6dii with 85mm 1.8 works better than 5div with 85mm 1.8

[alyssal]

My 6dii with the 85mm 1.8 catches focus for my portraits very well. I use Expand AF Area: Surround. I've noticed when the 85mm is paired with my 5div, the focus is not always accurate. For example, I'll focus on the subjects face, but her ear or hair ends up being in focus. I normally shoot at 2.8 or 3.2 on both cameras. Is there something that needs to be adjusted in the 5div to work better with that lens? Am I doing something wrong? My 6dii seems to get it perfect every time, while my 5div is very hit and miss with the 85mm, it does fine with other lens' like my 35mm. Help!

[Anonymous]

My suggestion would be that you use the center focus point (1 point AF) and one shot focus mode on the 5D Mark IV.

[kvbarkley]

You can send the camera and lens to Canon and they can "tune" the AF for your lens.

[Waddizzle]

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@kvbarkley wrote:

You can send the camera and lens to Canon and they can "tune" the AF for your lens.

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This lens doesn’t really refocus consistently enough to make it worth the bother.  If I use One Shot AF and Center AF point on a tripod, I can nail focus if half press the shutter 2-3 times.  

I can often hear the lens “tick” as it refocuses on a 2nd or 3rd half press.  When the lens remains silent after repeated presses, then I assume that focus has been locked down as good as it is going to get.

[Waddizzle]

The 6D2 does have more cross-type AF points than the 5D4.  Using the tight cluster of AF points allows you to put the entire cluster on a face, which usually results in more accurate focusing.

I feel the EF 85mm f/1.8 USM is “hit or miss.”  I believe the initial release date was in the early 1990s.  The lens design is 30 years old.  

The AF motors seem to have backlash.  The tend to undershoot or overshoot their target.  When I use this lens, I only use One Shot AF.  I also lock focus at least two or three times to make sure the focus motors stopped where they should.

Because of the narrow depth of field when shooting wide open, the lens may seem to be soft wide open.  I think it is because of the over/under shoot issue.  Plus, digital cameras are just a little too fast for the lens.  I get pretty good results when focusing manually and relocking focus when using AF.

I need to try it on a MILC body.  I would expect it to outperform the results from a DSLR.

[ebiggs1]

"You can send the camera and lens to Canon and they can "tune" the AF for your lens."

Although a possibility you ae a long way from needing that. As Bob said "My suggestion would be that you use the center focus point (1 point AF) and one shot focus mode on the 5D Mark IV."  That is my suggestion too. This is simple work so try to keep it simple. There is absolutely no need to complicate it with fancy multiple AF points and such. I do this type work a lot, a whole lot. I am about to start the 2023-2024 Senior photo season at the school.

But first reset both your camera to default. Clear all settings and clear all custom settings. Surprisingly cameras generally do exactly what we tell them to so lets start from ground zero. Now you need a tripod and a good solid 'pretty' subject. Set P mode. One Shot center focus point only. Never use Ai-servo for this test. ISO 200 or whatever works for best exposure, lower number is better. Daylight WB. Make sure the ef 85mm f1.8 lens is set to AF. You can do this indoors but outdoors on a nice sunny day is best. Take several shots of one of your beautiful subjects. I would put the center focus point on her eye. If these dozen or so shots confirm that the 5D Mk IV is missing sharp focus, it may need some servicing but I would also send the lens with it to Canon if you do.