Strobes tests: Alien Bees against Elinchrom. Lumopro against Canon 580x II.

Today I happen to have handy a bunch of different flashes I always wanted to compare. Yes. Which one is more powerful, and by how much? The best way to show this is to use a light meter, put it at ten feet from the flash set at full power and measure what people call the "Guide Number". Basically the required aperture to illuminate a subject as medium gray. This is a useful number for undiffused strobes as for them it turns that:

Guide Number = aperture x distance = constant.

So if we measured f4 at 10 feet, the guide number GN is 40, which means that at 5 feet we will achieve the same exposure at f8 (closer, brighter, and so we can use a narrower aperture).
The higher the GN, the more powerful the flash. This of course at the same ISO.

So here are the numbers, I used ISO100 in all cases. Packs and flashes were all at full power.

Elinchrom Ranger S head with standard reflector + "A" Ranger RX pack. GN 250 $2100
Elinchrom Ranger Ring Flash + "A" Ranger RX GN 220 $1500+$1700
Alien Bees B800 +standard reflector GN 130 $280
Alien Bees B400 + standard reflector GN 90 $225
Canon 580ex II (zoom 80/28mm) GN 130/90 $440
QFlash+standard cone GN 110 $1080
Lumopro GN zoom 85/28mm GN 90/71 $120
Canon 580x II + Coco Ring Flash GN 35 $440+$80

Btw, I have found another test here on Flickr. Results are similar.

So what have I learned?


1) more expensive flashes have more power and the area where they are able to light uniformly is *much* larger (and rounder!) than with the cheaper speedlites (see the image). But greater power comes with a price (and greater responsibilities, but that is another story).
2) The Canon 580x II is good! More powerful than the LumoPro and the QFlash, but *only* if you use the zoom feature. Read the manual..or pay $300 extra bucks compared to the LumoPro, which is a lot easier to use (see and extended review)...mmm.
3) The Canon+ the Coco Ring flash performs well, but the output is not that great, unless you are in studio. The zoom factor makes no difference with the Coco attached.
4) The QFlash is weak sauce for the price $1080 (head+pack)
4) The Speedlites are a tad cooler than the Elinchroms.
5) The Ranger pack has two outputs: A and B. A is 1+2/3 stops brighter.
6) the ABees Long throw reflector increases output by 1 stop! (from the Flickr Strobist group test)