AF microadjustment tricks

[arash_hazeghi]

Hi Ken,
I tested my 7D, the AF indicator box on the transmissive LCD screen seems to be perfectly aligned with the AF sensor, at least I can't measure any error, the target box is 5mm X 6mm approximately, I centered the AF box in the finder and then superimposed the sensor in DPP.

Are you sure your were looking straight through the finder? (you should look completely perpendicular to the eye piece, if you look at angle you will see a different area under the AF box. This may not be easy if you wear glasses). I suggest trying again, more carefully this time, if you see misalignment I would send the camera to Canon for adjustment.

Best

[Ken Foss]

Hi Ken,
I tested my 7D, the AF indicator box on the transmissive LCD screen seems to be perfectly aligned with the AF sensor, at least I can't measure any error, the target box is 5mm X 6mm approximately, I centered the AF box in the finder and then superimposed the sensor in DPP.

Are you sure your were looking straight through the finder? (you should look completely perpendicular to the eye piece, if you look at angle you will see a different area under the AF box. This may not be easy if you wear glasses). I suggest trying again, more carefully this time, if you see misalignment I would send the camera to Canon for adjustment.

Best

Thanks Arash, I checked my camera again to confirm the alignment. I agree that you must have your eye centered in the viewfinder as there is a significant amout of parrallax if you are off to one side. My test confirmed that there is a discrepency in the target location of the focus point when comparing the viewfinder with LV. The best that I could determine is that the difference between the two is 1.25 inches with my 300mm lens at 50 ft. For my test I used only the certer focus point. Again, I may be nit picking but I could see how this might be an issue when attemting to auto-focus on something such as a birds eye.

[arash_hazeghi]

Thanks Arash, I checked my camera again to confirm the alignment. I agree that you must have your eye centered in the viewfinder as there is a significant amout of parrallax if you are off to one side. My test confirmed that there is a discrepency in the target location of the focus point when comparing the viewfinder with LV. The best that I could determine is that the difference between the two is 1.25 inches with my 300mm lens at 50 ft. For my test I used only the certer focus point. Again, I may be nit picking but I could see how this might be an issue when attemting to auto-focus on something such as a birds eye.

Hi Ken,

I checked the AF indicator positions again, this time using a laser beam in the lab for each AF sensor, they all seems to be perfectly aligned with the respective frame in the finder which is not surprising to me at all, given that camera is a precision device. If I were you I would send the camera to Canon for calibration. I am sure they will notice this. BTW, It's not nit picking at all, 7D has spot AF mode for a reason, sure will cause issues in certain cases!


Good luck,