Manual focus vs AutoFocus in video

[DMKAlex]

Quite a few of you, particularly the profs and more sophisticated, seem to advocate manual focus over auto focus in video.

Can you tell me what's the biggest advance of manual focus?

And, how you address the situation that the subject move in and out of focus, like the subject is walking over you?

Doesn't that make the follow focus mechanism a necessary investment?

 

[StoneJack]

Sure, in a production like movies or big $$$ videos, there is a set and there is a crew. And there is time to shoot and reshoot. We amateur doing casual video for our vacation, family event or even a wedding, don't have that luxury where the subject is scripted.

Now what?

I think you are looking at things a bit too simplistically. You cannot simply group all types of video into one lump and try to decide if manual focus or autofocus is a better option.

In scripted narrative video and film making the point of focus and how the focus shifts is an essential part of the story telling process. A director will control that along with every other element of the production.

In casual non-narrative video recording where you are simply documenting an event manual focus is not as important. However, rather getting into the weeds on this topic I will simply point out that 99.9% of those videos are not compelling for an audience to watch.

Nobody want to watch your vacation video, except maybe you.

There is a saying that "the road to bad video is paved with no intent". If you haven't considered every scene and angle, clearly identified a "hero" to guide your audience through the narrative, carefully planned out your lighting and scouted your locations, and clearly FOCUSED in each shot where you want the audience to direct their attention than your video is going to suck.

Making video is easy. Making good video is incredibly hard and has almost nothing to do with gear.

"the road to bad video is paved with no intent" - that's a great saying, man. I like it so much! Indeed the goal decides the way - thats why I insist on scripting the videos to be shot to understand where it will lead to - and what artistic or other means should be used for the particular shot.

 

[StoneJack]

I'm really interested in the Fuji XT3, which not only has AF that rivals Canon's DPAF, but it has a touch focus feature that enables you to program how quickly touch focus changes to the new focus point. With Panasonic, a new focus touch creates a sudden lurch to the new focus point, which does not look good on video. With the XT3, a new focus touch can "glide" slowly into focus, making it appear as though you're working with a focus-puller. The XT3 also has a linear option for manual focusing, making their focus-by-wire lenses act like manual focus lenses

For AF on a gimbal, I got a Samsung Galaxy S9, which uses the same dual pixel AF as Canon. Granted, you lose a bit of image quality, but in my Youtube productions incorporating the S9 footage with my GX85s and G7, the S9 footage actually looks better, probably due to the increased saturation and over-sharpening Samsung bakes into their video. The Samsung does have a "pro" mode, enabling manual settings for exposure, SS, WB and ISO, which is helpful in avoiding the changes in hue and exposure you get with a moving camera set to auto mode.

I really was impressed by XT3 and even its smaller siblings of XT20 so I was very seriously considering buying X-E3, which is essentially same XT20 in different shape. However, I decided to invest in GX85, one of best my decisions, which later led me to possibility of upgrading to GH5, cause now I have 4 Lumix lenses.

The only limiting thing for GX is lower bitrate of 4K which, I believe, was about 25 Mbps (I might be wrong and need to be corrected). Anyway, its much lower than GH5's 150 Mpbs or even 400Mbps, all internal.

My point is that I also invested in gimbal for smartphone and I found that iPhone XS max 4K footage is actually at least on PC is as good as GX and even looks smoother. The point is that mobile video is rapidly becoming so good, that we can't ignore when discussing filming cameras. And its all AF.

 

[LingoDingo]

The only limiting thing for GX is lower bitrate of 4K which, I believe, was about 25 Mbps (I might be wrong and need to be corrected).

I also own a GX85 as my vacation camera. The GX85 records 4K at 100 Mbps. Not as good as the GH5, but still a very nice image. ( I just wish the GX85 battery was bigger )

 

[StoneJack]

The only limiting thing for GX is lower bitrate of 4K which, I believe, was about 25 Mbps (I might be wrong and need to be corrected).

I also own a GX85 as my vacation camera. The GX85 records 4K at 100 Mbps. Not as good as the GH5, but still a very nice image. ( I just wish the GX85 battery was bigger )

Oh thanks for clarification!

 

[ToxicTabasco]

Panasonic has good AF ability with video. I wouldn't believe too far into the negative generalization of LUMIX AF. Reality is, it's not all that bad. And it depends more on skill level and ability than anything else. It works for thousands of Panasonic video and photo shooters, but will not work for everyone. And the recent cameras have much improved AF over the GH4

Yes, in general I too think Panasonic's recent AF is very good, except for a very specific use case: AF-C face detect/tracking of a moving, talking head. This is where the complaints of the pulsing effect on background come from.

However, because this is also the very same use case that many popular YouTubers will look for (because it is the easy and convenient go-to setting), the issue also gets unfairly amplified on the platform.

Yes I agree, it sure does for the talking head videos. A lot of them use AFC or face tracking or eye tracking when there is no need for it. For talking head shots, the head is not gong to be moving all over the frame. Thus, with any camera regardless of AF system, the background will pulse when AFC is locked on to a eye of a talking head. Any small move that head makes causes the pulse in the background. Thus, the solution is f/5.6 with a depth of field for 12 inches at 35mm will work with manual focus and no pulsing. IF they want more background blur, just move the head farther from the background.

Almost 80% of what people shoot can be done with manual+AF one area. But some how, AFC seems to be the only mode a lot of people use.

 

[Adrian Tung]

Yes I agree, it sure does for the talking head videos. A lot of them use AFC or face tracking or eye tracking when there is no need for it. For talking head shots, the head is not gong to be moving all over the frame. Thus, with any camera regardless of AF system, the background will pulse when AFC is locked on to a eye of a talking head. Any small move that head makes causes the pulse in the background. Thus, the solution is f/5.6 with a depth of field for 12 inches at 35mm will work with manual focus and no pulsing. IF they want more background blur, just move the head farther from the background.

Almost 80% of what people shoot can be done with manual+AF one area. But some how, AFC seems to be the only mode a lot of people use.

I think that oversimplifies things and overlooks some issues, but I get your point. Your solutions come from a film-maker's perspective, similar to how an experienced photographer would tell the amateur to stop using the cheap auto-do-everything features and properly learn their craft.

But playing devil's advocate, I guess depending on each individual, as well as their style, certain things may or may not apply so easily.

For example the solution of fixed focus: I suspect for a lot of YouTubers that's not going to work because they just can't reach out to their camera to pre-focus before starting the video (either they can't reach period, or pre-focusing this way will just end up with a front-focused video), such as a typical scenario of using a 12mm or 15mm propped up on a tripod in front of them.

I know Kasey of Camera Conspiracies currently uses a wired remote on his GH5s to do it for him, so that's actually a real possible solution given his filming conditions -- though he jokes of accidentally stopping the video when he just wanted to half-press to refocus). For someone filming themselves out on the streets would probably not work as you don't want a random passer-by to bring your whole rig down. I'm not sure if the Panasonic app works for refocusing in the middle of the video, but I understand why a YouTuber wouldn't want to use it (you'd have to look down at the phone to tap to focus).

Fixed focus also has other issues depending on filming style. If sitting at a table, one may want to lean forward when talking on a serious subject and then lean backwards for lighter banter. For gadget reviewers they may want to hold up an item to show to the viewers (and yes, I know you can just cut to B-roll for that, but this is YouTube, after all).

And then for live streamers, they don't really have much options open to them if they want to have a dynamic style where they may move or change position a lot (even if it's just leaning forward or back), show off products without cutting to B-roll, and not look like they keep fiddling with a phone/device to refocus.

And finally, I'd like to address this one thing specifically:

Any small move that head makes causes the pulse in the background.

This isn't the issue. The issue is that when the talking head isn't moving much, the pulsing is still going on -- something which the other manufacturers (Canon and Sony in particular) have no problems with, which is why people are panning Panasonic's DFD for it. Your occasional head movements do trigger the continuous autofocus to follow, but not in a way that produces the kind of pulsing that people are panning DFD for.

DPReview TV's first impressions of the G95/G90 at 9:42 onwards is a particularly bad case of pulsing which I highly doubt a Canon with DPAF or modern Sony would struggle with:

Loading…

www.dpreview.com

 

[ToxicTabasco]

Yes I agree, it sure does for the talking head videos. A lot of them use AFC or face tracking or eye tracking when there is no need for it. For talking head shots, the head is not gong to be moving all over the frame. Thus, with any camera regardless of AF system, the background will pulse when AFC is locked on to a eye of a talking head. Any small move that head makes causes the pulse in the background. Thus, the solution is f/5.6 with a depth of field for 12 inches at 35mm will work with manual focus and no pulsing. IF they want more background blur, just move the head farther from the background.

Almost 80% of what people shoot can be done with manual+AF one area. But some how, AFC seems to be the only mode a lot of people use.

I think that oversimplifies things and overlooks some issues, but I get your point. Your solutions come from a film-maker's perspective, similar to how an experienced photographer would tell the amateur to stop using the cheap auto-do-everything features and properly learn their craft.

But playing devil's advocate, I guess depending on each individual, as well as their style, certain things may or may not apply so easily.

For example the solution of fixed focus: I suspect for a lot of YouTubers that's not going to work because they just can't reach out to their camera to pre-focus before starting the video (either they can't reach period, or pre-focusing this way will just end up with a front-focused video), such as a typical scenario of using a 12mm or 15mm propped up on a tripod in front of them.

I know Kasey of Camera Conspiracies currently uses a wired remote on his GH5s to do it for him, so that's actually a real possible solution given his filming conditions -- though he jokes of accidentally stopping the video when he just wanted to half-press to refocus). For someone filming themselves out on the streets would probably not work as you don't want a random passer-by to bring your whole rig down. I'm not sure if the Panasonic app works for refocusing in the middle of the video, but I understand why a YouTuber wouldn't want to use it (you'd have to look down at the phone to tap to focus).

Fixed focus also has other issues depending on filming style. If sitting at a table, one may want to lean forward when talking on a serious subject and then lean backwards for lighter banter. For gadget reviewers they may want to hold up an item to show to the viewers (and yes, I know you can just cut to B-roll for that, but this is YouTube, after all).

And then for live streamers, they don't really have much options open to them if they want to have a dynamic style where they may move or change position a lot (even if it's just leaning forward or back), show off products without cutting to B-roll, and not look like they keep fiddling with a phone/device to refocus.

And finally, I'd like to address this one thing specifically:

Any small move that head makes causes the pulse in the background.

This isn't the issue. The issue is that when the talking head isn't moving much, the pulsing is still going on -- something which the other manufacturers (Canon and Sony in particular) have no problems with, which is why people are panning Panasonic's DFD for it. Your occasional head movements do trigger the continuous autofocus to follow, but not in a way that produces the kind of pulsing that people are panning DFD for.

DPReview TV's first impressions of the G95/G90 at 9:42 onwards is a particularly bad case of pulsing which I highly doubt a Canon with DPAF or modern Sony would struggle with:

https://www.dpreview.com/videos/dpreview-tv?play=13291

Yes, my main point is, there are many types of focusing techniques and every camera has more than one way to use focus. Not ever situation will require face tracking AF and knowing which AF mode to use for a specific condition is the best way to go about getting the shot.

A lot of people struggle to get photos and video because of their adaptation to only one type of focusing. And that one type of AF will not work best in every situation. If they learn how to use all the focus modes on the camera, given any situation they will not struggle with the most simplest task of photography which is focusing.

Nevertheless, the trend and preference is to use tracking AF for everything. And regardless of what the outcome is for videos and photos. People will continue to use it, and re-shape what we accept as good or bad with AF tracking. And over time, that will become the standard of the masses.

 

[LingoDingo]

A lot of people struggle to get photos and video because of their adaptation to only one type of focusing. And that one type of AF will not work best in every situation. If they learn how to use all the focus modes on the camera, given any situation they will not struggle with the most simplest task of photography which is focusing.

I started shooting still photos professionally in the 80's, back when we shot film and everything on cameras was fully manual. ( a few of the consumer cameras like the Canon AE-1 had automated aperture control, where you could set the shutter-speed and the camera would set the lens aperture )

Today I still own eight fully manual Nikon AI-S FF lenses that I use for both photos and video, and I still find it a little hilarious when I hand a DSLR with one of these AI-S lenses attached to an assistant to shoot some close-ups or BTS shots, and they struggle to focus with a fully manual lens. ( usually they are in disbelief that anyone could actually shoot with manual lenses )

Myself, I have no problem tracking people with manual focus when I'm shooting video. ( I struggle a little with macro shots because of the magnification, but I'm not sure any AF systems would be much better at keeping focus when the camera is moving at high magnification )

 

[Jon555]

Quite a few of you, particularly the profs and more sophisticated, seem to advocate manual focus over auto focus in video.

Can you tell me what's the biggest advance of manual focus?

And, how you address the situation that the subject move in and out of focus, like the subject is walking over you?

Doesn't that make the follow focus mechanism a necessary investment?

Mainly that it doesn't decide to go off and focus on the background (or some-such) mid-video.

 

[mdandreas]

[snip]

Myself, I have no problem tracking people with manual focus when I'm shooting video. ( I struggle a little with macro shots because of the magnification, but I'm not sure any AF systems would be much better at keeping focus when the camera is moving at high magnification )

How much time did it take you to learn this skill? How long do you think it would take the average photographer with photography lenses to learn this skill?

 

[LingoDingo]

[snip]

Myself, I have no problem tracking people with manual focus when I'm shooting video. ( I struggle a little with macro shots because of the magnification, but I'm not sure any AF systems would be much better at keeping focus when the camera is moving at high magnification )

How much time did it take you to learn this skill? How long do you think it would take the average photographer with photography lenses to learn this skill?

I originally learned this because there were no autofocus lenses around in the 80's, so every time you took a shot you had to manually focus, and if your subject was moving around ( like a model might ) you have to track them and keep them in focus to get good shots. ( a good optical or electronic viewfinder makes a big difference to be able to see when your subject is clearly in focus )

I honestly think it's a matter of practice to get good at this, and to try and use lenses with mechanical focusing because many of the "focus by wire" electronic lenses don't give you a good "feel" about manually controlling the focus. ( the electronic focusing ring might turn different amounts to reach the same focusing point, which is very annoying when you are trying to manually keep your subject sharp )

 

[ToxicTabasco]

[snip]

Myself, I have no problem tracking people with manual focus when I'm shooting video. ( I struggle a little with macro shots because of the magnification, but I'm not sure any AF systems would be much better at keeping focus when the camera is moving at high magnification )

How much time did it take you to learn this skill? How long do you think it would take the average photographer with photography lenses to learn this skill?

I originally learned this because there were no autofocus lenses around in the 80's, so every time you took a shot you had to manually focus, and if your subject was moving around ( like a model might ) you have to track them and keep them in focus to get good shots. ( a good optical or electronic viewfinder makes a big difference to be able to see when your subject is clearly in focus )

I honestly think it's a matter of practice to get good at this, and to try and use lenses with mechanical focusing because many of the "focus by wire" electronic lenses don't give you a good "feel" about manually controlling the focus. ( the electronic focusing ring might turn different amounts to reach the same focusing point, which is very annoying when you are trying to manually keep your subject sharp )

I agree.
Manual focusing is not hard to learn. It is a developed skill but anyone should be able to manual focus. Some focus by wire makes it difficult on some lenses, but some are much easier to work with than a hard stop focus ring. Also, some cameras have focusing aids like focus peaking that make it much easier and faster to get focus manually. And there are distance scales and magnification on the screen/evf which can also help.

Also, not every situation requires AFC tracking. There are times when manual focus is the only way to go. Night landscapes, with extreme low light, macro, or static shots of landscapes, time lapse, focus stacking, etc...

For me, manual + AF is what I shoot 80% of the time. I use it for just about everything from BIF, to motorsports. This allows focus peaking, and the super fast and accurate AF one area. And the ability to switch to manual to fine tune or pull focus while shooting video. And, if I need AFC, I just switch the selector to AFC, and have instant tracking.

I try to take advantage of all the focusing features of a camera. Reason is, every situation is different, and knowing which focus mode to use greatly improves success, and reduces failure.

 

[StoneJack]

[snip]

Myself, I have no problem tracking people with manual focus when I'm shooting video. ( I struggle a little with macro shots because of the magnification, but I'm not sure any AF systems would be much better at keeping focus when the camera is moving at high magnification )

How much time did it take you to learn this skill? How long do you think it would take the average photographer with photography lenses to learn this skill?

I originally learned this because there were no autofocus lenses around in the 80's, so every time you took a shot you had to manually focus, and if your subject was moving around ( like a model might ) you have to track them and keep them in focus to get good shots. ( a good optical or electronic viewfinder makes a big difference to be able to see when your subject is clearly in focus )

I honestly think it's a matter of practice to get good at this, and to try and use lenses with mechanical focusing because many of the "focus by wire" electronic lenses don't give you a good "feel" about manually controlling the focus. ( the electronic focusing ring might turn different amounts to reach the same focusing point, which is very annoying when you are trying to manually keep your subject sharp )

Yesterday I saw quite a big production video which was shot on full frame Sony. The operator used automatic focus. In some cases, I noticed a slight focus breathing. Should have used manual. It was not very noticeable but still.

 

[Jon555]

[snip]

Myself, I have no problem tracking people with manual focus when I'm shooting video. ( I struggle a little with macro shots because of the magnification, but I'm not sure any AF systems would be much better at keeping focus when the camera is moving at high magnification )

How much time did it take you to learn this skill? How long do you think it would take the average photographer with photography lenses to learn this skill?

I originally learned this because there were no autofocus lenses around in the 80's, so every time you took a shot you had to manually focus, and if your subject was moving around ( like a model might ) you have to track them and keep them in focus to get good shots. ( a good optical or electronic viewfinder makes a big difference to be able to see when your subject is clearly in focus )

I honestly think it's a matter of practice to get good at this, and to try and use lenses with mechanical focusing because many of the "focus by wire" electronic lenses don't give you a good "feel" about manually controlling the focus. ( the electronic focusing ring might turn different amounts to reach the same focusing point, which is very annoying when you are trying to manually keep your subject sharp )

Yesterday I saw quite a big production video which was shot on full frame Sony. The operator used automatic focus. In some cases, I noticed a slight focus breathing. Should have used manual. It was not very noticeable but still.

MF wouldn't affect Focus Breathing, that's a lens property (focal length changing with focus distance). I suspect you mean the focus was wavering around a bit?

 

[StoneJack]

[snip]

Myself, I have no problem tracking people with manual focus when I'm shooting video. ( I struggle a little with macro shots because of the magnification, but I'm not sure any AF systems would be much better at keeping focus when the camera is moving at high magnification )

How much time did it take you to learn this skill? How long do you think it would take the average photographer with photography lenses to learn this skill?

I originally learned this because there were no autofocus lenses around in the 80's, so every time you took a shot you had to manually focus, and if your subject was moving around ( like a model might ) you have to track them and keep them in focus to get good shots. ( a good optical or electronic viewfinder makes a big difference to be able to see when your subject is clearly in focus )

I honestly think it's a matter of practice to get good at this, and to try and use lenses with mechanical focusing because many of the "focus by wire" electronic lenses don't give you a good "feel" about manually controlling the focus. ( the electronic focusing ring might turn different amounts to reach the same focusing point, which is very annoying when you are trying to manually keep your subject sharp )

Yesterday I saw quite a big production video which was shot on full frame Sony. The operator used automatic focus. In some cases, I noticed a slight focus breathing. Should have used manual. It was not very noticeable but still.

MF wouldn't affect Focus Breathing, that's a lens property (focal length changing with focus distance). I suspect you mean the focus was wavering around a bit?

Yes, focus hunting.

 

[DMKAlex]

Would I be better off with something like a Rokinon or Samyoung 12mm f/2?

These 2 lenses have the old mechanical focus an pull reliably, right? How about noise when turning the focus?I

 

[LingoDingo]

Would I be better off with something like a Rokinon or Samyoung 12mm f/2?

I own the Samyang 12mm f/2.0 lens. It's silent when manually focusing, but you need good eyesight ( or a good monitor ) to track someone when manually focusing. ( the DOF is still pretty deep wide-open with this lens, unless you are focusing very close to something )

Which is why I also own the Olympus 12mm f/2.0 for it's AF focusing. ( the Olympus also has pretty good manual focusing, so despite being more expensive, I would choose it over the Samyang )

 

[DMKAlex]

If the dof is deep, that means a wide latitude to stay focused, right? Isn't it good?

On the Oly, the AF works with GH4 just like a Pany native lens?

 

[Adrian Tung]

A lens with deep DOF can be both a boon and a curse. On one hand, the deep DOF helps keep things in focus, so even if your subject has a bit of movement going on it'll still be alright.

On the other hand, this also means without a good monitor to check focus, it's also hard to tell if the subject is really in focus or maybe just slightly OOF until you go home and look at the footage on a bigger screen. With shallow DOF you can look at cues on the ground (or any other flat plane) to tell where the plane of focus is, but it isn't so apparent with wide angles and deeper DOF.

I'm guessing the Oly 12/2.0 is suggested because it has the focus clutch which is the next best thing to a manual focus lens, and you can always fall back to AF when necessary.

 

[LingoDingo]

If the dof is deep, that means a wide latitude to stay focused, right? Isn't it good?

On the Oly, the AF works with GH4 just like a Pany native lens?

As Adrian said it can be both good and bad. Good because if your focus is close-enough you won't notice if it's off a little bit, but bad because it's a little hard to tell when you've got perfect focus. ( 4K video is not very forgiving for focusing errors )

The Olympus lens works well with Panasonic cameras, and like Adrian said it has a focusing clutch mechanism that gives a close simulation to a real manual lens. ( kind of a best of both worlds having the choice between AF or the clutch mechanism )

For me the Olympus lens AF is very handy for still photography where you want instant focusing to get the shot, where the clutch-mechanism is better for video work.