EOS 90D Autofocus Issues with EF 100-400mm L IS II USM

[canon_eos_90D]

I recently bought a Canon EOS 90D body.

Unfortunately I'm encountering focus issues when using the body with the Canon 100-400mm L IS II lens.

When I'm trying to focus (using OVF) on an object (like a race car for instance) that's coming towards to me, the camera/lens won't focus.

The settings on my camera are: Autofocus > AI Servo, shutterspeed: 1/1000 - 1/2000. Normally those shutterspeeds should deliver me a sharp picture. But that's not the case.

When I attach the lens to a Canon 6D or 5D Mark IV I don't have any problems at all; the focus issues don't happen with those two bodies.

I know when a subject moves closer to or further away of the camera, the sensor can have some difficulties in focussing. But with the fast shutter speeds I should get sharp images, which is not happening with the 90D body.

Anyone an idea how I can solve this issue?

[Waddizzle]

"For situations like that, your 90D MIGHT need to use a single focus point and the one in the center of the array is the desirable point for highest performance of the camera/lens combination.  If you can put and keep that single focus point on an area with some contrast, the camera is going to be able to provide its best AF performance in the extremely high closure rate situation you describe."

What is being said, but  not being emphasized is that you need to keep that AF point on the same area.  When you are using a single AF point, it is crucial that you keep it on the same part of the subject.  All the AF system "sees" is what is under that single AF point.  If the area keeps changing, if the goal posts keep moving, then camera  may get a little lost trying to lock focus.

Using 9-pt AF mode allows an adjacent AF point to detect the center AF point slipping off of the target, and can kick in to pickup the slack until you can get the center AF point back on target.  The larger zone AF modes work in a similar way, but just with more AF points around the center AF point.  More gives you a little more leeway when you slip off target.

However, on the 90D there are only two AF point choices that allow you to select the starting point for AF focus tracking: either 1 AF point enabled, or all 45 AF points enabled.  The 9-pt AF Assist mode is not featured on the 90D.  You would need to use the Large Zone AF modes.

[ebiggs1]

"I have never shot a 90D but I have shot a lot of different sports with my 1DX,..."

Rodger,

I do not own a 90D but I have used one just a bit. It is a very capable camera. A 90D and the Sigma 18-35mm f/1.8 DC HSM Art Lens is the best crop camera combo I have ever used bar none. That combo would not be embarrassed by my/our 1DX in most situations.

There are two cameras I didn't or don't own that I wished I did and now somewhat regret it. One is the Nikon D850 and the other is the Canon 90D with that Siggy lens attached.

[wq9nsc]

Ernie,

Everything I have heard about the 90D has been positive, it sounds like an excellent camera body.

I wasn't trying to disparage the 90D in any way.  I wanted to make the point that even with the highest end cameras, the user is still the key with difficult shooting situations even with all of the technology currently available.

That Sigma f1.8 wide angle zoom makes a good case for owning a crop camera.

Rodger

[Waddizzle]

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@wq9nsc wrote:

Ernie,

Everything I have heard about the 90D has been positive, it sounds like an excellent camera body.

Rodger

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There are a LOT of users who knock the 90D.  It is an excellent camera, perhaps too excellent for some people.  The very high pixel density on the image sensor will reveal all of the strengths and flaws of a lens.  It does the same to photographers.

[wq9nsc]

A friend sent me a pair of 5DS and 5DS R bodies when they first became very inexpensive in his country.  One difference I noticed with its 50.6 MP sensor was it has a higher minimum shutter speed for easy handholding because the higher density/resolution sensor makes camera shake more obvious.

I suspect the 90D would show the same issue when shooting handheld with shutter speed close to the reciprocal of the effective focal length and this is one place where the crop sensor play into the calculation of minimum "safe" shutter speed. 

Rodger

[ebiggs1]

My understanding is a 30MP crop sensor or a 50MP full frame sensor is the upper limit before this higher resolving power becomes a real factor.  It is not different than comparing a poor lens to a great lens. It all depends on the resolving power.

If one camera/lens combo can resolve an object of 5mm VS a camera/lens combo that can resolve 2mm, a higher SS is probably a good idea and justified. However, I always looked at the 1/FL reciprocal as a lowest figure. I.E. you have a 50mm lens so 1/50 SS but you actually select 1/60. 100mm FL you select 1/120....

[Waddizzle]

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@ebiggs1 wrote:

My understanding is a 30MP crop sensor or a 50MP full frame sensor is the upper limit before this higher resolving power becomes a real factor.  It is not different than comparing a poor lens to a great lens. It all depends on the resolving power.

If one camera/lens combo can resolve an object of 5mm VS a camera/lens combo that can resolve 2mm, a higher SS is probably a good idea and justified. However, I always looked at the 1/FL reciprocal as a lowest figure. I.E. you have a 50mm lens so 1/50 SS but you actually select 1/60. 100mm FL you select 1/120....

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I use 1 (2 *FL) with my 7D2 as a preferred minimum SS.  No doubt the 90D probably needs 3 times the FL.  But, a fast shutter speed is not going to correct autofocus and tracking problems.

I asked the OP if he tested the camera/lens combo on a tripod photographing stationary objects.  The response was a pretty gnarly negative.  Something about using tripods at a racetrack is not a good idea.  I don't think he understood the question.

But, I am still waiting to see sample photos of the issue.  If my 6D2 can photograph RC aircraft, then I am pretty sure the 90D can handle motor sports just as well, if not better.  The two cameras have similar AF systems.

[wq9nsc]

Good points Ernie!

The old reciprocal rule is definitely just a guideline with some gray area around it.  With extreme care, it is definitely possible to handhold below the guideline but it requires you to behave much like a sharpshooter OR get some help from a handy tree or other object that lets you brace your body and/or the camera.  If you are in a situation that requires immediately capturing a fleeting scene then 1/focal length probably isn't going to be fast enough to avoid some operator induced camera shake and that is usually the conditions I am shooting under.

I can shoot a few images handheld with my heavy and awkward EF 800 f5.6 lens but those are going to be at high shutter speed and the IS will be on because that lens/camera combo is just too heavy and awkward to hold in a stable manner for any reasonable period of time.  Guidelines are good starting points but often we are in situations that violate the underlying assumptions of those guidelines so thought and experience are needed.

With sports I normally wouldn't be able to shoot close to or at that limit because there isn't time for me to settle the camera sufficiently but that generally isn't an issue since I am using very high shutter speed to freeze the players. The only time I have run into this issue is with night events in poorly lit facilities where I toggle to my second set of shooting parameters for catching post-score celebrations (narrower aperture for greater depth of field and a drop in shutter speed to compensate).  In some cases, the desirable shutter speed puts me at the point where I do have to use care with the EF-400 / 1DX III combo to avoid blur.  I could leave IS on but it needlessly uses battery power when IS isn't needed for 99% of what I am doing with sports and usually I can go with an exposure triangle that provides sufficient depth of field without pushing the ISO too high or the shutter speed too low.

And on edit:  I do like using single point with expansion AF when appropriate because it is very useful when you don't have to pick one player out of a group, it makes framing a bit easier when following fast moving scenes.  I use single point with expansion when shooting softball and baseball and it works well for me with those sports, I just shared a few images from softball in the "share your images" section.  Shooting with AF point expansion takes a little pressure off of me, with many sports like soccer and football single point works best for me and that requires a lot of constant concentration while shooting softball is relaxing.

Rodger

[ebiggs1]

As your SS increases IS becomes less valuable. At very high SS it’s a no factor.

[jrhoffman75]

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@ebiggs1 wrote:
As your SS increases IS becomes less valuable. At very high SS it’s a no factor.

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While it's benefit at stopping motion blur at high shutter speeds is low it does have the benefit of stabilizing the viewfinder image which can help with framing.

There as a good discussion about this by Rudy Winston on the Canon site a few years ago, but Canon's revamping of the site has made it difficult to find material from past years.