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 p.2 #6 · Baseball: Working for the tack sharp shot | |
The first and most important variable and the variable that trumps all other variables when it comes to bokeh is focal length. It's more important than distance to subject, more important than aperture, more important than the amount of air behind the subject. And really, when I say, "important" I mean to say that it plays the biggest factor in determining the look of a background.
Lesson 1: Focal Length... Which image was shot at f/2.8?
If you said, the image on the left, you'd be wrong. That was actually shot at f/8. The second image on the right is at f/2.8. However, the image on the left was shot at 400 mm, while the image on the right is at 35 mm.
The second determining factor, and the one that Dennis and Scott have spoken about is distance to subject and distance behind subject. After your prime lens is in place, this is where the real skill of a photographer comes into play. Why? Because putting a 400 on a body, while costly takes no talent. Setting your camera settings while it takes some skill, really is rote for many photographers. Knowing when to fire the shutter... that's where the skill comes in. So, when Dan made the f/5.6 argument, it has to be stressed that knowing when to shoot to becomes more critical. You have to shoot tight and be conscious of the air behind the subject.
Lesson 2: Distance to Subject... Which image was shot at f/2.8?
If you said, the first, you'd be right. But, damn... it's pretty close aint it? Both hydrants were shot at 400mm, but the f/2.8 image is shot from a much greater distance... about 10 times further away. The second image, which was shot much closer was at f/8. I don't know about you, but I'd still take that bokeh, wouldn't you? Plus, we can now see how Dan's argument is coming into play. The image on the left is softer. It's soft because it had to be cropped, but also... it came out of the camera softer.
Lesson 3: f/2.8 vs. f/5.6: Which image was shot at f/2.8?
If you said, the one on the left... you'd be right. But, let me ask a more important question? Could you live with the background with the image on the right? The image on the right was at f/5.6 and more of a real world test because both hydrants were shot at the same distance with the same lens and at a distance where I would normally shoot a youth soccer player. I would probably have even more air behind the subject on a soccer field, but overall, the difference in backgrounds is negligible and the image on the right is sharper, which was Dan's whole point to begin with.
Bottom line with all this is that f/5.6 while it will be sharper for all lenses, is more suited for focal lengths at 300mm or greater. It is with those lenses, where stopping down will produce BG's that are stil more than acceptable. If you intend to shoot field sports with a 70-200, you're not going to get the BG that's going to rival the BG of a 400mm especially with a TC... plain and simple. And since aperture settings have already been shown to have less of a dramatic effect than focal length and DTS, you might as well stop down and work on your DTS patience. Let the action come to you and shoot tight and you'll have the best of both worlds... sharper photos and better BGs.
Edited on Mar 30, 2008 at 11:42 PM
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but I've never noticed a drop in focus speed when dropping down with a Mk2 and any L lens combo.
