topic Re: 16-35 f2.8 focus issue on video in EF & RF Lenses

16-35 f2.8 focus issue on video

Project — Tue, 07 Jan 2020 22:55:00 GMT

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?

Re: 16-35 f2.8 focus issue on video

RobertTheFat — Wed, 08 Jan 2020 03:58:05 GMT

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.

Re: 16-35 f2.8 focus issue on video

Project — Wed, 08 Jan 2020 01:02:44 GMT

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.

Re: 16-35 f2.8 focus issue on video

Waddizzle — Wed, 08 Jan 2020 02:44:55 GMT

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.

Re: 16-35 f2.8 focus issue on video

kvbarkley — Wed, 08 Jan 2020 03:15:51 GMT

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.

Re: 16-35 f2.8 focus issue on video

Project — Wed, 08 Jan 2020 03:32:17 GMT

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

Re: 16-35 f2.8 focus issue on video

Waddizzle — Wed, 08 Jan 2020 09:47:03 GMT

@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.

Re: 16-35 f2.8 focus issue on video

ebiggs1 — Wed, 08 Jan 2020 15:34:13 GMT

"... 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.

Re: 16-35 f2.8 focus issue on video

Project — Thu, 09 Jan 2020 03:21:41 GMT

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!!

Re: 16-35 f2.8 focus issue on video

Waddizzle — Thu, 09 Jan 2020 10:15:06 GMT

@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.

Re: 16-35 f2.8 focus issue on video

Project — Thu, 09 Jan 2020 14:12:59 GMT

I think you’re mistaken. The T6i is capable of servo AF in movie mode and I have the choice to turn it on or off. I can watch the AF work. It’s just slow on this lens.

Re: 16-35 f2.8 focus issue on video

Waddizzle — Thu, 09 Jan 2020 23:01:19 GMT

@Project wrote:
I think you’re mistaken. The T6i is capable of servo AF in movie mode and I have the choice to turn it on or off. I can watch the AF work. It’s just slow on this lens.

I beg to differ. KV was correct, as always. Your camera does not really track subjects.

"Movie Servo AF" is exclusive to cameras with Dual Pixel AF sensors. That camera has a Hybrid CMOS AF III sensor. Read the description very carefully. No where does it mention "tracking", just faster focusing. I have that same sensor in my M3, and it does not track in Movie Mode.

You must tell it where to focus, and hopefully your subject is under one of the AF points. Also, with a wide angle lens your subject may be a little to far away for the camera to pick up out of the background. Subjects almost need to fill the frame.

Re: 16-35 f2.8 focus issue on video

kvbarkley — Fri, 10 Jan 2020 15:32:25 GMT

Actually, the T6S does not have dual pixel either, just a slightly improved method for object tracking.

The T6i only has contrast detection focusing in video mode. This is inherently slower than phase detect focus. It can track, but not very well.

Re: 16-35 f2.8 focus issue on video

kvbarkley — Fri, 10 Jan 2020 15:36:22 GMT

From Adorama from an article comparing the T6S to the T6i :

"TheCanon T6salso comes with some notable shooting features including Canon’s SERVOAF in live view, allowing for some of the fastest refocusing and tracking capabilities in aCanon Rebel camera. If you’re an aspiring wildlife photographer or want to capture all theaction at a sporting event, SERVO AF will help keep the action tack sharp. Lastly, althoughboth the Canon T6s and Canon T6i can shoot 30 frames-per-second 1080P full HD video, theT6s includes an incamera HDRmovie mode."

https://www.adorama.com/alc/0015165/article/Canon-T6i-T6s-Comparison-An-Enthusiast-DSLR-That-Meets-the-Professional-Grade

Re: 16-35 f2.8 focus issue on video

RobertTheFat — Fri, 10 Jan 2020 16:11:27 GMT

@kvbarkley wrote:
From Adorama from an article comparing the T6S to the T6i :
"TheCanon T6salso comes with some notable shooting features including Canon’s SERVOAF in live view, allowing for some of the fastest refocusing and tracking capabilities in aCanon Rebel camera. If you’re an aspiring wildlife photographer or want to capture all theaction at a sporting event, SERVO AF will help keep the action tack sharp. Lastly, althoughboth the Canon T6s and Canon T6i can shoot 30 frames-per-second 1080P full HD video, theT6s includes an incamera HDRmovie mode."

https://www.adorama.com/alc/0015165/article/Canon-T6i-T6s-Comparison-An-Enthusiast-DSLR-That-Meets-the-Professional-Grade

Notwithstanding all that blather, the bottom line is what it's always been: If you need to shoot video well, get a video camera.

Re: 16-35 f2.8 focus issue on video

ebiggs1 — Fri, 10 Jan 2020 21:00:41 GMT

"If you need to shoot video well, get a video camera."

Seems reasonable doesn't it? I guess not.

Re: 16-35 f2.8 focus issue on video

Waddizzle — Fri, 10 Jan 2020 21:46:15 GMT

@Project wrote:
I think you’re mistaken. The T6i is capable of servo AF in movie mode and I have the choice to turn it on or off. I can watch the AF work. It’s just slow on this lens.

There is a crucial and subtle difference between the AF systems. Apparently, the T6i performs continuous AF by using contrasting colors. It is not capable of actual subject tracking and face tracking around the viewfinder, in either movie or stills modes.

You seem to be expecting face/subject tracking. By focusing on the closest contrasting colors, the camera may seem like it is tracking your subject. But, it is not really tracking the subjects. Subject tracking usually puts a moving AF square on the subject, as the subject moves around the viewfinder.

Re: 16-35 f2.8 focus issue on video

Project — Sat, 11 Jan 2020 20:09:11 GMT

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.

Re: 16-35 f2.8 focus issue on video

Waddizzle — Sun, 12 Jan 2020 00:37:47 GMT

@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.

Re: 16-35 f2.8 focus issue on video

Project — Sun, 12 Jan 2020 00:49:01 GMT

Awesome explanation. Thank you very much!!