GH2 & Focussing - Auto Focus & Manual Focus Tips

driftwood

What are your best tips and methods for AF/Focus tracking on AF lenses? The Panasonic 14-140 and 20mm pancake lenses employ the GH2's AF feature set but they have a tendency to go off and hunt for focus on their own. Here are some methods that can be employed to harness back control of focus without having to go manual / or by going manual.

Methods:
1. Start in AFS (Auto Focus Single) mode and turn off facial recognition & auto tracking in menus.
2. Switch to AFS and in menu turn off Continuous Auto Focus. You can now change focus only when you depress the shutter button half-way down. It will keep this focus setup unti you hold down the shutter button half-way down again. This works whilst recording.
3. Configure Custom Menu Settings AF/AE Lock to AF/AE & AF/AE Lock Hold to 'On'. When you now press the AF/AE Lock on the camera it will focus and lock both AF and AE until pressed again.
4. Whist in AFS recording, lock your focus then switch to Manual Focus and continue your own focussing.
5. Aiding focus: Toggle between Normal View and Magnified View by switching to Manual Focus mode and press & hold the Q Menu button then press 'Set' to assign a fn button for the switching.

Please, by all means, discuss your best methods below.

Nick

Alex_K

the AF/AE Lock Method does not work at v1 (14-45). When i press the AF/AE Lock during recording, nothing changes. Did i miss something?

Hallvalla

@driftwood

Learn something new everyday around here - thanks. Very helpful.

toxotis70

for me too... AF/AE lock doesn't work while recording.

Peter123456

Good tips, Driftwood. I use AF/AE lock on 99% of the shots I've set up for a film I'm working on with the 20mm f1.7 lens.

Peter123456

Lock does not work while recording. You must set it before starting recording.

kenoah

Sometimes im forced to record myself. And the autofocus doesnt work on a tripod. It works perfectly when im holding it and moving (maybe it senses my hands vibrations?) but when i put it on a tripod and attempt to take a picture of myself it wont autofocus

magnifico

thx Driftwood,
concerning manual focus one very small improvment should have help a lot : graduations on the horizontal line representing manual focus in evf....
May be in gh3 :-)

Mark_the_Harp

My best tip using the 14-140: do the half-press thing just before you finish a move or zoom. That way you don't notice the hunting because your eye is making sense of the move. Time it right so the focus is done just as your shot / zoom move ends. Makes focussing pretty invisible when you get the timing right.

Rambo

Af/AE lock is what i do on every shot, as my Gh1 is mounted in a waterproof case, that and the record, power, LCD/EVF button are all i have available to control the camera with 14 - 140.

Works perfectly on the 45 - 200 and 20mm pancake as well. I leave ISO on auto and exposure comp on one click up which stays set even when camera is powered down.

jasantana

Thank you. Very useful.

dtr

I can't for the life of me make tip 5. work. Holding Q-menu brings up the focus assist zoom targeting screen, then pressing set activates the zoom. But I don't see a way to link it to a fn button, which I'm after.

With a manual lens I had this linked to the thumb wheel button but that's selecting aperture/SS with a focus-by-wire lens like the Leica 25mm. Anyone know how to assign focus assist zoom to a fn button?

I don't like the auto mode. Every time I slightly brush the (super sensitive) focus wheel it jumps into zoom. Annoying when framing handheld shots.

mpgxsvcd

I gave up on manual focus a couple of years ago. It simply didn’t suite my needs anymore. I fully understand that there still is a vast majority of people here that MF is still the only option they will consider. However, if you are one of the few that want to try AFC during filming then here are a few tips that may help.

All of these tips imply that you are using a GH3 + 35-100mm F2.8 lens with AFC enabled.

Tip 1. AFC on the GH3 has improved so much specifically with the 35-100mm F2.8 lens @ F2.8 that manual focus isn’t always necessary. If you haven’t tried AFC with this combination yet you really should. It is really that good.

Tip 2. Always shoot wide open when using AFC. If you stop down at all it will not refocus fast enough and it hunt more.

Tip 2. Use the spot focus with a small box for AFC during video. Just keep the box on the point of focus and let the camera do the rest.

Tip 3. Half press the shutter button to get focus before you start filming. Then use the record video button to start filming. If you use the shutter button to start recording it will cause the camera to refocus at it will usually cause it to hunt right away.

Tip 4. Don’t half press the shutter button when you think the focus might be slightly off? You will cause the camera to hunt for focus. It is much better to let the focus be slightly off and clean it up in post than to have the camera suddenly hunt for focus.

Tip 5. Turn on AF+MF in the custom tools menu if you want to be able to manually refocus while still using AFC. You have to have press and hold the shutter there while turning the manual focus ring. It is tricky to do but it works with a little practice.

Tip 6. The 35-100mm is not parfocal. It will not hold focus if you zoom manually. However, if you are shooting wide open with AFC it can change focus while zooming and simulate being Parfocal. The trick is getting the zoom speed to match the refocus speed. The ideal zoom speed for this is slightly faster than you would want to normally zoom.

Here are some samples of focus pulls using AFC.

2nd clip

Near the end is a focus pull back and forth and then at the end is a long slow AFC all the way to just about the minimum focus distance in very low light. It is isn’t perfect but nothing else could even come close to this with that shallow of a depth of field and this poor of lighting.

stoney

@mpgxsvcd Is there any subtle difference between AFC and AFF?

mpgxsvcd

@stonebat

According to the manual AFF is AFC without motion prediction. For the type of events I am doing AFF works great. However, AFC would be the best choice if the motion is continuous like when the camera was tracking towards me at the end of the 3rd video.

I plan on testing the AFF vs. AFC tomorrow at the Park with my kids. One thing I have never seen a camera do is focus on a child swinging on a swing with very shallow depth of field. If you put the GH2 on Face detect it will come close but eventually it gets off.

I wonder if AFC with the focus tracking will work for the swing scenario. I tried it with my daughter riding her horse towards me and it didn't work. The spot focus mode or the face detection mode was much better.

stoney

Thanks @mpgxsvcd. I just read about AFF.

It sounded to me that AFF works like AFS or AFC depending on subject's movement. If a subject moves very little, AFF works like AFS. If a subject moves a lot, AFF works like AFC. I can't confirm it since I have only old M43 gears like GF1 and GH2.

About shallow dof AFC like f/1.4 or 1.8, it might require hybrid PDAF/CDAF. Intuitively it would be harder to process in CDAF at shallow DOF cuz images are out of focus. It was pretty amazing how M.Zuiko 17mm 1.8 nails down AFC focus at 1.8 during video recording from E-PM2. There was a bit of delay though. Prolly PDAF processing delay.

Yeah AFC & face detection does some wonder when it works. But candid shot is difficult. I concur with you. But face detection is a nice feature. Fuji X-series has no face detection. Haha. Olympus has face detection, eye detection, left eye detection and right eye detection. Crazy.

Anyways AFC is getting better on each product cycle iteration. It is definitely one compelling reason to get M43.

dtr

"I can't for the life of me make tip 5. work. Holding Q-menu brings up the focus assist zoom targeting screen, then pressing set activates the zoom. But I don't see a way to link it to a fn button, which I'm after. With a manual lens I had this linked to the thumb wheel button but that's selecting aperture/SS with a focus-by-wire lens like the Leica 25mm. Anyone know how to assign focus assist zoom to a fn button? I don't like the auto mode. Every time I slightly brush the (super sensitive) focus wheel it jumps into zoom. Annoying when framing handheld shots."

Answering my own question: turns out you can tap the display to get focus assist zoom... Still would prefer a fn button though. When working handheld with the display folded out you can't reach the screen with the right hand holding the grip nor the left one holding the lens so you have to release 1 or the other to go and touch the display.

Brian_Siano

I have a possibly Good Tip for manual focus and the use of a follow-focus rig. I found a small problem with using a follow-focus rig with a Panasonic MFT lens. Normally, you should be able to make marks on the FF rig, so you can turn the knob to those marks and be assured that the proper objects are in focus. However, with lenses that enable auto-focus, there's a lot of drift, and using the FF marks doesn't work reliably.

Here's a possible way around this. When you're focusing while shooting, a scale line appears on your screen (the mountains-to-flowers icons). This is probably a more reliable focus scale. But, you can't draw on your screen. So, for your marks, simply use small, thin rubber bands wrapped vertically around your screen, and space them at the focus points. That way, when you focus, you can watch the focus indicator as it lines up behind your rubber bands.

TATZU

After Setting Up These Settings How Can I Switch Back To Manual Automatically Just By Touching The Manual Focus? Because When i Touch It It Stays In Auto.

Vesku

When using autofocus it would be very handy to lock focus with AF-lock button when subject stops moving and again start autofocusing with same button when subject starts to move again. But of course that is not possible with Panasonic cameras because they wanted to make this thing also differently than other brands. GH3 works same way. Will they never learn?

You can still "handily" do the same thing by pressing shutter half way to lock focus when autofocusing but that leads very easily to stop recording and it is not comfortable to maintain half press long time.

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