the particular diving activity in which one is engaged. However, the basic DIR configuration uses a single primary light canister attached to the diver’s hip and two reserve lights clipped to the diver’s chest D-ring. They are held to the harness by two elastic bands. The size and weight of the canister light usually depend on the particular diver’s needs. Lights are optional for shallow open water diving; however, most experienced divers prefer the versatility offered by the above configuration, even for open water diving. Divers should use primary lights with a beam that can be focused. This focused beam gives divers a better visual reference and provides the diver with excellent means of communicating with other team members. The primary light is very useful in open water diving as a signalling device, and is also very handy should a properly trained team encounter an overhead or need illumination in a darkened recess. 

I like having my primary canister dive light for a few reasons, and they are more apparent than ever since mine has malfunctioned and I have been diving without light or using my backups. 

The main reason is its comfort when on a dive where your buddy isn’t totally within your visual field. Being able to see your buddy’s dive light beam allows you to know their location when you otherwise would not. For example, as my buddy and I dive, our beams will meet somewhere ahead of us, so we always know where the other is. That way, I can just enjoy my dive without the worry of losing my buddy and know that if he needs my help, he can move his light side to side, alerting me that I should look over my shoulder as my attention is needed. Likewise, if I see the beam drift away from mine, it will warrant my attention the same way I saw the beam shake violently.

 Because of the conditions that I dive in here in Ontario, Canada, visibility can sometimes be questionable in lake Ontario, making a canister light especially useful and even vital. However, I find even in the best of conditions, such as in Tobermory where there could be 100 ft visibility, having the intense beam of the canister light is very useful as it is an easy-to-use as an effective communication aid. 

Another reason I like having a primary canister dive light is that it allows me to stow my long hose nicely under it, keeping me streamlined and tidy. Finally, I like that the weight of the canister light is factored into my total gear, as I am not a very big guy. Having the extra couple pounds makes a difference if my tanks ever get down to less than the 500 Psi (although that is very rare), and it allows me to have a little more air in my drysuit on those frigid dives.

What to look for in a primary canister light

Light Beam 

The colour temperature of the light beam and its intensity are both things to pay attention to, as this tool is not just for illuminating your way through a cave or when you are penetrating a wreck. Of course, when you’re in these situations where there is no visible light, any light source will seem bright. Still, your canister is your primary light, which means you will use it in various situations, both for visibility and communication purposes. 

For that reason, it should be your brightest light with effective colour temperature and the longest burn time (time the light will stay on, on a single battery charge). As the primary canister light is your primary signalling device, its brightness will be directly related to how good the light will be. Most lights will state their brightness in Lumens and colour temperature in a Kelvin rating; you may see it as something like max 2000 lm/5700 K.

Lumens are defined as “A unit of luminous flux in the SI (system international) units, that is equal to the amount of light given out through a solid angle by a source of one-candela intensity radiating equally in all directions.” That definition hurts my head, but from what I understand in more lay terms, the more Lumens a light has, the more visible light it delivers.

The Kelvin is an SI unit of thermodynamic temperature equal in magnitude to the degree Celsius. What this means in plain English is that the lower the Kelvin number, the warmer or more yellow the light is and the higher the number, the more white to almost light blue the light will be, similar to the way daytime light is outside. 

I recommend not getting anything less than 5700 Kelvin, which is pretty close to white and should work well for most driving conditions. There are lights on the market that state having up to 8,000 Kelvin when at full strength, which is a very bright, noticeable light in the water. Having a light in the 3600k range makes the visible light quite warm or in the orange to yellow spectrum colour. Keep in mind that while light with lower Kelvins will be less costly, if you are in tannic water or water with low visibility due to a lot of organic debris, yellow light may not stand out enough to be an effective signalling device. Your safety is worth spending the extra money for a better quality light. 

Focus vs wide

More and more, lights are coming on the market that gives you the option of either a narrow beam with 3-7 degrees or an adjustable beam where it can go from 3-35 degrees. So what is this all about? 

This has to do with how focused you can make your beam during a dive. Some people only plan to use their dive light as a signalling device and illuminate their dive while they follow their line for a long time. That was the only option. 

More and more lights are coming on the market that allows you to adjust your beam while diving. Now, while I don’t think this is a necessary feature to a dive light in terms of safety and it does add a significant amount to the price compared to just having a narrow bream, having an adjustable beam can sometimes be nice because it adds to the enjoyment of a dive. Let me give you some examples. 

 If you are hardcore into cave diving, then you already know this, but being able to see the line your following in and out of the cave is, technically, all you need your dive light to provide for you. However, when you enter a cathedral room in a cave, these are enormous rooms in caves where the bottom falls away from you. Therefore, only having a tiny narrow beam means you will be limited to how much you will experience the vastness of your area. Whereas, if you have an adjustable light, you will be able to widen your light beam to flood far more of your viewing area so that you can truly appreciate the beauty of it. 

This feature may make your light marginally less effective as a signalling device, but I think it’s a fair trade-off for having a total view of the vastness you may experience in settings such as a cathedral room in a cave. The adjustability feature is also helpful in other overhead environments, such as when penetrating a wreck. It is nice to have the ability to illuminate the whole room that you had entered in a wreck so that you can see anything sitting on the shelves or any details of how the equipment was left before the wreck went down. 

I would caution against buying an adjustable primary canister light and using it as a video light. My dive buddy spent the extra money on the adjustable light beam for his canister light, hoping that it could double as a video light for his GoPro and found that, for him, it creates a hot spot on the film. So instead of a well-lit shot, there is a spot completely washed out by the light so that you can’t see anything in that area on the film. I don’t know if others have that same experience, but further research may be required if you are looking to add lighting for videoing.

Burn time 

Burn time, or how long the light will run on a single charge, is always something I pay attention to. Even though 99% of my dives never really push any of my equipment to the limit, burn time on batteries is always something I want to maximize on my gear, if just for my peace of mind. 

Where you are in your dive journey will determine what kind of burn time is necessary for your dive light. If your Cave 2 rated diver is doing long deco dives or exploration dives, having the longest burn time will be required. It is not a luxury when one cannot afford to run out of battery 2 km into a cave. There are canister lights on the market offering over 5 hours of burn time depending on whether the light is on the max setting or not.

I usually use my canister light for dives averaging 40 mins and, at most, I am doing three dives a day. Having a canister light with a burn time of 3-4 hours is more than I need for any typical dive trip. That way, I know I have plenty of light for the multiple dives I will do that day and can charge my light at the end of the day to get ready for the next day of diving. I would not want a light that needs to be charged after every dive, as that wouldn’t be practical on most charters here in Ontario because there are no power outlets on the boat or surface intervals long enough for a charge. 

So again, if you’re planning on doing training and advancing in your diving, get a light you will grow into, keeping in mind the max bottom times that you will need your light to support you through. That way, you’re not caught having to upgrade your light because you outgrew it.

HID vs LED 

HID is less of an option now than in the past when HID lights or High-intensity Discharge lights were the top of the line. Then, they required larger batteries to give them enough amperage to get the lights to be bright enough to be useful for signalling devices and extend the burn times. Now that technology has advanced, I don’t think there are many HID lights on the market anymore, as the advantages of LED have superseded HID in almost every way. 

LED lights don’t have a filament, making them much more durable in rugged dive conditions. However, gearing up and doing shore entries caused a lot of bumping around of equipment and HID lights were notorious for breaking even before a dive began. If you’re not careful enough, another disadvantage is that HID lights get very hot, so turning them off in a daytime environment would for sure shorten the light bulb’s life, if not burn it right out.  

None of these issues is a problem with LED lights. They usually are very stable and rugged with very long, useful lifespans. An LED light will outlast most filament lights because they give off very little heat, which makes turning them on at any time safe and also, with little or no heat wasting energy, they have much longer battery life. 

With LED lights, divers can adjust brightness during a dive to match the ideal conditions or conserve battery life on long drives. In my opinion, LED is superior in almost every way then HID, and I feel unless you’re getting an almost free HID light, don’t waste your money on HID. LED is the only real option if you’re serious about diving and don’t want to throw away your money. 

Handle 

The handle is an important detail that is not to be overlooked. After all, that is what you’re going to be hanging onto every minute of every dive, or instead, it should be hanging on to you.

 The standard handle that most primary canister lights come with is a Goodman handle (find out why). The handle is an adjustable square handle that attaches to the light, and you then adjust it, so it is snug enough that the light won’t fall out of your hand, even if you’re not gripping it. This way, even with a light in it, your hand is free for running line, using bolt snaps, or adjusting buoyancy. 

 Having a good handle will make all the difference. You may have great light, but if you’re constantly fiddling with the handle because it is not comfortable in your hand or always feels like it’s going to fall off, this will add significantly to the task load during a dive. Also, having a good handle means one less thing lingering in your mind taking the focus away from staying safe and enjoying a great dive. 

Halcyon has recently come out with a fully adjustable handle that works differently than a Goodman handle. Rather than being fixed to the palm, the Halcyon Grip is attached to your thumb, using an elastic bungee cord which in theory frees up your whole hand.

I have dove with this style of light once and, given that I was diving cold water with dry gloves and a thick insulating glove, the thumb grip handle didn’t feel secure to me. I felt like the handle needed constant readjusting as there were so many adjustment points. I should caveat this by saying I only had one dive with this handle and didn’t have time to get comfortable with it pre-dive. My canister flooded, and I could borrow a buddy’s light right before my second dive, so it was all very new to me.

When it’s time to buy a new light, if you have the opportunity, try out a variety of lights and handles and make sure to bring your dry gloves with all the underlayers you usually use so that you can get an idea of how it will feel when you use it fully geared up. Don’t wait until after you buy it to realize that you will have to use a thinner glove because the handle doesn’t expand enough or it doesn’t fit your hand at all once you have a glove on it. I can’t emphasize enough how a good handle can make or break a dive, especially if you’re at a new site or on a new wreck. You don’t want to be fiddling with your dive light handle at 85ft. 

So you have this great light, and you know what you want, but where do you wear it or how do you store it?

Naui states it like this:

“The light battery canister is worn to the right side of the waist belt and is held on either by the same buckle that fastens the waist belt or by a separate second buckle slipped onto the waist belt. The light is part of your weight and balance. It is under your shoulder where it is protected from the slipstream, thereby reducing drag, and can be conveniently operated or removed if necessary. The canister is worn on the right side so as to keep it out of the way of the decompression cylinders and completes trim out from the decompression cylinders.”

Suggested lights on the market

Halcyon Focus 2.0 Primary Light

https://www.halcyon.net/focus-primary-light-corded,1475,en

Features 

Approx 80klux at 1m 1550 lux at 5 m on high power (using standard 5.2- amp hour battery)

Approx 2.5 hours burn time on high and 5 hours on low

Standard with a 5.2-amp hour li-ion battery pack

Offers an adjustable beam to switch between intense focus or wide beam

Halcyon blue light head.

Halcyon Flare Primary Light

https://www.halcyon.net/flare-primary-light-corded,347,en

Features

11,500 Lux at 1 m 1799 lux at 3 m on high power

Approx % hours burn time on high and 10 on low 

Dive Rite HP 50 Light system

https://www.diverite.com/hp50-light-system/
https://www.diverite.com/hp50-light-system/

Features

24-watt system producing 3500 lumens@ 6500 Kelvin.

Beam angle 10 degrees

Four output modes high, medium, low, and strobe

There is more than one canister size for this model with a range of battery life from1.5 hours to 5 hours.

SeaYa

http://seaya.com/en/led/led-32w-zoom/

Zoom32 adjustable light beam

Light source 1xCREE XHP50/19w/max.2000lm/ 5700K

The adjustable light beam from 6-35 degrees with constant glow 70 degrees

Burn time all depends on the battery back you choose, 13.8Ah 24.15 Ah 41.4 Ah

Narrow 30

Light source 3x LED CREE XP-L Hi

30watt max 3600 lm /5700K

A 6-degree angle on the light head

Two power modes

As you can see, there are several options when buying a primary canister dive light. Given the cost of one of these lights, it’s good to know what dive conditions and situations you will need the light for before you make a purchase. Also, be sure to consider if a particular light will grow with you or if you will have to upgrade if you level up your skills or if there is a dream dive site where the light may not meet the demands. So those are the things that I’m currently considering as I look to purchase a new light for myself. I hope you enjoyed this article and found it helpful!

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