Problem with the Lens Focus

[maxpizzo]

Hi All,

 

I've a problem with my Canon 70-200 f/4 but it's not clear to me what

it is due to. I'm using a digital camera, Canon EOS 300D, and I'm not

sure if the problem is the lens or the camera. Please have a look at

the posted pictures and give me your opinion.

 

http://www.photo.net/photo/3110284

http://www.photo.net/photo/3110299

 

In the first example the bottom part of the left tower is correctly in

focus while the top is out of focus. That's very starnge since the

object was very far and it was on the same "focus" level. This picture

was taken with 200mm and f/4.

 

The same problem with the 2nd picture. The top part of the cupola is

out of focus, even if the picture was taken very far from the the subject.

 

Can anybody help me to understand what the problem is?

 

Thanks in advance

[digitmstr]

>>The same problem with the 2nd picture. The top part of the cupola is out of focus<<

 

At f/4 and 200mm you DOF is very limited. Clearly, your lens is pointed upward possibly causing the focus issue. Where did you focus? Did you use the center AF point? How did you focus?

[alan_olander1664878205]

If the subject isn't parallel to the film plane, you wouldn't be able to keep it all in focus especially with the limited depth of field at f/4.

[maxpizzo]

Alan,

 

I agree about the limited depth of field of the focal lens, but if I take a picture of a tower from 30-40 meters with f/4, I should not have problems with the depth of field. I expect the whole tower in the focus area.

 

ciao, Max