Sony's video autofocus is an incredibly powerful tool
that in recent years has really come into its own.
It has gone from something I would never use to something
I rely upon for a lot of my filming.
But it isn't something that you just turn on and it will always work perfectly.
You need to understand how to get the best from it and that comes down
to a number of key settings, your lens choice, cameras, filming situations
the light, and so many other factors, which I will go through with you.
It's easily the most complicated part of the camera's operation to truly master
which is ironic considering it's just replacing the focus ring of your lens
but it's worth it.
I'm Philip Bloom, and I'm a director of photography and filmmaker from England
and I'm going to show you how to get the best out of
the video autofocus of the Sony Alpha cameras.
From now on, when I say autofocus or AFI, I'm referring to video autofocus
and not the stills mode, because there are many differences
I just want to keep saying that video word.
In these videos, I will be using the Alpha cameras
with the more in-depth options for AF, which started with the A7SIII.
A lot of what I will be going through does apply to the older cameras
but not all of them, they don't have all the features that I'm going to cover.
Some cameras have identical systems in them, like the FX3 and the A7SIII
and they are very similar to cameras like the Alpha 1 and A7IV.
The bigger cinema cameras, the FX6 and FX9, are also similar
but they do have a few differences in operation.
But because at their core, the AF system is the same
I will be showing shots from all of these throughout these videos.
Autofocus has been around for decades, but it's taken a long time to get
to this point where you can actually use it and trust it.
With stills, it doesn't need to be smooth, it just needs to be fast and accurate.
If it misses the odd frame here or there, it's not the end of the world.
But with video, if the autofocus gets it wrong
then the whole shot is ruined.
And that's why autofocus needs to be not just good, it needs to be great.
If I can't trust a camera's autofocus, I simply won't use it.
You also want it to look as natural as possible.
You want it to look like a human is pulling focus, just very, very well.
I spent most of my 33-year career using manual focus and I do still today
but Sony's autofocus has now given me the ability to shoot in a way
that just wasn't possible before with large sensors.
I can film talking heads wide open with a shallow depth of field
which there is no way I could do manually unless the subject didn't move at all.
It's of course even harder if you're filming yourself like I am here.
I can have people walk towards me and be confident
that they will stay in perfect focus throughout the shot.
I can follow any subject just by touching it on the LCD screen and it will track it.
It's a very freeing way to shoot.
I can concentrate on composition, exposure and the story
but I do still manually focus at times as autofocus isn't for everything.
When using AF on location, I generally use it in combination with manual focus.
Using these together, even during a shot is often the best way
to get the great results
because this is you in full control of the autofocus.
It's what I call manual autofocus.
Before I show you what any of the autofocus settings do
the best advice I can give you
is to customise your camera's custom buttons and function menu
to give you quick access to the key autofocus settings of the camera.
You often have to quickly adjust these settings or switch modes
so having these quickly to use a hand will not just help you get better results
it will be a lot less frustrating to use.
You really don't want to be going through the menus
to change something during a shot.
Speaking of menus, the cameras with the new menus make it much easier
to find the settings you need as they only show you functions that are appropriate
to which mode your camera is in.
I also use the custom menus to organise all the camera's functions
in an order that works for me, and I've got a dedicated page for autofocus
with all of the functions I use in one place and in the order I want them to be.
With the old menu system, it can be a little confusing as there are
two different sections for autofocus, one for stills and one for video.
Whilst the video part is the main one you want to use
there are some functions that you need to use and are only in the stills part.
That's why I strongly recommend using the custom My Menu on these cameras too
so you can put them all on one page for quick access.
There are slight differences in how I set up my cameras
mostly due to the features they have, but also the amount of buttons
the A7C for example has a lot less and the FX3 has a very different layout
as the buttons are all video-centric.
So, to make things simpler, I'm just going to use my A7SIII
as the camera that I will set up for demonstrations purposes.
In Operation Customize
this is what I have set my custom buttons to when in the video mode of the camera.
AEL is now AF/MF Selector Hold.
The AF on button, I have changed to AF/MF Selector Toggle.
C1 is set to Face/Eye Priority Select.
C3 is set to AF Subject Shift Sensitivity.
Pushing in on the joystick is Focus Standard.
The centre button of the wheel is Focus Magnifier.
The left-hand button of the wheel is which focus area you are in
and the right is peaking, and the bottom is for AF Transition Speed.
On the top of the camera, custom button 2 is set to AF On.
In the Fn menu for video, the autofocus functions
I've put in there are mostly already set to custom buttons
so you don't have to follow this.
It's just in case you don't want to change your custom buttons for whatever reason
you really should though.
One very important thing to have in the Fn menu
that isn't assigned to a custom button is the Focus Mode option.
It's essential for a particular way of using AF
which I will explain why later on.
If there is a custom button on your lens, this is by default, Focus Hold.
I don't tend to use it so though, so I just leave it as that.
This is what I have set up my A7RIV with the old menu system for
which is very similar to a number of other Alpha cameras.
The custom buttons are set up differently
because you cannot assign either sensitivity or speed to them.
But the others, you can still assign to the important functions.
You also cannot assign speed and sensitivity to the Fn menu
so it also is set up differently.
It's not ideal, as it means you have to go into the menus to change them.
This is why you really must set up the My Menu first page
so you can change them as quickly as possible.
You can download the camera settings file for my A7SIII
as well as for some other recent Sony Alpha cameras at gopb.co/settings.
All you need to do is copy the Sony folder into the private folder of your SD card
and then when the card is in your camera, go to the section of the menu where
Save/ Load Settings is, and load up the file.
This is for all your camera settings
and will overwrite what's already in the camera
so I would definitely recommend backing up your own settings just in case.
You also may not like how I have everything
but you can, of course, change anything you want.
But I would definitely recommend leaving the AF shortcut settings as they are.
For everything that I am going to show you, even manual focusing
leave the switch on the lens set to AF.
We can switch between AF and MF very easily using the AF/ MF Selector Toggle
which I have assigned to the AF On button.
If you set the lens switch to manual focus
then you have no ability to use autofocus in combination with it.
One thing that I need to mention before we start seeing the AF in action
is that with the newer cameras like the A7SIII
autofocus is fully functional in every frame rate and every resolution.
The older cameras have various different limitations
which could stop some types of AF from working.
Common ones are proxy recording, smartphone control and HDMI outputs.
The newer cameras do not have these issues.
There is one thing that does kill all the face tracking, touch operation
and even zones and that is when you use clear image zoom.
The only camera that does let you use clear image zoom
and not affect the autofocus is the FX6 cinema camera.
When using autofocus, the most common mode to be in is AFC
continuous autofocus.
This means the AF is continuously working to make sure your subject is in focus.
There are many times when we don't want this though
especially on static subjects.
All we want is to simply grab a fixed focus.
That's where autofocus single, otherwise known as AFS, comes in.
Unlike in photo mode, when you are set to video, you cannot select
AFS using the Focus Mode Selector, the one in the Fn menu.
To access AFS in video, you simply set your camera to manual focus
using either of those two methods I just mentioned.
There are three different methods you can use for AFS.
The first is to use the AF On shortcut, which I've set to C2 on my camera.
Each time you press the button, it locks onto your subject.
It will generally go for the most prominent thing in the frame.
You may want to use the Focus Area button to switch to Zone or Flexible Spot
if you want it to be more specific where in the frame you want it to focus on.
The second option is to push in the joystick
and it will then do AFS on the centre of the image.
You could use this mode to get past the camera selecting the wrong subject
with that previous mode.
It's a bit like the old stills AF methods, you grab focus, and then recompose.
This will only work if your focus area is set to wide or centre fix.
For everything else, like zone and flexible spot
it recentres the focus area.
Now, my favourite mode
by far, the easiest mode is by using the touch screen.
First off, make sure it is turned on as it tends to work better when it is on.
There are two ways to use the LCD screen for touch focus.
If you are in AFC mode
then press the little icon near the top right of the screen
it will cycle between three options, off, touch focus, touch tracking.
Set it to touch focus.
Now, set your focus area to wide or centre.
Now, choose your subject by touching it.
This way, when you touch your subject
you will see the display change from MF to AFC.
What it's doing is engaging autofocus to get your chosen subject in focus.
And once it has focus, it will then turn back to MF.
The amount of times I say focus in this video.
Touch focus is where we first need to use one of our key settings
AF Transition Speed or focus speed for short.
As you just want to grab focus as quickly as possible
have it set to the fastest speed possible.
And in this camera, that's seven.
I shot 95% of the A7SIII launch film.
Now, I see part two using touch focus and touch tracking
which I will get onto shortly.
This is such an easy way to shoot, but if you are using an external monitor
be aware that you cannot set the on-screen display to be shown on it
otherwise, the LCD of the camera will turn off
along with the ability to touch focus.
You need to make sure your monitor output is clean.
The FX6 and FX9 cinema cameras don't have this issue
but all the mirrorless cameras do, including the FX3.
If you're using the EVF of your Alpha cameras
then you can still use the touchscreen for autofocus.
You can set how much of it will function as a touchpad in the settings.
When you've done that, use your thumb to move the cursor around
and when you take your thumb off the subject, it's chosen.
This is the same for touch focus and touch tracking.
Touch focus is the best way to do focus racks from one subject to another.
You can also do focus racks with continuous autofocus and touch tracking
but that brings in a number of potential problems, which I will cover later.
So I recommend just using touch focus.
We had the AF Transition Speed set to the fastest setting
to quickly grab the focus of a single subject, but when we want the focus change
to be part of the shot, then we need to slow it down.
There isn't a magic number to give you the most natural speed
it depends on many factors, not just the cameras.
For example, newer lenses have fast motors so you tend to keep
the speed lower for those than on older lenses.
But it's also the distance between the camera to the subject
and then to the subject you are moving to.
On most of the older cameras
you can change the speed between slow, normal and fast.
With the cameras released since the A7SIII
we have a scale from one to seven, and seven being the fastest.
This is why I have the speed on a custom key
so I can very quickly change it until it's spot on for that particular shot.
You will eventually get to know your lenses, and how they behave
the more you use them so you will have a pretty good idea
of what the right speed will be.
Something to keep in mind is that if you are shooting slow motion
you will need to make sure your speed is set to compensate for that.
In this shot, I was at the maximum focus speed
and it looked way too fast when actually doing it
but when played back at 100 frames per second, it was perfect.
Something that can be quite visible with certain lenses
when doing focus racks is focus breathing.
When the focus changes from one subject to another
it looks like a slight zoom is happening.
Most stills lenses do this, as it doesn't matter in photos.
And it generally costs more to make a lens that doesn't breathe.
Expensive cinema lenses generally barely have any breathing.
Some lenses are most definitely worse than others.
The Sony 35mm F/1.4 GM is a fantastic lens
but it has quite a lot of focus breathing.
But the Sony 35mm F/1.8 has barely any
which is part of the reason why it's one of my favourite lenses for shooting video.
Sony have introduced a new feature on some of their cameras called
focus breathing compensation, and it's terrific.
When it's turned on
and you can see the 35mm F/1.4 GM no longer has any breathing.
It does this by digitally cropping in on the sensor
but perfectly upscaling at the same time so quality is maintained.
When at minimum focus, there is no crop.
But when you go to infinity, you'll get around a 10% to 12% crop.
This is a fantastic feature and makes all the supported lenses look as good as
if not better than the very expensive cinema lenses when racking focus.
There is also another huge benefit, which I will get onto later.
Touch focus is a fantastic way of using autofocus
but it's of course no good for moving subjects.
For that, we need focus tracking and to be in continuous autofocus.
This is where things get interesting and much more complicated.