5DmkII AF bad alignment problem!!

I tried the search function here on POTN but didn't find anything on this problem...

I was reading on a Swedish forum about a serious AF aligment problem on the 5DmkII.
The guy testing could not get consistant results when trying to adjust a lens with the Micro Adjust feature. The results shown was just terrible.
He had two 5DmkII and both showed the same problem. Another guy did the same test with his camera and had the same result!!
Now, I thought this was a bit alarming so I decided to check it out.
This is how the test was performed
- Lense used, my brand new 50/1.4, set at 1.4
- Camera on tripod
- Distance to object abt 1 meter
- AF mode in One Shot
- Select center AF point
- First auto focus on your hand or whatever
- Refocus on object and take the shot
- Repeat/refocus between each shot
- After the third shot, use manual focus, live view, magnify x10, and do your best

(let's forget about the exposure... I had different light during the sessions)

The full picture

So you have to go through all those steps to archive this?? The hand between the subject??

???
It was just to explain to avoid any further discussion on how/what was done...
And sorry for my bad English.... text rephrased

Kris_2020 wrote in post #7276755
So you have to go through all those steps to archive this?? The hand between the subject??

I think what the OP is saying is that this accuracy problem is occuring when the AF moves between shots. Presumably if you are asking for it to refocus at the same point over and over it does not occur. So the hand trick is just to get the AF to move for every shot.

That's not a problem. That's manufacturing tolerance.

The tolerance for the autofocus system is to place the focus point within the Depth of Focus range (which is a calculation of the distance to subject, the maximum aperture of the lens, and the permissible circle of confusion). It only has to get the focus point somewhere within that range--and not necessarily at the same point within the range each time.

The goal of the system calculations is to produce a print that looks sharp at the intended focus point when the image is enlarged to 12x16.5cm and viewed at a distance of 25-30cm (according Canon's "Lens Work III," page 204). If you print the image to that size and view it from that distance, I suspect every shot will look sharp.

At your enlargement, you're looking "within" the tolerance and seeing the permissible variance.

canon 50 f/1.4 has some inconsistency. I'd doubt this is the camera.
my 50 f/1.4 behaves similar in crummy lighting, on my former 30D and my 1Dmark3. (the sigma 50 f/1.4 was worse for me so i stuck with the canon)

btw, exposure is important.. u should try these tests with adequate lighting and proper exposure in M mode imo.

I think the problem is with your 50mm f/1.4 and not with the camera.

Bob_A wrote in post #7277664
I think the problem is with your 50mm f/1.4 and not with the camera.

Yeah...I would suggest microadjusting the lens for the 5DMkII...

I've yet to try a 50mm f1.4 usm lens that has reliable focussing. I think it's because it's not using a ring type USM motor but a variation of the older micro motor design but using a slightly better motor. My copy is probably the worst AF accuracy in my entire lens collection. Even my old 50mm f1.8 mkI is more reliable. Even my 85mm f1.2 II L blows my 50mm f1.4 away for focus speed and accuracy, which is surprising.

is it the canon 1.4 or the sigma 1.4? neither have good trackrecords with AF.

roger767 wrote in post #7279241
is it the canon 1.4 or the sigma 1.4? neither have good trackrecords with AF.

It's the Canon 50/f1.4 lens

I can relate to what RDKirk is writing about this being within tolerance.
With the high resolution these types of issues are more visible.

Nevertheless I want my camera to focus properly and exact.
And as I understand from the guy that had this problem sorted out, it is possible to correct at Canon Service.
The next step is to have the lens checked (it's working fine on the 40D though)

1 metre is too close for a 'normal' (not macro) lens, try again at a greater distance - 50x the focal length used to be the distance used for lens testing ( a real pain with long telephotos............​...)

With a distance of only a metre and f/1.4 the DoF is going to be wafer thin.

I suspect anyone trying to achieve consistant results using those parameters would struggle. After all there will always be slight inconsistencies in the system.

At f/4 the DoF is obviously greater.

Canon recommends to do focus test with subjects at least 2m (~6ft) from the camera.

silvex wrote in post #7280770
Canon recommends to do focus test with subjects at least 2m (~6ft) from the camera.

Thanks. Point taken
I will do more tests with a distance of at least 2,5 meter