Fenix LD20 vs. L2D

[selfbuilt]

Both lights are compared in 2xAA round-up thread:
https://www.candlepowerforums.com/threads/214890

Realistically, there's isn't a huge difference in the performance or beam - although the LD20 is a bit more focussed with a slightly narrow spillbeam width.

As for the reduced runtime on Turbo, that may have more to do with variability among samples (especially for emitter Vf, etc.). I notice on mine that there is little output/runtime difference on Hi mode, for ex.

P.S.: You can't take % differences of raw lux, since it is a non-linear scale (i.e. light decays by an inverse square law). So for example, a light that has 4000 lux at 1m would only have 1000 lux at 2m - not 2000 lux as you expect if it were linear. So, you can't use % changes, or you will incorrectly amplify the difference (in the example above, the light is NOT 4x brighter at half the distance, obviously). To get accurate results, you need to compare the square-roots of raw lux data for % difference calculations.

 

[noisebeam]

Actually I think it has one bad feature: when the light drops it drops instantly to darkness. If you don't carry extra batteries or another light you will be suddenly left in the darkness. But of course the most users of LD20 have some extra light, like a LOD or similar...

What does this mean?

I have used an L2D-q5 for about a year as a bike light, but neeed to replace it, so I go the LD20-q5.

When the L2D does not have enough battery left to run in Turbo (the only mode I use) it drops to a lower brightness mode. This is very important on the bike as it lets me continue with cycling group with some visibility until I get to place I can stop and change batteries. Usually about 1:30 into night ride, hopefully the LD20 will give me a bit more time.

Is my understanding correct that the LD20 does not do this? I can't test as I want to be able to return it.

My other initial impressions are:
LD20 has greener/yellower tint vs. pinker/blue tint of L2D
LD20 has an annoying dark ring around the hot spot
LD20 non turbo modes seems dimmer (might be the light color fooling the eyes)

 

[I Know Nothing]

When the L2D does not have enough battery left to run in Turbo (the only mode I use) it drops to a lower brightness mode. This is very important on the bike as it lets me continue with cycling group with some visibility until I get to place I can stop and change batteries. Usually about 1:30 into night ride, hopefully the LD20 will give me a bit more time.

Is my understanding correct that the LD20 does not do this?

Yeah, I read in a review somewhere the LD20 pretty much went straight out when the batteries got low. That was one of the reasons I got an L2D instead, along with the fact it was cheaper, didn't have a clip I didn't have a use for, didn't have knurling, didn't have the uneven bezel rim or clunky anti roll bar, I thought the beam pattern of the L2D might be more to my liking and that the low of 12 lumens compared to 9 might make a little difference in being able to use that for ultralong battery life. L2Ds are still available.

 

[noisebeam]

I've decided to return the LD20 to 4sevens and pick up a L2D from somewhere that still has them.

 

[noisebeam]

I returned the L20 and now have a new L2D. Interestingly the turbo beam is more like the LD20 than like my older L2D. The hot spot is brighter and narrower than my old L2D, it also yellower in tint and has more of a dark ring around the hot spot. Because the hot spot is brighter it makes the spill look relatively dimmer, even though it is probably about the same. I guess I should have just kept the LD20. I wanted to get another L2D because I liked my old L2D which gave more apparent spill - which works better as a bike headlight.