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16-35 f2.8 focus issue on video

Project
Contributor
I’m having focusing issues when using this lens on video with T6i body. Images are as sharp as can be expected out of this lens but video is just unusable. Camera is mounted on a tripod and I have tried about every focus setting I can think of. Vlog style video but moving or standing still everything is out of focus. I’m working inside a room and need the wide angle to capture as much as possible. I don’t think anything is wrong with the lens due to the fact it is sharp on photos and camera body is fine because other lenses are fine on video. Any ideas of where to start?
1 ACCEPTED SOLUTION


@Project wrote:
I may be totally wrong and maybe it’s a gimmick from canon but there is a Servo AF function in video mode that I can turn on or off. If it’s turned on, I can touch the screen on the subject I want to track and it will put a little white box on the subject and follow it around the screen as long as it’s within the field of view.

Yup.  My M3 does the same thing.  It probably works just like your T6i does in both Live View and Movie Mode.  The "tracking" leans a little toward the gimmick side, though.  As long as what you're tracking is the closest thing to the camera, it mostly works, albeit slowly.

 

Try this.  Switch to Live View, and keep the camera stil..  Use AI Servo focusing..  If you can still Touch AF, then do it, and keep the subject still.  Now half press the shutter, and the camera locks focus.  How could you tell it locked focus?  The box changed color.

 

When you touch AF, the white box appears on the subject, and stays on the subject as the subject moves around the screen.  Now try half pressing the shutter as the subject moves around the screen. The focus box stays on the subject.  What happens when the subject suddenly stops moving?  The camera locks focus, right?  How could you tell it locked focus?  The box changed color.

 

In both tests, the focus did not lock until the subject was still.  The camera is not maintaining focus as it tracks a subject.  The focus lags behind the tracking.  The subject must come to a near stop for the AF to get a lock.

 

Now, if you try that same test on a camera body equipped with a Dual Pixel AF sensor, the camera maintains near perfect focus while the subject is moving.  It does not have to wait for the subject to stop moving before it can get an accurate focus lock.  Half pressing the shutter maintains a focus lock at all times.  

 

THAT is the performance difference between CMOS AF III sensors and Dual Pixel AF sensors.

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"The right mouse button is your friend."

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19 REPLIES 19

What are the "other lenses" that are fine on video? With the possible exception of STM lenses, I didn't think that any lenses auto-focused in video on a T6i.

Bob
Philadelphia, Pennsylvania USA

Project
Contributor
24-105 f/4
24/70 f2.8
50mm f/1.2
Kit lens 18-55
70-300 f/4-5.6
All canon lenses and I don’t seem to have an issue with any but the 16-35. It has me puzzled for sure.

There is something you are not telling us, so I will tell you, instead.  No, I do not think you are trying be deceptive. It is more like the camera does not behave you seem to assume it does.  Mainly, I do not think the T6i has a Movie Servo AF mode, which means it does not do "AI Servo" like subject tracking in Movie Mode.  KV, correct me if I am wrong.

 

Without knowing more about your shooting conditions, I cannot say why you get your worse results with super wide angle lens. 

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"The right mouse button is your friend."

Correct, one of the few improvements of the T6S over the T6i is video focusing. However, neither is as good as the T7i which has the phase detect on sensor.

 

In this case though, I think the OP wants to use Av mode and set a shutter of f/8 or f/16 for a wide DOF - which should be easy with a wide angle lens (though 16mm is not particularly wide on a crop sensor. That is why they made the EF-S 10-18). You will prbably need more light.

"... I don’t seem to have an issue with any but the 16-35. It has me puzzled for sure."o 

 

Well for sure if you said almost any other Canon lens besides the ef 16-35mm f2.8L, I would be puzzled too.  I don't video so I am no help there. Perhaps little help elsewhere also but the one lens in my Canon inventory that I never use any more is the ef 16-35mm f2.8L It is a huge disappointment and surprise.

 

I like the suggestions from above that recommend the ef-s 10-18mm or ef-s 10-22mm not that I can claim either is a good lens, never having either, but they have to be better than the ef 16-35mm.

EB
EOS 1DX and 1D Mk IV and less lenses then before!

Project
Contributor
The 10-18 is cheap enough to give it a try as well. Thanks for all the fast input.


@Project wrote:
The 10-18 is cheap enough to give it a try as well. Thanks for all the fast input.

The EF-S 10-22mm is a much better built lens.  It has both internal focusing and zooming, and an all metal body. 

 

With a camera body that cannot do subject tracking in movie modes, then it is perfect for doing the type of "head shot" videos that you see all over YouTube.  Always be aware of your available Depth of Field whenever you are shooting.  I see people shooting at f/16 when they could have had nearly the same results at f/5.6.

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"The right mouse button is your friend."

Project
Contributor
I did a few tests today. If I sat still in front of the camera like I was doing an interview, the focus was just fine. I could pan side to side using a tripod and as long as I moved extremely slow, focus was fine. If there were anything moving very fast or pan at a moderate speed, everything was out of focus. I think the lens just can’t focus fast enough to keep up with the movement. I think I’ll get the EF-S 10-22mm and see if that’s better. Thanks everyone for all the input!!


@Project wrote:
I did a few tests today. If I sat still in front of the camera like I was doing an interview, the focus was just fine. I could pan side to side using a tripod and as long as I moved extremely slow, focus was fine. If there were anything moving very fast or pan at a moderate speed, everything was out of focus. I think the lens just can’t focus fast enough to keep up with the movement. I think I’ll get the EF-S 10-22mm and see if that’s better. Thanks everyone for all the input!!

The lens can focus plenty fast enough.  It is your camera body that is NOT refocusing in movie mode.  If you believe that your other lenses are refocusing in movie mode, then I suggest that you retest them..The T6i is incapable of Movie Servo AF.

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"The right mouse button is your friend."
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