[selfbuilt]

JetBeam Jet-I MK IBS Review: Runtimes, Beamshots, Pics, Ramps + UPDATE: Shipping ver!

UPDATE MAY 1, 2008: JetBeam has sent me a full shipping version of the Jet-I MK IBS (courtesy of bugoutgearusa.com). I've updated all the runtimes in this thread, although there was little difference to my engineering sample MKII IBS. There are some build differences, though - scroll down for more info. For a comparison of this same IBS circuit in CR123A format, see my Jet-II IBS.

REVIEWER’S NOTE: This is a three-part review. The first part is a build and runtime overview of the new JetBeam “infinite brightness system” (IBS) circuit, in the form of the engineering sample Jet-I MKII IBS. The second part is a build update with the full shipping version, now renamed the Jet-I MK IBS. The third part is a detailed beamshot and runtime comparison to other similar lights. The MK/MKII IBS lights were provided free of charge by JetBeam for review.

PART I: Jet-I MK IBS Build/Runtime Comparison

Specification: (according to the Manufacturer)
LED: CREE 7090 XR-E (Q5 bin)
Max Output: 225 Lumens (“Torch Lumens”)
Reflector: OP aluminum reflector
Lens: Sapphire crystal
Material: T6061 T6 aircraft aluminum alloy
Finish: HA III Military grade hard anodized
Battery: one AA battery or any other batteries of the same size
Input voltage: 0.7-4.2V
Switch: Reverse push button switch
Waterproof: Accord to IPX-8 standard
Dimension: Bezel diameter 21mm, Tail diameter 20mm, Overall length 91mm
Weight: 40g



As you can see, exterior styling is very nice. Light comes in a dark slate grey HA finish, similar to the earlier MKII models. There is some color mismatch between the head and body on my engineering sample, but that’s not uncommon for dark grey anodizing. Lettering is generally good, although the MKII and IBS labels on the head are not uniform in intensity/brightness (again, not uncommon for Jetbeam lights). The light lacks knurling, but the smooth body has indentations to improve grip or allow addition of trits. I have always found this model series to have an elegant look.



The light comes with double o-rings at both ends of the body tube. The o-rings are a bit thicker than most lights, leading to increased resistance when screwing the head and tail to the body tube. Although this makes a tight fit which should help for water-resistance, care needs to be taken to insure you don’t accidentally “pinch” an o-ring while tightening.

As you can see, the head contact board has a spring on it, so flat-top 14500 batteries can easily make contact. However, the increased resistance due to this second spring means that you may find it difficult to fully tighten the head/tailcap with a longer protected 14500 in there. I was able to manage this without too much force on my AW protected 14500s (NOTE: see update with shipping version in Part II below).

As with all JetBeam AA-model lights, the tailcap switch retaining ring is made of plastic. This is a concern for some, although I haven’t experienced any problems as yet on any of my JetBeam lights.



As you can see above, the MKII IBS uses the “silver” version of the Cree Q5 emitter (i.e. the area outside central die is silver in color, instead of the standard Cree yellow). My understanding is that there are no output differences between the silver and yellow versions, and these simply reflect different manufacturing plants.

Screw thread comparison:

From left to right: MKII IBS, JET-I PRO, MKII X



The threads on the MKII IBS are improved from the early version of the MKII series. As you can see in the pics above, the MKII IBS (far left) has fewer but thicker threads than the original Cree MKII X (far right). This should reduce the risk of cross-threading. These threads are not as substantial as those on the JET-I PRO (middle) which are square and thick (a favorite with machinists). However, the MKII threads are anodized, allowing for tailcap lockout.

The reverse clicky switch is fairly stiff, similar to other JetBeam models. The traverse is also fairly short (i.e. how far you have to press to activate the light), but accidental activation is unlikely given the resistance and flat-top switch cover. However, you may find getting into the “hidden modes” takes some practice, as you need to quickly flash the switch 3 times in less than one second (I've found this a bit challenging - see the Interface section below for a discussion). Light is able to tailstand.

From left to right: MKII IBS, JET-I PRO, MKII X


Early versions of JetBeam 1AA lights (i.e. the MKII X and the C-LEs) had fairly sharp edges around the tailcap lanyard attachment. As you can see above, the newer MKII IBS and JET-I PRO have an improved smooth edging.

PART II: Build Comparison to Shipping Jet-I MK IBS




As you can see, the full shipping version comes in a new hard-shell box with proper identification labels. Inside, securely packaged in foam inserts is the light, manual, warranty card, extra o-rings and switch boot cover, and wrist lanyard. A definite improvement over the current Jet-II and Jet-III packaging.

Build Differences:



A few obvious differences stand out. The anodizing is better match across the whole light, similar to the head of the engineering sample. However, the lettering is not as clear or sharp as the engineering sample. It's not quite as bad as the above pic makes it look, so here is another one:



Body tube and threads are the same between the two lights. O-rings are less orange and more red on the shipping version.



Now this is a little strange - the o-ring around the lens is much smaller on the shipping version, and hence a lot more noticeable. It doesn't seem to interfere with the beam, though.



Now this is significant - notice how much longer the tailcap spring is on the shipping version (on the right). I understand now the complaints from some people about not being able to fit some protected 14500 batteries in this light. With the extra spring in the head, that's a lot of tension on the battery (threads are anodized, so you need a full tightness fit of both the head and tail cap to make contact). Cranking it tight thus runs the potential risk of damaging your battery.



It seems like JetBeam is using the more substantial switch spring I noticed in my Jet-II review. But while that spring fits the bigger Jet-II tailcap fine, it is a bit wide at the base for the smaller red plastic retaining ring of the MK IBS. The first rung or two of the spring are jammed under the retaining ring, making it hard to separate the retaining ring from the switch assembly.

This is not really a problem when using standard batteries, but I find it very difficult to tighten the tailcap on most of my AW protected 14500s. I strongly recommend JetBeam revert to using the smaller springs in this light.

Digital control:

All JetBeam lights use PWM, to my knowledge. On this light, the frequency is high enough that I can’t detect it by eye or instrument, even at the lowest output settings.

Interface:

The MK IBS allows you to set three defined output states (A, B, C) through a continuously variable brightness mechanism similar to some Liteflux, EdgeTAC, and DBS lights. Interface is as follows:

Mode Switching
According to the JetBeam manual and published specs, default settings for the three modes are: A is High brightness (~80-85% max), B is Low brightness (~10-15%), and C is the warning signal. There is no memory mode - when switched on each time, the light enters mode A. Lightly press the tail cap button (i.e. quick flash), and the light will go from mode A -> B -> C in cycle. Note that on my engineering sample, A and B were both pre-set to Max (100%) brightness.

Changing the Brightness Level
To access the IBS cycle, lightly press the tail cap button three or more times within one second in any mode to enter the “Hidden Menu” for that mode. This allows you to set each of A, B and C modes individually.

After 3 quick flashes, the light immediately goes into the “Brightness Setting” mode where it will ramp brightness from Min (5%) to Max (100%) gradually. Once it reaches Max, the light then starts over at Min and repeats the process. A complete cycle is supposed to take about 8 seconds according to the manual, but I’ve found that my engineering sample takes about twice that long (see Ramp graph below). During this process, the light flickers once at Min (5%), twice at 50% output; and three times at Max (100%). Simply turn off the light to select the output level you want. It will then retain this setting the next time you turn the light back on.

Special Functions Mode
After entering the Brightness Setting mode of the Hidden Menu, lightly press the tail cap button once, and the light enters the Special Functions mode - which goes from 1HZ to 15HZ strobe, warning signal, standby signal, 100% SOS and 5% SOS. Again, if you want to select any of these functions, just turn off the light and it will be set for the next time you turn on.

Reset Function
From the Special Functions mode, lightly press the tail cap button once and the light enters Reset mode. Turn the light off, and when it comes back on you will be in the factory set default A, B, C settings (i.e. A: High brightness; B: Low brightness; C: Warning Signal).

Although this interface seems to work pretty well, I personally found it hard to consistently flash the reverse clicky 3 times within one second to enter the Hidden Menu on my engineering sample. Either I was too slow, or I sometimes pressed too hard and clicked the switch off. I did find it a bit easier on my shipping sample, but of course, YMMV.

For comparison beamshots and a summary of throw and overall output, please scroll down to Part II of this review.

Testing Method: All my output numbers are relative for my home-made light box setup, a la Quickbeam's FR.com method. My relative overall output numbers are typically similar to his, although generally a little lower. You can directly compare all my review graphs - i.e. an output value of "10" in one graph is the same as "10" in another. Throw values are the square-root of lux measurements taken at 1m using a light meter.

Variable Output Ramping

Below is a graph comparing ramping outputs on both 14500 and Sanyo Eneloop. I’ve marked the graphs with the approximate time points when the light flashes to indicate 5%, 50%, and 100%.



First off, I should explain that the “50%” flash setting is based on ~50% max output on 14500, regardless of what battery type is in there. Since the max output on standard alkaline/NiMH is only slightly brighter than the 50% level on 14500, this gives you the strange looking Eneloop curve shown above where “50% flash” is actually pretty close to the output of max “100% flash” on this battery type, but takes an extra ~7 secs or so to reach it.

Now with the corrected lightbox results, you’ll see the ramping results make a little more sense, although they are still not perfectly visually linear. You’ll also note that the ramping time is about twice as long as the 8 secs reported in the manual. For a comparison to other lights with a variable output interface, please see Part II of this review.

Runtimes:

Note: all the runtimes below have been updated with the full shipping sample (including the default Hi and defaul Lo settings, that weren't available on my engineering sample). If you don't see the new graphs, just hit your browser's refresh button.









Note: “50% flash” on the graphs above refer to the point when the IBS circuit flashes to denote 50% on 14500 (which is actually near maximal on NiMH/Alkaline). “~50% (std batt)” refers to an arbitrary point I picked that gives you roughly 50% initial output on standard batteries.

Preliminary Output/runtime observations:

• The maximum output on 14500 is an outstanding ~95 relative units on my scale.
• Output/efficiency on 14500 seems good, with no signs of the problem that plagued the initial release of the Jet-I PRO.
• As JetBeam has pointed out, the circuit has some efficiency problems at the med/high output range on NiMH. For ex, the Default Hi and “50%” flash level (which are both just slightly lower output than max) have equivalent runtime to max.
• Low output is nice and low – as low as I’ve seen on a multi-stage 1AA light. Runtimes are still progressing, but output levels are marked on the graphs above for your reference.
• Higher output alkaline runtimes are disappointing, but that’s not entirely surprising given that this light is optimized for maximum brightness on 14500.

PART II: MKII IBS Comparison Beamshots/Runtimes



For this part of the review, I am going to compare the engineering sample Jet-I MKII IBS (Q5) to the original JB MKII X (P4), EDGETAC NDI (Q5), Fenix L1D (Q5), and JB JET-I PRO (R2). The shipping version Jet-I MK IBS doesn't look appreciably different.

Comparison Beamshots

All lights are on max/100% on AW protected 14500, about 0.5 meters from a white wall. From left to right, top row is MKII IBS, Fenix L1D, EDGETAC NDI. Bottom row is MKII IBS again, with JET-I PRO, and MKII X.




As you can see, the MKII IBS has the greatest output of all the lights shown (it’s even more noticeable in real life). It also has the widest spillbeam. Tint is white with a slight violet hue on my sample, but it’s not as pronounced as the above pics seem to show.

Throw/Output Summary Chart:

As I mentioned earlier, my original lightbox recordings were in error (now corrected). Below is a summary chart, including some “ceiling bounce” numbers taken in a small windowless room (with light and lightmeter on the floor, both pointing straight up).



As you can see from both the revised lightbox and ceiling bounce tests, the IBS is quite a bit brighter than the competition on max on 14500.

In terms of throw, on 14500 the MKII IBS is producing the following according to my lightmeter:
5%: 46 lux
50%: 1950 lux
100%: 3750 lux

Runtimes:



















Note: “50% flash” on the graphs above refer to the point when the IBS circuit flashes to denote 50% on 14500 (which is actually near maximal on NiMH/Alkaline). “~50% (std batt)” refers to an arbitrary point I picked that gives you roughly 50% initial output on standard batteries.

Output/runtime observations:

• No doubt about it, the Jet-I MK IBS is the brightest light on 14500 that I have tested.
• Given the incredibly high output, heat is a concern: JetBeam recommends against running the light this way unsupervised, as it could get hot enough to burn something! I concur, and advise caution in using 100% on 14500.
• Maximum output on standard batteries is similar or greater than the other lights test here, with typically equivalent output/runtime efficiency.
• There is some loss of efficiency on standard batteries at near maximal output, which according to Jetbeam is a trade-off in order to have maximal output on Li-ion (which so many of you seem to want ).
• Low output is as low as I’ve seen for any of these newer multi-stage 1AA lights – certainly as low as my excellent NDI (and with equivalent runtime to boot). Very impressive that such a wide range of output is possible on the IBS circuit.
• Regulation is excellent on all rechargeable battery types. Like the NDI, it’s clear that this light was designed to excel on rechargeables (NiMH and Li-ion).
• High output performance on alkaline is certainly less impressive, but that’s not surprising on such a high-end light.

Variable Output Ramping

Below is a graph comparing ramping outputs on 14500 for all my lights that have this feature. The graph has been adjusted to percent maximal output for each individual light, to allow you to better compare the differences. I’ve marked the graphs with the approximate time points where the MKII IBS and DBS DI circuits flash to indicate 5%, 50%, and 100%.



As you can see, ramping time is fairly long on the IBS, and slightly more visually curvilinear than most.

Preliminary conclusions:

• Highest output on 14500 of any 1AA I’ve seen. Good news for all you output freaks out there! … but I must caution about the risks of excessive heat if run this way in a prolonged fashion.
• Runtimes on higher output levels are very good on rechargeable battery types, but lower than the competition on standard batteries in the Med-Hi range. This may be a trade-off to get such a wide dynamic range on Li-ion. Further Med mode testing on NiMH is underway.
• Lowest output mode (5%) is as low as I’ve seen on a multi-stage 1AA light – with output and runtime as good as my EDGETAC NDI. Well done!
• Regulated output on rechargeable battery types in all output modes is very good (e.g. unlike Fenix or earlier JetBeam lights on 14500, where you run on direct drive initially)
• The feature set and user interface on this IBS circuit are more advanced than most lights, and is a considerable improvement over earlier JetBeam models. However, I found triple-flash to enter variable brightness and other modes a bit cumbersome compared to the simpler NDI interface.
• Light lacks a memory mode as such, but the flexibility to set 3 programmable states (accessed in a cycle) more than makes up for this, IMO.
• Build quality on my samples are very high, consistent with other JetBeam lights. Standard issues like anodizing mismatch, lettering imperfections, and plastic switch retaining ring persist, but overall quality is still quite high. Note the larger tailcap spring on the shipping version is problematic for longer protected 14500 battieres.

I’m not sure if this JetBeam IBS will replace my NDI as my EDC (I’ve grown fond of the NDI’s forward clicky and elegant interface). But the higher output and 3 programmable states of the MKII IBS are certainly nice features, and I’ve always been a fan of the more elegant styling of the MKII series.

Hmmm, decisions, decisions … I’ll keep you posted on my experiences with it!

------------
UPDATE: After EDCing the Jet-I MK IBS for a week, I thought I'd share my personal experiences with it relative to my NDI.

MK IBS advantages:

• Higher possible maximum output on 14500 (pretty much an even wash on standard batteries, though).
• 3 output levels you can set (i.e. 5%, ~60%, 100% works well for me in practice), instead of just one set-able level plus max on the NDI. This is a major point in the MK's favour, as far as I am concerned.
• More elegant and refined look - but that's just my personal preference (the NDI's "tactical" look may be your thing ).
• Can tailstand in stock form (but I find it more usable if you mod the switch cover so it doesn't - see below for discussion)

MK IBS disadvantages:

• Reverse clicky is stiff and harder to activate than the smooth forward clicky of the NDI. The mod suggested by Nake in post #41 helps a lot (see my follow-up post #4, but still doesn't let you momentary flash like you can on the NDI.
• Although overall output is similar on lowest setting - my preferred output level - the IBS has a brighter and more defined hotspot than the NDI (the NDI has a relatively brighter spill and smoother transition from the hotspot). Result is that I find myself "following the bouncing ball" with the MKII's hotspot when walking around the house at night, which I never felt with the NDI. Note the difference isn't huge between the lights, but it is noticeable to me.
• Less "grippy" texture of the MK IBS - I'm always a little worried it will slip out of my hand. No worries with the NDI!

For my personal preferences and daily usage, I find the balance swings slightly in favour of the NDI, despite its lack of a set-able "medium" level. Plus it happens to have a warmer tint that I personally like (of course, that's a complete lottery - YMMV). The Jet-I MK IBS is going into my computer travel bag for now (I leave the NDI at home when travelling through airport secuity ...)

Bottom line: I see the two lights as roughly equivalent overall, and I'm sure most here would be happy with either. Just go with whichever one seems to best match your personal tastes and preferences.