Why do lenses that need MA work fine on my 5D?

I find microadjustment (MA) to be a very mixed blessing. Thankfully, most of the lenses I've owned have not needed it.

My V1 70-200/2.8 IS was my first frustrating foray into MA. This lens worked fine on my old 5D but with some testing on the 1D Mark III it favored a bit of tweaking. The problem was, it needed different amounts and directions at 70mm, 135mm and 200mm. How to deal with that?

I dealt with it by moving to the 70-200/2.8 IS II. This lens also wants some MA, now on the 1D Mark IV. This time it wants the same -11 setting at all focal lengths so that is solved.

But now for the strange part. I adjusted my new 70-200 II on the 1D4 mainly because I was clearly getting focus errors. When I was done, the lens hits perfectly.

But when I mount the lens on my three year old 5D and shoot the exact same test target from the exact same position, the focus is perfect. How is this possible? Why does the camera that can do MA need it and the camera that cannot do MA not need it?

bodies and lenses have different calibration tolerances. unlike others, uou are just lucky that you have matching pairs.

Yep - different tolerances w/different bodies. My Sigma 30mm, which is also my only lens that needed MA, was fine on my T1i but needed adjustment with the 7D.

Crop factor.

No, seriously!

You may be enlarging the 1D image 30% more before comparing, making any focus errors more evident.

My 1D-MkII focuses perfectly with every lens I've ever attached to it. It doesn't matter who makes the lens, or if I owned or rented it.

I was talking with a couple of my fellow photographers while photographing Skate America in Portland a couple of weeks ago. They were both using the 1D-MkIV and said they never bother with MA. They just put the lens on and shoot. I guess some people are just more obsessed than others.

i was thinking the same exact thing. When i had my T1i the nifty fifty was SPOT on SHARP. When paired up with my 5dmkII it was way off. I ended up adjusting it to +18.

Hmm. Of course xarqi is right, but it may be possible that Canon used MA as an excuse to loosen tolerences.

I doubt it since loosening tolerances would get noticed fairly quick by those using camera bodies without MA - which is to say all the camera bodies before the 50D - the new 60D and the entire rebel line. It was brought in as a feature more to allow customers the ability to make small, fine adjustments themselves and I suspect it also helps to educate them as to the fact that a "soft lens" is both a camera and lens factor.

Also remember a "soft" lens when bought new is fixed under warranty - so its biggest factor is saving on warranty realignments for canon - since they still have to pay their staff to repair the problem/finance the repair centres

Jeff,

My 70-200 mk2 needs a minor tweek on my 1d3 and 5dmk2. My 5dc I find this lens to back focus a hair but still achieve sharp images at f/2.8 (could be better).

All of my other lenses are spot on with my 5dc. I'm not too concerned since I can always send the 70-200 back for free calibration. I'll probably get another new body with MA to replace my 5dc "someday".

Noticed this with my 7d/5dc
on the 7d most of my lenses have varying amounts of MA, from -4 to +12
on the 5d, theyre ALL spot on, even the siggy 50 1.4 wich has a reputation for schizophrenic focus problems and the sort.

Always found it odd, but the last thing im doing is complaining about it
it just proves the point (to me) that the 5D classic is a beast.

OK - here is another question.

Does anyone have two bodies capable of MA, and if so do you always use the same amount of MA for any one lens on both bodies?

JeffreyG wrote in post #11348006
OK - here is another question.

Does anyone have two bodies capable of MA, and if so do you always use the same amount of MA for any one lens on both bodies?

7D and 5DII, very nearly the same and the difference is +1 between the two, leading me to believe its the mount on the bodies that are slightly out of tolerance.

Ya that's what I would think

JeffreyG wrote in post #11348006
OK - here is another question.

Does anyone have two bodies capable of MA, and if so do you always use the same amount of MA for any one lens on both bodies?

You need to test both bodies seperately to be sure.
If one lens falls on the same setting on both bodies then it's just a coincidense...