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March 11, 2009 Comments (0) Gear & Equipment

Fenix TK10 LED Light Review

Fenix Lights TK-10 and included items.

Having some practical experience with personal cutting-edge lighting, I was asked to evaluate the Fenix TK10 LED flashlight.  I served on a 26 man SWAT team for 11 years. During this time, the team evaluated numerous lighting products from various manufacturers.  At first glance, the TK10 appeared to be more of the same old design. However, through the course of my evaluation, I learned this was not the case.  The TK10 is a two setting high intensity LED light with a claimed high output of 225 lumens and low output of 60 lumens.  It is said to operate for 1.5 hours on high and 10 hours on low with a fresh set (2) of CR 123A batteries.  It ships with replacement “O” rings to maintain the moisture seal when the originals wear down.  Also included are a lanyard, removable pocket clip and extra fastening screws and wrench, as well as a replacement tail cap boot and a nylon sheath.  I found this light listed on internet supplier sites for between $73.50 – $82.50 plus shipping.  If you purchase the TK10, or any other Fenix light, through www.4Sevens.com you will receive a no questions asked lifetime warranty via 4Sevens.  If you purchase it through another retailer, the standard factory warranty is: any defective products will be replaced within 15 days of purchase and lights will be repaired free of charge for one year if problems are related to normal use. After the first year, Fenix charges only for the parts needed to affect repairs.

I know many of you are familiar with the classic Surefire 6P flashlight.  I don’t intend to compare these two lights as they are different lamp types, but size wise, the TK10 is very similar.  It measures right at 5.5 inches edge to edge where the 6P is 5.2 inches.  The TK10 weighs in at 4.8 oz (without batteries).  The Fenix ships with an optional 4 point “star” collar which threads on ahead of the tail cap.  This aids in gripping the light when pressing the tail cap push button switch.  It is especially handy if you employ the “cigar” method (see photo).  This “star” collar can be removed and replaced by a gold color collar that fits flush with the battery tube.  As mentioned above, a lanyard is included in the kit.  I am very fond of this idea, having dropped and damaged similar lights due to the inability to hold onto them.  If you are using the light with a firearm, you can loose your hold on the light and attend to magazine changes or whatever else, then snatch the light back up without having to look for it on the ground or in a pocket.  This concept has applications in non-firearm related activities as well. 

TK10 in its

The short version – the lanyard will save the light from unnecessary falls and damage.  I’m unclear on the utility of the screw fastened metal clip.  I’m sure it is meant to clip to a pocket or MOLLE strap, etc.  However, I found the clip to be stiff and inflexible when trying to clip it over anything. Once you do clip it, it does not have any type of hooking feature to prevent it from coming unclipped. Therefore, I would only use this clip the same way you use a pocket knife clip, to maintain position in a pocket for quick access.  Frankly, the light is too large for comfortable carry in pants pockets unless we’re talking cargo pockets.  If you clip it to a belt, web gear or camping gear outside of a pocket, you’re going to loose it.  The majority of the battery tube and tail cap have a checkered pattern cut into the metal, aiding in maintaining a secure grip.  Both the light head, and tail cap, incorporate a wavy edge design, which to some degree provides protection for the light components, and may also be useful as a striking weapon.  I disassembled the light as far as seemed reasonable for the average user (see break down photo).  Examining the details of construction I was duly impressed.  The materials were consistent, and threaded areas were done perfectly and deeply.  The light head contacts were substantial, unlike other lights I have examined. The light head is a sealed unit.  The anodized finish was excellent and not easily scratched.  I did not find anything substandard about the construction of the TK10.

Fenix TK10 Head and Relector

Ok, how does it work as a flashlight you ask?  I’ll try and cut through the clutter of verbiage used by manufactures of all lights to state how bright their light is, and give you the regular guy’s assessment of this model.  I have amassed pages of data related to quantifying light output specific to LED lights as well as other factors that you might consider when shopping for a LED flashlight.  That will be discussed in a separate article soon to follow.  For now, let us address just a couple of the most prominent, confusing, terms related to these lights.  You will see a number of terms used to describe the amount of light produced by an LED light; Wattage or watt (measure of power), lumens and lux.  Sometimes they throw candlepower in the mix as well.  I know you don’t want a lecture on luminance from the scientific angle, so let me try and break it down into back yard logic.  The best way I find for one to comprehend any of these terms, is to take a light of a particular rating, shine it on a wall in the dark, and observe the intensity.  Then, compare it to another light you have.   

Inside view of Fenix TK10 head component.

I compared the 6P to the TK10.  The 6P, rated at 65 lumens, was shined on a wall, followed by the TK 10 on low, then high power.  I then had a basis to decide how many “lumens” would serve my lighting needs.  To increase my understanding, I also tested two head lamps rated in watts.  One light was a 1 watt LED, the other a 3 watt.  My unscientific visual analysis of the 3 watt lamp was that its was about half the brightness of the 225 lumen light, and easily overpowered the spot from a 65 lumen light at a distance of 3 feet, or 1 meter.  So I’m suggesting that my 3 watt head lamp probably emits around 100 lumens.  Now that being said, you have to realize that other factors will affect the amount of perceived light reaching the target at a specific distance.  These include the color temperature of the source light, the light’s reflector design, battery condition, environmental temperature, etc. 

Okay, back to the TK10.  This is how I conducted run time and output tests on the Fenix light.  As a photographer, I have in my bag, an incident light meter.  The Sekonic Flash Master L-358.  Normally this meter provides me with shutter speed, and aperture values, for a given ISO setting.  This meter also has the ability to provide a readout in EV (exposure value), which can be converted to LUX via a conversion chart, but we’re not going to go there.  You can find the chart on the Sekonic web page under documentation for the L-358 if you really feel the need to convert EVs. 

Endurance testing Fenix TK10 with Sekonic L-358 lighter meter.

Here is the set up.  I load the TK10 with brand new Surefire CR123A batteries, then place it on a table, positioned exactly 12 inches (plus meter thickness) away from a wall.  I set the light to low power by rotating the light head, which has two positions (low and high).  Press the tail cap switch turning the light on, and then take a meter reading.  The initial meter reading was 11.8 EV.  Fenix documentation states that this setting produces 60 lumens, and that it should burn for 10 hours at this setting.  I continued taking meter readings every hour.  At the 13 hour mark, the light output was measured at 11.8 EV.  At 13 hours and 35 minutes, the light output became unstable and flickered.  I terminated the low power run time test at this time.  The end result was that the light emitted a rock steady 11.8 EV for over 13 hours; 3 hours and 35 minutes longer than claimed by the manufacturer.  How about the light coverage pattern?  The pattern of this reflector (orange peel, or textured reflector) created two distinct perfect circles.  One high intensity circle in the center measured 3 inches across at a distance of 12 inches from the test wall. And the outer, less intense circle, measured 10 inches across at 12 inches distance.  When moved back to a distance of 6 feet, the inner circle measured 10 inches, and the outer circle was 77 inches.  I’ll go into more on the throw of the light later. 

Testing the

The high power run time test lasted exactly 80 minutes.  With fresh Surefire batteries installed, the measured EV was 13.9 throughout the test (measured every 10 minutes).  At 80 minutes, the light began alternating between low and high intensity.  As I handled the light I noted the entire body was hot to the touch.  It wasn’t too hot to handle, but it was definitely uncomfortable.  I then removed the batteries and left the tail cap off to facilitate cooling.  After I felt the batteries and light had cooled, I reinserted the batteries, and set the light to low power.  The light provided a constant 11.8 EV output for an additional 110 minutes on the same batteries used in the high power test before it began to flicker.  I think the TK 10 as well as the Surefire brand batteries performed very well in these tests. 

As I read through the features that Fenix published on the TK10, I notice that they claim it is waterproof to IPX-8 standards.  I wondered what that meant.  So, with I little internet research,  http://en.wikipedia.org/wiki/IP_Code  I learn that they are claiming this light can be submerged beyond 1 meter.  I decided to administer a lesser, yet still interesting, test.  I filled a 5 gallon water cooler type plastic container with water.  I then tied a filament from some paracord to the TK10, turned the light on high, and dropped it in for a 30 minute swim.  End result – no problem at all.  I took the light out, dried it off and it works just fine. 

Image of light throw in different modes.

The last feature I wanted to evaluate was the throw distance of the light/reflector.  Refer to the comparison photos.  I took these photos and made minor adjustments to them. Although these images were created by using long shutter times, and corrected in Photoshop, I assure you, they are accurate representations of what I witnessed with the naked eye.  The photo showing the spot illuminating a tree in the distance shows the light potential at approximately 50 yards.  The side-by-side photos show a comparison of high and low power settings at a distance of 10 yards. 

In summary, I give the TK10 a five out of five star rating.  The light has a solid build, great finish, long run times, and the high power mode is “put your eye out bright”.  My favorite feature – the price tag.  Similar lights by other companies list for $70 to $100 more than the TK10.  I’d like to see Fenix start offering this light in a 3 pack because one is not enough.  I’d like one for the car, the house, the garage, etc.  This is an excellent light by any measure.

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