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How much power required to over-power the sun

I'm typically a natural light portrait shooter just because it's much lighter not to carry around extra equipment. Here's my question...

How much power is required to "over-power the sun" in order to shoot large aperture primes (f/1.4)? I'm considering both the Godox AD360 and the AD600BM which have 360 and 600 watts respectively. Two options, either HSS or max sync of 180/s with ND filters.

My question is, with either 360watts or 600watts and a desire to over-power a bright background on a sunny day shooting large aperture... how many stops can I hope to over-power the background? Is 1, 2 or even 3 stops possible?



  • TrevTrev Moderator
    edited March 2017
    Hi sbcampbe,

    I shoot the AD600BM personally, and have shot @ f1.8 but in HSS and it works good.

    With the 600W I can be around 3m (10ft) away with the light shooting near full power and shutter up around 8000th, but I do 'pick' my location and placement of the subject carefully so as to get a more natural feel.

    I've never used ND filters under those circumstances, only for a normal landscape where I want smooth & soft shots like flowing water in a creek or a waterfall to allow the drop down of my shutter to around 1/8-1/4 sec.

    I love the AD600BM's and often shoot a lot of my outdoor wedding ceremonies in HSS in full sun around the f2.8-f4/4000th-8000th range, especially when I need the background to really blur out with distracting things.

    Having the ability to go to full power on light around 6000th+ in HSS works a treat.



  • Trev - does this unit have TTL capability? If not, do you find that you miss it?

  • rs_eosrs_eos Member
    edited March 2017
    Assuming you're in f/16 light (sunny 16 rule), your light would need to put out f/22, f/32 or f/45 (1 to 3 stops over).  But that power will be dependent upon the light's distance, whether or not you are using it with a modifier and if HSS is being used.

    Generally, to maximize the output, bring the light as close as possible for the look you want, limit/omit any type of diffusion and try to avoid HSS.  Using ND is a good option to avoid HSS (e.g. with speedlights, you get anywhere from 1 to 2+ stops power loss simply going to HSS).

    Another solution I've seen (by Joel Grimes) is to set up a 1 or greater stop black mesh to cover the background.  This assumes you have a mesh large enough and that your desired aperture will blur that mesh.  This setup allows you to then only need f/16 light from your light to get 1 stop over the ambient.

    For those using speedlights in these situations, the only other possiblity beyond the above tips is to gang them up.  But this can get very costly.  Four flashes will provide 2 stops, but then you'd need eight to get you to a 3rd stop.

    Finally, in terms of running your light on full power... one other variable to keep in mind is how much stopping power you need.  In many cases, running lights at lower power will reduce the overall flash duration which gives you more stopping action.
  • TrevTrev Moderator
    edited March 2017
    Dave, you can buy the unit with TTL and also manual, (TTL version around $200 more) but I don't use TTL except on the camera's own flash on camera, The AD600BM's I have are not the TTL versions, and no, I don't miss that since any off camera flash I have used has always been manual, starting with normal speedlites off camera, then going to Quantums, then the Cheetah (still by Godox) 180W, then 360W now the 600W big boys, so much power. :)

    After a while you get used to settings, especially in sunlight which is very easy (manual on the camera I mean) and also I know with the flash after some use what power I need to be at a certain distance (if I work with my normal distance of 3 meters - 10ft) so also that's easy to get to in 1 to 2 test shots.

    rs_eos, yep, you are absolutely right of course in what you say, but I think the poster was meaning over-powering the sun in terms of using a wide aperture like he quoted f1.4 where he would most definitely need HSS, or, an ND filter to open up the Aperture, but still lots of flash power to get subject lit up. At least that's what I took it to be, hope that's right as my reply was along those lines.

  • Trev - Thanks. The reason I asked about TTL is because of the price difference. One of these days I'm going to move on from speedlites to something like what you have, and wondered if the extra expense is worth it.

  • TrevTrev Moderator
    You will wonder why the hell you did not do it sooner mate, I can guarantee you that for sure, especially with the radio control you get with it, all from camera position and not having to walk up to flash head to change.

    Bit of more mucking around with stands, the 360W are fairly light and easy to carry, but, they come with a drawback, you have a cord and battery dangling from the head; whereas with the 600W ones battery is built in (removable and rechargeable of course) and it's capable of 500+ FULL power pops to boot which you would never use.

    By the way, the BM at the end denotes 'Bowen's Mount' which I have softboxes, etc., using BM so on that front a win win also.

    You can buy other mounts to suit of course, just to let you know.
  • Trev - The reason I don't take the plunge is I do very little with off-camera flash at the events I shoot. If I do anything, it's a "step-and-repeat" type where the attendees pose for a photo or two with the featured guest. One time a real-estate agent hired me for a customer-appreciation party, and I had a setup where families could come and have their photo taken. But really not much more, as I am neither a "portrait" of wedding photographer. So, a couple of speedlites and reflective umbrellas have done the trick ... so far.

  • Neil vNNeil vN Administrator

    Others have answered your question thoroughly, but I would like to summarize and then add a few things:

    rs_eos has it right: 
    "Assuming you're in f/16 light (sunny 16 rule), your light would need to put out f/22, f/32 or f/45 (1 to 3 stops over).  But that power will be dependent upon the light's distance, whether or not you are using it with a modifier and if HSS is being used."

    When people say "overpower the sun", they usually mean "matching the sun" in order to bring up the shadow areas to the same level as the sun-lit areas. 

    If you want to progressively give more light form your flash than the sun, you will have to push out f/16 or better.  That's a lot of juice. Keep in mind that as you go into HSS territory,  you lose about 2 stops of light from your flash.  One stop of this is compensated for by the higher shutter speed.  So the net loss in light is usually around 1 stop.  This might make a difference ... or not. 

    That's where the higher-powered flashes come into their own.  And for this alone, I would recommend a 600 W/s flash over a 360 W/s flash (if it is portable.) When you add that softbox or some kind of diffusion, you're especially going to need more power. 

    Then everything else in your equation depends on your flash-to-subject distance. 

    With that it isn't easy to give a specific answer with numerical values. However, the higher-powered flash is the better option. 

    Some more info here: 
  • Been following this. Even though I'm not a Portrait Photographer in any sense, in another financial life I would like to get a studio-type strobe. The power recommendation you give I will keep in my head.
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