AK_2
Veteran Member
Actually it's absolutely 100% true, and I have done the homework to prove it. http://www.canon-dslr.comAbsolutely false. Any EF lens will work with 100% functionalityAs whole system's.
Canon has so much varience across it's range - it's not what you
could call an interchangeable system. Whilst a EF lens fits on an
EOS body, you get issues with certain combinations.
with any Canon EOS body. I have a ten year old all-plastic Rebel X
film SLR that will work with any EF lens from any year with all
autofocus, metering, and Image Stabilization functions fully
functional. It's one of the hallmarks of the EOS/EF system and is
much more than you can say for other lens systems.
If you can find a 50mm 1.4 and 20d lens and body that works with the promised 1/3 dof, or even 1 x dof - lets have it to test, and I'll prmise to dissapoint you. Nothing to do with calibration. It's a fundamental issue between the body and lens. They may fix it at some time, with a lens update, body update etc. But as recent as 2 months ago I've had reports of these same issues by pros that know what they are doing with the big apertures on the 20d.
What have you done ??? Do you have pro af system (one you know works to pro accuracy) that you have compared to ??? Have other photographers tested your claims ??? Do you work for Canon UK ???
Back or front focus can be adjusted - although canon uk haven't managed to on my systems, they actually made it worse by using the wrong test target and method - http://www.canon-dslr.comBack-focus issues exist practically across all of today's autofocus
systems. Some are reported more than others, but that's likely
tied to the popularity of that particular system But it has
nothing to do with the compatibility of the system. I have the
20D, and I had the 10D. I never had any focus issues with any of
those bodies or any of my lenses. But the issue does occur from
time to time, from various bodies from various brands.
However, what I am talking about is varience, the different distance that the af system will focus at for the same subject at the same distance, when taking multiple shots in a row. Calibration will only help the average of the different focus positions, it will not prevent the two extremes, which with a 20d and 50mm1.4 or 85mm 1.2, the two extremes are both outside of the dof, and can be alternatively front or back focussed outside the dof. Clearly not what I would term interchangealbe - as for me the af has to work to a reasonable standard within that.
Put the same lenses on a d60, or 1d series (1d, 1ds, mk2's) and they were fine.
Even the official canon test is flawed, in that it only starts the af, from the same fixed position each time. Which ignores the fact the lens may start from a short or long ditance from the target. But by doing this, they dramatically improve the tolerance, which is obviously cheating the test results.
Regards,
Kev