Help Me Understand AFF/AFS/AFC

[Ian Atkins]

What is the primary difference between AFF/AFS and AFC on the GH3? I do a lot of wedding videography work and I'm trying to figure out what setting to use.

I really would like a setting that automatically focuses, but that I have to option to overide with the manual focus ring on the lens. Does anyone knof of a way to do that?

[Dan Carter]

Page 142 of the manual explains it very clearly.

[Ian Atkins]

Well, I obviously don't understand the manual as clearly as you do. Can you please provide an explanation? I'm looking for a more functional type of application explanation. For example, I do a lot of wedding videography, so I am trying to figure out what the best type of focus would be for me. I would prefer to have some sort of constant autofocus with the ability to manually override if needed.

[Chris Hurd]

Just a friendly reminder about the way I have intended for DV Info Net to work: simply telling somebody to just read the manual is counter-productive to the spirit of the community here. No matter how basic the question may seem, please chip in cheerfully with some helpful advice -- and if that's too much to ask, then please refrain from posting at all.

I have seen too many other forum sites suffer from "RTFM." I want DV Info Net to stand far above the typical internet message board experience. Thanks in advance for your cooperation and understanding.

If anyone has a helpful suggestion for Ian other than "read the manual," then I would greatly appreciate it. I don't have any direct experience with the Panasonic GH series otherwise I'd answer the question myself.

[Dan Carter]

Whoops! Guess I should have pasted the text of page 142 instead. Sorry to be so lazy.

[Bruce Foreman]

Originally Posted by Ian Atkins

What is the primary difference between AFF/AFS and AFC on the GH3? I do a lot of wedding videography work and I'm trying to figure out what setting to use.

I don't have my GH3 yet (it's on pre-order) so I have no idea of what "AFF" means. But AFS should stand for "auto focus single" as on the GH2, meaning a single autofocus operation on "half press" of the shutter button.

AFC stands for "auto focus continuous" which provides for continuous autofocus as you record. I don't know how much this function may have been improved on the GH3 but on the GH2 it is problematic enough that I don't try to use it. If the subject has enough contrast to "overcome" background contrast it seems to work in that it tries to maintain focus on the primary subject I focus on. But if the background has equal contrast it continually tries to shift focus back and forth between subject and background.

Originally Posted by Ian Atkins

I really would like a setting that automatically focuses, but that I have to option to overide with the manual focus ring on the lens. Does anyone know of a way to do that?

Again I can only explain from a GH2 perspective, but if the GH3 has an AF+MF configuration setting and an MF ASSIST setting, configuring both to ON should do this. Set the focus mode to AFS and press the shutter button half way to autofocus. Then while continuing to hold that "half press" touch up focus with the focusing ring. But the minute you let go of that half press on the shutter button that will be where the focus remains.

Hope this helps a little.

[William Hohauser]

It really depends on the style of shooting you intend to do which is why Panasonic includes such a bewildering set of options for focusing. And while the manual is helpful to a point, it lacks clear functional explanations (at least to me).

Most of my current focusing practices are from the GH2 and I haven't really had the time to see if I should adjust for the GH3. The GH3 has changed the position of the focus controls on the back of the camera.

Usually I use MF Assist when I am shooting interviews. Face Recognition continuous auto focus is great when you have to run around and get b-roll but it isn't fool-proof. Once I get my LCD viewfinder loupe for the GH3 it will be inconvenient to use the touch screen zone auto-focus but I have used that in the past with the GH2 and it works as long as you are in a situation with sufficient light. And your fingers are reasonably clean.

This week I am forced to use my GH2 with it's Varavon loupe to shoot a theater festival with a paying audience because I can't have the LCD disturbing people sitting behind my position. And shooting continuously with your face pressed up to EVF for 90 minutes is uncomfortable and results in a wet camera from breath condensation. AFS is good when you are preparing for a take but in low light situations it will cause a brief video level shift if you use it while shooting so I have tried to get good at manual focusing. And situations like a stage play, with it's changing lighting and characters running around can drive the auto focus on a camera like the GH2 mad. Yes, a video camera might be better for this situation but the GH2 or GH3 is the perfect size to bring to a small theater and get exceptional quality. When Varavon releases their GH3 loupe (they say next week), I will get that immediately.

[Paul Matwiy]

Originally Posted by Ian Atkins

What is the primary difference between AFF/AFS and AFC on the GH3? I do a lot of wedding videography work and I'm trying to figure out what setting to use.

I really would like a setting that automatically focuses, but that I have to option to overide with the manual focus ring on the lens. Does anyone know of a way to do that?

Looks like these are the definitions:

AFS -Auto-Focus Single: Focus on subject then shutter 1/2 depressed. Will not refocus if subject moves.

AFF - Auto-Focus Flexible. Will focus on the subject once, then will refocus if the subject moves.

AFC - Auto-Focus Continuous. Continuous Focus with an attempt to anticipate the motion of a moving object.

AFF and AFC are similar, but AFF is more geared towards stills with a time lag on refocusing if the subject moves.

Is that clearer?

[Ian Atkins]

Paul,
I also read that in the manual.
What's weird is that I have found the functional application of these settings to be different than the manual states.
For example, I find ACC to be CONSTANTLY searching for focus...sometimes even on a relatively static shot. The AFF seems to the best best for auto focus that will stabilize once the camera steadys.

The only problem I am having is manually overiding the focus. Has anyone else figured out how to do this? I have tried turning the focus ring on the lens both with the shutter button pressed halfway and not pressed halfway. Either way, I don't notice a change in the focus.

[Guy Smith]

Originally Posted by Ian Atkins

What is the primary difference between AFF/AFS and AFC on the GH3? I really would like a setting that automatically focuses, but that I have to option to overide with the manual focus ring on the lens. Does anyone knof of a way to do that?

I use a GH1 and GH2 so I just have Auto-Focus Single (AFS) and Auto-Focus Continuous (AFC).

These settings pertain to shooting still photos, not video.

AFS – great for product photography, portraits, landscapes – basically anything where the subject isn't moving. Pre-focus by pressing the shutter button half way down; if the area of interest isn't in focus, reframe the image and try again. As long as the shutter release is pressed 1/2 way, the focus will hold on the original focus point even if you change the framing... Or if the subject moves, which is why we have AFC.

AFC is useful for situations where the subject is moving – sports, for example. This mode will eat your battery a lot faster.

When shooting video on the GH1 or GH2 the camera will focus continuously even if you're in AFC mode. The manual states this and my experience confirms it. For my purposes I leave the camera in AFS because that works best for me.

When in AFS/AFC manual focusing is not possible.

With respect to RTFM, I have also found Panasonic's manuals to be nearly incomprehensible.

[Anthony Marotti]

Originally Posted by Ian Atkins

Paul,
I also read that in the manual.
What's weird is that I have found the functional application of these settings to be different than the manual states.
For example, I find ACC to be CONSTANTLY searching for focus...sometimes even on a relatively static shot. The AFF seems to the best best for auto focus that will stabilize once the camera steadys.

The only problem I am having is manually overiding the focus. Has anyone else figured out how to do this? I have tried turning the focus ring on the lens both with the shutter button pressed halfway and not pressed halfway. Either way, I don't notice a change in the focus.

Hello

There are a lot of methods suggested by Panasonic, and some shooters, but in my opinion AF is a questionable proposition.

In a production shoot where I have a crew and can block every shot with paid actors, it's easier to stay in manual mode because you know where the action is going. But in your line of work, you have to be ready for the unexpected and you have to follow the action instead of direct it.

The problem with auto focus, in general, is that it isn't human and it can't read your mind. So it can tend to wander finding what "it" believes should be in focus at any given time. That is just the way it is and you have to modify your workflow around it.

Now there are various methods of how a particular camera will achieve auto focus, but that's for another conversation; suffice it to say that the GH2, GH3, GH4 will work well under certain conditions and not so well in others. Lighting is important. If the camera can't see, it can't find differences in the scene and will just hunt. If the subject you are trying to focus on is of less contrast than the background or other near-by objects, it may choose to leave your subject out of focus.

Although there are settings to manually focus with the ring after the auto focus does its thing, I haven't gotten it to work recently, and let me say a thing or two about that.

I have a few GH3s and I just got a GH4 and they are very similar in this regard... Settings Aren't Always What They Appear to Be.

What I mean by that, is that settings aren't just straight forward "set it and forget it" they are interdependent on other settings. So depending how you have your camera setup, certain settings may not be functional, or may function in unexpected ways. This is a perfect case of "sometimes more is just too much" when it comes to the abundance of settings these cameras have.

Unfortunately you are not always shooting in the best of lighting conditions either, so you are probably opening your lens up as wide as possible to avoid the negative effects of high ISO settings. This has a compounded result as the focus will be that much more critical. Whereas the out of focus background is a coveted effect, you still have to focus on your subject so that it doesn't become part of the effect. Wide apertures obviously give you a shallow depth of field, which gives you less leeway in critical focusing.

Outdoors I think the auto focus will work much better for you, and in still mode it is very fast and accurate. However if you are using AF and shooting people, I would highly recommend the "Face/Eye Detection" setting, and the "Tracking" setting is pretty good for sports when you're shooting things like cars. It will lock onto a big thing and keep it in focus as long as you keep it in the frame. The problem with that is that if you want to focus on another car you will have to get the previous car out of frame, and then AF will have to "Find" the new car... OR you can use the touch screen and "Click" on the new car and it will grab it pretty quickly. The problem is, if you are hand held, touching the screen requires one hand and it will certainly cause some camera movement... So it might just be better ti use "1-Area" where you can select the area in the frame you want to stay in focus and the AF will focus on anything in that area. It is pretty stable and you can still touch an object on the screen for selective focus or to rack focus.

I would throw a pizza party and invite my friends over letting them know that I was going to be taking shots and video for testing purposes. Then in a, close to real life situation, you can experiment with the camera's various options.

AF will always be an issue for video, you just have to know your gear and work out the compromises.

Anthony

[Geoffrey Chandler]

Positioned at the front of the church with the bride and father slowly walking toward you, would you trust the auto focus of the 35-100 f/2.8 lens and GH3 camera? Or should I stick to manual focus which is sketchy too?

[Terry Wall]

I have suffered the "wandering auto-focus" that Anthony alluded to, and it can be quite annoying. Even with a fast f1.7 lens, in a darkened wedding reception room, the lack of contrast can be an issue to watch for. In cases like that, if I can find just enough light for, say, an f8 exposure, I can get a little more DOF and more leeway for the shot. If you're shooting for "wedding highlights," if you can get a 5 - 8 second clip without the AF kicking in, that's a pretty good thing!

Happy shooting!
~TW

[Anthony Marotti]

Originally Posted by Geoffrey Chandler

Positioned at the front of the church with the bride and father slowly walking toward you, would you trust the auto focus of the 35-100 f/2.8 lens and GH3 camera? Or should I stick to manual focus which is sketchy too?

Hello Geoffrey

To maintain your professional image, don't tolerate wandering focus when shooting video. This camera has great auto-focus when it comes to stills, but no camera in this price range (probably any price range) has usable auto-focus, at least in my opinion. It seems to let you down at the worst time, and usually when you don't have any coverage to fill in during editing.

Personally I fit my GH3 and GH4 in a rig that is equipped with a follow focus. If you're shooting on a tripod, or a shoulder rig, you can lock in the endpoints of the action's travel and with the big knob, smoothly follow the talent and focus at the same time. It takes a little practice but once you do it a few times it's a breeze!

Now using a rig is less run-n-gun if on a tripod, although I have used a tripod with the legs folded in as a man-powered jib, but on a shoulder rig you should be fine.

Anthony