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New Contributor
Posts: 4
Registered: ‎04-14-2017

Will a 100-400 help with focus accuracy on a 70D for motorsports

I shoot mainly motorsports with my current setup a 70D with a 70-200 F4. It seems that the focus accuracy is decent but there are a lot of shots that miss focus. I'm currious if getting a 100-400 F4.5-5.6 will help that situation. Where I shoot there is a fair amount of elevation change, they are turning at the same time as well, I dont know if that messes with the focus. I also try and shoot at a low shutter speed if that matters.

 

I shot an drag racing event with a rented 70-200 F2.8 and the results were really good when compared to my F4. But I dont know if it was because of the lens or where I was located in the stands, or what.

 

 

 

 

 

 

Or should I just upgrade to a 7D Mk II. Smiley Happy

Reputable Contributor
Posts: 827
Registered: ‎02-06-2013

Re: Will a 100-400 help with focus accuracy on a 70D for motorsports

Focus accuracy increases in some cases with larger aperture lens...that explains better results with a f.2.8 lens versus a f/4 lens. So the 100-400 will not help because it's got smaller apertures (f/4.5-f/5.6).

 

Having said that, you should have no problem focusing for motorsports with the 70D with the 70-200 f/4. Going to a 7DII will help a little bit but it will not solve your problems (I suspect lack of technique).

 

Here's one tutorial on Canon 70D focusing.

 

Canon 70D Focus Tutorial

 

There are plenty more guidance but not on Canon sites. You should search for them on the internet

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Esteemed Contributor
Posts: 2,172
Registered: ‎11-14-2012

Re: Will a 100-400 help with focus accuracy on a 70D for motorsports

You're description of the local may explain some of the problem. How slow a shutter speed & are you using AI Focus? If the cars are both turning towards or away from you through an arcing motion the AF will be hard pressed to keep up & you will need a very smooth pan. Does your current lens have IS and if it does are you using mode 2? A lens with a panning mode of IS will be a big help at slow shutter speeds.

"A skill is developed through constant practice with a passion to improve, not bought."
Honored Contributor
Posts: 5,250
Registered: ‎08-13-2015

Re: Will a 100-400 help with focus accuracy on a 70D for motorsports


Stzvero wrote:

I shoot mainly motorsports with my current setup a 70D with a 70-200 F4. It seems that the focus accuracy is decent but there are a lot of shots that miss focus. I'm currious if getting a 100-400 F4.5-5.6 will help that situation. Where I shoot there is a fair amount of elevation change, they are turning at the same time as well, I dont know if that messes with the focus. I also try and shoot at a low shutter speed if that matters.

 

I shot an drag racing event with a rented 70-200 F2.8 and the results were really good when compared to my F4. But I dont know if it was because of the lens or where I was located in the stands, or what. 

 

Or should I just upgrade to a 7D Mk II. Smiley Happy


Missing focus on some shot is normal.  Not every shot will be a keeper.  But, part of it could be technique, which takes some practice.  Technique begins with how you hold the camera/lens combo.  Make sure a fingertip is not drifting onto the focus ring.  If entire photos are out of focus, then your technique may failed you.  Sometimes, you can simply miss a shot.


Your 70D has an AI SERVO, which mode should be able to lock onto subjects and track them fairly well.  Enable all of the AF points, but you should be to go into the menus and set the camera to always start with the center point, instead of letting the camera pick its' own AF starting point. 

 

Note, this is not quite the same as manually selecting the center AF point, which disables the remaining AF points.  For AI SERVO mode tracking, you want all of the AF points to be enabled by selecting them with the button. 

 

The EF 70-200mm f/2.8L II IS USM is a fantastic lens that is capable of capturing breath taking images.  I would expect the f/4 versions to be really good, too.  The latest EF 100-400mm f/4.5-5.6 II IS USM is another very sharp, quick focusing lens.

 

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Occasional Contributor
Posts: 18
Registered: ‎01-08-2016

Re: Will a 100-400 help with focus accuracy on a 70D for motorsports

Could the redundant out of focus with the F.4 be caused from a lack of light that hinders proper focus lock. This might be the reason the 2.8 images were sharper since the 2.8 maximizes more light in lower illuminated situations.
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