The Case for a Flashlight

O.K.,
Since this is a hot topic, I’ll put up some pictures for comparison.

Note: All of the pictures beams are in the same location. You’ll notice the light switch in the in the bottom right hand corner of the center beam.
It is really easy to see in the 2 highest settings.

I also did the math to give you everything in candle power, (CP), the way flashlight-review does them, (not lumes). Note that the lume power of the 2AA Cree is 9, 20, 40, 80, 135.

First picture is the 2AA Cree on the lowest output 550 CP

The 2AA Cree in Med power 2325 CP

The 2AA Cree in High power 4650 CP

The 2AA Cree on Turbo power 7850 CP

Here is my 4.7 ounce Nuwai headlamp that I thought I loved.
Runs on 2 CR123 batteries for 5 hours. This is about the same as the Cree on Med, but the Cree will last for 10 hours.
The Nuwai has 2200 CP

As you can see, the Cree’s light is so much cleaner and pure than the Nuwai, and the Nuwai is actually pretty good. You must realize though that the headlamps have difusers on them to disperse the center area’s beam.

Here is the 2AA Mini-Mag Light with it adjusted to have the same size center mass, (No, this picture is not a joke).

From post below this.
O.K. PJ, here ya go.
I have the PT EOS. I don’t like it because this is the 2nd one that has broke on me. It comes on for about 4 seconds then turns itself off.

I do not own the Tikka XP, but I do have the MYO XP.

Here is the MYO XP on Low-Med-High & Turbo. CP is 430, 1220, 2100, and 4500 for the Turbo. *All batteries in these pictures are fresh*.

Here is the PT EOS on High, 1200 CP

I also measured the distance these photos were taken.
I wanted the distance to be simalar to that of what what would be projected in front of you while hiking.

Distance is 8.5 feet.

Great pics. Many thanks for taking the time to take them and post them. I'd like to see the any of the PT, Petzl, or BD headlamps also if you are able to take more pics.

There ya go P.J.

Wow! A picture is worth a thousand words!! Pretty telling aren't they! Many thanks Aaron.

Thanks PJ,
Yes, you may think the EOS is the bomb, but it just doesn't pack that much of a punch compared to the Cree's.

The pictures don't do justice in a few ways.
If you look, the Cree at low power with only 525 CP looks t twice as bright as the EOS on High.

This is only because the Cree's center beam isn't diffused.
There really is a "little" more light coming from the headlamp than what you see.
The clarity of the Cree is just so much better that it lights up the painted wall better.

In trail condition the headlamps light out-put would be about the same as the Candle Power comparable to the Cree's. However, the clarity would still be that much better.

If these pictures were taken on a black wall, they would be a better compairison.

What's hard to believe is the 1AAA Cree at 1160 CP, (20 lumes) is almost identical to the PT EOS's 1200 CP and will last for the same amount of time to the EOS @50%, (which goes down hill really fast from there for the next hour(s)).

Thanks for the reply. Certainly some interesting info here. One comment…

>> If we have no doubts that a PT Apex can produce 60 lumens of output in 3W HI mode

Actually, I'm not so sure that the Apex actually does make 60 lumens. Sure, it's a pretty bright light, but subjectively speaking, my Surefire E2d seems brighter and with a further throw than my new Apex Pro, and the SureFire is rated at 60 lumens.

I read somewhere that the Fenix L0D CE uses Pulse Width Modulation to decrease the brightness of the high setting down to the medium and low brightness. The low, which I would want to use most often, blinks the light at 8hz! That has to be incredibly annoying and disorienting along with the normal cold glare of LEDs.

If anyone has experience with this, please let us know if you find it annoying.

I think I'd rather go with a lower lumens light that didn't do PWM.

Darrel, oh my.. That was not mentioned anywhere on the two sites I read, nor by pj. In fact, the link to the review pj sent says the light "does not appear to use PWM for dimming".

What is your source of the PWM usage? If true, that absolutely kills the light in my opinion and I would return it immediately. Blinking at 8-20hz is perfect prescription for 'flicker vertigo'
http://www.iflyamerica.org/flicker-vertigo.asp

FIRST:
I've noticed no flickering with any of my Fenix flashlights – even on the lowest o.p. setting.

SECOND:
IME, 8Hz – 20Hz would be too slow at low duty cycles to perform proper digital square-wave PWM. Furthermore, an 8Hz PWM would be presposterous at low duty cycles. Not even that young intern "Asok" in Dilbert would design a PWM system that flickers at an 8Hz rate. It doesn't pass a sanity check/filter!!! Even 20Hz sounds way too slow to me at low duty cycles – which is what is used for lower output levels. Commonly, PWM uses 300Hz and up, but i've heard of freqs as low as 100Hz – as long as the light output isn't too dim. 1KHz is sometimes used. However, several KHz is better for LED PWM due to that very quick thermal recovery rates of LEDs (IIRC, ~<10ms), so that premature failure of the LED due to thermal cycling is avoided – just another reason why 8Hz-20Hz doesn't make any sense in a LED application. Remember, we're talkin' PWM here, not just high-frequency constant 50% duty digital "switching". Furthermore, there's a reason why video is generally at least 24 frames per second and often 30fps for TV (had this explained to me by a PhD Physicist when i was working at our Corporate Research Center). Under certain conditions, the 16Hz human flicker threshold just wouldn't cut it. Again, 20Hz sounds way too slow to me for LED PWM, even more so at low duty cycles which is what low output levels would use if PWM is employed for brightness control.

Maybe someone misunderstood and the strobe modes are 8Hz or 20Hz???

The Fenix literature does say that the current is digitally regulated. This does NOT have to mean PWM in the sense that it is normally meant (i.e., changing the duty cycle of pulse of light). It could mean an extremely high frequency switching supply with frequency (some operate at tens of thousands of cps) and not pulse width being the method used. Though hi-freq switching has its own problems, viz., EMI, which must be dealt with.

REMEMBER, PWM IS NOT THE SAME AS VARIABLE FREQUENCY SWITCHING. PWM IS PRIMARILY DUTY-CYCLE SWITCHING.

Anyway, i simply don't know the precise regulation approach used by Fenix. In approx. 30hrs of combined Fenix models use at this point, other than one "issue" (see below), i saw nothing out of the ordinary with any of the Fenix light output (other than it seemed way brighter than it should be for such little flashlights and that it seems to stay constantly bright for the several hours that i've used them at a time).

I've used PWM lights and built two myself some yrs ago. The PWM is performed so quickly that the human nervous system is unable to recognize the "flicker".

'Bout the only time that i've even seen a flicker in any commercial PWM lighting devices is in near daytime conditions and at very low o.p. levels. Who in their right mind uses a lighting device in broad daylight at very low lighting levels?!!! I'm not talking about peering into shadows here either.

It is my understanding that the 7-LED Photon Fusion and newer 8-LED Photon Fusion Freedom do use PWM as definitely do EternaLights handhelds. I've only seen flicker at extremely low o.p. levels in brighter ambient light (NOT in the dark) with the EternaLights outputting 3% or 5%, and this only when you move your hand rapidly in front of the light.

Now, all that said, I don't know if any of the Fenix flashlights use PWM. I did however, notice a jewel-like "sparkle" when a small cascade of cold water was running over my Cantene and hand. This made me think of PWM, but i'm not sure. It just could have been light refracting and reflecting off of the the surface of the water drops that formed under the small cascade of water. It certainly wasn't too disconcerting, nor did it make me "motion" sick. FWIW, i get quite motion sick, just short of vomiting, from most anything, even when in a commercial jet banks for landing approaches.

Minor visual disturbances make me quite stomach sick. I have NOT had any problems at this point with any Fenix model.

Again, i have no idea what is the regulation mechanism employed in any Fenix model. However, here is a quote from someone who knows way more about lighting than i ever will. The following quote comes from the FLR website review for the Fenix P1D and P1D-CE:

"When using the three different constant output modes, the light does not appear to use a PWM for dimming. Many LED lights use a PWM circuit for dimming which causes the light to flicker very rapidly. This fools the eye into thinking the light is dimmer, while allowing the light to conserve power since it is actually "off" part of the time (the space between the flickers). This flicker can often be seen by moving your eyes or the light very rapidly and some people find this flicker to be quite annoying, especially when reading. The output of the P1D is constant with no visible flicker, even while on the "Low" mode."

Hope this helps.

pj,
Just found this review. The guy has a clever test for duty cycle PWM; he darkens the room and shines the light on a spinning fan. He was able to make the fan blades appear to 'stand still', thus proving PWM. Good news is that is much too fast to be noticed by the human eye. Your keen observation of the water droplets seems to have predicted this result.
Anyway, Im not worried about this rapid PWM and looking forward to testing my light.

http://www.amazon.com/gp/cdp/member-reviews/A3E3T8MS11VGKP?ie=UTF8
"On low, I could make it appear like it was standing still! "

duplicate, disregard

Brett, many thanks. This now makes sense to me.

Also, i read the review at that URL. I don't agree w/everything that he is saying. Color = pure white on mine. "Donut hole" is the VERY BRIGHT WHITE center "spot" w/sharp falloff or demarcation. However, IMO, the "donut hole" is only small at close range (which is precisely what i want when viewing things up close), and is sufficiently large further away. IMO, if someone doesn't mind the Eos tiny "spot", then they won't mind the L0D-CE and certainly not the other Fenix models.

Thanks again.

I mis-read the article. Yes, the *strobe* rate is 8hz. The low setting seems to be 100hz. That makes a big difference.

"PWM rate on primary/low is 100 Hz which is the same as my L0P SE. Strobe rate is 8 HZ, same as P1D CE. Measured with an optical tachometer I use for checking rotor speed on r/c helis."

http://candlepowerforums.com/vb/showthread.php?t=150892

I'm still worried about the 100hz flicker being noticable or annoying, but it is good to hear the it doesn't bother you, PJ.

Darrel, many thanks for the clarification and info. 100Hz is pretty slow, but perhaps that's why the the LED has only a 50K hrs MTBF vs. 100K hrs MTBF [i.e., Mean Time Between Failures] – of course high current could come into play here also with the relatively low expected service life.

As far as noticing the flicker, my guess is you normally won't notice anything with a 100Hz flicker. However, it can have a strobe effect, as you seem well aware of already, and only in those situations (which are prob. almost never encountered in the backwoods at that freq.) will the stobe effect be perceivable.

Remember 15Hz is generally considered to be the human flicker threshold. 100Hz is a long way up fr/there. So, unless you have a phenomenon that can be strobed (like moving your hand sufficiently fast – unlikely, IMO, or many little water drops cascading down while filling your Nalgene Cantene, like in my case,) i'd wager that you won't see the 100Hz "flicker".

pj,
Wow, I didn't realize the lowly AAA was equivalent to 6 coin cells. Actually I found a copy of the photons at the local $1 store here, in red or white. So I'll keep those as zipper pulls and use the L0D as my Every Day Carry (EDC).

I never thought anything could equal the lumens/gram of a photon, but given the low weight of the L0D, and the constant beam brightness vs. the photons, I believe the lifetime average lumen-hrs/gram would be higher for the Fenix, right?

I dont know if the L0D I ordered comes with the belt case/clip you mentioned, but I usually wear a bill cap, so that will work GREAT! If it performs well I will be getting an L2D for my mountain bike, that many lumens cost big bucks at a bike store. You mentioned you do not mind mounting a relatively large light to your head; does the old maglight head band work on the L2D? Seems like maybe a good solution?

Thanks so much for turning us all on to this great new product. When a product is good, sometimes your honesty and skill in informing a technically minded customer (as you find here at BPL) is all that is needed, pj.

Brett,

I've become disenchanted with Li coin cell headlamps. The PT Scout being the exception due to its very long task lighting capability. Even the e+LITE has proven to be a very great disappointment due to the fact that it produces just 15-30 minutes of bright light. The e+LITE does fine in this capacity too, but given its initial light output and the way it falls off so quickly, I was hoping for more and b/c of this my disppointment with it is greater. So, w/o doing any calcs, as regards the lumens/gm test that you proposed, i'd put a "blind" wager on the Fexnix. The tiny L0D-CE at 0.7oz w/alk. batt, but w/o the clip will blow away a Photon microlight, IME – 7.5 lumens for 8.5h; the Photon is close to being dead at that point. Plus, the L0D-CE at 7.5 lumens can be used for camp tasks (NOT reading, IMO), and non-technical walking where you don't need to see more than 6'-10' ahead (some young'uns might be able to comfortably see further, like maybe 15'???). I know indoors, where a lot of light gets reflected back by walls, etc., 20-25 feet is no problem at all w/the L0D-CE on its lowest, 7.5 lumens, o.p. level.

The L0D-CE comes with a clip, but mine didn't come w/a "holster"/case. The other 1xAA, 1xCR123A, 2xAA Fenix models that i have seen do come with a holster, but mine didn't come with a clip.

I don't have the old MagLite band. I have a homemade "JakStrap" [the extreme limits of my Fornshell-like (and in my case i use the term very loosely) fabrication capabilities]. The JakStrap is like the old Maglite band.

I have both an elastic loop on the homemade band & a non-elastic adjustable velcro loop. So, two mount points to prevent the flashlight from twisting about the axis of the single forward elastic attachment point. Of course, for task lighting, when i want the light pointing more down than ahead, i either move the back of the band up further on the back of my head, so the band as a whole is angled down in front, or i undo the velcro, allowing the light to torque around the forward elastic loop mount and point more downwards towards the task at hand.

So, yes, based upon my limited use of my homemade "JakStrap" (an actual product's TradeName), using such a band works well with the Fenix. I wear non-progressive bi-focal glasses – the old one's with the ole'geezer line across the middle, separating the near and far lenses. This arrangement works for me. I haven't noticed any more head tilting accomodation than i might normally need to do to see through the bottom lens or the top lens, as required, of the bifocals.

Some additional tidbits of info someone might like to know:

Before everyone runs out and buys a Fenix, i'd say again that if you find the Eos's tiny "spot" objectionable, you might want to see a Fenix in use before shelling out the bucks.

I don't find the Fenix as objectionable as the Eos even though it has a "spot" ("donut hole" it was called in a link someone else provided in an earlier Post in this Thread). Why? First, the spot is most noticeable at the lowest output setting. However, this is used normally for seeing things closer at hand (tasks), or if just trying to see a few feet ahead when walking a non-technical trail (we sometimes call 'em "paths" in my neck of the woods). When performing task, i find this brighter spot more useful than a somewhat duller more diffuse light, e.g. when removing a sliver of wood for instance. Second, when viewing things farther away two things mitigate the "spot": a) the spot gets larger as one shines the light out futher, and b) higher output levels are used & in my ~30hrs use to date (~30hrs all uses & models combined – i've been playin' with my new toys – hey, it keeps me off the streets and out of trouble!) the higher o.p. levels put out so much light that even the relatively "darker" ring around the "spot" is bright if i happen to focus the light beam on something closer, or i'm looking so far ahead that the "spot" is sufficiently large for my uses. All that said, the PT Apex does put out a broader beam of light, IME.

Personally, the woods are so dark at night (especially when the leaves are on the trees), or in more populated areas (more air pollution) that preserving dark adaptation in one's vision is meaningless. I've switched my light off; stood still for several minutes and couldn't see my hand moving inches to a foot in front of my nose. So, for me, at least, what's the point of preserving dark adaptation – can't see w/o a light anyways. Of course, one could easily purchase a AA MagLite accessory kit (~$4.95) and get a metal clip, a lanyard, and some colored plastic disks which can be taped to the Fenix for use as a colored diffuser for both task lighting and preserving dark apdatation for those out West in wide open spaces with no air pollution.

Also, for clipping the light to a ball cap brim, in many cases i wouldn't just trust the clip (IME only the L0D-CE comes with a clip. I used a couple of old AA MagLite clips for th e P1D-CE and for use with the L1D-CE & L2D-CE). I've "reformed" (in other words "bent") the clips to provide more clamping/compressive force, but i still either use a bit of velcro, or duct tape to secure (especially the L2D-CE) the flashlight to my ballcap brim and to provide a second mount point to prevent side-to-side movement of the capbrim mounted Fenix if i turn my head rapidly to the side.

Hope this info helps.

pj, Thanks for the disussion of lumen hrs per gram. I found a lumens vs. hr. curve for the Felix lights; it would be a simple matter to curve fit and integrate w.r.t. time to get the total light output and compare with such a graph for the photon.. an exercise best left for a rainy day.
Thanks also for the explanation of how you mounted the light on your cap in an adjustable manner. I will try something similar with my L0D.

Regarding night vision, one thing I think I will like is that it STARTS in the low setting, whereas my Petzl Zipka and Princeton Tec quad both start in the high setting, and 9 times out of 10 I have to click down to the low setting for general tasks, thus washing out alot of the rhodopsin in that moment of bright light. Eventually I just covered the light during that process; annoying. I like the red after-market filter available for the Zipka, and I hope to improvise something similar for the L0D.

Brett,

L1D-CE & L2D-CE both have to MODES of operation with multiple lighting levels/settings each. Ignoring, strobing/flashing/SOS -type lighting levels (both MODES have one), these two modes (selectable by turning the bezel/head fo the light) break down as follows:

General Mode: Lo, Med, Hi
Turbo Mode: the-maximum-output-possible which is HIGHER THAN the General Mode's 'Hi' level

The tailcap switch controls turning these two lights on-and-off (full button presses), with BD-like partial presses controlling switching/cycling through the lighting levels.

L0D-CE & P1D-CE don't have a tail cap switch. The head/bezel is used to turn these two on-and-off. Repeating the off-and-back-on head-turn switches/cycles through the lighting levels. Turn it off for 2+ sec. & the last operating light level is "forgotten", so switching the light back on, begins the sequence again with the first lighting level.

Now, the L0D-CE & P1D-CE have their lighting levels IN A DIFFERENT ORDER from the L1D-CE and the L2D-CE (which go from lo-to-med-to-hi). The L0D-CE & P1D-CE begin in their PRIMARY lighting level (20 lumens and 72 lumens respectively), cycle to their LOWest lighting levels (7.5 lumens and 12 lumens respectively), and then next on to their MAX lighting level (50 lumens and 135 lumens respectively). I agree with you. I'd prefer to have the lowest lighting level first in the sequence like in the L1D-CE & L2D-CE. I'm guessing that the two AA models are probably diff since, for tactical purposes the head/bezel of these two models could be tightened and then the tail cap will bring the ON and immediately into TURBO-MAX-OUTPUT MODE.

Lastly, FYI, by dark adaptation i mean more than rhodopsin, i'm also talking pupil aperture as well which as one ages takes longer to respond.

Hey PJ,
On the L2D-CE, if you have the head turned out for low mode, you can turn it back on and it will be back on low.
The button takes you through the low to high and the lower power flash settings.
The only way to get to turbo mode is to tighten the head. With the head tightened it cycles through only two selections, the fast high flash mode and turbo mode.

What you wrote is exactly right.

That's what i was attempting to explain.

Wasn't sure, when i read your Post, if you were correcting my poorly written explanation, or making sure that you understood my poor written explanation. The L1D-CE & the L2D-CE operate identically (just some of the higher output levels & the burn times change).

pj, Thank you, I understood your instructions well. I must have misread the website thinking the L0D started in low as the other two do. Maybe they thought the low of the L0D was TOO low, so started it in med.
I did not know pupil reaction times decreased with age. These LW backpacking threads can take a turn an many interesting directions; and Im always jumping on to Google to learn more about these ancilary subjects!

Brett, yes pupilary response/rxn time incr. w/age. in fact, 10+ yrs ago that was my first clue that i was going to be needing bi-focals – when alternating b/t near & dist. viewing, it would take 1-1.5 sec. after looking up fr/reading for some dist. objects (e.g. digital clock) to focus properly.

As far as why they start in Primary vs. low. Who knows? i just figured that the L0D-CE & P1D-CE didn't have a "General" and "Turbo" modes which gives the best of both worlds (General starts on the lowest light output, and Turbo starts on the highest light output)

I think starting lights on something other than the lowest setting first (many headlamps do this also) must be for some emergency or safety related issue (like, so i can see what's about to eat me?!). So, instead of the light coming on to a bright light in just less than 1/4s (one button push), it will be just less than 1/2s (two button pushes). I don't know. Hope someone has a better understanding of why than i do. I'm just guessin' here.

Vick, I agree with you that a hand held light while on the trail is far better than head mounted. However, this is not a vote to eschew the headlamp; the're the best for virtually all other applications. Running through the night on the JMT I simply held my Tikka Plus headlamp in my hand. Surprisingly, by sunrise my hand wasn't fatigued. It's true that I do have to move my light to my head when using trekking poles, but that's only when I'm going slow uphill.

If you've never experienced this phenomenon, I recommend finding a dark, rocky trail. Stand still and point your light at the trail 20-25 feet in front of you while holding your light next to your eyes. With the light in this position all of the shadows cast by the trail irregularities are PERFECTLY hidden behind their corresponding features producing the illusion of a smooth trail. Next, move the light away from your eyes (I hold it about hip level while I run). You will be amazed as a rugged moonscape suddenly appears as the shadows move out from behind the rocks and into your view. The result of this exercise is truly dramatic. I stopped tripping at night when I moved my headlamp off my head and into my hand while on the trail.

The two Fenix lights I bought are nice lights but IMHO they are Ergonomically challenged for anyone intending to use them clipped on a hat as a headlamp. You have to remove it from the hat to turn it on or turn it off. The part you rotate to switch it on or off is located behind the clip instead of in front so you can't really switch it on or off very easily while wearing it on a hat. On and off is always a two handed operation. An Arc AAA Premium can be turned on and off one handed when it is clipped to a hat.

One of the two models I bought, the E0 has electrical contact problems. I guess you need to shine the contacts right out of the package if you want it to turn on. Mine still doesn't work very well so I will need to focus more effort on finding the problem area. It's weight is identical to the Arc AAA at 0.8 oz with alkaline battery. The ARC AAA is brighter.

The other model I purchased is the LOD CE and it weighs a full oz. It has multiple modes. Changing the brightness levels – well, there will be differing opinions on the ease of this. Significant to me is that it won't remember which level you last used so if you want to use the low level for max battery life most of the time you have to do the twisty on twisty off then twisty back on in less than 1.5 seconds thing every time you turn it on. To the eye, the ARC AAA is brighter than the low mode (but low mode is useful) about the same or marginally brighter in the center than the standard mode and significantly dimmer than the high mode when compared at short in camp distances. The high mode is bright – brighter that most people will really need IMHO and short lived. The SOS mode is a fully automatic distress signal which is kind of cool. Turn it on in this mode and it will code SOS continuously. The Fenix has a hot center focus to the beam which throws to illuminate things at distance much better than most single led lights including the ARC AAA. If Spotlighting things at a distance with a mini light is your need then the Fenix is a better choice than the Arc AAA premium.

Neither Fenix model is reverse polarity protected so you might fry it in the field if you goof up putting the battery in.

I can't comment on the advantages of the regulating circuit over the ARC AAA. Reportedly there is an advantage but it would take some comparison tests to see and document them. I don't have enough interest to do the tests in light of the ergonomic issues that will keep me from taking either of these Fenix lights on the trail.

IMHO as an overall package the current version of the ARC AAA Premium nails it for the needs of lightweight backpackers and seems to provide a good balance of performance to battery life. Especially with intermittent use. Even if Fenix tops the ARC AAAs regulation circuitry other issues will cause me to leave them at home. The ARC AAA Premium remains the gold standard of AAA lights IMHO. The ARC AAA Premium has met my needs in camp and night hiking. I do not have a need for spotlighting things at distance. For me it does what I need for lightweight backpacking. Some may choose Fexix for a particular feature that meets their needs better. They are fine lights but mine will languish in a kitchen drawer.

Donald,

You can do one handed on/off with a Fenix AAA with a custom clip like this one I made from a rotating Photon light clip.

I like the simplicity of the ARC too, but would like to see them use the new more efficient CREE LED’s.