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 By John Shaw 
Then Nikon introduced the SB-24 flash along with the F4 camera. This smart flash system changed everything, and all the other manufacturers soon followed with new equipment which allowed electronic communication between flash and camera. Basically a flash meter was added to the bodies, which could quench the flash output when a predetermined light output level was reached. Fill flash became 
simple and easy. Easy, that is, if you could interpret the confusing user manual and figure out how to program the flash for the results you wanted. Even though these flash units have been around for some time there still seems to be quite a lot of confusion about what to do. Here's a quick primer on flash for units similar to the Nikon or Canon ones.Current Nikon and Canon flash units try to ALWAYS act as fill flashes. They always try to fill in the shadows created by a natural light exposure. If there is no ambient light to be had — you're photographing at night, for example — the flashes will light the entire scene as essentially everything is in "shadow." This is what I call "total" flash, and I want to make sure you understand the difference between it and fill flash. Here the flash is the only light source; there is no ambient light exposure at all. Fill flash is a flash pop added to a natural light, ambient exposure. In both situations you want to use your flash set to its TTL mode, where the camera reads the total amount of light coming through the lens, and the flash is either in the hot shoe or mounted on the proper off-camera cord. When you're lighting the subject totally with flash, the exposure is not controlled by shutter speeds and apertures as it would be for a normal, natural light shot. The camera must be set at its flash synch speed — 1/250 second on most current cameras — or slower. Many cameras will default to this speed when you mount a flash, even if the shutter speed is set higher. Change the shutter speed and nothing happens to exposure since there is not enough ambient light to record on film. Change the aperture set on the lens and again nothing happens. The flash is set on TTL so that it puts out the proper amount of light for whatever -stop you choose. Change the -stop and the flash changes its output to match. But — and here's the catch — all TTL metering systems are programmed to render the subject as a medium tone. This works great if you're shooting average subjects, but what if you're not? To control subject tonality you must tell the camera/flash combo just how light or how dark you want the subject to appear on film. Then set the compensation either on the flash, using the "plus or minus compensation" scale, or on the camera body itself, using the exposure compensation setting. You can use either one of these regardless of the exposure mode set on the camera. Let's assume you're photographing a moth at night, and you want to record it as about one stop lighter than medium (about the tonality of the palm of your hand). Set either the flash compensation to +1 or the exposure compensation to +1, and fire away. You're controlling exposure tonality in the same manner as you would normally, but with a different mechanism. Just remember to reset back to zero when you're finished. Fill flash is controlled in a slightly different manner. Remember that now you're taking a normal ambient light exposure, so meter and set your camera. All you're doing with the flash is opening up the shadows, not controlling the total exposure of the photo. You still have to take into account the synch speed of your equipment; you can't add flash to a 1/500 second exposure. Keep the shutter speed at synch or slower and you'll be OK. If you're using an autoexposure mode, such as aperture priority, you might discover the camera won't let you drop below 1/60 second. Set the flash for "rear curtain synch" and you can use the slower speeds. Most current flash units offer two fill flash modes: you can have the flash unit automatically set the fill flash amount, or you can manually set it yourself. Both systems work but I think they should be used at different times. In my mind the "automatically set fill flash" mode is best for active subjects which might move around and change their relationship with the direction of the light. I reserve the "manually set fill flash" mode for static subjects. Here's my reasoning for this. Let's assume you're photographing your dog out in the yard on a sunny day. It's bouncing around, always changing its angle with the sun. When it's sidelit you need quite a bit of fill flash to open those shadows, but when it's frontlit you don't need as much. If you're setting the fill flash ratio manually you need to keep punching in the compensation amount on the flash every time the dog moves. Yeah, right. So let's use the automatically set amount here. Nikon users, here's how to tell the difference in the fill modes. You'll need to have your flash in the hot shoe and a lens on the camera. In "auto fill" either a matrix symbol, or a man-and-sun symbol, appears on the back of the flash unit's display immediately 
next to where it says "TTL". In "manual fill" neither symbol shows. In the spot metering mode you can only get "manual fill" no matter what. (By the way, with current Nikon cameras the ambient metering pattern does not correlate to the flash metering pattern. The flash meter uses a 5-segment matrix all the time, totally separate from the natural light meter.)In the automatically set mode the flash has a one-stop leeway, a fudge factor if you will, which we can use to our advantage. The amount of fill will be set 
between "0" and "-1" stops; that is, it will be somewhere between balancing with the ambient light and one stop less. "Balanced" means that the flash will give the shadows the same amount of light as the ambient exposure puts on the rest of the scene. Try this, and you'll discover it's way too much. You don't want to get rid of the shadows, you just want to open them up a bit. Dial in some compensation, something like "-.7" (minus stop, that is) and you've moved that one-stop leeway over this amount. The flash will now light the shadows to between -.7 and -1.7 stops. And that's exactly the neat part of this system: as the dog moves around it might need more fill flash and, sure enough, it gets more fill. As it moves on-axis with the light it might need less, and it gets less. You need more, you get more; you need less, you get less.If you want to figure out the exact starting point for your taste, run some tests. I actually use a teddy bear as a subject for this since I wanted a furry critter that I could position (my Schnauzer just won't stay in one place long enough!). Set the flash to "auto fill" then fire off a frame with different amounts of fill dialed in. I'll bet you come up with about -.7 stops. 
It's true that you could do exactly the same with "manually set" fill flash. You would just have to set the exact amount of fill you want for each situation. That's why I reserve this mode for static subjects where I have the time to determine precisely what I want to do. With these subjects, based on how strong the ambient light happens to be, I decide on how dark I want the shadows. I set my flash to the "manual fill" mode, then set the flash compensation amount accordingly. Here the flash works as "what-you-set-is-what-you-get." Punch in a"-1" amount and, sure enough, the shadows are lit to this exact level.For either fill mode the only real question is just how dark should shadows actually be. While that's a matter of taste, current slide films can record only about 2 stops from medium to detail-less black. You'll always be working somewhere in this range. Questions and Answers Here's the first installment of answers to your questions. Every few months I'll pick out the most commonly asked questions to answer. Sorry, but due to the large volume of questions I am not able to answer your questions directly, so please don't expect to get an email back from me. Remember that I'm writing about general photo techniques, so questions such as "How do I get my pictures published?" are not the province of this column. The email address is: johnshaw@photosafaris.com. This email is not my own personal or business mailbox, but is for photosafaris.com questions only.Q. Right now I own a 50mm lens what should I buy next?A. Ill answer your question with a question: what subjects do you most want to photograph? Purchase the lens(es) that let you work the subjects you are most interested in recording, then fill in your system with other focal lengths. Given today's optics, I would suggest buying mainly zoom lenses, with fixed focal lengths as the longest lenses and macros. Let me state right up front that I'm an advocate for purchasing the absolute best quality lenses you can afford. If at all possible I would urge you to get your camera manufacturer's own lenses. Why? In general they work better as they are made exactly and specifically for your camera brand, and in most cases they are more rugged than off-brand lenses. If you have a Canon, buy Canon; if you own Nikon, buy Nikon. I see many starting photographers purchase low-end gear only to replace it shortly thereafter with quality equipment. Skip that step and go right to the good stuff if you can possibly afford it. By the way, it is certainly possible to purchase good quality used lenses. Photographers tend to treat their lenses better than their cars, and we do buy "pre-owned" cars. I would not consider lens for sale on the Internet auction sites, but rather would check specialized publications such as Shutterbug or, if you're an online person, photo sites like www.photo.net or AOL's photo buy-and-sell bulletin board.As to focal lengths, most photographers purchase lenses by roughly doubling or halving what the focal lengths they already own, sort of an -stop theory of lens purchasing. Let's start with that 50mm lens you own. For a wide angle, I would suggest a 24mm lens. If you find a great deal on a 28mm, so be it. The difference between 24mm and 28mm is not that much. However, I wouldn't go wider than 24mm as a first wide angle lens; don't get a fixed 20mm to start with as the jump in coverage from 50mm to 20mm is pretty extreme. Again, I would seriously look at zoom lenses. Every working pro I know shoots zoom lenses. Nikon and Canon both offer 17-35mm lenses. To save some money I would look at the 20-35mm lenses both companies made; they can be found used as people trade them in on the wider lenses. In fact I carry a 20-35mm Nikkor and see no reason to go wider.For a longer focal length I would look at one of two lenses, either a fast 80-200mm 2.8 or a slower 70-300mm. Personally I would pick an 80-200mm just for extra focusing light and a tripod collar, if for no other reasons. If you're only planning on working landscapes the 70-300mm range is fine. The drawbacks are the lack of lens speed most of these lenses are around 5.6 at the 300mm end and lack of sharpness wide open. My advice: get a faster fixed focal length 300mm. Then save up your dollars and get a big gun 500mm 4.Q. Why do most of the photos in magazines always list Nikon and Canon as the cameras used? I'm a beginning photographer and have a Minolta.A. This one's simple: most pros want to own a camera system and right now there are only two, Nikon and Canon. All other manufacturers have gotten out of the professional market. Minolta cameras are fine and the lenses are good optically, but Minolta just doesn't offer the wide selection of lenses or of camera bodies that the two big companies do. Pick up brochures from Canon, Nikon, and Minolta and compare the specs on what's available and you'll see the difference. Need a fast 400mm 2.8? Minolta doesn't make one. How about a 500mm 4? Again, theyre not available. How about rechargeable packs for motor drives, 8 frames per second motor drive rate, interchangeable finder screens, and depth of field preview buttons? See what I mean?Q. I want to go on an African safari. Will my 70-300mm lens be enough? I plan on using it with 1.4X and 2X teleconverters.A. First of all, don't even consider using a 70-300mm or similar lens (a 75-300mm or 100-300mm) with teleconverters. Very few zooms work well with converters, and the ones that do are high priced, top-of-the-line optics such as the 80-200mm 2.8 from Nikon and the 70-200mm 2.8 from Canon. There are several problems with using a converter on a 70-300mm. First of all, you will lose autofocus ability. All current 70-300mm lenses are around 5.6 at the long end. Add a 1.4X and you're at 8 wide open, while a 2X gives you 11. Almost no AF system will work at these -stops and I wouldn't trust those that might. That's just not a lot of light coming through the lens.Adding a converter to a zoom, especially these lower priced zooms, will give you pretty soft results. First of all, you'll need to shoot the lens wide open since it's now so slow, and wide open apertures are not the sharpest aperture on any lens. Secondly, you'll be forced to use fast film to make up for the lack of lens speed and the faster the film, usually the less the quality. Remember that birds and animals are most active early and late in the day, and that's also when the most beautiful light occurs. Find an elephant at high noon, and you won't like the pictures on any film because of the lighting. But try to work early in the morning with a lens which is 11 wide open and you're stuck with pushing ISO 400 film to 800. That is, if you can even see through the lens to find the subject, let alone focus.Used straight, without any added teleconverter, the lens would be OK for general photography on an African safari. But for mammals, and especially for birds, the focal length is just too short. 300mm is not a very long lens unless your subject is quite big elephants and giraffes or extremely close. In most cases, even if the animal walks right up to the safari vehicle the more pleasing photo is when it's further away as then you're not looking down on the animal, but viewing more at it's own eye level. My most used lens in Kenya is my 500mm, and still I often add a 1.4X converter to gain focal length. On my very first few trips I had a 400mm 3.5 lens and I shot with the converter on the majority of the time.So what option do you have besides purchasing a new lens? One possibility is to rent a lens. Most Nikon and Canon big glass is available for rent through the larger camera stores in New York, Los Angeles, Chicago, Miami, and Seattle. A little Yellow Pages searching (and Internet checking) will lead you to some stores. You could also ask your local camera clubs to see if anyone has a lens they would lease. Renting a lens is not exactly cheap, but weigh the cost of doing so against the value of the trip. How often will you be taking an African safari? For most people this is a trip of a lifetime. If you're going to photograph, why skimp on the one item that determines how good your pictures can possible be? Spend a few extra dollars for a lot more enjoyment. You don't even need to rent the latest autofocus models, and indeed the manual focus lenses will be less expensive to rent. In the Nikon line you should be able to find 400mm 3.5 and 500mm 4 manual focus lenses rather easily. One additional thought: taking that trip might just be the justification you need to borrow the bucks and buy that big lens you've always wanted.Q. I want to photograph landscapes, wildlife, and low to the ground macro work. What tripod should I buy? Do I need different ones for these different subjects?A. Most nature photographers use either Manfrotto tripods (the ones which in the US used to be called Bogen tripods) or Gitzo models. The Manfrotto tripods cost less, but are not quite as rugged as the Gitzo models. One well-made, sturdy tripod will work for all subject matter you want to photograph. But note right away, there is no such thing as a light-weight, sturdy tripod. What makes tripods sturdy is mass, and pencil-legged tripods just don't have enough of it. By the way, we often see extremely light-weight tripods blow over on Photo Safaris, usually resulting in major damage to the attached cameras. Of course this often happens at the most inopportune time such as the first landing of a month-long Antarctica trip.My recommendations for all-around tripods: the Manfrotto 3221 or Gitzo 340. By the way, the Gitzo is not much heavier (a few ounces) than the Manfrotto model, as it does not have any centerpost assembly to add weight. This particular Gitzo is probably the tripod used by most professional nature photographers. It is certainly the tripod carried most often by the Van Os staff.Both of these tripods come without heads. For landscape work a three-way head is fine, but for any sort on critter photography you'll want a ball head, where one control locks movement in all axis. A good ball head will allow you to work all subject matter including landscapes. Right now I think the best buy on the market is Mike Kirk's BH-1 quick-release model (from Kirk Enterprises, www.kirkphoto.com). This head is not cheap; at $340 it's actually more expensive that either the Manfrotto or Gitzo legs. However, it will keep working for years of field use. Make sure you get the quick-release model, and plates to fit all your cameras and lenses. These are available either from Kirk Enterprises, or from Really Right Stuff (www.reallyrightstuff.com); both companies make excellent products. By the way, plates and clamps from both are absolutely interchangeable.Q. What do you think about the Canon IS lenses? Do I need a tripod if I have an IS lens? Leaving it at home would make packing a lot easier.A. Canon's IS technology Image Stabilizer, that is does work. Turning it on gains you about three shutter speeds of hand-holding ability. The old rule of thumb was that you could safely handhold at a shutter speed no slower than the focal length of the lens in use. Mount a 500mm and you would need to use 1/500 second or faster to get acceptable results when handholding. An IS lets this shutter speed limit drop; three stops slower would be 1/60 second which is a big difference.For the nature shooter I see this as particularly helpful with extreme long lens photography. But there are still two questions to ask: how often do you actually handhold a lens, and are there advantages in not handholding even when you could do so? In my day-to-day shooting I almost never handhold a lens, mainly because I always have time to set up my tripod. Can you think of a situation when you absolutely couldn't use a 'pod? Sure, aerial photography comes to mind, but would you shoot those pictures with a 400mm? I doubt it.I see the big advantage to a tripod as being a compositional aid. You can compose far more precisely when you're not waving around a handheld lens. This is particularly true in respect to the edges of the frame. One of the early gripes about autofocus was that the AF sensor was located dead-center in the frame, the worst composition position for subject matter. Yet if you hand hold a lens all too often that's exactly where you'll end up placing your subject since as the frame moves around, even a little, you try not to cut off sections of the subject. Another reason to not handhold, especially a long lens, is that you physically can't hold it up for long periods of time. Let's say you're working on a grizzly at Brooks Falls. When will the best action occur? Inevitably just after you lowered your long lens. A tripod keeps holding the lens centered on the subject regardless of what you're doing.If I were a Canon shooter and was in the market for a long lens I would certainly consider the new IS versions. Is it worth trading lenses to get? Or trading systems? I don't think so, unless you're doing lots and lots of handheld action work at slower shutter speeds. Even then, I've always maintained that all of my lenses have an image stabilizer. It's called a tripod. And remember, the IS system will not work with the camera mounted to a tripod — turn off the stabilizer before shooting!
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Joseph Van Os Photo Safaris, Inc. P.O. Box 655, Vashon Island, Washington USA 98070 Phone: (206) 463-5383 Fax: (206) 463-5484 Email: info@photosafaris.com Copyright © 2008, Joseph Van Os Photo Safaris, Inc. |