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sc_radar Mar 7, 2006 7:59 PM

Which lens gives a good bokeh ? I am wanting a decent lens to possibly go along with a new 20d I am thinking about getting. I am looking to take decent action pictures ...drag racing, rodeo, sports events,. I want to be able to blurr the background as seen in alot of the action pictures posted here. I am looking for a lens also for portraits at home ( 50mm f/2.8 ) . I am having a hard time deciding. As you can see I am a newbie but wodering what actually causes the nice bokeh I see in alot of the pictures that totally make me say... hey I want to be able to do these type pitures.

PS : I still got the Nikon d50 on my mind also with a good 80-200 f/2.8 lens. I am willing to spend around $1,000 if I go with the Nikon deal.

rjseeney Mar 7, 2006 8:15 PM

Bokeh is strictly a subjective measurement. Bokeh refers to the quality of the out of focus area, specifically highlights and how well the subjet transitions from the background. Ask 10 experts about bokeh and you will get 10 different answers.

The larger the aperature, and the more distance you can put between the subject and the background, the greater the blurring effect. If you're in bright sunlight or can control the lighting, you will be able to choose larger aperatures and achieve greater subject to background seperation. All lenses are capable of giving a sharp subject over a blurred background.

Don't worry about's subjective, and you'll likely not be able to notice good or bad bokeh anyway.

JohnG Mar 8, 2006 7:39 AM

Just to add a little to rjseeney's exlplanation:

The focal length of the lens also contributes. A 400mm 2.8 will produce more background blur than a 50mm 2.8 lens. Also, the focus distance plays a part - as your lens gets to the 'infinity' part of it's focus, the background blur diminishes. I'm sure there's a technical write-up on all the optical physics somewhere. But in lay-man's terms: wider aperture, longer focal length, subject seperation from background, don't focus at infinity.

Now, when you're talking sports - especially outdoors, you really want a long lens capable of 2.8 to get a good blurred background - unless the action comes close to you. Here's a couple examples:

This is a 400mm lens at 5.6 - but it's focusing near infinity - see how in-focus the background is?

Now, here's the same lens at same f-stop and aperture (400mm 5.6):

The blur is a lot better? Why - because I'm not focusing near infinity.

Now, here's the affect of a 200mm 2.8:

But, as you get near 'infinity' on the 200 2.8, you start to lose the blur:

It's still way better, in my opinion than the affect of the 5.6 lens near infinity but not nearly as good. What does this all mean? If you want the consistant blurred background, you need a lens that has a focal length long enough and you need to be sufficiently close enough to the action so that you aren't always at the maximum focus distance of the lens. For best results (we're talking sports still, not portrait) - you want a lens capable of 2.8 and long enough for your sport.

Now, one final word, for racing and other sports, the 'blur' is also a result of a panning technique. In this regard, you shoot with a wide aperture still, but rather than a very fast shutter speed to freeze the action you use a slower shutter speed and pan the camera across the frame matching the speed of your target as you press the shutter. It's a difficult skill to get down - but the results are amazing you get a much better sense of movement and you really get a nice blurred background. But, the technique requires a pretty much constant moving target is a general strait line (i.e. a car going left to right in front of you vs. a bull rider where the bull's motion is less predictable).

Hope this helped.

sc_radar Mar 8, 2006 4:41 PM

Thanks for the replies. I really appreciate the pictures John. My wife read these also and was glad to see the pictures as it helped describe the effect. If I go with the 20d I was thinking about getting a Sigma 70-200 f/2.8 . I still have the D50 with 70-200 in the back of my head that would put me around $1000 if I buy the lens second hand. I also see the option of getting the D50 with the 2 lens kits to start with and learn. . I have alot of learning to do but as I see here it is all worth it to be able to take great pictures as I always have wanted to.

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