Flash Photography outdoors

CianOReilly · Dec 24, 2013

Hi guys. I've been shooting flash photography for a few months now but it has all been indoors. I set my camera to manual and use ETTL for the flash, and then I usually bounce it off a ceiling.

However this New Years Eve I'll be shooting a parade outdoors in the dark, and I'm just wondering what the best way to do this would be?
I'll obviously have to shoot with the flash pointed directly at the subject, but should I use ETTL? or go full Manual on the flash etc..

Robin Usagani · Dec 24, 2013

Keep it on ETTL because each float will have different brightness but keep adjusting the flash compensation. I would use manual with very high ISO (3200 or higher).

tirediron · Dec 24, 2013

What Robin said. ^^

TCampbell · Dec 24, 2013

Whoops... I just replied but missed that you are shooting at night so let me revise.

Which flash (and or what's the guide number) do you have?

The baseline for the guide number is ISO 100 and f/1.0 When you increase the ISO to 3200 you are increasing the ISO by 5 stops. But if you shoot at f/5.6 then you're cutting the light by 5 stops (down from f/1.0) -- which means the flash's effective distance actually is whatever the guide number is.

In other words if you have a Canon Speedlite 580EX II then your flash's effective distance actually is 58 meters. The flash would be able to handle that and the light fall-off at long distances will be pretty gradual. Close subjects will have a dramatic light fall-off problem and for those situations, "dragging the shutter" (using a longer shutter speed then you'd normally use to allow more ambient light to fill the shot) ... but that will require a steady camera (and preferably non-moving subjects -- although the light will "freeze" a subject even with a slow shutter... I'm going to guess these floats have holiday lights on them and those will blur anything moves.

For daytime shots I normally dial down the flash exposure compensation so that what you get is a shot that looks like it was taken with available light... and the flash just adds in a bit of fill to brighten up shadows that would otherwise be too dark. For this I suspect you'll still want the flash exposure compensation slightly reduced...

Derrel · Dec 24, 2013

TCampbell said:
Use E-TTL. Start by setting the flash exposure compensation to -1. You may ultimately decide that you want -2/3rds or maybe -1-1/3rd. Salt to taste.

The camera is going to want the flash to provide enough power for a proper exposure... but outdoor daytime is already providing enough power for a proper exposure. You don't want the flash to match the light... you want it to be just a bit weaker. By setting flash compensation to "-1" that tells the flash to identify the amount of power needed for a proper exposure... but then only fire using HALF that power. That creates a flash contribution ratio where the flash provides 1/3rd of the light and the sun (or ambient source) provides 2/3rds of the light. This creates a look in which the shot appears to be lit by available light... but the shadows have been filled in by your flash (not completely... you still get shadows but they aren't as severe.)

And this is where the "salt to taste" comes in... you might prefer slightly more flash power or slightly less, but if you start at -1 you'll be at a good starting point.

The OP mentioned the parade will be held at night..."outdoors in the dark"...

If the OP has a d-slr, and I imagine he does, then elevating the ISO setting might be advisable, since a single speedlight outdoors, at night, doesn't really have an overwhelming amount of power. With most speedlights, using Manual flash power setting, the FULL power output setting recycles fairly slowly when a speedlight is being powered by four, 1.5-volt penlight batteries. After more than two dozen shots, the batteries might be providing very slow recycle, so using an AUTO-flash setting of some type will more than likely cut the recycle time quite a bit.

How about some details as to flash and camera and lens that you plan on using? WHat are you after? FULL-float shots from say 30,40 feet distant? CLoser-in shots of smaller parts of the floats, or participants riding on the floats?

With a shorter lens lengths, like something between 16mm and 30mm, you might be able to use a fairly wide f/stop, like say f/4, and ISO 800 to 1,000 and get "decent" recycling speed, and also decent exposures.

TCampbell · Dec 24, 2013

Derrel said:
TCampbell said:

Use E-TTL. Start by setting the flash exposure compensation to -1. You may ultimately decide that you want -2/3rds or maybe -1-1/3rd. Salt to taste.

The camera is going to want the flash to provide enough power for a proper exposure... but outdoor daytime is already providing enough power for a proper exposure. You don't want the flash to match the light... you want it to be just a bit weaker. By setting flash compensation to "-1" that tells the flash to identify the amount of power needed for a proper exposure... but then only fire using HALF that power. That creates a flash contribution ratio where the flash provides 1/3rd of the light and the sun (or ambient source) provides 2/3rds of the light. This creates a look in which the shot appears to be lit by available light... but the shadows have been filled in by your flash (not completely... you still get shadows but they aren't as severe.)

And this is where the "salt to taste" comes in... you might prefer slightly more flash power or slightly less, but if you start at -1 you'll be at a good starting point.

Click to expand...

The OP mentioned the parade will be held at night..."outdoors in the dark"...

Yeah I caught that *after* I hit the submit button... then re-edited my post (how embarrassing). I missed the "in the dark" bit.

In any case, the OP will want to know what the guide number is for their particular flash.

For Canon brand speedlites, just delete the "0" from the numbers in the model number and whatever numbers remain are your guide number in METERS. E.g. if you have a 580EX II, then it's 58 meters. If you have a 430EX II then it's 43 meters, etc. BTW... don't try to apply this rule non-Canon speedlites because it's just something Canon did and not an industry standard naming convention. It does make it convenient though.

The guide number is the distance that the flash can provide adequate lighting for an exposure with the assumption of ISO 100 *and* an aperture of f/1.0. Multiply the guide number by 1.4 for each stop of increased exposure and divide by 1.4 for each stop down. But as I mentioned above... if you have a zoom lens where the best f-stop you can use when zoomed in is f/5.6 then that's 5 stops down from f/1.0... but increasing the ISO up to 3200 would be 5 stops up -- so they would just cancel each other out.

If you have a faster lens (e.g. f/4... or an f/2.8 zoom perhaps) then so much the better.

CianOReilly · Dec 25, 2013

Thank you all for your replies and a Merry Christmas to you all.

I'm shooting using a 600D, with a Canon 17-55mm f/2.8 mainly and a Canon 50mm f/1.8 which I'll probably just use for candid headshots.
The flashgun I'm using is a Canon Speedlite 430EXII, so I have a guide number of 43.

I'm very weary about bumping my ISO up to 3200 due to the amount of noise I might get with the 600D.

Most the shots I take will be of individual street performers, and getting close to them won't be a problem as I have an all access press pass for all the events happening that night.

John_Olexa · Dec 25, 2013

I'm not the best with flash, but get yourself a base exposure, check early shots and make adjustments from there as needed?

Robin Usagani · Dec 25, 2013

Correctly exposed photo with high ISO is always better than underexposed low ISO. On the top of that, your flash will work too hard with lower ISO.

Derrel · Dec 25, 2013

TCampbell said:
Yeah I caught that *after* I hit the submit button... then re-edited my post (how embarrassing). I missed the "in the dark" bit.

No big deal Tim. I think we've all done that, fired a post out in the dark that we regretted in the daylight. lol. Your posts are always information-filled and enjoyable no matter what time of day they're about.

I had no idea that Canon had linked the flash model numbers to the GN in meters! "Who knew"? YOU KNEW!

CianOReilly · Dec 25, 2013

I guess you're right. If needed, I'll bump up to 3200 and hope that I won't get too much noise

tirediron · Dec 25, 2013

CianOReilly said:
I guess you're right. If needed, I'll bump up to 3200 and hope that I won't get too much noise

Don't forget that there's lots of software out there that can help reduce the impact of high-ISO noise on your images.

Derrel · Dec 25, 2013

Well, keep in mind, as the flash's beam spread is widened, the Guide Number effectively drops somewhat; I looked at some on-line information about the 430 EX-II and its beam spread figures, here
Canon 430EX II Speedlite Flash Review | Speedlights.net

and I see that at wide lens settings, the GN is somewhat lowered--this is yet another reason to favor a somewhat higher than normal ISO setting. Maybe go to ISO 1250, instead of 3200 if you're worried about the 600D's ISO performance. I just mention this because with the 17-55mm zoom, you'll effectively lower the flash power down at the 17mm end of the range, while at the longer end of the range, the flash's effective power will go "up". Not by a whole lot, but by a noticeable margin I think. What REALLY lowers the GN is the use of the "wide" panel, which is true of all flashes.

Good luck, and have fun. One suggestion...maybe before New Year's take the camera out and review some of the basics. For example...I wonder about how well the camera will focus at night. In autofocus SINGLE-shot mode, the camera's AF assist light system will be active...in AI-Servo mode, the AF assist lamp system is unable to be used...you'd want to know how well that works, before hand. Just sort of advocating maybe a trial run out on some city streets at night, to get things sorted before the event.