A field report on my copy of the TN40.
Received my TN40, charged it (fast), and well after sunset walked out into a very muggy buggy night to check it out. I brought along my LD75C with roughly the same lumen output on turbo for a cross-check of beam types. Test objects at many distances were trees, docked boats, a dam, a smallish warehouse area, paths in woods, and wooded back roads.
The bugs drove me back to my apt, but, my initial impression was "WoW!". In particular, the lumen step from high to turbo really demonstrated what was possible for lighting up distant objects and adjacent area well beyond ~100 meters.
The turbo level provided enough spill at a distance to not feel that I was looking down a lighted hole in the dark. And therein lies the catch: The TN40 is optimized for mostly throw, and that objective was achieved nicely. However, thereby the beam is less useful at shorter distances and especially at lower output levels, exactly because there is relatively little spill at short distances w/o increasing the lumens. If I increase the power to provide spill, the spot is too bright. By comparison, for my walks in/out of vantage points, I quickly reverted back to the LD75C with it's relatively broad spot and good spill yet still some distance, but no where near the distance reach of the TN40.
Tonight I will drive to a more open area of mixed grassland/woods to see how the TN40 performs at still longer distances. I need mixed trees & grassland such that the grassland shows the spill out to the distant object better. Water on a lake does not reflect very well.
Frankly, the TN40 reaches out farther than I can usefully discern what may be moving out there. I could see eyeshine, but had no idea what the animal was, except maybe a guess from the height of the eyeshine above the ground.
I also estimated the TN40 size correctly - the TN40 does fit in my various coat pockets, no matter if an uninsulated mountain parka, or a down parka. The overall length is more than short enough, even if the lens is broad. I could not do that with my TN35. The stubbiness of the TN40 is useful!
On a broader note: the TN40 with the battery pack was actually lower in cost than an LD75C since quality 4x18650 cells at ~$18/each raised the effective cost of the LD75C above that of the TN40.
For me, the TN40 is useful, but in more specialized circumstances where the beam needs to reach out, find, and 'touch' something. The TN40 is not an all-arounder like the Fenix LD75C or the Eagletac MX25L4C, nor was it intended to be.