Saturday, April 16, 2011

Time Lapse - Set up for Michael Gayden Shoot and balancing the subject/ background Exposure

It was my first chance after a long, cold winter to go outside and try shoot something with speedlights during the day to see how they stand up in bright, late afternoon daylight. It was tricky to use any modifiers since they eat up so much light.

The step that really helped the most to prepare for those conditions was to go to the location(s) first without any lights at all and see what my settings were going to be to get the background exposed the way I wanted during that time of day.

It also turned into the idea that I've started to implement, which is keeping a folder of possible locations for future shoots.

Aperture controls flash/Shutter Speed controls ambient light:
Straight out of the camera (SOOC)
Here's a location I decided not to use in the end. The first step was to take the picture on "Aperture Priority" mode to control... aperture so that my camera could give me its advice as to what the shutter speed would be to give me (at least its interpretation of) a "correct" exposure. The object is to get the shutter speed within the limits of my max sync speed for my lights, which is 1/250 sec (the standard).

SOOC underexposed by almost 1 stop
This brought me to f/16 at ISO 100, which gave me a shutter speed of 1/125 sec. That means that I still have wiggle room to drop the exposure of the background by 1 stop (1/250 sec.). Here's a second shot of the location at 1/200 to give you an idea.

Then I went home and pulled out the lights to see how they would perform at those settings. Turns out...speedlights (my Canon 580 EX, Nikon SB-26/SB-24) have a hard time keeping up with such a closed aperture at that ISO setting. They still worked bare within a range of 5-8 or 10 feet on full power individually, but my modifiers were nearly useless.

In the location below, there was a lot less light since it's between two buildings. There's some nice bounce light from the brighter building directly across from the scene here in this picture and settings were much more small flash-favourable at f/8, ISO 200 (a 3 stop difference!). But take a look at the second photo too see what happens as soon as that sun disappears behind a cloud. I was quite surprised at just how much light you lose! ...and at how much the white balance is thrown off.

SOOC-backround exposed "normally"
It's also a good illustration of how aperture controls the flash (look at the highlights from the rim lights almost at 45° to Cristy, our test subject) and how shutter speed controls the ambient light. Cristy has 3 lights on her here. The artificial light (the speedlights) is the same on the model in both shots, but the ambient light has changed quite dramatically as you can see.
SOOC-same camera setting-sun behind clouds

Since you're in full manual mode by this point anyway, it's not that difficult to ride your shutter speed to compensate.

All around a great day and huge learning experience now 6 months or so into learning about off-camera lighting! It's highly addictive and the theme of the warmer months is going to be to get out there and shoot as often as possible to try out some great things I learned from the Flash Bus Tour in Buffalo, New York last weekend! More on that another time....


Anonymous said...

I love the time lapse, and you 'floating' towards the camera. It was really interesting to see how much the light and therefore fstops, changed when the sun went behind a cloud! But also good to know, that shooting out during early afternoon, when the sun is still pretty strong, you can find nice shady spots like these to utilize.

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