Canon 70-200mm f4 is

[erics500d]

I recently bought a Canon 70-200mm f4L is and I´ve noticed that the quality isn´t like I´ve expected now and then at 200mm and f4. I think it might be a problem with the focus, it is occasionally a little soft focusing... The problem with focusing is especially seen when taking photos of subjects that are far away, like a mountain. The quality oftens get better when I use the manual focus.

Do anyone of you that have this lens have the same problem, and should I return the lens or make canon fix it?

[Quoth the Raven]

I've no experience of Canon lenses (as I'm a Nikon shooter) but many lenses aren't quite as good wide open at the extremes. However, if you are able to focus manually and get a sharper shot, it may be an issue with the AF.

Can you post some images taken at 200mm f4 which show the problem? It might help with diagnosis.

[cosmicma]

i'd be tempted to return it under warranty if it's an intermittent fault because it won't get any better thats for sure

[erics500d]

I´ve tried the lens much the past few days. When I use a tripod and set the focus limiter to 3m-infinity I think the images are sharper. But I think it´s hard to get sharp shots handheld, I don´t know what I´m doing wrong. I use IS and I will say that I keep it mighty steady. Any tips here, and how to get the best possible focusing with this lens, especially handheld?

[cosmicma]

it sounds like it might be a camera shake issue
IS isnt perfect and you might still be getting a little shake hand held
the obvious answer is to keep the shutter speed high the general rule of thumb is a shutter speed at least as high as the focal lengh IE 200mm - 200th of a second but if your as shaky as me i would double that figure

[waveydavey]

so, which camera are you using?
From personal experience, I would expect this from a 7D, as, I have the same issue with a 70-200mm 2.8 IS.

[Markulous]

I suspect camera shake unless the shutter speed is well up - have you an image that shows it? Don't forget that the IS is the older version - not as good as the newer Mk IIs (or of some Sigmas!)