Lens Problem? - pics

decimal

I got a 70-200mm f4 (non IS) and I've been playing around with it and I think there may be a problem with it, although I'm just not sure. There seems to be some blurring at certain points in the lens. I've 3 photos all at different apertures and the blurring isn't as visible with a smaller aperture, but it is noticeable.

The pics were taken on a tripod at 200mm, I'm using a 40D. These are just test shots, I'm not stalking the neighbours

Shot 1: F4
Shot 2: F9
Shot 3: F18

If you look at the concrete wall on the right, the part beside the window is blurred a little, then it returns sharp as you move right and then gets blurry as you move to the drainpipe. There are a few areas where ghosting is at f4 (drainpipe, cut outs in the windowblind), but is this from being wide open?

Any advice is appreciated.

Ricky91t

Are you using a uv filter might be that?
And also could you take better examples i find that too hard to pick out anything on it :pac:

decimal

ricky91t wrote: »

Are you using a uv filter might be that?
And also could you take better examples i find that too hard to pick out anything on it :pac:

I'm not using anything other than the lens hood.
The examples are pretty poor, didn't spot it until I imported it into LR tonight. I'm gonna try and get some better ones tomorrow.

hussey

Doesn't look like it is anything wrong ...

depth of field depends on three items (not just aperture)

Focal length
distance from subject
aperture

in the first one you are using a zoom + far away + wide F = a shallow DOF, anything close to you is very very soft, I would expect this since you are zooming

in the third, the narrow (is that term for Large number F?) aperture compenstates for the other two factors, and give a much deeper depth of field, which is why we can slightly see the pegs.

all in all this is just a feature of a zoom lens
more info : http://www.mir.com.my/rb/photography/fototech/htmls/depth.html
http://en.wikipedia.org/wiki/Depth_of_field

decimal

Don't think it's anything to do with DOF, I've tried taking a few more test shots to pinpoint the problem and it's only happening at 300mm....

Shot 1: F4
Shot 2: F9
Shot 3: F18

So I retried this again at 70mm and there seems to be no problem....

Shot 4: F4
Shot 5: F9
Shot 6: F18

Should I go for calibration? I've read some of the stories about calibration and it's really putting me off :mad:

smash

I have the same issue... see right hand side of photo, and front of car!


I was told aprox €200 to get it fixed - I say bring or send the lens back with sample pics.

decimal

steve06 wrote: »

I was told aprox €200 to get it fixed - I say bring or send the lens back with sample pics.

Must've been a faulty batch. Where did you get that quote?

I bought mine from kerso, have to find my warranty and see if i can send it back and if it'll cost any money

Took some good samples tonight to make sure.. the problem occurs at 200mm, it's fine at 70mm but I have yet to check anything else.

F4
F18

At F4, you can see the blur easily, I'm heading to NY next week and want to bring this to the bronx zoo, it's gonna be a pain trying to work around using the smallest aperture and no IS

jackdaw

I'm surprised .. I didn't expect such problems with canon L lenses ..

is this common ??

I so far have found nothing wrong with my 70-200 f2.8 IS ..

Paulw

Like anything, you can get a faulty lens.

Have you tried that lens on a different camera body?


It might be the lens, it might be the combination of that specific lens with your specific body.

Worst case, you'll have to ship to back to whoever you bought it from.