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?

 

[mdandreas]

I'm not a video professional, but I've done some study on it. As I understand, when you have a full crew with director, actors, scripts, etc, a scene is rehearsed and there are marks where an actor is supposed to stand at certain points. Getting the focus settings could be regarded as an addendum to script, and the focus puller needs to learn that.

I think that a one-man operation shooting unscripted activity that manual focus would be pretty hard to pull off (if you'll forgive the weak pun).

 

[StoneJack]

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?

It is just convenient to have focus where director wants it, rather than allow the camera to choose the focus point (and sometimes in wrong way). In same way you want a specific composition, color or DOF, you choose focus, that's it. However, recently some advocate for AF video shooting, which makes things very, very easy (albeit less controlling). However, what is OK in an amateur video, where the focus focused on wrong thing is not a tragedy, you can't allow camera to decide focus for multimillion dollar productions - if focus is wrong, you to have to reshoot etc, spend more money - instead just hire a focus puller and thats it.

 

[DMKAlex]

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?

 

[Pete Berry]

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?

Alex, I found the MF "focus peaking" of the GH4 very helpful, as it's AF-C wasn't that great. As long as you keep in mind which ring-turn direction goes deeper or shorter! Takes practice, and some fiddling with the peaking settings, though.

I've used it at with adapted MF primes in theater shoots w/ GH4, and at extreme focal lengths in nature shoots with my adapted Canon 100-400-II w/ no AF-C w/ GH5 & G9.

Pete

 

[mdandreas]

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?

Use a camcorder or a DSLR that has good continuous autofocus.

 

[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?

Though I don't own GH4, I have GX85 and by analogy i think that GH4 has AFF. I found Panasonic's AFF closest to Nikon's mirrorless AFF, thats very good. So you can AFF all the way. In addition, GH4 should have touch focus - and thats the manual focus you probably would prefer - so much better than pulling focus like in big productions. I use touch-AF even with Nikon DSLR which ain't got a great AF and it works great.

BTW, the analogy with Hollywood I used here probably was wrong. What I wanted to say is that focus pullers are for big production, and everybody else - including indie moviemakers, documentaries, music videos, educational videos etc -- they mostly use AF, cause it is cheaper and you are not creating an art masterpiece, but rather convey bits of important information, without need to pull focus in artistic way.

However, I watched your videos and it seems that you actually want to create an artistic video. In that case, you can use use the ring on Lumix lens *to pull focus or use Touch AF

 

[mdandreas]

Also, for cinematic films a small depth-of-field can be used to focus the audience's attention on the important story element. For personal videos, you probably don't want to do that so a large depth of field may be better. Camcorders tend to have smaller sensors and larger depth of field, but maybe low-light performance may not be quite as good.

 

[StoneJack]

Also, for cinematic films a small depth-of-field can be used to focus the audience's attention on the important story element. For personal videos, you probably don't want to do that so a large depth of field may be better. Camcorders tend to have smaller sensors and larger depth of field, but maybe low-light performance may not be quite as good.

True that. In analogy with smartphones, which shoot everything with large DOF, you can just either put aperture like F/8 or F/11 and have everything focused.

If you want to experiment with shallow DOF and touch stacking, just as I mentioned earlier, you should create a story which utilizes touch stacking - like a music video, or travel video, or a wedding (by the way a great way to try your video skills), and THEN use the focus stacking. Otherwise, keep everything in focus and everybody is already used to because of smartphones.

 

[deslok]

IF you are using the onboard mic, try recording in a quiet place and check if you can hear the autofocus:

https://www.dpreview.com/forums/thread/4252319

I don't use it for that reason. Fortunately most of my videos are wide angle, so I can have a very large manual DOF. e.g., at 8mm f/2.8 I can have 2.5ft to infinity in focus. Longer focal length will increase the near limit, and higher f-stop will decrease it. I calculate with an app called HyperFocal Pro on Android, but I'm sure there are others.

 

[Andrew S10]

Here's my random thoughts:

One factor in people defaulting to manual focus is the fact that DSLR's and Mirrorless cameras haven't had usable AF for the most part. That's changed in the last few years with several of the big brands, but manual focus still has it's place.

As others have mentioned, your camera doesn't know for sure what you want to focus on, so it might get it right and it might get it wrong.

I think manual focus makes sense with a true manual lens, but I would find it very frustrating to pull focus with a focus-by-wire lens, as consistent focus racks would be nearly impossible.

I have a Fotga DP500 IIS follow focus that's pretty good for the money. They should be under $50 used these days. I also put custom 3D printed ABS lens gear rings on my lenses.

Focus peaking helps, but it only gets you 90% of the way there.

Auto focus can struggle in low light, so manual focus can yield better results.

Focusing manually is a skill that takes time and practice to develop.

Manual focus gives you complete granular control of focus speed.

 

[ToxicTabasco]

I'm no pro. Although I do have some collaborations with Pros, and often get offers for projects.

As for video focus, I use both AF and manual focus. Just like photography, in video manual focus has it's place. The main reason I use it, is for full control over the focus. I also shoot video from behind the camera, not in front. Also, manual focus allows the camera to maintain a specific focal plane. Thus, not shifting small amounts causing the background to pulse. With manual focus, you can control the speed of the focus change to adapt to the motion of the scene or the mood of the shot.

I also use manual focus with Lumix lenses. These that have focus by wire or electric focus rings. Very smooth light one finger turn focus rings. And with a long throw.

The cameras have focusing aids such as focus peaking, PIP, and the focus distance scale which show up right there in the EVF or live view in real time while rolling. With Lumix cameras, focus peaking shows up in manual focus mode, not on AFC modes or AFF. Thus, with these focus aids and lenses, manual focusing is real easy to do. And best part is it can be done hand held without compromising smoothness and stability.

Nevertheless, there are times I'll use AF one area, or AF tracking. It all depends on what the situation is and what the shooting conditions are. Much like photography, knowing how to manual focus, and knowing when to use it is a great skill to have.

There's no rule that says you must only use one type of focusing. And no rule to use one type of tracking focus mode.

 

[uncle dunc]

Manual focus with a focus-by-wire lens can be unpredictable. The focusing reacts to how quickly you turn the focus ring, not the position of the focus ring, rendering a follow focus rig virtually useless, other than giving you better ergonomics for turning the focus ring. If you want to pursue manual focus, it would be good to get a couple of manual focus lenses. You'll have no AF, but you will have predictable focusing.

Panasonic's AF is the most unreliable of any of the manufacturers, due to its tendency to hunt for focus even after focus has been established. If the GH4 is similar to the GX85 and G7, you can set it to manual focus + AF and program the focus lock button on the back of the camera to AF to whatever's in the focus box. Between that and manual focus with focus peaking, and using higher F stops to create more depth of field, you can keep a pretty good handle on focus.

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.

 

[LingoDingo]

Panasonic's AF is the most unreliable of any of the manufacturers, due to its tendency to hunt for focus even after focus has been established.

The latest Panasonic AF is pretty good, but you have to know how to adjust it's settings to get optimum results from it. Here's a video on how to use the AF with the new S1 cameras, that gives you some idea about where Panasonic is going with their AF tech...

 

[ToxicTabasco]

Panasonic's AF is the most unreliable of any of the manufacturers, due to its tendency to hunt for focus even after focus has been established.

The latest Panasonic AF is pretty good, but you have to know how to adjust it's settings to get optimum results from it. Here's a video on how to use the AF with the new S1 cameras, that gives you some idea about where Panasonic is going with their AF tech...

I agree, 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

In this later part of the video (AT 5:14), are a series of manual focus ,I pulled using focus by wire hand held (my preferred form of manual focus).

 

[Retzius]

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.

 

[Adrian Tung]

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.

 

[StoneJack]

Panasonic's AF is the most unreliable of any of the manufacturers, due to its tendency to hunt for focus even after focus has been established.

The latest Panasonic AF is pretty good, but you have to know how to adjust it's settings to get optimum results from it. Here's a video on how to use the AF with the new S1 cameras, that gives you some idea about where Panasonic is going with their AF tech...

Thanks! This is a great video, very informative

 

[StoneJack]

Panasonic's AF is the most unreliable of any of the manufacturers, due to its tendency to hunt for focus even after focus has been established.

The latest Panasonic AF is pretty good, but you have to know how to adjust it's settings to get optimum results from it. Here's a video on how to use the AF with the new S1 cameras, that gives you some idea about where Panasonic is going with their AF tech...

I agree, 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

In this later part of the video (AT 5:14), are a series of manual focus ,I pulled using focus by wire hand held (my preferred form of manual focus).

nice video! I guess you shot mainly on AFF except the 5.14 focus pull part? Nice BM

 

[StoneJack]

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.

I found that AFF basically eliminates focus breathing. In my use of GX85, I have not really seen it. Granted, I used only native lenses with either power stabilization or OIS. I liked GX IBIS so much that I decided not buy any gimbal for this camera.