Canon has finally admitted that there are “serious” problems with selected Canon and Tamron EF lenses used in their DSLR Camera’s.
At this stage Canon Australia have not issued any warnings to the media relating to the problem which results in users having problems with the auto focus functions of the lenses, when used with Canon DSLRs – EOS 50D, EOS 40D, EOS 7D, and EOS 60D.
The lenses affected by the problem are: EF 35-80mm 1:4-5.6, EF 35-80mm 1:4-5.6 II, EF 35-80mm 1:4-5.6 III, EF 35-80mm 1:4-5.6 USM, EF 35-105mm 1:4-5.6, EF 35-105mm 1:4-5.6 USM, EF 80-200mm 1:4.5-5.6 II and EF 80-200mm 1:4.5-5.6 USM. Tamron has not confirmed the issues with its lenses, but Canon Rumours suggest the problems lie with the following models: 17-50 f/2.8 VC, 60 f/2 Macro, 70-200 f/2.8 and 10-24 f/3.5-4.5.
Trusted Reviews claims that the problem relates to the cameras peripheral AF points, which are cross types (horizontal and vertical sensors) and should therefore work together to produce more accurate results, but in this case are working separately and thus causing problems.
A Canon statement says “When using one of the eight telephoto lenses, the measurement fields work in the border area is not as cross-spot sizes, resulting in vertical and horizontal lines that are detected simultaneously. Vertical and horizontal lines are detected only separately.”
On their German site Canon said: (translated) “The problem is due to the optical properties of the AF sensor and lens of the camera. If the maximum aperture value of EF lenses and EF-S lenses, is to 1:5.6, all measuring fields function as cross-field measurement, and vertical and horizontal lines are detected simultaneously.”
SmartHouse has not been able to contact Canon Australia due to the weekend.