Sunday 6th March 2016: 1.45am.
What I'm reviewing today is the Favourlight PLA0W4D001 camping lantern (http://www.favourlight.com/products/lantern/details/pla0w4d001) which is the Chinese OEM for a vast array of relatively affordable but not half bad own branded camping lanterns available, mine here being rebranded by the German company LiteXpress as "Camp 71". This lantern takes 4 D-size batteries, has a variable brightness rheostat adjusting between 50 and a claimed 1000 lumen via PWM on 12x 0.5w Nichia LEDs, and provides three selectable colour tints of cool white (I estimate 7000K), warm white (I estimate 2500K), neutral white (i.e. both cool and warm LEDs on together, I estimate high 4000's K). Each of the cool and warm LEDs alone outputs half the wattage, only together do you get the maximum.
Runtimes are claimed to be 10h @ 1000 lumen to 240h @ 100 lumen 4750K tint, 16h @ 480 lumen to 270h @ 70 lumen 7000K tint, 16h @ 370 lumen to 300h @ 50 lumen 2500K tint. Therefore assuming 4x D-size batteries provide 100Wh which is optimistic given how rapidly alkaline batteries voltage droop, that makes a luminous efficiency at maximum illumination of 4750K 100 lumen/watt @ 10w, 7000K 76.8 lumen/watt @ 6.25w, 2500K 59.2 lumen/watt @ 6.25w; at minimum illumination of 4750K 240 lumen/watt @ 0.42w, 7000K 189 lumen/watt @ 0.37w, 2500K 135 lumen/watt @ 0.37w. All of which sounds plausible if a touch high, essentially running this lantern even a touch below maximum will confer large battery life savings because of the non-linearity of LED power consumption, and this lantern drives many LEDs at a lower voltage to maximise luminous efficiency especially in the natural white setting. Note the PWM appears to run even at maximum brightness judging from my camera photos, so anyone sensitive to PWM might want to avoid this product.
Needless to say given this feature set this lamp isn't hugely cheap, about €70 which might seem expensive until you see what the big brand LED camping lanterns cost which is at least three times more for a similar lighting power. The build is all plastic except for the metal grille at the top and the handle, and the battery screw in (which is great because by unscrewing the base a little you physically disconnect the batteries, therefore vastly improving their lifespan whilst inside a turned off lantern). The 24 LEDs are surface mounted inside an area no more than 3cm square, and hence the glare off this lantern is retina searing though its top mounted angular plastic deflector is quite good at scattering a directed light around as you'll see in the photos below. As you'll note in some of the photos, I fitted a sheet of parchment paper inside the plastic top housing which is detachable which makes an enormous difference to the glare by dispersing the light fairly evenly across the entire top housing (thanks to candlepowerforums.com for the tip!), nevertheless at 1000 lumen even a maximally dispersed light source remains quite glare-y leaving worrying after images on the retina, at slightly lower brightness it's much nicer and it illuminates a room well with far less glare.
Caveated by the fact I haven't run a set of batteries dry yet and therefore cannot say anything about the quality of its DC-DC converter which ought to maintain brightness despite the rapid voltage droop typical of alkaline batteries, I am pleased with this purchase even though it's far more expensive than my USB LED tube + battery pack. It's far brighter than my USB LED tube and more than easily illuminates a room - unlike the USB LED tube which claimed 1000 lumen but really produced no more than 500-600 lumen at best, I reckon this lantern to produce at least 900 lumen. At the lowest brightness setting, it could run continuously for ten days which isn't bad, and the variable brightness means you get to balance brightness against battery life.
It is quite pricey though given the likely frequency of usage, and put another way for €25 you can get 500 lumens of emergency light assuming you have a USB power source already. At €70 even for twice the brightness you are not winning. However, you do get a much more portable setup, so if say I were putting Clara to bed during a power outage I would hardly drag the LED tube + battery pack with me, not least because she wants to swish it around like a lightsaber any chance she can get with no regard at all to the light itself or anything around her. The camping lantern is therefore much more useful when you need to move, and for that I think it solves a closely related need case to the one the LED tube solved. I believe I am pleased with my purchases.