Continuous Auto focus problem?

[RitchM]

Last week I flew four flights at a location shooting videos with auto focus on. When I got back and reviewed the footage, the video from the first three flights looked as it should, but video from the last flight was soft. Originally, I assumed I must have gone into manual focus mode by accident, but today as I'm checking out the drone on the bench, I can't get it to actually "continuous" auto focus. The setting on the screen is in "AF", but as I move the camera or move things in front of the camera, the focus is not adjusting. If I tap the screen to focus on an object, it will focus. I can also put it into manual mode and I can focus manually. Is there another setting I'm missing for a continuous AF? I also reset the camera settings to default, but this didn't help.
Any help would be appreciated, thanks.

 

[MaxHam]

Unless you are shooting something a few feet away best is to manually set the focus while in AF mode by tapping the screen after take off
on something at mid-distance and then switch to manual focus.
That way your setting will be kept and around f-stop 4-5.6 you'll have a depth of field from a couple of meters to infinity.
For an airborne 28mm lens there is not really a need for continuous auto focus.

 

[DanMan32]

I had a battery length of video recording that ended up a bit out of focus. I don't think it does continuous AF and I don't think you want it to either. In recordings I sometimes see video 'skipping' which I think is really the AF seeking.

 

[4wd]

There's another setting in the app will cause it to refocus every few seconds, it doesn't autofocus continually.
The AFC on option allows tap to focus while Manual you have to use the slider thing which pops up.
Generally you are better using the tap or manual rather than let it decide to focus on something you might not have wanted.
Assuming you are 50 feet or so away from subject, infinity on manual is probably the best option.

 

[Kilrah]

Continuous isn't continuous as you'd have on a DSLR, or it would just continuously hunt and ruin your footage at unexpected times. Just means it will refocus at every recording start if it's more than some time after the last refocus.

 

[FiShBuRn]

Beware that if you go MF and slide all do way to Infiny you will be out of focus!!

 

[parkgt]

Beware that if you go MF and slide all do way to Infiny you will be out of focus!!

If you slide all the way you are not at Infinity, but past it. If you tap the Infinity symbol you will note that the slider does not go to the end of its range.

 

[Paul2660]

Continuous isn't continuous as you'd have on a DSLR, or it would just continuously hunt and ruin your footage at unexpected times. Just means it will refocus at every recording start if it's more than some time after the last refocus.

This is the way I also understand it, however the MPP (not sure on the MP2), often would try to focus on the sky, and not get a hit, depending on where the drone was in the sky. Thus the footage would be out of focus. This issue came with DJIgo4. I still always hit the AF, then move to MF before video after shooting stills. You can see the slight jerky movement while the lens is re-focusing, but it's being done at the beginning of the footage. I assume the MP2 has the same focus design. The MPP can also miss focus in dim lit scenes and you get the red box showing a miss for AF. So if using continuous the and in low light you can get a video that is out of focus.

Paul C

 

[parkgt]

I don't understand the need to use Autofocus at any time?

 

[Kilrah]

This is the way I also understand it, however the MPP (not sure on the MP2), often would try to focus on the sky, and not get a hit, depending on where the drone was in the sky. Thus the footage would be out of focus.

Sure. I personally disable C-AF, leave it on AF, and just tap on something that is a good target and check it focuses correctly on it once at the beginning of the flight and since C-AF is off it will not move again.

I don't understand the need to use Autofocus at any time?

C-AF was added some time after Mavic launch becasue too many people forgot to focus, didn't notice the live view was all blurry, and came back with unusable footage.
The camera triggering AF on its own once in a while doesn't ensure footage will always be in focus (as noted it is not guaranteed that the camera will be pointed at a suitable object when AF triggers, or that AF will succeed even if it is), but it does give an extra chance to someone who completely forgets about focus.

As noted as much as it is capable of saving you by focusing when you forgot it is also capable of screwing everything up if it engages and fails to focus when everything was fine before, hence me disabling it and relying on myself to focus like in the early Mavic days.

 

[Paul2660]

I don't understand the need to use Autofocus at any time?

The Mavic series, on iOS devices has to be focused, unlike the Spark or Mavic Air. You have two options, Manual or AF. The Live View on the DJIgo4 screen on a iPad, or iPhone is soft not tack sharp. You can't dial in exact focus, just like you can't really view the image on your iOS device at 100% to check for focus, as they are not sharp. This is because the DJIgo4 app doesn't "respect" retina resolution. The term respect is a iOS developers term meaning that an app is taking full advantage of the full resolution of a screen. Some apps will give the option to "respect" the retina resolution. Reason to not respect is you can play back the images faster at a lower resolution. Some apps give the option to respect retina resolution, the DJIgo4 doesn't. The first time I looked at images on DJIgo4 from my Spark, I was shocked as everything looks soft and out of focus and zooming in makes it look worse. Once you view on a good PC or MAC, you realize the images are fine. Same with the Video. Note with the Crystalsky, the image on the monitor is sharper I guess due to the Android OS version of the CS. Live View on the CS does allow for better manual focusing. I have not viewed DJIgo4 on a Samsung phone or tablet and they very well have better resolution for live view or playback.

So if you attempt to focus manually only, on a landscape image, with a large hyperlocal distance 3 feet to the horizon, you have a good chance of not getting the focus exact, and or getting a side of the image out of focus. There is lot that needs to be checked to have a 20MP shot in good focus if you are doing it manually. You only have around 20 minutes of real time in the air, and attempting to manually focus a shot take a lot of time.

Good news is the AF on the Mavics is good, most of the time. There are times it will miss and give a red box, especially in low light or subject that is low in contrast. However if you get a lock, green box, and have a reasonable aperture set then odds are you will have a good focus. If you are using AF-C and the Mavic hits a piece of sky or low contrast subject matter, you will not get a good focus, but the drone will keep filming.

Thus I use AF, hit my subject, get AF confirmation, and move to MF. Just make sure you don't hit the MF slider which now appears on the right side of the DJIgo4. Quick, easy, no time taken to zoom in out etc.

Paul C

 

[Kilrah]

Again, no point moving to MF if you have disabled C-AF (well, unless you fear you might tap the screen inappropriately).

 

[kilomikebravo]

If you slide all the way you are not at Infinity, but past it. If you tap the Infinity symbol you will note that the slider does not go to the end of its range.

This is exactly what I’ve been doing and after tapping the infinity symbol, I leave it in MF all the time. I also see no need whatsoever for AF.

KB

 

[RitchM]

I found the setting for AFC, turned it on and could see how it would cause problems constantly focusing. I'm sure I never used this during my flights. That being said, I can't see what being in "AF" mode does. Someone suggested it auto focuses when you hit record, but mine isn't doing that at all. I experimented with mine by putting an object about 5ft away, manually focusing on it (background was out of focus), then removing object and putting it in AF mode. The camera didn't grab focus on the background, then I pressed record, it still didn't refocus. It never refocused until I tapped the screen for a quick focus. I realize that most of the time while flying, I should be grabbing a quick tap focus or manually focusing, but I'm just wondering if my "AF" mode isn't working properly.

 

[kilomikebravo]

Ritch: Just try the technique that ParkGT mentioned above...it works like a champ and it's a "set and forget" option.

 

[Kilrah]

AF does nothing in itself, it just enables the "tap to focus automatically on what you just tapped". MF disables that and gives you a slider.

 

[AvatarWings]

I found the setting for AFC, turned it on and could see how it would cause problems constantly focusing. I'm sure I never used this during my flights. That being said, I can't see what being in "AF" mode does. Someone suggested it auto focuses when you hit record, but mine isn't doing that at all. I experimented with mine by putting an object about 5ft away, manually focusing on it (background was out of focus), then removing object and putting it in AF mode. The camera didn't grab focus on the background, then I pressed record, it still didn't refocus. It never refocused until I tapped the screen for a quick focus. I realize that most of the time while flying, I should be grabbing a quick tap focus or manually focusing, but I'm just wondering if my "AF" mode isn't working properly.

This is how my Mavic 2 Zoom works. I believe that manual zoom gives the slider so that we can set the zoom to whatever we want. AF means we can tap on the screen and it will focus. AFC means that it will occasionally refocus on its own. At least that is my best guess as to how it works.

 

[wsettle]

Good thread. When using Litchi, I kept seeing an odd, out of focus shot in my panos and even though I had AFC turned off, it appears that Litchi would auto focus before every shot. I just tried another pano where I auto focused on the horizon then switched to manual focus and it works as expected now. This group is a weath of information. Thanks!

 

[Spinmeout]

I have recently stopped using AFC mode and reverted back to AF instead. I have replaced my camera and gimbal separately due to an accident and was testing the camera. I noticed the auto focus shift happening during long flights and this ruined a few shots. Turning off the afc has stopped focus change randomly happening during filming and flying. Setting my focus on take off and checking sharpness using the Peak Focus Threshold function set to high. Using AF has stopped this focus change happening and random focus shifts while flying. Before each photo I do a quick refocus then take the shot. Seems to work for me. My other concern was perhaps the camera was getting hot during long flights and the camera was perhaps refocusing for some heat related issue. Has anyone used a thermal paste when replacing their cameras? I just swapped the camera, reusing the original heat sink material from the original camera. It may not be perfect.

 

[kilomikebravo]

This group is a weath of information.

It most certainly is..best forum with which I have ever been a member.