Overpower sun using speedlites?

[psyphy]

I'm slowly gaining experience with my trio of 580EX II's. But I'm curious of the techniques other speedlite strobists use to overpower the sun in let's say mid-late afternoon... Like which combo of camera/flash settings, light positioning, modifiers, etc.

 

[unpopular]

I don't know how to set this up in auto modes, and I can't give you specific answers, but keep this in mind when working with a flash: the available light is affected by aperture and exposure time, while the flash is affected only by aperture due to it's very brief duration.

So, without flash, if the proper exposure is F:8 1/80, and you adjust your flash setting such that it provides good exposure at F:8, if you decrease exposure time without adjusting the aperture, the regions affected by available light will become darker, while the regions affected by the flash will be remain perfectly exposed. The problem with this is that the flash is adding light to the available light, so such a case won't actually exist in nature.

My advice to you as an exercise is to get your flash out, set it to manual. Obtain the proper exposure for the scene by adjusting aperture at some predetermined exposure time, and then start cutting exposure time so that you can see the effect you have. You'll notice that which is affected by the flash changes little, while that which is unaffected by the flash changes significantly - and the more powerful the flash, the more less significant the affected area will be.

More powerful the flash, the more control as the proportion of light that the flash produces is greater relative to the available light. So, you can also get the effect by adjusting flash intensity and compensating on the camera. You could increase power by one stop, and decrease the aperture by one stop. Because the available light is affected by aperture as well, it will get darker - just as if you had decreased exposure time.

Obviously, you'll need a flash that is capable of producing more light than that which is available, otherwise you cannot get the effect you're looking for. I'm not familiar speed lights, so I'll let someone else go into the equipment specifics.

 

[KmH]

Unless you gang speedlights, say 3 or more at each lighting position, they don't have enough power to overpower direct sunlight.

Monolights are much better suited for doing that.

 

[unpopular]

^^ just curious, for my own sake - approx how much wattage (or GN) do you think someone would need? I'm guessing like 800 w/s @ 5-8'?

 

[Derrel]

How much GN is needed is pretty straightforward...what f/stop do you want? How far away is the subject?

400 watt-seconds with a 102 or 103 light unit and 11.5 inch grid reflector will output f/13-ish or so at 13 feet at ISO 100 over a broad, 60-65 degree swath of coverage from what they call "the standard 11.5 inch grid reflector".

 

[camz]

Given the amount of subjects, I've stopped down ambient quite a bit with just one 580 EX II. Your question is a little vague as there is sun given the ambient ground exposure, there is also the sun given the ambient sky exposure. distance, coverage. It really depends, however I think it is possible and even more possible in later afternoon or early to mid morning. You can literally shoot against the sun with the sun in the frame.

Here are some samples with just one 580 EX flash and a softbox with the sun in the frame.

 

[camz]

Yep Derrel pretty much explained it, I think I was looking for the sample shots as he posted. It really depends. There's The winter sun and the summer sun and the results you're looking for to consider before we even start talking settings and modifiers.

 

[kundalini]

It's not always about overpowering the sun, but balancing the flash with the strong ambient light. Here's a run-through I did when I was trying to help someone (and myself) understand flash with outdoor shooting. Maybe it will help you.

http://www.thephotoforum.com/forum/...armonizing-ambient-light-ocf.html#post2214725



It may seem like I spend a lot of my Sundays drinking tequila, but hey, if I'm not going anywhere...... :biggring:






EDIT:
Here's one along the same lines, but with a flash mounted on the hotshoe.

http://www.thephotoforum.com/forum/...you-take-pictures-black-cats.html#post1891866

 

[unpopular]

Considering Derrel's estimates, then a Sunpak 622 Super Pro would easily - and affordably - provide enough light to do this in about any situation, right?

http://www.bhphotovideo.com/c/product/800797553-USE/Sunpak_622_Super_Flash_with.html

 

[psyphy]

While the responses here have provided insight that greatly deepened my understanding of guide numbers and watt-sec output, in regards to how flash is balanced with ambient lighting, I found this article which seemed to more directly answer my question.

http://neilvn.com/tangents/2010/02/09/balancing-flash-and-ambient-exposure/

 

[KmH]

Balancing sunlight with flash is not overpowering sunlight with flash.

Neil van Niekerk has a couple of good books too.

 

[sactown024]

bringing back a 4 year old thread because of a google search here....

The bigger question here is not how many speedlites you need, its how much power you want to use on each one. Yeah a 580ex ii can overpower the sun at full power from 3-6ft away, but do you really wanna fry your flash, have slow recycles, and kill your batteries?

Multiple flash setup, say 3 gives you 1.5 stops of light, this allows you to overpower the sun at a 1/4 power rather that full power, allowing fast recycles times and saving battery power.