What's the most powerful speedlight available?

I get so confused with footcandles, and watt seconds and guide numbers, and testing at 1 foot away vs 3 feet, etc. It seems like every speedlight measures power in a different way so there's no direct comparison between them. What's the most powerful speedlight out there? Is there a chart, or someone that tests lights based upon ONE common measurement? What's the best way to compare speedlights?

Flash power is determined by GUIDE NUMBER. The higher the number, the more powerful the flash. I believe the Canon 600 series are about the most powerful you can get. They are accordingly expensive. I use a bunch of Canon 550EX units. 92% of the power for about $50 each.

I am sorry to crash your posting. Guide number is depending on different factors and the flash power is one of them.

Guide number is heavily depending on how good the reflector is shaping the flash beam to throw it a long distance.

Speedlights run on 4 batteries or one battery pack to run and have to repeat the flash fast and often. So the power output can't be enormous because you will melt the flash.

An bare bulb system can be stronger because it can dispensate the heat better so more power can be put in.

The AD360 (300 Watt) is the strongest I know. A normal speedlight is max 70-80Watt.

Canon 600 flash is not at all 'more powerful' than the Canon 580 flash.

Unfortunately the manufacturers play games with flash model number and flash power, based upon the highest guide number which is AT THE LONGEST FL COVERAGE. The Canon 580 = Canon 600 in guide number when both are set to cover the 105mm FL lens...GN58(m). The Canon 600 zooms to cover 200mm, so it has an even higher guide number only at 200mm...GN60(m).

The Metz 76 has a higher guide number at 105mm, at GN76(m).

When comparing flash power, compare at an in common angle of coverage.

mmmfotographie points out an important characteristic...zoom head flash units which are 'enclosed' have to be very careful about heat dissipation. Flash units like the Quantum T5DR or AD360 can better dissipate heat into the open air, so are less constrained in power output than zoom flashheads.

I mix strobes and camera flash in the studio so lumen output, light pattern, recycle time and overheating are regular concerns. The common flashhead fresnel allows GN inflation and reduces effective use of modifiers like SB and lanterns. To compare output of flashs or dished strobes, I bounce off a matte white wall and measure the light level off the facing wall. This test determines, for example, that the SB-800 is fractionally brighter than the SB-5000 even though the latter has a higher GN due to the 200mm zoom setting.

It is interesting to see the comments from folks with way more flash experience than I have. I use multiple flash units, and various modifiers when working in the studio (kitchen), but all of my gear is Canon EX (II) units: 550EX x3 and 580EX II x2. All I have to compare is GN 58m vs. GN55m at 105mm zoom coverage. I guess my point of view is clearly 'inside the box', relevant but hardly all-inclusive.

With high power, come the high heat.. Choices will vary since not everyone wold be shooting at full power

I am going to throw out the Nissin MG8000 with a studio style tube and has power plugs to fast recycle


LINK~~http://www.nissindigit​al.com/mg8000.html

PhotogNY wrote in post #18562866
I get so confused with footcandles, and watt seconds and guide numbers, and testing at 1 foot away vs 3 feet, etc. It seems like every speedlight measures power in a different way so there's no direct comparison between them. What's the most powerful speedlight out there? Is there a chart, or someone that tests lights based upon ONE common measurement? What's the best way to compare speedlights?

Are you interested primarily in on camera flash?

If PhotgNY has not already noticed, the Guide Number in meters is most often buried with the model number of the flash, and if you verify that the GN is indeed for 105mm FL (and not for 200mm FL) you can directly compare the numbers. Note that for fixed head coverage flash units, they may well output more light at the same coverage angle than all zoom heads!

• Metz 76 = GN76 at 105mm (GN45 at 35mm)
  
• Metz 60 = GN60 at 33mm (not a zoom head, covers about 33mm FL)
  
• Canon 600EX = GN60 (but at 200mm FL) (GN36 at 35mm)
  
• Canon 580EX = GN58 at 105mm (GN36 at 35mm)
  
• MG8000 = GN80 at 105mm (GN40 at 35mm)
  

Left Handed Brisket wrote in post #18563754
Are you interested primarily in on camera flash?

Not on camera per se, just something small enough to be handheld and walk around with, without having a big battery pack to lug.

Sounds like the Godox AD200 is right up your alley.

Nismode wrote in post #18569887
Sounds like the Godox AD200 is right up your alley.

Yup.

This is why I always ask questions. if the flash is not needed to be on camera, the 200 is WAY more powerful than any speedlight that I am aware of.