Mjölnir, thy competition has a name: KLARUS XT20 (review, runtimes, pics, beamshots)

[varuscelli]

I like the idea of the additional mode button at the throat, it reminds me of the TK21 set up and would allow one to change modes while utilizing a underhand grip.

Yeah, I think when you do the underhand grip on the XT20 the thumb would very naturally have access to a switch on the bottom part of the head. For handling/ergonomics that would be really useful. The manufacturers who are doing those dual switch positions are really onto something functional, although I'm sure design is that much more complex and there are more parts that could potentially fail with more switches.

 

[candle lamp]

As I posted above, did you notice the swing of the output in real world? It's very curious that the range of relative output is very wide in the runtime graph.

The relative output varies from 0 to 240. Is the relative output relative value to distinguish the max. & the min. lux? (If incorrect, please let me know.)

 

[turboBB]

As I posted above, did you notice the swing of the output in real world? It's very curious that the range of relative output is very wide in the runtime graph.

The relative output varies from 0 to 240. Is the relative output relative value to distinguish the max. & the min. lux? (If incorrect, please let me know.)

The swings are absolutely not noticeable in real life, it's really more the artifacts captured by the light meter. So on the High chart, you'll notice that it's "swinging" mostly between 90 and 210 (after the step down), this is the effect of the rate that the light meter is able to capture at (1 sec intervals) vs. how many times the PWM rate is actually cycling in that second. Sometimes it'll catch it at the top of the cycle and at others it'll capture it at the bottom of the cycle. But in reality because of how fast it's flashing in one second it's not noticeable to the eyes.

It's kind of hard to explain (and if anyone has a better way of interpreting this, please chip in) so I'll try recording a video to demonstrate what I'm talking about. Also, I'm not sure how familiar you are with PWM, but here is a great thread explaining it. The frequency on high is so fast that it'll look like the last pic in the first post.

Cheers,
Tim

 

[candle lamp]

The swings are absolutely not noticeable in real life, it's really more the artifacts captured by the light meter. So on the High chart, you'll notice that it's "swinging" mostly between 90 and 210 (after the step down), this is the effect of the rate that the light meter is able to capture at (1 sec intervals) vs. how many times the PWM rate is actually cycling in that second. Sometimes it'll catch it at the top of the cycle and at others it'll capture it at the bottom of the cycle. But in reality because of how fast it's flashing in one second it's not noticeable to the eyes.

It's kind of hard to explain (and if anyone has a better way of interpreting this, please chip in) so I'll try recording a video to demonstrate what I'm talking about. Also, I'm not sure how familiar you are with PWM, but here is a great thread explaining it. The frequency on high is so fast that it'll look like the last pic in the first post.

Cheers,
Tim

Many thanks for the reply & the thread related to PWM. Yes, I know the very informative thread.

I still wonder the swing range is too big than expected even though the light is on high mode.
I think light meter capturing (every second interval) will not affect the swing of the output on high mode. There may be other reason.

It surprises me that you could find each LED's just the opposite in that the LED is now shifted just slightly towards the left & right, and this creates a nice giant beam. :thumbsup:

 

[scaramanga]

Very nice review, my XT20 is just about ready to be picked up at the local post office... Can't wait to get my hands on Mjolnir!

 

[varuscelli]

I was wondering if there would be an easy way of rigging a diffuser for the XT20, so I dug through some of my photography gear and came up with a couple of Sto-Fen Omni-Bounce diffusers to try. These rectangular diffusers are made for use on various external flash units for cameras and they come in a variety of sizes (something like 40 different ones are sold as sized to different manufacturers flash head sizes).

The diffuser shown in the photo is not an exact fit but it's close enough that I bet there is an Omni-Bounce that would probably be an exact fit or near to it. To make this particular diffuser fit snugly, I had to give the XT20 head a couple of wraps of a strip of old bike tire inner tube that I keep for bike mount shims. I doubt the XT20 would get so hot as to cause problems with the inner tube wrap -- but it would be nice to have one of these that was a near-exact fit so it would slip on and stay in place without being shimmed.

In any case, the diffuser effect of the Omni-Bounce on the XT20 is fantastic, putting out a really effective amount of diffused light. I'll see if I can so a couple of comparative beam shots and post at some point.

 

[varuscelli]

I was wondering if there would be an easy way of rigging a diffuser for the XT20, so I dug through some of my photography gear and came up with a couple of Sto-Fen Omni-Bounce diffusers to try. These rectangular diffusers are made for use on various external flash units for cameras and they come in a variety of sizes (something like 40 different ones are sold as sized to different manufacturers flash head sizes).

The diffuser shown in the photo is not an exact fit but it's close enough that I bet there is an Omni-Bounce that would probably be an exact fit or near to it. To make this particular diffuser fit snugly, I had to give the XT20 head a couple of wraps of a strip of old bike tire inner tube that I keep for bike mount shims. I doubt the XT20 would get so hot as to cause problems with the inner tube wrap -- but it would be nice to have one of these that was a near-exact fit so it would slip on and stay in place without being shimmed.

In any case, the diffuser effect of the Omni-Bounce on the XT20 is fantastic, putting out a really effective amount of diffused light. I'll see if I can so a couple of comparative beam shots and post at some point.

The Sto-Fen Omni-Bounce diffuser can also be pushed all the way onto the XT20 and this actually makes for a better diffused light if hand-carrying the flashlight. The problem with the diffuser in the previous pic is that even though it puts out a lot of light, the upper panel puts too much light back into the eyes of the user. With the diffuser pushed all the way on like in the photo below, all the light goes outward and none back up into the eyes of whoever is carrying it. Diffuser use might also make another good reason for wanting the XT20 to be able to tail stand on its own.

 

[turboBB]

Many thanks for the reply & the thread related to PWM. Yes, I know the very informative thread.

I still wonder the swing range is too big than expected even though the light is on high mode.
I think light meter capturing (every second interval) will not affect the swing of the output on high mode. There may be other reason.

It surprises me that you could find each LED's just the opposite in that the LED is now shifted just slightly towards the left & right, and this creates a nice giant beam. :thumbsup:

I'm working on graphing the PWM w/my Fluke so when that's ready, I'll post it up and hopefully it'll clarify what I'm trying to explain. And yes, outdoors with some particles in the air, you can clearly see the beams converging. I'll get a shot of that soon and post that as well.

Very nice review, my XT20 is just about ready to be picked up at the local post office... Can't wait to get my hands on Mjolnir!

Congrats, feel free to share your experiences with it!

Comments removed for the greater good of the thread.

fyrstormer: sorry for the slight misunderstanding. No harm done, I hope.

Thx guys! It would've been a shame had this thread got locked down. Can we get a :grouphug:

Also, thx for sharing those pics varuscelli, great idea using that diffuser on the XT20!

Cheers,
Tim

 

[HKJ]

I'm working on graphing the PWM w/my Fluke so when that's ready, I'll post it up and hopefully it'll clarify what I'm trying to explain. And yes, outdoors with some particles in the air, you can clearly see the beams converging. I'll get a shot of that soon and post that as well.

Your lux meter is fast to capture the pwm, I measured it at nearly 1 kHz and did not see anything on the lux meter. You can see the actual pwm in my review, captured with a oscilloscope.

 

[turboBB]

Thx HKJ!! As a FYI I'm using an Extech HD450 and capturing at a rate of 1 sec. interval.

@Candlelamp, if you check out HKJ's review, it's basically where the time interval gridline (in his case in ms) intersects with the PWM curve. So in my case, imagine there were more gridlines for the y axis and you can envision how certain of those lines will intersect with the curve at the peak of a curve and certain at the trough and others in between thus the major swings you're seeing in my runtime charts. Who knows, maybe it could just be my sample that exhibits this but again, I'll post up a chart later to demonstrate clearly what I'm talking about.

Cheers,
Tim

 

[HKJ]

Thx HKJ!! As a FYI I'm using an Extech HD450 and capturing at a rate of 1 sec. interval.

I am also using the HD450, but at a slower sample rate and have newer seen any problems with pwm.

 

[candle lamp]

@Candlelamp, if you check out HKJ's review, it's basically where the time interval gridline (in his case in ms) intersects with the PWM curve. So in my case, imagine there were more gridlines for the y axis and you can envision how certain of those lines will intersect with the curve at the peak of a curve and certain at the trough and others in between thus the major swings you're seeing in my runtime charts. Who knows, maybe it could just be my sample that exhibits this but again, I'll post up a chart later to demonstrate clearly what I'm talking about.

Cheers,
Tim

I understand what you mean. Thanks a lot for your reply again. Tim!

 

[SlavaKey]

Good diffuser!

I was wondering if there would be an easy way of rigging a diffuser for the XT20

Looks like very suitable.
Are there some beamshots with diffuser?
Via.

 

[varuscelli]

Re: Good diffuser!

Looks like very suitable.
Are there some beamshots with diffuser?
Via.

I don't have any beam shots with the XT20 and Sto-Fen Omni-Bounce diffuser yet, but this diffuser coupled with the XT20 produces the most impressive "big" diffusion effect I've ever seen.

Part of the problem in doing photos of the diffusion effect is that even though I have some extreme wide-angle lenses that I use in my photography, but I won't be able to capture the full effect in one shot. The diffusion covers a full 180 degrees and even seems to throw perceptible light somewhat beyond 180 degrees (behind the head of the flashlight) because of the way the diffuser is made.

But I think I can still capture something that shows most of the difference between the XT20 with and without the diffuser -- I just won't be able to show the full effect of the diffuser (at least not easily).

 

[varuscelli]

The Sto-Fen Omni-Bounce diffuser can also be pushed all the way onto the XT20 and this actually makes for a better diffused light if hand-carrying the flashlight. The problem with the diffuser in the previous pic is that even though it puts out a lot of light, the upper panel puts too much light back into the eyes of the user. With the diffuser pushed all the way on like in the photo below, all the light goes outward and none back up into the eyes of whoever is carrying it. Diffuser use might also make another good reason for wanting the XT20 to be able to tail stand on its own.

Using the Sto-Fen Omni-Bounce diffuser on the XT20 as shown in the previous pic, here's what I got as a sample. This room is roughly 18x22 feet and the distance here is about 20 feet away from the far wall. Camera lens was a 14mm Canon lens, so it was about as wide as I could go and it still wasn't able to capture all of the diffuser effect, but still these two photos do give a fairly accurate reproduction of what I saw with my eyes.

Without diffuser, light on highest setting:

With diffuser, light on highest setting (and the diffused effect went well beyond what the camera could capture, so it doesn't quite do justice to the effectiveness of the diffuser):

 

[looman]

Well, I dunno. I've tried taking the tailcap off and tail standing the XT20 on end of the body tube (with batteries in to account for the extra weight) and it does a reasonable tail stand that way. While it's true that the designed functions of the tailcap control buttons could be a problem, I don't think the tailcap would necessarily have to be enlarged to allow it to tail stand with reasonable stability. It would just need to be rounded in form like other tail standing flashlights. For the added functionality of the flashlight (especially one that provides so much light), I think a reasonable tail standing ability is better than no tail standing ability at all. Still, I know there would be design/use challenges associated with the tailcap buttons if the tailcap had a lip that was well rounded enough to allow tail standing.

Another thing I'd like to see would be another set of control buttons on the head much like the Spark SL6-470NW (which has buttons on both the tail and head). I posted this mockup elsewhere, too...but buttons on the head as well as tail would make the XT20 a much more user-friendly flashlight, especially given the bit of awkwardness that seems inherent in its length. When I imagine holding the XT20 in one hand but not in head-high momentary position, one handed operation (waist to chest hight) would be much easier in many cases with buttons on the head. Just fantasy wish list stuff.

I agree with this. I have a thrunite catapault V3 and the tailcap button is a pain in the arse if your only a single hand free. A button below the head in addition to the tail cap one would be a super idea.

 

[turboBB]

I've added long distance beamshots to the review (search 10/12) and wrapped up runtime testing w/RL3100's (search 10/13).

As for the idea of the sideswitch, that would've definitely come in handy during my long distance beamshots (check sig for link). It was really difficult to keep a good grip on the light in an overhand grip (just so I could have my thumb ready to activate the strobe) while running around on uneven ground.

@varuscelli, thanks for sharing pics of the diffuser, that really is an amazing set up!

Cheers,
Tim

 

[varuscelli]

@varuscelli, thanks for sharing pics of the diffuser, that really is an amazing set up!

I hope I haven't intruded too much in your review, Tim. But this seemed like a good place to put in what I hope were a few relevant bits of my personal thoughts and experiences with the XT20. You've done an excellent job with the review and I hope I haven't violated etiquette with so many extra posts in someone else's review.

Although I have a few areas where I think the XT20 could use some improvements, I'm liking it for my uses. Fortunately, when I use it on a bike, the tail switches are easy for me to work with and the amount of light for riding is fantastic. I'd love to see a dedicated diffuser for this thing and a second switch on or near the head as we've discussed previously (well...tailstanding, too). But hey, it's a great light in many ways -- especially in terms of output.

 

[SkyPup]

Thanks for the excellent review, I just ordered mine and will be using it as a night weapon light.

 

[yifu]

Great review! I like the idea of using both the XR20 and SC600 as bike light, thats like what 2000OTF lumens? Probably brighter than the H3 incans used in cars.