Canon 7D Tips – Magnification plus F-stop equals Blurred Background


Take a look at the above photos.   Both photos were shot with my Canon 7D and the Canon 100mm-400mm L lens at 200mm and 1/350 shutter speed.  The only difference was the f-stop.  Even an f/5.0 f-stop can produce a great blurred background (bokeh) when the lens magnification is high enough.


So what about an f/2.8 f-stop?  Well, an f/2.8 alone will not produce a significantly blurred background. Take a look at the above photos.  Both photos were taken with the Canon 15-55mm EF-S lens at 55mm.  The background in the f/2.8 photo was blurred, but not as much as in the 200mm photo.  The background is simply too close to produce a significant blur even at f/2.8.

Spring flowers are just starting to bloom, so experiment with this simple formula:

magnification + wide open f-stop + distance = blurred background

You can produce a pleasant blurred background even with a f/5.0 f-stop when the magnification is high enough.  Now you might be asking, what would happen if you had a faster lens like the Canon 85mm f/1.2 L?  The wider f-stop would produce a smoother blurred background.  (Take a look at the bokeh comparison in my review of  Sigma’s 50mm f/1.4 lens.)  But, don’t let that stop you from being creative with the lenses that you already have.


4 thoughts on “Canon 7D Tips – Magnification plus F-stop equals Blurred Background

  1. another factor to take into acount is the distance from your subject. You don’t need a tele-zoom lens to create ‘bokeh’, if you just move your 18-55 closer to the subject, the background will start to blur more too.

  2. Does this also pertain to video also? Especially when panning the cam while recording, the subjects can get blurry. Will this work for vid as well?


  3. Yes! The 7D is a DSLR which just happens to also shoot video. You can use the full Manual mode or the AV Aperture Priority mode to control the f-stop for shooting either video or still photos. Just flip the switch to either Live View or Movie Shooting.

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