Banquet photo with flash bulbs???

[Neal Shields]

Our photography club is going to have an annual Christmas banquet. What is more appropriate I thought than taking a “banquet” photo of a photo club banquet?

The room is 90’ x 30’ and everyone will be sitting at round tables. There will be about 100 people in the room.

My plan is to use my 8x10 camera set to vertical format on a tall tripod (so I can get everyone’s face without a lot of stage direction) , Tmax and a bunch of flash bulbs that I have been hording. (If not now when?)

I will have to use 1/30th of a second on my 250mm Protar as the shutter has been upgraded and I don’t have M sinc. Vertically it gives me about a 44 degree angle of view which looks about right to catch most of the room if I point the camera into the room at about a 45 degree angle. (I want to position the left edge of the frame so that the flash fixtures are just out of the field of view.)

Note: the Protar is a convertable to about 400 but I don't think that will work or that I can tilt enough to keep everyone in focus at that focal length.

At 1/30th Press 40s have a guide number of 320 and Press 25s a guide number of 280. I plan on stringing 6 flash holders down one long side of the room and shooting from a corner in one end of the room to the other end 90’ away. Even with that much light it looks like I will be at F16 and d.o.f. won’t “feed the bull dog”, so I expect to have to tilt the front till I run out of lens and then accept distortion by tilting the back.

A 6” reflector gives a 120 degree angle with a press 40 and I am planning on using reflectors pointed into the room at about the same angle as the camera.

I have a flash meter and 4x5 Polaroid holder but at the price of bulbs I don’t want to make a lot of test exposures. Besides which making a fool out of yourself in front of people that don’t understand photography is one thing but in front of a group of very good amateurs and some retired professionals is something else. Beyond, which at 1/30th I expect to have to shout, “hold it” every time and people will get tired of that quickly.

I am wanting everything I use (except the flash meter) to be reasonably circa 1940 as I want to demonstrate what could be done before pixels.

I will (if it works) probably get a drum scan and make a 4’ x 5’ print made digitally unless I can find someone with optical capability to enlarge an 8x10 negative to that size without taking out a mortgage.

Questions:

Should I space my bulbs evenly every 20’ from the camera or should I place them progressively closer as I get farther from the camera, say 30’, 15’, 10’ 8’ 5’…

Should I try to bounce some light off the ceiling or just keep them level?

Do I need light on the other side of the room (in which case the fixtures will be black round balls in the picture) or can I get away with all of them on one side?

How much do you think I can tilt the back before people start looking like political cartoons? I am assuming I am going to have to just about lay my focal plane down on top of the tables and 100 year old protars don’t have that much image circle.

Is this a “fools rush in” project??

Other comments?

[Ralph Barker]

Sounds like a fun project, Neal, and one that the dinner participants are sure to enjoy, as well.

I think you'd want to keep the spacing of the flash units consistent down the long wall, so the distance between the individual lights and the subjects each illuminates is reasonably consistent. The increasing distance from the camera is not an issue - it's the light to subject distance that matters. With that in mind, the distance across the room may be an issue - causing fall-off between the near diners and those near the opposite wall. You'd need to consider the height of the room to calculate how much of a problem that might be. You may also need to do some testing of the variation of light intensity within the 120° spread. It might be that by pointing the flash heads at the people against the far wall, the level of illumination will come close to being equal across the room.

I'd suggest doing either a scaled drawing by hand, or by using drafting software. That will allow you to "measure" the flash-to-subject distance and the angle of spread on paper. Thus, you should be reasonably close on exposure with your first test, er, uh . . . shot. Working it out on paper in advance will also minimize the risk to your ego within the group.

[Neal Shields]

You address exactly the problem that was giving me trouble I was thinking that I had to light a face 75' from the camera brighter than one 20' from the camera.

Sinse I don't have to do that, the room being long and narrow may actually be better for me.

I have done some drawings and the 102 degree angle causes a lot of overlap between the flash units which makes everything harder to figure.

It is times like this that you really give thanks for type 55 Polaroid.

[Ralph Barker]

What I'm not sure of, Neal, is how much fall-off you get with bulbs as you get near the edges of the area of coverage. I'm assuming the guide number will be accurate for the center area, but will decrease toward the edges. So, you might end up with something like what I've tried to illustrate below. The overlap between the bulbs, however, may act to even things out.

To determine the spread and the fall-off in advance, you'd need to burn some bulbs to take readings at different angles off center.

[Neal Shields]

That is exactly what I am contemplating. As the subject shouldn't have a wide brightness range, I am hopeing that I can just set the exposure for the middle and live with variation from left to right. The only other option would be to try to do something with a graduated neutral density filter by most of my filters have a pretty defined line.

Please keep the advise comming.

Thanks
Neal

[Neal Shields]

Ralph,

You are actually getting the little gray cells in my mind to work. I couldn't figure out why the inverse square law only works from the flash to the subject but not from the subject to the camera.

Then it hit me, if two subjects are different distances from the camera, and both are lit the same with one twice as far away, the one twice as far away will be half as big on the film so the absolute brightness over a given area on the film will be the same.

Right??

[Jim Galli]

You could do it with a half dozen Vivitar 283's. All slaved to the one at the camera. If you could hide some in existing light fixtures to get some reach toward the rear, even better. I've used both my 7X17 and my 8X20 for 3 banquet shots but so far I've taken the less heroic posture of doing the shots outdoors. All 3 shots came out excellent though. The 717 pano was a group of about 150 hard core no nonsense professional photogs. They all dug the big camera. Will your bulbs sync right with the newer shutter. You need an older shutter with m sync for bulbs.

[Neal Shields]

All my literature says that x sinc is fine as long as I use 1/30th or slower. That not only sincs with the bulbs but gives me the full burn time so I get all the light and the 320 guide number.

I thought at first it was a handicap but the more I look at the "problem" the more I see that I would have needed to be at 1/30th anyway unless I used enough light to burn out my billfold and my subject's retinas.

How cool would it be to have an unlimited supply of flash bulbs and a government budget?

See below:



P.S. If I understand guide numbers correctly isn't a flash bulb with a guide number of 320 about 16 times more powerful than a 100 guide number electronic flash...that's a lot of vivitars!

[Ralph Barker]

Jim - electronic flash is too modern, too easy. A bank of WhiteLighning X3200s would probably let Neal shoot at f/45 with a single pop. But, large flash bulbs are way more fun. In fact, it would be kinda neat for Neal to use multiple trays of flash powder, but the hotel might get a little upset about that. ;-)

[Neal Shields]

My 82 year old friend that used to be the local authorized Graflex, Kodak, Bell and Howell service center goes nuts when he sees flash bulbs used in movies set in the '20s. The link where the aircraft carrier is posted has a section that sells trays and flash powder, but I have managed to stay away from it.

320 is only 8 times as powerful as a big shoe mount flash but 120 degrees is a wide angle. I got to thinking I might be better off to use reflectors that have a narrower angle to get the light to the other side of the room.

I have some old bulb heads that are adjustable, maybe I should use those but I figured the wider the angle that I used the less chance for hot spots.