8 March 2001

There's always an issue when it comes to learning a new technique. I'm not that set in my ways with my equipment--probably because it's still relatively new--so changing my methods isn't as much of a problem like it is with others. Still, it takes a while for me to adopt a new technique. And, this isn't any different than anything else.

Here's the situation. My compositions when using the AF sensors on my Nikon F5 was being restricted. Even though the camera is equipped with five different sensors, none were at the classic compositional intersections--1/3 of the way up, down, or across the scene. If you were depending on AF, you were restricted to focusing with your subject in horizontal or vertical lines across the middle of the frame. Essentially it was causing "bullseye" compositions on a lot of my images. The Pectoral Sandpiper image above is a perfect example of this. I'm using the center sensor to focus on its eye. A better composition would be if the eye was slightly higher in the screen. This technique was showing a clear dependence on technology. So I tried to offset my subjects. First I tried to focus with the sensor then offset to something more pleasing but as soon as I re-pressed the shutter button, the camera would attempt to re-focus where the active sensor was pointed. If I tried this with our Sandpiper, the camera would probably try to focus on the water in the background with limited success. In this case, it probably wouldn't have been success and I would've lost the shot. What's there to do?

I first tried to depend on manual focus to tweak the image after initially capturing the image. This works fine if you keep the shutter button depressed. As soon as you release and repress the shutter button, the camera would try to focus through the active sensor. By the way, I'm talking as if you're still keeping the camera setup as follows: Dynamic Auto-Focus, Focus Priority, AF active with shutter button. Note: Continuous Servo AF defaults to Release Priority but I reset it to Focus Priority. Why? You'll find out in a bit. One nice feature of this mode was if manual focus was used, it over-rode the Focus Priority mode and allowed the camera to shoot even though the camera thought you were out of focus. I think the logic was if you're willing to command manual focus, you must know what you're doing. Not bad logic. Still, this method required lots of attention keeping the shutter button depressed which I wasn't willing to commit. Also, I wasn't always going to keep my left hand on the manual focus ring to exercise this technique. Sometimes I needed my left hand on the camera body or tripod. I couldn't keep it on my lens barrel all the time. So, I had to figure out another method.

One of the F5's features is Focus Priority. This mode essentially requires the camera to register an in-focus condition before allowing the camera to take a picture. The opposite is Release Priority where you press the shutter button, the camera takes the picture. The idea is you won't ever get an out of focus image when it Focus Priority is active. I had this set when I got my first F5 two years ago and very much looked forward to taking 100% in-focus, sharp as a tack, in-flight images of birds. I figured the only way I could only get a blurry image would be due to camera shake or something. Well, I can tell you this feature is a bit over-rated. I've gotten dozens of slightly soft images when shooting at fairly high shutter speeds. Though I can tell when the camera waits momentarily to shoot, predominately I don't think my precentage of in-focus images is that much higher. So, began the quest to determine if Focus Priority was really useful. A bad feature of Focus Priority is you have to have a focus sensor on the subject for the camera to register an "in focus" condition. Even if you have the camera set to single shot mode, you had to have something under the active AF sensor. This wouldn't allow you to initially focus and re-compose the image like the situation with our Pectoral Sandpiper. You still had to have something under that AF sensor. The cure for this problem? Turn off Focus Priority--Custom Function 1 set to 0. I've had it off for about six months and haven't seen any increases of more out of focus images.

Where are we now with respect to improving our ability to compose images while still using Auto-Focus? I can now initiate AF and then recompose without having to keep a AF sensor on the subject. Still, there's a problem. This situation works great if you're using the camera's single shot mode where the camera focus' once and you can move the AF sensor all you want if you keep the shutter button depressed. But how often do you use single shot mode? I never do. I always have the camera set to continuous AF. If I move the AF sensor off the subject, it tries to refocus. I use continuous AF I guess because I shoot wildlife 95% of the time with my F5s. I just never found the need to use single shot. How was I going to get the flexibility of re-composing my images while still using continuous AF. How about deactivating AF at the shutter button--Custom Function 4 set to 1? That would mean I'd have to use those tiny AF buttons on the back of the camera to command AF. And, I'd have to learn to keep those buttons pressed with my thumb while simultaneously depressing the shutter button when the action got exciting. Sounds pretty complicated doesn't it? Well, I did it about six months ago and haven't looked back. That is, after I got used to using those switches.

Here's how things work when you're setup this way. First you find your subject and position the active sensor on where you want to focus. Since I'm re-composing the image, I set the center sensor as primary 80% of the time and focus with that. After setting the focus by pressing the AF button with my right thumb, I release the button and re-compose the image as desired. Okay, none of the focus sensors are on top of anything of interest most likely after re-composing. But, it shouldn't matter. You only have to wait for the critter to move his head, adjust that wing, or do whatever while you wait with your right index finger on the shutter waiting to squeeze and get the shot. Sometimes while waiting I will recheck the focus by resetting the active AF sensor on the subject then quickly move it back as before. This whole process seems to save a bit on batteries as well since the AF isn't continually on when the shutter button is depressed. Why do I keep the shutter button depressed while waiting for everything to come together? I think it has more to do with keeping the camera steady. If the shutter is partially depressed, you don't have to move much farther to shoot the image. Otherwise you're in danger of jabbing at the shutter button which may cause some inadvertant camera shake. Anything you can do to avoid that with long lenses is a good thing.

What do I do with active subjects like flying birds and such? That takes a bit of practice. Until now, the techniques I've been recommending haven't required your hand to do two things at the same time. Golly, two things at the same time?! How hard can it be? So far you've only had to depress the AF button to focus your image and then you had to squeeze the shutter to get the image. However, with active subjects you have to do both simultaneously. You have to keep that AF button depressed while squeezing the shutter button when a bird is flying at you. I haven't even mentioned the challenges of keeping the image composed--which is a different article by itself. Pushing and squeezing simultaneously does take practice. It takes opportunities out in the field to really train you hands to do the right thing. There's a phenomenon called muscle memory. This concept describes physical functions that you don't have to devote conscience mind control to accomplish. Running, walking, and such are all muscle memory items. This is no different. The act of pushing the AF button and squeezing the shutter button simultaneously requires conscience thought at first. After a bit of practice, it begins to become muscle memory where you don't have to devote thought or brain bites. After a while when that bird you've had in your sights for hours finally takes off, you'll be prepared and instinctively ready to push that AF button and squeeze the shutter to get your string of images. In fact, you may even be able to think about squeezing and releasing the shutter button as required without even thinking your thumb was keeping things in focus. At least, that's the goal.

What do we have now? The AF function on the shutter button is deactivated so you can't command AF from there. You have to use one of the two AF buttons on the camera's back with your thumb to command AF. You can however shoot shots without unintentionally activating AF. At the same time, your shutter button priority is now set to Release Priority verses Focus Priority. That means the camera will allow you to take a picture without regard to it thinking if you've got something in focus or not. It may mean you'll get a couple soft images but I haven't seen that much of that yet. Release Priority, turning off AF on the shutter button, combined with a bit of practice will dramatically improve the flexibility of your camera. This will hopefully allow you to compose more interesting images without having to depend on the static positions of the camera's AF sensors.

Cheers

Tom