Fenix TK21 vs. TK40, very different.. but similar.. plus a video

The TK40 was the first "large" high performance light I got about a year and a half ago. I've been very happy with it.. great balance of spot and throw, AA batteries, & great output. very effective finding my dog or other animals or walking around the property which goes back more than 400 feet or so. The TK40 can light up to the very back of the 400 feet while I'm standing on the back porch.

As I've added to my light collection, I've been getting spoiled with these small very powerful lights.. i.e. LD10, PD31, ThruNite 1A, 4sevens MINIX etc.. In most situations I grab one of the smaller lights to get the job done, vs going for the TK40 like I used to all of the time.

So of course to justify my latest purchase.. I realized I have all Large lights (Stanley HID too).. or small lights.. I needed something in the middle.. something not EDC size, but pocket-able with plenty of power to be a good flood as well as spot to cover every need around my house here.

I decided on the TK21. I knew the XM-L would provide a good wide/flood beam but with the larger smooth reflector/head it would have decent throw. Rated at 468 Lumens I was a little nervous it couldn't touch the TK40 rated at 630, but surprisingly they seem pretty close.

I need to spend some time with both lights outside to really get a feel for the differences, but initially it the pros with the TK21: definitely has a better flood, color temperature, momentary on, & size of hotspot. The TK40: probably has a bit farther throw, wider spill, and takes regular AA batteries

I have one video comparing the two lights in my basement.. I'll soon do some outside videos well:

http://youtu.be/uWgyZLwgu7Q

Hi, just wondering, have you got your camera's video exposure locked down? Seen quite a couple of excellent A-B comparison vids on youtube that compared good lights, have a great HD low light camera etc.... but unfortunately the exposure varied all over the place and you can clearly see the difference in frame speed/sky glow even between the lights. Just for example http://www.youtube.com/watch?v=Q65DF2s0k_g (incidentally we were playing with the CWSL Night Reaper which is prob similar to the PH50 in output/throw, TK70 and some other HIDs 2 weeks ago)

If it's outside you just have to look at the sky glow or any ambient light glow, one look and i could detect that they are different, couple of days ago i detected one which had only a 1/3 stop difference so that was a surprise to me as i never knew my eyes or rather brains are that sensitive LOL! Thus i checked the EXIF and yep confirmed that they are different. With photos it is easier to verify and confirm because of the EXIF data embedded in the pictures, can tell within 2 seconds.

But it seems like the exposure did not change much, at least not detectable by me.......so yeah they are like nearly 80% similar in throw. Actually the thing with throw is that you need to test outside at fringe areas (which you probably have already done), with indoors the eyes usually shuts down the extra light.... I have tried many times, with somewhat dark adapted eyes, indoors a 50k XM-L light looks nearly the same in intensity as a 18k XM-L light, same lumens from ceiling bounce, same current drawn from the cells etc.

Anyway, nice work bro..... still quite surprised that the TK40 and TK21 look so similar even for the spill (lumens output). But i guess 468 and 630 is not really a big difference, seriously with our eyes it is just a 25% difference is noticeable but not large. My personal "target" is that anything less than 20%, they'd look around the same, same class of lights/reflector/emitter size of course.

thanks for the comment! I'm still experimenting with the "best" video setup for low/no light testing like this.. but I'm a bit of a photo guy as well so I tried to pay attention to the video exposure before anything else. I shot this video with a Canon 7D in HD with a manual exposure. keeping the aperture wide open at 2.8 on the 24-70 f/2.8L, then setting the shutter speed for 1/60th of a second. From here I would watch the display while shining the light and adjust the ISO until the exposure on the display matched what my eyes perceived where the light hits the subject (as close as possible! not perfect since our eyes can register many more stops of light than any camera). Usually smaller dimmer lights I have to bump the ISO up in the 3200-6400 range. For these shots I believe I was in the 2000 neighborhood.

I was mostly looking for blown out highlights both in real life and on screen.. from there it was a bit easier matching the exposure up or down a notch. The outdoor shots on my youtube channel were actually done in auto exposure mode. I didn't have enough time to setup the exposure "properly" but I was still pretty happy with the results since the exposure wasn't bouncing too bad. The fringe areas are tough outdoors since our eyes will always be able to detect a lower level of illumination than what a camera can capture. The fence posts in real life in my yard were much better lit than what my videos show.. but the camera just doesn't have the dynamic range that my eyes have.. even with the ISO bumped up to 12800..

Now you got me thinking and I'm itching to head outside with these two lights and my 7D!

Hmm, TK40 should be around 20,000 lux, the TK21 is around 10,000... so it should be a noticeable difference :S

Something somehow seems amiss

AusKipper said:

Hmm, TK40 should be around 20,000 lux, the TK21 is around 10,000... so it should be a noticeable difference :S

Something somehow seems amiss

Click to expand...

I just came inside from really putting these next to each other in an area of my yard that I have a clear >300ft shot. The TK21 is definitely brighter up close (<200ft).. the spill with the XM-L is much larger and brighter than the TK40. But the TK40 definitely out throws the TK21.

So twice the lux?? hmm I don't know... It seems like a combination of the large bright area of illumination in front of me and the cooler color temperature makes me feel like the TK21 is "AS" bright as the TK40 if not brighter! The noticeable difference is really in the throw. The TK40 can illuminate an area beyond 300 ft where if my dog or an animal was up there I could see it in good detail. With the TK21 I'd probably see the animal, but probably not so much detail.

I made a quick video about it... think it's still uploading though (ugh HD & DSL). It should be up on my channel soon: http://www.youtube.com/user/energythoughts

sorry it's a bit front focused.. next time I'll focus on the trees in the distance. it was shot in manual mode, so the exposure should be consistent between the lights.

energythoughts said:

I shot this video with a Canon 7D in HD with a manual exposure. keeping the aperture wide open at 2.8 on the 24-70 f/2.8L, then setting the shutter speed for 1/60th of a second. From here I would watch the display while shining the light and adjust the ISO until the exposure on the display matched what my eyes perceived where the light hits the subject (as close as possible! not perfect since our eyes can register many more stops of light than any camera). Usually smaller dimmer lights I have to bump the ISO up in the 3200-6400 range. For these shots I believe I was in the 2000 neighborhood.

Now you got me thinking and I'm itching to head outside with these two lights and my 7D!

Click to expand...

I'm a photographer too, i am using Nikon. Then there shouldn't be a problem. If you are in M, that means everything is set before you entered into video mode, it is ok and EV shouldn't be an issue.

energythoughts said:

I made a quick video about it... think it's still uploading though (ugh HD & DSL). It should be up on my channel soon: http://www.youtube.com/user/energythoughts

sorry it's a bit front focused.. next time I'll focus on the trees in the distance. it was shot in manual mode, so the exposure should be consistent between the lights.

Click to expand...

In this new vid, yeah it's more or less pretty clear that it throws farther esp if you check out the pole. 10k vs 20k cd, yeah i'd believe that's the case. But to throw twice the distance, you more or less need 10k vs 40k.

TK21- can't even see the grasses on the ground behind the pole (let alone the treeline), TK40 you can see it.

In the TK70 thread, there is quite some discussion on the distance that one should adopt to measure the lux of it. I realised that i get quite a noticeable higher number when i measured at 50m instead of like 8m. Seriously I guess it makes sense, with throwers it makes sense to film it at the distance where it is supposed to be used. But sometimes we make do with in-room beamshots of course, better than nothing!

This is why most of the time my first comment would be, "do it outside"...

PS. For manual focusing in Live Preview mode, actually you can zoom in on the LCD (when you are not recording yet - just preview) and focus, much easier.

Looking at the Lux numbers (this U2 version is actually 11,489 cd) and looking at the ratings of other lights I own.. it's interesting. I usually don't pay much attention to the intensity ratings when deciding on my next light purchase.. Yes it will tell me relatively how bright the hot spot might look, but to me that isn't always that important. There is so much more to a beam than just lux and lumens numbers. There is no measurement that can really describe a beam overall... I guess that is why so many of us on here enjoy beam shots, videos etc. I'm more interested in the width of the hotspot at a particular distance and overall size of the spill area... so back to the TK21 vs. TK40.. Yes the TK40 puts out 20k cd, but that level of intensity is focused in a smaller area vs. the TK21. I guess what I'd love to see in addition to the ANSI spec, is a 3D "cone" model of the beam, with size measurements at various distances. Exactly what you see on a foggy night. I love taking my lights out in the fog because it's the only way you can really appreciate the beam differences.

For me the best measurement for distance: can I identify the animal and what direction is it going at 200 or 300 feet away.. can I find the trail opening from a few hundred feet away, etc... for close up: where is my dog in the yard, what damage occured on the property during the storm etc..

I think my next video will be the E21 vs. PD31. very similar intensity.. 4918 cd vs. 4510 cd... but twice the Lumens 304 vs. 150.. very similar distance at 140m vs. 134m.. after this discussion and reading the TK70 thread I'm now a bit more in tune with lux.

this is perfect! exactly what I'm looking for.. wish all the manufacturers would adopt this type of graph: