Mine with a  14500 destroyed (still waiting the DX replacement, I dont know why has not arrived yet, hope DX does not fuck me)

Also, viewing your photos, on mine, the driver is different, the down part is different.

Also the difference in lumens between HI and MED on mine wasnt distinguisable....... On MED mine draw 1.0A about  90-100 lumens.

Also mine doesnt had the plastic protector on the clip...........

Yes, mine was from DX, apparently the same, but mine was without the plastic protector in the clip, and the driver board looks different.....

Probably different batches (or suppliers/manufacturers)

Thanks Matt for the nice review.

The LT version looks considerably nicer than the DX version. Does the mode memory work without too much delay? How's the runtime on low?

Thanks!

Hmm, I saw those current draw numbers, by which I would calculate about 10 hours of runtime on a 2000mah Eneloop. Not too good. They seem to have upped the low mode quite a bit. My Trustfire from DX seems to be about 7 lumens on low, and the runtime is near 24 hours with a good battery.

old4570 wrote:

 

On AA

High = 130L - 1.8A

 Medium = 55L -  0.78A

Low = 19L - 0.19A 

 

On 14500

 

 

High = 0.97A - starts 230Lumen , sags to 210L after 30 seconds 

Medium = 0.42A - 105Lumen

Low = 0.1A - 24Lumen 

 

Mode memory is fast ....  Very fast ... 

 

 

OK taking into account this:

- The current draws (very different than mine from DX)

- The plastic protector in the clip (dx ones not have)

- The very accurate memory mode (dx ones needs several minutes to act)

- The photo of the driver (different than mine from DX)

- Hasnt failed with 14500

I can say 2 possibilities:

1) Different supplier/manufacturer than the DX ones

2) Same manufacturer as the DX ones but driver changed.

My F20 replacement should have arrived last monday but it doesnt. Tuesday was holidays in Spain, today wednesday not arrived also....

When my replacement arrive I will check if the driver is like in yours........... (if it really arrives, hope DX does not screw me this time)

Wow, didn't found F20 @ LT  Only K-106 for $13,59. Will have to search better next time 

Man, for less than 12 it's a good torch. And like fran, I really like the driver, hate those awful soldering. Clean driver, like on mine Kingpower. Only one question: what about regulation? On 14500 on high it drops from 230 to 210 in 30 seconds. Could you make the same test but waiting a little bit longer? Thanks 

Ahms, didn't know that. Thanks for the info  And the led? Really Q5? Have you checked it?

P.D.: hey, fran, are you from Spain?

I think he is and is coming from HERE. Hmm, sometimes I wish I had taken Spanish lessons instead of computer science back in school.

Vectrex wrote:

I think he is and is coming from HERE. Hmm, sometimes I wish I had taken Spanish lessons instead of computer science back in school.

Haha, it's true. And Xrayboy too 

Vectrex, better late than never (if you have free time) 

Hi SashiX, yes I am from Spain

It's the Spanish Armada ... we are surrounded.

@old4570

I have been watching your photos of the F20. The body of yours looks like to be more silver than gold.... I explain, the color of mine is brownish-gold

The akoray k-103, and the uniquefire AA-A1 are silver.

Yours?

OK, so not silver, more bronze, brown, gold....... OK like mine

Still my replacement not arrived XP

Hi again, old. One question: do you test the flashlights the same way Don does? I mean, can I use your lumen info and compare it to other Dons lights that he reviewed?

You can calibrate with any specific light and just make sure the boxes reasonably resemble an integrating sphere  with a laser.

For example, you check your box with a cheapo pointer at different angles, ship him the laser, and do the same there.

--

I've also been thinking of another way to do lumen measures with only a camera. It should be possible to integrate the image projected on a wall/flat plane (subtract a the dark shot and do geometry/addition on the rest) provided the sensor is not in saturation. As long as the angle to any point is known, easiest if the camera is right by the light, it should be possible to calculate a relative unit. Then cal that unit against a known light.

With manual exposure and RAW files, it's relatively simple in theory.

Another followup idea would be to do a simplified version of this. Assume that either led light hits the reflector or goes out the front, either of which is reasonably uniform. Then you need at a minimum these measurements:

1. Hotspot size in degrees

2. Hospot intensity in lux and degrees measured from center

3. Flood size in dregrees

4. Flood intensity in lux and degrees measured from center

Still need calibration from the unitless numbers from this.

Not really sure if that's going to be accurate, but can't be too far off.

Only need 3-4 above for zoom light in flood mode.

For example, you check your box with a cheapo pointer at different angles, ship him the laser, and do the same there.

This isn't too hard. I believe it's close to the simplest possible to get consistent results.

--

The other idea is just a way to get lumens without a lightbox, or even a lightmeter.

Hi guys, I received now the replacement of my TF F20. It was destroyed on 13 september after using a 14500. DX shipped the replacement on 23 SEPTEMBER!!!! and arrived today.

All I have to say: DX version SUCKS. Purchase the LT One. And the LT one is even CHEAPER....

Why purchase the LT one instead of the DX one?

The replacement I received has the SAME driver board that the one that broke with 14500, so I will not put a 14500 on it. The driver board that I am talking about is the one which has a "red path joining 2 parts of the circuitry" clearly visible in the part where the battery makes contact.

The LT one works perfectly with 14500, the driver looks very different and includes the plastic protector in the clip. Meaning that DX and LT have different suppliers for the same product..........................

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 All your images are dead, Matt  Not only in this review, but in other too.