06-18-2020 01:51 AM
I hope everyone is keeping well?
I am wondering if someone can solve this frustrating issue for me...?
I have a Canon 5D mrk iv with these 3 lenses :-
ef 24-105mm f/4l is ii usm
ef 16-35mm f/2.8l is iii usm
ef 70-200mm f/2.8 is iii usm
My issue is, when I attach and start using the 200mm, even with auto focus and image stabilization on, the focal point of the image isn't perfectly clear once I put on my laptop, even at 70mm range. I previously used this lens with my Canon 5D mrk iii, and have no issue with the focusing.
Strange thing is, both the other 2 lenses with the mrk iv, there is no issue, the images are very sharp on the big screen. Its just the mrk iv & 70-200mm combination I am having trouble with.
Can someone please help??
Many thanks in advance.
06-18-2020 07:02 AM
It sounds like you need to adjust the focus calibration for this lens to your camera. Here is a link to Canon's micro focus adjustment guide: https://cdn.static-bl.com/images/manual/Canon-AF-Micro-Adjust-Guide.pdf
It is a simple process but I use a slightly different procedure to speed things up. I follow the Canon process EXCEPT that I take multiple shots at different offsets in a single test run so that when I examine them on the computer I will either have the exact calibration offset in the set or will know exactly the range that I need to zero in on.
Once I have the target set up, I take images with the micro-adjust set at 0, +3, +5, +8, -3, -5, and -8 and then check on the computer to see which of these is exact or closest.
A yardstick or similar set in the grass makes a good target and the grass blades provide a clear example of where the optimal focus range is located. With a zoom lens, there is a calibration at the wide and tele ends and I would do all of the test images at both ends (a total of 42 test shots in your first run since you will take 3 shots each at each offset for both the 70 and 200 ends).
Shoot in manual mode with the lens wide open (f2.8), single shot AF, with enough shutter speed to avoid shake (in daylight 1/500 or greater should be possible) and set the ISO to auto. Take three shots at each setting just to ensure that you don't make a judgement on a one shot aberration in the AF performance. The micro adjustment offset is contained in the EXIF data so you can clearly identify the offset when looking at the image in DPP.
06-18-2020 10:23 AM
"It sounds like you need to adjust the focus calibration for this lens to your camera."
Hold on there cowboy! Micro focus adjustment isn't the first thing to think about. In fact the better the camera and lens the less it seems to be needed. Of course some lenses do but not many.
"... the focal point of the image isn't perfectly clear once I put on my laptop,..."
What exactly does this mean? WHen you look at a photo is the area just in front of the target in precise focus, or directly behind it? If the answer to that question is, yes, than AFMA, might help. Otherwise it will not. AFMA never makes any lens sharper or better in focus. It can not. A lens is as sharp when it is made as it will ever be. AFMA simply moves that precise focus point forward or backward.
Now if large areas or all the photo seems soft, it is not a AFMA issue. It could just be a DOF issue and that is normal. It could be camera motion, etc, several other things. AFMA is not the first thing to try.
06-18-2020 12:12 PM
The micro adjustment offset is contained in the EXIF data so you can clearly identify the offset when looking at the image in DPP.
I can't see the above in DPP, where can I find please?
06-18-2020 12:16 PM
Click on (or open) any image in DPP and either click on view in the menu and choose info or press CTRL I with a PC (not sure what the key shortcut is for a Mac).
The window with EXIF data will open and the micro AF adjustment setting used for that shot is about midway down the list of EXIF data in the AF section.
06-18-2020 02:37 PM - edited 06-18-2020 02:39 PM
I am not sure if DPP behaves differently on Apple but it seems like the EXIF data should still be there. Attached is a screenshot from my PC setup.
If it doesn't show up with the Mac version of DPP, you will need to keep track of it by shot (i.e. the first 3 were shot at 0, the next 3 at +3, etc.) however it is sure handy to be able to read it from the EXIF.
On Edit, you might try it with RAW instead (which is how I capture all of images, maybe you will get the full EXIF that way with the Mac version of DPP).
07-04-2020 08:19 AM
I had a chance to go out and shoot today with the adjusted lens callobration. Unfortunately its still terribly out of focus, i am a track and field photographer so i photograph fast moving objects, I had the shutterspeed at 800 but still blurry. I attached onto my 5D mrkiii and was perfectly sharp!
I am really lost with this, all my other lenses i tried with both cameras are fine, and the 200mm on the mrkiii is fine, its just the mrkiv with the 200mm is the issue...