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M2Z Lost Focus Mid-Flight

Rackminster

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I tend to record my entire flight so I can opt to do whatever I want with the video later. I noticed during one of my flights yesterday that my drone suddenly lost focus mid-flight over some trees while turning to head back to me. I'm using a smart phone in daylight, so couldn't see that I was recording a slightly blurry video until later.

What will make the drone lose focus like that? One moment, the skyline and trees below were crisp and clear. The next moment, after turning back towards where I was standing, everything was slightly blurry and stayed that way for the rest of the flight - nothing was in focus, not even when I got closer to the ground and started getting people in frame.

If it's something I can correct or watch for, I'd like to know. If it's some kind of defect, I'd like to address it.
 
Did you observe the yellow focus box appearing on screen and appearing to refocus during this event?
 
Did you observe the yellow focus box appearing on screen and appearing to refocus during this event?
Unfortunately, no. My visual focus was on the drone itself since I couldn't see much on the screen. It was only on reviewing the footage that I noticed it went from crystal-clear video to blurry video in one turn.
 
I see. Screen recording of the flight as well as to the Micro SD card would have given us this information. It certainly sounds like the Mavic re-focused on an object that was in the foreground and stayed at that focus point.
 
I was up around 250' ... watching the 'event' - it happened during a sweeping turn. One moment I had a clear picture of the ground and trees below, the next moment the ground and trees were blurry. Even as I came down and there were other objects to focus on, the camera didn't focus.
 
You never want to use autofocus while fliming, unless you are OK with what you are describing (focus hunting). Autofocus on DJI's drones is very, very, bad compared to something like a high-end DSLR camera or something similar you may be used to. On a M2Z, pretty well everything will be in focus beyond a few feet in front of the drone, so if you're flying around at any normal altitude you can just set the focus once and be done with it. At 250' there would be no reason to ever use autofocus - just set and forget. The easiest way is to turn on focus peaking, send the drone up, adjust manually until everything looks good (probably just a bit behind the infinity mark), and you're all set.
 
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I'm going to have to look into how to set the focus and disable the auto, then.

In all honesty, I wouldn't even rank myself as an amateur photographer. I don't know composition, lighting, filters, or anything else really. My M2Z is the best camera I've ever owned.

Right now I'm mostly enjoying flying with thoughts of filming and photography coming later.
 
I was up around 250' ... watching the 'event' - it happened during a sweeping turn. One moment I had a clear picture of the ground and trees below, the next moment the ground and trees were blurry. Even as I came down and there were other objects to focus on, the camera didn't focus.

What were the images/videos like after you looked at the ORIGINAL images from the drone? Maybe your signal was bad or breaking up and what you see on the controller is not the actual footage/files. Also, depending on what is being reviewed, you might be seeing the cached, lower quality stuff stored on device or SC.
 
What were the images/videos like after you looked at the ORIGINAL images from the drone? Maybe your signal was bad or breaking up and what you see on the controller is not the actual footage/files. Also, depending on what is being reviewed, you might be seeing the cached, lower quality stuff stored on device or SC.
This is strictly during the review of the original video footage. I was unable to view the screen because the sun was fairly bright, making the screen barely useful, and I was eyes on the drone - not nose to the screen. As such, I can't say if an error came up on the DJI Go 4 software or not, or what it looked like in real time. I only discovered the issue when I got home and downloaded the videos from the SD card and reviewed them.
 
<snip>The easiest way is to turn on focus peaking, send the drone up, adjust manually until everything looks good (probably just a bit behind the infinity mark), and you're all set.
Can you explain "focus peaking" please
 
Can you explain "focus peaking" please

Sure - it is an option that you have to turn on in the menu. You can also determine it's threshold. In the simplest terms, it highlights the portions of the frame that are in focus, usually with a colored line around the edge of what is in focus. This is especially easy to do with drones (even more so with the tiny sensor of the M2Z), because once you're a little ways up in the air, it's possible to have virtually everything in focus at all times. The reason this is so helpful is it allows you to quickly and easily determine precise focus when manually focusing. What it's really doing is identifying the areas in the image with the highest contrast, which also means the sharpest focus. It is far more useful on a traditional camera, but still a really nice tool to have on a drone, if for no other reason than to have a constant confirmation that everything is in focus.

In practice, you would send your drone up, adjust the manual focus until everything is lit up in red (or whatever the peaking color is), leave it there and off you go. Unless you are flying extremely close to something you likely won't have to change it under any normal scenario.
 
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You never want to use autofocus while fliming, unless you are OK with what you are describing (focus hunting). Autofocus on DJI's drones is very, very, bad compared to something like a high-end DSLR camera or something similar you may be used to. On a M2Z, pretty well everything will be in focus beyond a few feet in front of the drone, so if you're flying around at any normal altitude you can just set the focus once and be done with it. At 250' there would be no reason to ever use autofocus - just set and forget. The easiest way is to turn on focus peaking, send the drone up, adjust manually until everything looks good (probably just a bit behind the infinity mark), and you're all set.

I use autofocus all the time and have never seen a problem with “focus hunting”. I fly a M2 Pro and it seems to do a very good job, especially with how quickly it refocusses. Now, I consider myself at best only a casual photographer so I suspect my standards are pretty low.

Do you think the zoom is different than the Pro in this regard?
 
I use autofocus all the time and have never seen a problem with “focus hunting”. I fly a M2 Pro and it seems to do a very good job, especially with how quickly it refocusses. Now, I consider myself at best only a casual photographer so I suspect my standards are pretty low.

Do you think the zoom is different than the Pro in this regard?

The Zoom has phase detect autofocus, which is theoretically much better at tracking motion (it can tell the camera not only how far to move the focusing lens elements, but also which direction). Contrast-detect autofocus is essentially a guess & check algorithm, checking each "side" of the focus plane until it eventually sees the point of highest contrast. The M2P only has contrast-detect AF. Neither drone is using even close to the maximum potential implementation of each though, it's very basic on both. In the camera world, Digital SLRs and high end mirrorless cameras use PDAF (different implementations but same idea), and cheap point & shoot cameras use only CDAF.

Neither implementation makes you immune to focus hunting or missed focus, but PDAF in general is vastly superior to CDAF for motion and predictive tracking.

The M2P shouldn't change AF often (or at all) if AUTO mode is working properly when you're way up in the air - there is almost no need to change focus as everything from about 3 feet onward is in focus if the camera is set properly. The problem is if it ever decides to misbehave, or something obstructs your path even briefly, your potentially irreplaceable footage is ruined, especially if you don't notice it right away. Using manual focus eliminates this possibility entirely with no downside or additional effort. A brief period of hunting or refocus may not bother everyone, but if you are trying to get one long shot of something important, having that happen ruins everything and it's easily avoidable.
 
The Zoom has phase detect autofocus, which is theoretically much better at tracking motion (it can tell the camera not only how far to move the focusing lens elements, but also which direction). Contrast-detect autofocus is essentially a guess & check algorithm, checking each "side" of the focus plane until it eventually sees the point of highest contrast. The M2P only has contrast-detect AF. Neither drone is using even close to the maximum potential implementation of each though, it's very basic on both. In the camera world, Digital SLRs and high end mirrorless cameras use PDAF (different implementations but same idea), and cheap point & shoot cameras use only CDAF.

Neither implementation makes you immune to focus hunting or missed focus, but PDAF in general is vastly superior to CDAF for motion and predictive tracking.

The M2P shouldn't change AF often (or at all) if AUTO mode is working properly when you're way up in the air - there is almost no need to change focus as everything from about 3 feet onward is in focus if the camera is set properly. The problem is if it ever decides to misbehave, or something obstructs your path even briefly, your potentially irreplaceable footage is ruined, especially if you don't notice it right away. Using manual focus eliminates this possibility entirely with no downside or additional effort. A brief period of hunting or refocus may not bother everyone, but if you are trying to get one long shot of something important, having that happen ruins everything and it's easily avoidable.

Thanks for the great, as usual, information. Realistically, none of my shots are that important. See my signature line. [emoji3]
 
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could you list the steps to set "peak focusing?" thanks

Sure it's fairly straightforward. In the GO4 App menu, turn on "focus peaking" and set your threshold (Low, Normal, High) - this is personal preference, but if the threshold is too low you might find there is too much distracting red on the screen as it tells you everything is in focus pretty much all the time. When enabled, all it's going to do is draw a red line around the edges with the highest contrast and therefore the areas best focus with regards to your image - when you're up in the air, this is pretty well every edge because everything is in focus all the time.

Once you have focus peaking set, send the drone up into the air and with Manual Focus enabled, move the MF slider until everything is in focus (outlined in red on your divice screen). This point is likely about 2 clicks before infinity focus, but you can move it around either way and it should be obvious where the optimal point is. That's about it, leave it there and you're all set unless you plan on flying very close to something. You can set focus on the ground too if you want, just make sure the drone is pointed at something a ways in the distance.
 
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Sure it's fairly straightforward. In the GO4 App menu, turn on "focus peaking" and set your threshold (Low, Normal, High) - this is personal preference, but if the threshold is too low you might find there is too much distracting red on the screen as it tells you everything is in focus pretty much all the time. When enabled, all it's going to do is draw a red line around the edges with the highest contrast and therefore the areas best focus with regards to your image - when you're up in the air, this is pretty well every edge because everything is in focus all the time.

Once you have focus peaking set, send the drone up into the air and with Manual Focus enabled, move the MF slider until everything is in focus (outlined in red on your divice screen). This point is likely about 2 clicks before infinity focus, but you can move it around either way and it should be obvious where the optimal point is. That's about it, leave it there and you're all set unless you plan on flying very close to something. You can set focus on the ground too if you want, just make sure the drone is pointed at something a ways in the distance.

Thanks for that!
 
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