Transcript of "Birds in Flight - High Speed Flash Techniques"


Copyright 1998 R. W. Scott

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Hello. This is R. W. Scott. It's May 15, 1997.

The object of making this tape is to explain how I personally photograph small birds in flight without blur, in other words, high speed bird photography.

The Camera:


First, lets go into the mechanical portion of it. What camera do you choose? Well, a 35 millimeter is less expensive. It must have a remote release so it can be triggered by an electric eye. Therefore it also must have a motor drive. This motor drive has to be fast; in other words it has to shoot about 8 to 10 frames per second. Otherwise the bird is here and gone after breaking the electric eye beam and you don't have any bird in your negative!

Mirror lock-up is desirable because that cuts down an inch or so from the lead that you must give to the bird when you focus. But it's not required because you can incorporate that inch or so into your lead distance. We'll talk more about that later.

The Lens:


In order to get good sharp pictures of small birds such as the goldfinch or the cardinal, and in that range, you need a macro lens, because in order to fill the frame, and not have it take up too much space in your setup, you need about a 55mm macro or a 100mm macro lens. It is not necessary to have a real fast lens.
In order to get good depth of field with these small birds you have to shoot at F8 or smaller in order to get sharpness from wing tip to wing tip.
So the lens should be macro, 50 to 100 mm. It should have a motor.
This camera, naturally, is not hand held. It's held on a tripod of some sort.
There are wires leading to the electric eye, and wires leading over to the safety switch, which you'll probably want to have.

I guess we'll talk about the safety switch next, because that's most closely related to the camera. What this is, is a bypass to the electric eye, so that the camera won't fire every time every time the beam is interrupted.
If you have a camera that fires and automatically (re)winds and automatically resets the trigger, you may get a whole roll of sparrows coming into the feeder perch, so you have to have an interrupt circuit that the electric eye feeds into so that you can either fire the camera or keep the camera off. That's the two functions of the interrupt switch.

Next come the camera settings.


I'm often asked, "Don't I use a real high speed film?" No, the speed of the flash determines the speed that the picture is taken at. So the aperture setting on the camera is adjusted to merely get as much background as you want. The farther open the aperture is when the picture is taken, the brighter the background. You can easily get too far open. You have to balance this against the power of the flash. Not the speed, but you balance it against the power of the flash. You see, what's going on here when you take a high-speed picture with a flash, is that you are really double exposing. You're exposing once with the high-speed flash, and you're exposing once with the background brightness. You must keep the background brightness 1½ to 2 f-stops lower in intensity than the brightness of your flash. Otherwise, you'll get a ghost. You'll get actually a tree limb growing out of the belly of a cardinal, or something like that. And that doesn't make a good picture.

Lets talk about the film to use.


Well surprisingly, all the latest and best films don't work on high-speed photography. This information I'm giving is kind of iterative, because when I say one thing I have to explain the other thing. But here goes: The film should be fairly fine grained. ASA 100 is right in there. You needn't to go to ASA 50 if you're going to enlargements up to 16 x 20 inches. So for instance if you go to ASA 400 of an enlargement of the right size, you begin to see a fair amount of grain, at least with present day film. Now if we establish that ASA 100, or ASA 64 is also in range, this automatically sets how must power we must have in the flash And when we say how much power, this limits the speed of the flash.

Early Flash Setup


For instance, when I first started out in high-speed photography, I had to
go to four Vivitar 292 flash heads, which was the most powerful on the market at that time. It had a thyristor control, that you could use to set the intensity of the flash, because it had an electric eye that would sense the amount of light that was reflected and cut off at the level that you set. Well, I put the piece of white cardboard over the electric eye on the Vivitar 292 flash, so that the flash bulb would have part of it's light reflected down into the electric eye of the flash. So that it was strictly a function of how fast the flash could operate the thyristor to shut off. It took about 1/2000 of a second from the time you triggered it until the flash went off, and the flash reflected from the cardboard into the
thyristor and the thyristor quenched the flash.

But since it was shooting so fast, I needed four flash heads (flash units). I later tempered this by putting some filters over the electric eye at one or two f-stops so it wouldn't cut off so fast and so it would give a little more light. This was necessary because even with four flash heads operating at maximum speed, I was forced to shoot at f4 and lower. My depth of field was very poor, of course, since the distance from my film to the bird was
about 30 inches when the flash went off.

Even so, to make that go off, I had a cardboard box, which contained four slaves. When they sense the high light they set off the four Vivitar 292's. And also in this box was a small flash that was wired to the PC connectors of the camera. So the camera would open up its aperture and the PC connectors would connect. That would fire off the single flash in the cardboard box, and the flash heads from the cardboard box would go off simultaneously about 2 thousandths of a second later.

There's also the time involved in getting the trigger. The electric eye trigger has a time constant of it's own, somewhere around 1 or 2 thousandths of a second.

And then the camera aperture opening is maybe 50 thousandths of a second, and then the PC connection closes about 50 thousandths of a second later. So this all adds up to a time constant of perhaps 150 thousandths of a second between the time the electric eye senses the shadow of the bird, and the four slave flashes go off.

Now during this time it takes between the electric eye trigger to the four slaves going off, I found, by trial and error that the bird traveled about four inches. So I would set up a target perch for the bird. Four inches beyond that was where I wanted the bird to be, and then four inches beyond that is where I would set the electric eye.

So the bird would fly in, activating the trigger, fly another four inches, his wings nicely outspread for the landing, and the four flashes would go about 4 inches in front of where the bird would finally land.

So there I had him, but at f4 at the beginning, and later on when I biased the thyristors on the flashes I could get it up to maybe f8. (This is important because more light allows a higher f-stop, which gives a greater depth of field that results in more of the bird being in sharp focus.)

The Electric Eye Trigger


The use of the electric eye required some development. I shot off many rolls of film inside the house I put in plastic windows instead of glass windows so I could bore large holes in the plastic, and put covers over them when I wasn't using them.

At first I actually mounted both the transmitter and receiver of the electric eye outside. This worked, but it was horribly inconvenient when I wanted to adjust the distance from the perch. Different birds come in at different velocities, and I quoted the distance for the goldfinch, and for the cardinal I had to trip another inch or two further out, and the pileated woodpecker I had to trip a whole lot further out. Of course I had to use a wide-angle lens on him.

Back to the setting of the trigger. Initially I had both the transmitter and receiver out of doors, mounted on brackets, and my camera on a tripod, pointed out through a large hole in the window. And my flash units are also shooting through the window, which is clear. This was too cumbersome. So I arranged a mirror overhead at a 45-degree angle, and I directed my electric eye transmitter at that mirror, which reflected the beam down in front of the perch and hit another mirror, which was placed horizontal. It hit this horizontal reflector, bounce back to the mirror and back to the electric eye.

This time I had a different kind of electric eye, which had both a transmitter and a receiver built into the unit itself. These cost about $100. 3M and several other manufacturers make them.
Banner Engineering makes the one I use the most. With this electric eye system I could keep the electric eye indoors, and rain or snow wouldn't bother it. The beam would travel, hit the 45 down, and hit the auto tail light reflector, then back up to the 45 then back into the receiver. So if a bird shadowed the beam, it would trip the camera. I did have some trouble with the horizontal reflector getting covered with rain and bird dirt and snow, so I put a 45 degree clear glass shield over this which also helped make the bird choose the perch instead of the framework. It's very frustrating when the bird lands on the framework, which trips the eye anyway, so you get a blank picture. This slanted glass protected the reflector and encouraged the bird to land on the perch.

More about Film


I first started out with black and white film, which had a little more speed and resolution. But of course, a gold finch or a cardinal in black or white is not at all satisfying to people who enjoys birds, they want the color. So does the photographer. So I started out primarily with Kodak film. I soon found that some Kodak color film was OK, and others had a horrible reciprocity failure. Now in one color film in particular I had a 2 f-stop speed loss and about a 40 unit orange shift. So I had to put in filters in my enlarger to correct it, and I had to crank the power way up in may enlarger, because this film was very thin, very weak. I didn't want to do that, so I shot it at a lower film speed. But when I'm shooting an ASA 100 film with a two f-stop loss, gee, I'm shooting at ASA 25 and that's a terrible loss in speed. So I shifted to another film, and got the full speed and full color. That was Kodachrome 64, which was successful. That was fine for quite a few years I stuck to that. In the meantime, Kodak was coming out with family type of film that unfortunately has a color loss,a and could not be used.Lately, I'veshifted to Fuji Velvia. It's excellent.
It's got maybe even a little bit over-saturated color, but it does not change color at speed, whereas, with Fuji Sensia
I have to adjust 1 f-stop for speed loss and its color is not nearly as good. Velvia is ASA 50.

More about the camera and lens


I'm limited to cameras where we have a motor drive that goes fast, 8 or 10 frames a second, in other words that triggers quickly when the electric eye goes off.
And mostly I've used Nikon camera and 55mm-macro lens with a motor drive, now I'm mostly using a cannon with a 100mm macro. I've also used a horseman 2.25x 3.25 film back. It will go 4x5. I tried that, but that's just a horrible expense on the film, so I went back to 2.25 x 3.25. And that real neat, because you can have a little more latitude on placing the bird properly on the film, cropping at the enlarger. You can even make a 35mm film out of a 2.25 3.25 slide if you don't get the bird too big. But you know it's very difficult to get the bird on the film in the exact place you want. It's a matter of iteration. You have to see where the bird goes, and then you have to aim your camera and focus it accordingly. And then he goes somewhere else. And so it's quite a bit trial and error in the in-the-room type setup for the small birds. I chose the horseman because it was the only large format camera I could find that I could afford with the electric remotely operated trigger. You have to have the remotely operated trigger, so you can get away from the bird area or use an electric
eye.

Why I don't use an electric eye for hummingbirds:


It turned out I didn't use the electric eye very much with the horseman. I mostly used a remote hand trigger. But again that's required because you've got to get away from the bird some distance so he'll feel free to come in. Mostly these were hummingbirds we're talking about. Hummingbirds are a whole new thing here, because the hummingbird doesn't work too well with the electric eye. If you set the camera to focus close to the flower, he'll be there and gone before triggering. Each time he backs up (which is where you want him) it seems it just takes too long for the electric eye to work. What's faster and more selective, it turns out, is to use a button on a remote release. You can begin to anticipate this bird. He has one little habit that allows you to nail him. He will sip for a while and then he backs off, and parks there for a while, buzzing his wings. Of course you must use a flower setup or nectar setup so there's no perch there. He want's to back up and catch his breath or something, He backs up and hovers there, and that's when you nail him. Your finger-mind reflex speed has to be fairly fast, but you can nail him. During the backup, is where you get your best pictures. Of course there are all kinds of things you can add to the composition, like having local flowers in the picture, and have him back off from a flower a little bit so you get both the flower and the hummingbird.

How to get better photos through on site processing:


With the hummingbird, there's one disadvantage. I'm away from my darkroom, and a darkroom certainly helps if you're going to take the rolls and rolls and rolls that it takes to get the bird with a good composition, and in focus, and placed properly in the frame. It takes hundreds of rolls to get a really outstanding picture. So on location in Arizona, I would come home with all my hummingbirds out of focus or too lightly exposed. To check this by iteration, you develop the negative, and you look. Fuji has a kit, and Kodak has a kit for film development. You need a black film changing bag to take the film out of the camera and put it into the little tank. But from then on you can come out into the daylight, and if you've got your chemicals already mixed, you can do this process in daylight. Then you dry the film and you take your magnifying glass and see: Is he in focus? Is it a good composition? And usually the answer is "No." But you can see from that how to adjust, and you take another roll, and you develop it, and you check again. So it's really not too difficult to develop your negatives on site. My favorite is slides. Slides are really no more difficult to develop then negatives when you're talking about these small kits. They're kind of expensive, but when you talk about coming home, after spending 4000 miles and two months on a field trip and having no results that are good, they're not expensive at all.

Backgrounds are nice to play with. One reason I like the Fuji Velvia is that white comes out white. None of the Kodak negative or slide films will give you a true white with a high speed. And by the way, out in Arizona, I'm still using a high-speed flash. It's the most severe requirement for a flash that there is, probably. Well, some bugs may be more difficult. But, in birds, the hummingbird has got the fastest wing speed, going around 60 to 80 beats per second, and that will be a blur unless you have a really high speed of at least 1/10000 of a second. For the hummingbird 1/10000 second and 1/20000 second is better. 20 to 40 thousandths is the range I've been shooting at. Otherwise, you get a slight blur. That just ruins the picture. Unless, of course, high-speed photography is not everything. You can get some very fine hummingbird and small birds pictured where the body is still and the eye is in perfect focus and the wings are a blur. Those are very fine photographs also. Of course, that's not high-speed flash, that's ordinary flash speed, down around 1/1000 second or 1/2000 second flash duration.

Another thing about the flash equipment, when I first started out these flash units were powered by batteries that were rechargeable, and then I also used flash units that plugged in 110 volts at 60 cycles per second. But when I go to Arizona what is required is battery-powered equipment. This is a little bit more complicated; I won't get into that.

Now to answer some specific questions:


Typical bird room setup:

the camera is on inside mounted on tripod or similar device, shooting out through a hole in a Plexiglas window, toward the perch, with the perch in the bottom part of the viewfinder.

For focus, I have a yardstick with a red dot on it for a target, and I poke that out to a predetermined distance beyond the perch, and focus on that red dot, with a black cross on it. This distance gets trimmed according to the results I get on the negatives. Then the camera mirror is locked open. Next it's connected to the flash unit. The camera PC connector goes to the flash or to the cardboard box with the trigger flash and the four slaves inside. The four slaves are wired to flash units mounted at various places around the window through which I'm shooting in order to get light all the way around on the bird. Top side, sides, and underneath.

The electric eye:


I have the electric eye on the inside, and it shoots out, through the window. It's mounted on a mount which I can shift left, right, up, or down in order to be able to change the composition and the distance to the trigger point. So again I poke the yardstick out the window, and move the electric eye around until it triggers the flash at the point I've found to be the best, or I keep adjusting that according to the results on film. The eye is connected to the trigger interrupt button before it goes to the camera, or in other words, the "hold" button that I hand hold, and then it goes into the camera motor drive. So that's the typical setup. I'll sit there so I don't get a whole roll of nothing. I will be observing and will arm the interrupt box when a desired bird approaches.

Lens focal length, Camera, f-stop, Shutter speed, Film: I covered those pretty well already.

Flash:


I covered the 4 Vivitar 292's. I've had two generations of custom flashes since then.
The custom system I'm using now has a power supply with 4 outlets on it, and I'm using 4 flashes. Before I got this nice setup, I was using the setup I described before with the cardboard box containing one small flash triggered by the camera to set off the 4 slave sensors also in the box.

But that gets kind of complicated, if somebody's really interested in flash equipment I'll go into that later.

Exposure control methodology:


I already told you about putting the white cardboard in front of the thyristor on the Vivitar 292's. That made it maximum fast, then I put the filters over the eye that slowed it down a little. That's one method of exposure control from the flash source. But then there is also the exposure control from the ambient light. And that is like any photographer uses, it is through the aperture. The aperture is only important for the ambient light. Any aperture will do for the flash. You must be careful, however, about the shutter. Don't use a shutter speed that's too fast, or you'll only get a fraction of the frame because on most 35mm cameras, the shutter is only part way open for the very high shutter speeds. You're more limited on the older cameras than on the newer. The older cameras required a maximum shutter speed of 1/60 second when using flash exposure. Later cameras permit up to 1/250 second..

Trigger circuit info:


I think we've gone over that, except the electronics, and I don't think you need me to do that.

Tips on controlling the approach:


At first I used a little feeder made out of aluminum with bent up edges, only 8"x 4" and ¾" deep. It holds about ¼ pint of birdseed. I have to fill it up every hour or so. It's small to restrict the bird's approach position to the feeder. It gives me a better chance to have him in focus and on the frame. Also, don't give him any place to perch near that feeder, except the perch that you want him to feed on. And even more than that, if you want him on a particular spot on the perch, which is smaller than 8", you can put a thorn at each end, and put them in tight and he'll avoid the thorns. Of course that appears in your picture. One problem is you must have a way for the bird to come swooping down rather than climbing up when he hits the feeder. You must have something outside, like a tree, which is considerably higher than the perch, and then he decides it's ok and comes swooping down,that gets him above the perch as he approaches the feeder, instead of half of his body masked by the feeder and the perch if he is approaching level, or from below the perch.

Do you lock up the mirror? Yes, if the camera has this feature.
Does this affect the delay between trigger event and flash? Yes. It takes a few microseconds for the mirror to flop down. It's just one more thing that has to happen before the flash goes off.

Distances from camera to subject:


I use a yardstick. It's an iteration process between where you expose your film to determine where you set the electric eye. If he's already on the perch by the time you get your pictures, then you have to set your electric eye further out. And if his wings are folded tight to his body, and he's quite a way out, then you have to set the electric eye closer in. Anything more detailed than that, to get him in focus, you do by trial and error. You have to look on the negative or slide and see If his tail is in focus, but his beak is way out of focus, then you want to bring the beam closer in, or focus closer in.

Distance of camera to subject:


You want to have a nice close up shot. If you have a little dot in the middle and that's your bird, it won't enlarge very well. You want to have the frame filled pretty well, and yet have a little space around him so it makes a good photograph. So you can put a little cardboard image out there, if you want to, of a full size bird. Or you can develop your film, and see if you're too far out or too close in, and see if you're clipping off his beak, and so on. The same goes for left and right. If you have lots of room on the left, but you're clipping off his tail on the right, then you can adjust your aim that way. Generally, I am shooting with my camera about 20 to 30 inches from the focal point. The focal point is about 4 to 8 inches from the perch.

Distance of flash to subject:


That varies. If I've got 4 of them, I place them so the bird is well lighted-- so there is some underneath as well as on top and to each side. The closer the flash is to the bird, the more intense the light is. I get them as close as I can conveniently get them without affecting the picture, without having the flash show in the picture, generally about 24" to 36".

Edited 7/22/98 RWS
Copyright 1998 RWS
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