Microadjust - What aperture?

I'm trying to MA my 24L - it's a tad soft wide open. So should I do the MA at a wide aperture since that's where my concern lies, or is there some rule like you always microadjust at F/8 I don't know about?

Thanks,

Wide open is the standard advice, since DOF is thinnest there.

Do be cautious of focus shift with some lenses though - if it was still giving you trouble then you could try at your usual shooting aperture (if you have such a thing) but there isn't much sense in doing MA for a less precise setting (i.e. a wider aperture) otherwise.

Good luck!

Thanks!

Is your lens just optically soft,,or is it misfocusing?

There is a difference.

yogestee wrote in post #13186065
Is your lens just optically soft,,or is it misfocusing?

There is a difference.

It's missing focus. I'll lock focus on a subject's face, but the face will be soft and their chest will be sharp. That sort of thing. This is what MA fixes right?

snakeman55 wrote in post #13186097
It's missing focus. I'll lock focus on a subject's face, but the face will be soft and their chest will be sharp. That sort of thing. This is what MA fixes right?

Correct, microadjust only fixes front/back focusing issues not a soft focusing lens.

Aren't lenses, by default, wide open while achieving focus and only stop down at moment the shot is taken?

crn3371 wrote in post #13186677
Aren't lenses, by default, wide open while achieving focus and only stop down at moment the shot is taken?

Yep. That's why you should always MA at wide open setting.

You set the lens at maximum aperture and select a subject at least 50 times the focal length of the lens being adjusted. So for example a 100mm lens would bet set to focus at least 5000 mm away (50 x 100 = 5000mm). (I use the Spyder Lens Cal device which gives a nice target to perform micro-adjustment. There are various other brands available). Set up on a tripod as this test requires accuracy. Start with MA set at 0. Take three shots. After each shot manually focus the lens away from the selected focus to make the lens refocus on the second and third shots. Then set MA in camera to +5 and repeat. Then go to +10 and repeat and then +20. Then set to -5, -10 and -20 repeating as before. Take notes to be sure you know which shot was taken with their respective MA setting. I then download all the shots to Lightroom and see which setting looks best and set the camera appropriately. Once you see which setting looks best you can fine tune the MA in increments of 1 unit for absolute precision. Good luck.