Monday, June 30, 2008

On Assignment: Night Chopper, Pt. 1

In this two-part On Assignment, we'll be walking through a night shoot of a Bell 407 helicopter, photographed for the Howard County Police Department earlier this month.

Just like the CFL On Assignments, we'll break this one up into two parts: Planning and problem solving first, then the shoot itself. Keep reading to learn more about the prep, to be followed next week by a walk-through of the night shoot.
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Visualizing the Photos

Normally, when I shot aerials for The Sun, we would fly in a dinky little Toys R Us Robinson R-22 helicopter with the door removed. You say a little prayer, try not to put your full weight down and knock off your shot list with an 80-200mm. If you keep your camera on a shutter speed higher than a 1/500th of a sec everything is usually hunky dory.

What I wanted for this shot was ground-to-air shooting, at dusk, with the chopper's interior lit by a group of SB-800s. I explained the idea to pilot (and, fortunately, former Sun shooter) Perry Thorsvik, and he was up for it.

If it worked, it would be pretty cool, and would hopefully produce some neat photos. But there were several problems that would have to be solved first.


First Problem: Flash Sync

Apologies in advance for the Pocket Wizard geek-out session here, but I was going for as much range as possible.

I knew I would be using PWs, but it would be a stretch even for them. To complicate matters, mine were the old "Plus" models which were only rated to 800 feet.

The new Plus II's are rated to 1600 feet. But even if I dug into the wallet for a set, that 1600 feet does not account for things like the metal fuselage of the helicopter and RF interference from the avionics. So the first order of business would be figuring out a way to improve the reliability and range of what were already the best remotes going.

So I sprung for two new Plus II's. Not cheap, but fortunately they are compatible with with my Plusses -- and every previous model PW has produced. So I could be assured of at least one 1600-foot capable signal between the camera and one of the flashes in the helicopter.

I decided to try to improve my odds by putting one of my older Wizards on every flash in the aircraft, and to set the SB-800's into slave mode.

A quick test showed the flashes would sync in both modes simultaneously -- way cool. This meant that if even a single PW'd flash picked up a radio signal to fire, all of my flashes would go off. This worked brilliantly, and gave me both more range and more reliability than a single PW.

Again, those SB-800s aren't cheap. But having both a PC jack and a super slave built in makes them fantastic little speedlights.

I also considered using a second PW Plus II transmitter, in relay mode, (explained here) to broadcast a simultaneous second sync signal on a different channel. The I could put at least one PW receiver on that second channel to get another layer of signal diversity.

But that would have involved buying a third Plus II to daisy chain the relaying PWs together, so the kids would have had to eat cat food for an extra week. Ummm, no.


Second Problem: Light Design


I did some research on the Bell 407. This gave me an idea of what to expect when I went to the airport to scout the actual helicopter I would be shooting in the air later.

Next step was to pop over to the airport to see if I could light it realistically with a few flashes.

Think of the chopper's interior as a tiny, two-room suite with big windows, small pass-throughs around the headrests and transparent floors in the front. Not an easy place to hide lights -- especially when you also are trying to mimic the ambient that would exist in the cabin.

BTW, that last idea is also known as "motivated" lighting. It is old-school, classic MoLaD stuff. There should be a logic to the light, or it just looks unreal.

You wanna stick an up-lighting SB in a toilet, knock yourself out. But just because it looks cool, doesn't mean it is going to register as logical to the viewer's brain. So the idea is to imitate -- but shape and amplify -- the light that might normally be there.

So I decided to go with gelled, diffused SB's in the front and back. I wanted the light to be omnidirectional, like the cabin's ambient light fixtures. Same principal as with the motorhome in Lighting 101.

A 1/2 CTO on the back cabin lights and a 1/2 CTB on the front would give me two options: First would be cool, instrument panel pilot lights and warm cabin lights. Or, I could lasso and easily color shift the whole cabin warmer in Photoshop, to give me daylight pilot lights and full CTO back cabin lights. I liked the idea of having that choice after the fact.

No real good place to mount motivated lights, either. Especially the one(s) that will ape the lights coming from the instrument panels. All of the glass will mean I can see the cabin. But I will also be able to see many places I would like to stick a flash.

Ugh. Not good.

I need at least one bare-bulb light coming from relatively high in the back, and a light coming from low front. I considered a Lumiquest Soft Box II, on top of the instrument panel but even that was too big -- and not omnidirectional enough. Not to mention too high.

Besides, there was no good real estate on the panel in which to mount the flash. I decided to file that little problem away for later. (Procrastinators: The leaders of tomorrow...)


I always like to test as much as possible, and this shoot was certainly not gonna be an exception to that rule. So, my stand-in chopper a few evenings before the shoot was our Toyota Highlander, parked in an empty lot at dusk. Not exactly an Apache Longbow, but it'll do for testing purposes.

This gave me a little more confidence in both the lighting design and the sync range. Although the former would have to be adjusted when we saw the results in the helicopter later. And the lights would be subject to additional problems with the high visibility and RF noise in the cabin while flying. Still, this kind of exercise helps me to not worry as much before the shoot.


Third Problem: Flash / Ambient Balance

This was the one I was saving until last. (Well, before I put off figuring out the front light position, anyway.)

I have pretty much figured out how to do the ambient/flash balance thing by now. It's all about shutter speed manipulation. But what if your ambient will be quickly dropping, and the rotors only look right on the fast-moving chopper at speeds of 1/100th or below.

I could decide to shoot through my ambient light window, and then try to get someone to quickly adjust all of the lights down two stops when it got too dark. Then I open my aperture (or bump the ISO) to get some ambient shutter speed back.

But since I could not count on an SB-savvy passenger in the chopper, I would have to live with the window and try to stretch it as much as possible. I would start shooting at 1/125 -- but do so when the sky was one stop too hot at my shooting aperture. Then I would let the sky settle into the right exposure. That would buy me a little time.

As the sky further dropped, I would open my shutter until I got to my bottom limit (say, 1/50th). As it dropped still more, I would keep my shutter speed constant and underexpose the sky as the ambient fell more. That would stretch my window even more, and I could fix it some in Adobe Camera Raw if need be.

So, there was everything that I could control before the shoot. The biggest wild card turned out to be the weather, which rained us out at least three times. But we finally got out to the fairgrounds on a nice night.

In Part 2, we'll look at the shoot, and those last couple of pesky problems.

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NEXT: Night Chopper, Pt. 2

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