Hello,


Much has been written about the Mavic Blurry Edge / Uneven Focus issue. My unit appears to be affected. I wanted to collect more information and hopefully get more clarity on this from DJI and or others who might be more familiar with the problem.


By way of background,
There was a good thread here: http://forum.dji.com/thread-69767-1-1.html
A good whole blog here: https://www.capedigital.com/journal/my-mavic-has-a-lens-issue
And more here: http://mavicpilots.com/threads/h ... d-uneven-focus.717/


Symptoms
Most of those affected report a "blurry edge" or a "washed out" portion of the image - sometimes on the left, sometimes on the right. A few have figured out that if you tap on the blurry area, it will come into focus but at the expense of another area becoming blurry. Unlike the "blurry background" effect that is natural when taking a closeup (and sometimes desired), this issue involves blur affecting objects that are roughly the same distance away from the camera. Some have described it as a "tilt-and-shift" effect. In clinical parlance, it's as if the Mavic has somewhat of an astigmatism.

What causes it?
Alas, I haven't seen a "real" explanation from DJI staff as to the root cause of the issue. It would be really nice to know! Absent any official explanation, some have proposed that, perhaps it's a manufacturing defect in the camera. The lens is, possibly, installed at a slight angle relative to the sensor; not perfectly parallel. This is explained well in this thread, around Page 3: http://forum.dji.com/thread-69767-1-1.html That explanation makes the most sense to me. However, perhaps others have similar symptoms for other reasons too.

I've done a few "tests" if you will which seem to confirm the hypothesis. My results are below.

The "Table Test"
Place unit on edge of table, camera looking down over the edge. Keep drone completely stationary. Aim camera straight down at (old) hardwood floor. Set camera mode to RAW. Tap to focus in the upper-left corner. Take a picture. Press "center focus" button and take another picture. Don't drop drone. Tap to focus in the lower-right corner. Take another picture.

All three images look roughly like this:


But zooming in on the top-left and bottom-right corners we notice stark differences in focus:



All of my RAW DNGs are on DropBox here:
https://www.dropbox.com/sh/8kjwfv5hybv6wyj/AADFhVp6loODMrfWVrVL-G0Na?dl=0



What this means is, just as we suspected, the camera is incapable of keeping the whole frame in focus. Thus every time you take a picture, something is bound to be blurry. Good news is, we have at least some control over where the focus will be. Another important point to make here is that the drone is kept completely stationary during this test. Thus we can say with relatively high confidence that the problem isn't caused by gimbal vibration, propeller vibration, compass and so on. One thing I haven't done is calibrate the IMU. I'll be extremely surprised if that fixes the issue! But will try soon.

The "ark Test"
Same idea but now we are hovering with some altitude above ground, looking well-textured objects below. Also shoot 3 pictures, focusing on top-left, center, and bottom-right:


And we get similar results:





Again, all the original DNGs are here:
https://www.dropbox.com/sh/8kjwfv5hybv6wyj/AADFhVp6loODMrfWVrVL-G0Na?dl=0


The alarming bit is, now in the "focus on center", the right side appears much more blurry than the left! It looks like the blur is now less centered, more biased towards the right. Does this have to do with being a further distance away from the subject? I'll admit its only an initial impression. Perhaps someone can with more imaging experience can look at my DNGs and have more to say.

Many Questions
I'll say it again - DJI - it would be really nice to get a technical statement from you as to what the cause of the problem is. Going with our assumptions, the next natural question is - can the blur be centered symmetrically?

That is, by tapping on a certain sweet spot (between center and bottom right?) or by playing with manual focus, can we get an image where the edges appear blurry to about an even degree on each side. That would probably be most visually appealing and perhaps even livable. I haven't managed to achieve that with stills, but only tried a couple of times. With video, I got mixed results. Of course, video frames are much more problematic, prone to blur from vibration, compression and so on. I tried a few things and here are some video frames:




Of course, very often when flying a drone, blur on the top (where the sky is) may not even be apparent.



Next question - if the blur indeed can be "centered", then can this issue be addressed with software? That would be nice... I can't tell...

So what do we do?..

I've read a few stories of people complaining to DJI, sending their Mavics back, waiting 10 days or more, and then receiving a different unit that's also blurry! That is a bummer . DJI folks, your silence on this isn't really helpful. Most of all right now I'd appreciate more information:
1. If I send my drone back, how do I know I won't be one of those unlucky customers that receives another blurry drone?
2. You guys must've seen this many times and you must know what the problem is. Can you tell us definitively?
3. Maybe you're working on a way to fix it in software? Is that possible? Can you tell us that?

As far as other customers - anyone manage to solve this manually? Any advice for me? For what it's worth, thanks a lot for reading. Cheers!

I'm sorry you are experiencing this.
The only thing you can do it send it in for repair.
http://www.dji.com/support

DJI-Ken Posted at 2017-3-3 19:37
I'm sorry you are experiencing this.
The only thing you can do it send it in for repair.
http://www.dji.com/support

Thanks, DJI-Ken! That was a very quick reply. I appreciate it!

The thing is, in many of the links that I mentioned - many people wrote they sent theirs in and then received back a unit that was still blurry :/ Can you tell me like... would the same thing happen to me?

Any thoughts on how long the repair would take? Since people are saying their repairs are taking a while right now - realistically, am I likely to get a better result if I send mine in a little later?

DJI-Ken Posted at 2017-3-3 19:37
I'm sorry you are experiencing this.
The only thing you can do it send it in for repair.
http://www.dji.com/support

Hey Ken! Any way we could get word on what is causing this? Is R&D aware of it? The source problem fixed for problems being fixed now? If you don't know it or are not allowed to tell us the status just know that would be nice.

geofox784 Posted at 2017-3-3 19:49
Hey Ken! Any way we could get word on what is causing this? Is R&D aware of it? The source problem fixed for problems being fixed now? If you don't know it or are not allowed to tell us the status just know that would be nice.

Thank you! I definitely second that sentiment. It would be great to know. Or, at least, we want you to know that we'd like to know
Silence has a way of making people assume the worst. :/

Did some more fooling around with this today.
The Video / Manual Focus Test
Set drone to look out of the window. Keep completely stationary. Record video. Set the focus to manual. Modify the focus wheel very slowly while recording. Make sure to watch in 4K:


This is amazing! The disparity in my drone is much more than I thought. At around 0:43 you see most of the frame is completely blurry but the bottom-right is razor sharp! Then at around 1:07-1:08 I hit that equilibrium point - the left and right appear about even. The blur doesnt disappear! But it becomes evenly distributed. So - at least with manual focus - I can do it. Ok. If I could have a software button to "do that even thing" - that would be nice. Then after 1:08 the left gets sharper and the right gets worse.

The Video / Auto Focus Test
Here I try to achieve the same "equilibrium point" but using tap-to-focus:


Approximate schedule:
0:03 - Focus on center
0:15 - Focus on Left side
0:30 - Focus on Right side
0:42 - Focus between Bottom Right and Center
0:58 - Focus on Center
1:14 - Focus between Bottom Right and Center
1:38 - Focus on Center
1:47 - Focus between Bottom Right and Center
2:02 - Focus on Center
2:14 - Focus between Bottom Right and Center
2:26 - Focus on Center
2:38 -  Focus between Bottom Right and Center



The logic is - every time I use the "center focus" button, I tend to get more blur on the right than the left. Therefore, if I tap to focus to the right of center, then, maybe I'll even out the blur. Of course, tapping to focus is very inexact so I tried several times. Since this is video, every time you do it you have to wait a few seconds and watch it carefully. So far - I haven't been able to hit it as well as I can with manual. I get either blurry right (brown building in the back) or blurry left (top left corner of big building). After doing this I got the idea to to turn on the grid-lines in the app and use those as a guide of where to tap. Maybe that'll help. I might try this again tomorrow.

More on trying to "even the blur" with tap-to-focus. The camera options have a switch for a grid and we can use grid lines as a guide with a few points:
Basically, "1" means tap between center and the vertical line. "2" means tap along the line. "3" means tap past the line. Tests from yesterday suggested that you really don't want to tap too far from the center.

Some results:



So, for me, with my particular camera (which tends to blur on the bottom-right when I hit "center focus"), tapping around 1 or 2 will about even out the blur. They are about the same, suggesting the control over focus probably isn't perfectly continuous. 3 is too far if I want all corners to look semi-presentable; but might come in handy if I'm shooting the side of a cliff or something like that. I tried tapping along the diagonals - essentially similar results - the 1,2,3 above are easiest for me to remember. This is far from ideal but it's good to know! Happy if it helps anyone else on here.

As luck would have it, I have a trip coming up and won't have time to repair my unit right now. May have to wait a month or so. However it appears that the official Warranty on the Mavic Camera is 6 months, so I can't wait too long. Also  checked to see if anyone is selling a spare mavic camera as a standalone part. Looks like absolutely no one! Curious :/

In the meantime I might take advantage of the assymetric blur to do some proper art. Sure, some other lucky guy's Mavic may be perfectly crisp, but can it to this?


Yeah! Exactly! Didn't think so.

Cheap optics is what this looks like. They don't have this issue with the Inspire or Phantom 4 Pro. Hey DJI whats up!!

I'd like some feedback on this too please

Excellent write up, I am one of the lucky ones but am very unhappy with the autofocus and I think your post helps me to understand why. You said that when testing for the sweet spot, that tapping diagonally gives the same results as horizontally; I've been trying to get unqie focus by positioning an object in one of the corners, but when I do that it always seems to focus on what would be in the middle of the left or right side. When I position the object mid frame on the left or right it works correctly.

Some weird voodoo going on with the AF and with some problems also in lens mounting position.

DrEMHmrk2 Posted at 2017-3-6 18:22
Excellent write up, I am one of the lucky ones but am very unhappy with the autofocus and I think your post helps me to understand why. You said that when testing for the sweet spot, that tapping diagonally gives the same results as horizontally; I've been trying to get unqie focus by positioning an object in one of the corners, but when I do that it always seems to focus on what would be in the middle of the left or right side. When I position the object mid frame on the left or right it works correctly.

Some weird voodoo going on with the AF and with some problems also in lens mounting position.

I also had this issue but mine was really noticeable. There was at least one part of the image that was really blurry. Eventually got a replacement a few days ago and took some test shots from my balcony (too windy to fly!) and it looks evenly in focus all over. It seems this is mainly a hardware issue.

Nice white up and I would suggest you follow Ken's advice and send your Mavic back to DJI so they can repair the camera. It is not fair to ask Ken what the lead-times are on the repairs (he cannot answer this)... You can figure it will take about 2 weeks depending on the workload in the shop. If you have DJI refresh it will be faster than the rest of us that do not have the insurance.

I had the focus issue with my camera on the right side and it is in the shop now waiting for repair. I hope to get it back next week. This tiny camera need's to be cared for by the experts.

DJI will do their best to get you going again.  

Rich

I think a lot more people have this issue and just don't realize it . . . . Sad DJI still hasn't found a solution, received mine March 3rd, and the issue still exists . . .

In my case DJI want me to pay for the issue out of the box.

I've also had a blurry edge issue on my drone. One thing I did notice which I haven't seen mentioned before is that when watching the live feed on my iPhone the areas that were always blurry for me (top left and bottom right) seemed as if they were flickering in the video. Like moving pixels (difficult to explain). A bit like when recording a video and it's too dark and you can see the noise in the image jumping about. Just putting it out there...

hi guys,

I dont know whats going on but I am extremely unhappy that my Mavic Pro has the same issue ie. blurry or washed on the right side. I've pretty much tried everything i could which includes IMU calibration and gimbal calibration. Sadly this blurry issue is still there. I just got my unit about 3 days ago and did a couple of test flights. All of the footage showed the same thing. Blurry on the right side.

DJI need to come forward and be honest. My advice to DJI is to be honest as quickly as possible and not treat its users as if they're dumb as this is going to severely affect DJI's reputation globally. If it is a product defect then come forward and admit it and then replace the camera (if it is a defect issue with the camera or any other part for that matter). I've been flying my Phantom 3 for more than a year now and I have been extremely happy with its performance and build quality. I expected more from DJI to be honest.

Keeping quiet and hoping that people will stop talking about this issue is not going to happen as this isn't really a $5 dollar piece of kit.

The whole point of a drone with good optics is to allow us to fly and take photos and videos that can be shared so who the heck wants to share photos and footage that's blurry? come on DJI its basic common sense. I would fire the person at DJI who says otherwise.

I'm sure they're doing everything possible to avoid a recall, I'm expecting some sort of fix that doesn't work on the next firmware update and will go from there

Yup. All these posts by DJI staff here to send in the drone for "repair" to solve this issue is total non sense.  From what i've read here, they dont even test after they are done with the repair, or a the replacement unit. So you are basically gambling to see if you will receive a mavic better or worse than the one you sent in...
Such a shame they are not held accountable for selling that is clearly defective in some way. Now the fault seems to be in the camera module itself. Obviously them being DJI will never publicly acknowledge even if they find or already found a problem with the camera modules!! But they should atleast come clean and say that they can for sure 100% have this repaired/replaced if we send our Mavic in.

On top of that they refused my request for a refund because its not in there goddam* "Accord" to issue a refund for defective garbage and that i was past the 7 days!!!

I did a bit more digging and things just keep getting curiouser and curiouser.

First, the problem might be made worse by cold temperature. I went back thorough some of my testing footage and saw some days were notably worse than others. I looked at the dates-created on the files, went back through weather history and, sure enough, the "blurriest" days were also the coldest! Many caveats: I was shooting at different times of day, there were different lighting conditions. Many of my shots were videos which means the angle wasn't exactly the same and the compression algorithms may be screwing with me. So I can't say that I eliminated all the other variables but it sure appears to make a difference. This guy seems to corroborate exactly: http://mavicpilots.com/threads/c ... nd-the-bubble.3328/  He even suggests that keeping the plastic cover on will help keep the camera warm! What do you know...

Secondly, I discovered the "peak focus threshold" feature. It's an option under main settings that appears to continuously run an edge detection algorithm over the phone video feed and displays bright red lines over sharp edges. In other words, it "colors" the edges that are in focus as you fly. It does not change how the Mavic auto-focus algorithm works but it gives you a good feedback of what's focused and what's blurry at the moment - which is very useful on the small phone screen! This dude has a nice explanation, starting at around 3:40 . A good experiment is to aim at an even, equidistant space with texture, turn on Peak Focus Threshold (medium), turn on Manual Focus, and adjust the manual focus wheel as you watch the red lines move on the screen. In my case, I definitely see them migrate from left to right - confirming the underlying "astigmatism." But it's a good way to find a "sweet spot" in the middle. At the very least, it can tell you what will be blurry before you take the shot.

Some things to play around with, as it were.

A bit more about the "cold makes it worse" hypothesis. It possibly makes some sense. The camera is made of various metals, plastics and glass which are likely to contract at different rates in cold, and even conduct temperature differently. The camera is tiny, and so perhaps - perhaps - a small warp in the materials makes a big difference in the captured image. I wonder if my blur will become barely noticeable and/or within DJI's tolerance level at 70F. I don't know - I haven't flown at 70F yet! The indoor shots look good but they also involve a different focus distance.

This hypothesis may also explain why the return-to-DJI process is a gamble: it's probably much more expensive to test the camera at different temperatures! Assuming cold is an issue, and assuming DJI knows about it, DJI US in LA may need to set up a large fridge-like thing to test their cameras in. That sounds like a lot of money and a lot of time! Is that what's happening?

Anyway I'm just asking questions. Wondering if anyone else noticed the dependency on the cold as a factor?

I think we need to send Maviс for repair or replacement for a new one - nothing else will help.
For Russia, the cost of sending costs does not cover - so I think for a long time. But I'll probably send Maviс to Germany soon.

Hi,

Below my long-short story (long: total time of "owning" Mavic Pro - 3 months. Short: total time of having mavic in my hand and have "fun" - 3 weeks.... )
1) Purchased Mavic Pro January 5th in Dji Official Store. - Returned after 1,5 week with massive "jelly" issue.
2) I got replacement, but with some fight - Dji was trying to prove me that i was flying in bad weather conditions. No way... I got replacement after 4,5 week
3) Returned "new" mavic with blurred image in 20% of right part of footage after 1 week of "fun".
4) This time only camera has been replaced in Germany. Received mavic at the end of February. Blurred image issue was little smaller , but still..
5) I returned Mavic and got refund.... For mavic only... no DJI care refresh refund. Fighting last 2 weeks to get my money back.
Dji - shame on you. You have implemented perfect business model - release "dream drone", which is piece of trash and earn on Dji Care refresh.

Thanks for taking the time to do the research.  Check out some tech info on the actual sensor and more the part of the aliasing it does at higher resolutions here .  Googling around you realize  that this sensor is used in camera phones of course it's a combo of sensor and the glass that's the important combo.  Cheap, or defective glass can cause issues. I'm not staying that's the issue here but worth suggesting.

Also I would like to note I'm also having this issue, and it may be compounded by living in Lake Tahoe were we are having winter now.  I'm going to send mine in and see what comes back.
Also a good read about decentered lenses.

Acidsnow Posted at 2017-3-7 07:23
I think a lot more people have this issue and just don't realize it . . . . Sad DJI still hasn't found a solution, received mine March 3rd, and the issue still exists . . .

received mine yesterday.... Right side is a blurry mess... I'm joing the club, sadly.

Yesterday send my Mavic back to DJI...

Just a slight update - did more flying in warmer temperatures and still seeing the blur
After pondering this for a while, looks like I'm gonna send it back to DJI after all. I guess I would recommend that to other affected folks as well.

poliakov - Thanks for all the thoughtful and logical expositions in all your postings.  It definitely is well laid out and makes a lot of sense to me.  I want to go dig out my old Optical Targets and do some additional experiments . . . if I can find them.  Many, many years ago I used large-format cameras and had precision optical focus targets for calibration and critical focus.  If I can find these, it will be a good test for the lens in my Mavic.

Nikon 1 Posted at 2017-3-21 16:44
poliakov - Thanks for all the thoughtful and logical expositions in all your postings.  It definitely is well laid out and makes a lot of sense to me.  I want to go dig out my old Optical Targets and do some additional experiments . . . if I can find them.  Many, many years ago I used large-format cameras and had precision optical focus targets for calibration and critical focus.  If I can find these, it will be a good test for the lens in my Mavic.

It would be good to get some of those tests done, I posted above about potential decentered lenses which can cause issues on one side , both or just issues in general.  

Also the image sensor is what you find in some current smart phones and well maybe its not the one for aerial photography to be honest.  As with every product I would assume the next rev will have a bigger/better image sensor

anyhow looking forward to seeing what you come up with your tests (I already sent my mavic in for repair)

Would love to see an official statement from DJI, because I dont know if it's a good idea to buy a Mavic now considering all those problems with camera.

poliakov Posted at 2017-3-21 16:07
Just a slight update - did more flying in warmer temperatures and still seeing the blur
After pondering this for a while, looks like I'm gonna send it back to DJI after all. I guess I would recommend that to other affected folks as well.

chances of getting one that is perfect is extremely rare . . . . just browse YouTube, and you will see 9 out 10 have the issue in varying degrees . . . .

Acidsnow Posted at 2017-3-27 11:24
chances of getting one that is perfect is extremely rare . . . . just browse YouTube, and you will see 9 out 10 have the issue in varying degrees . . . .

Did you have a similar experience ?

It's so sad. I have the same issues. Bought the magic brand new and realized after the first flight that one side was blurry. I now sent it to DJI. Makes me angry that I now spent the money and got no drone after all. Some people report more than 50 days for the drone to return from service. Well -in that case  I'd rather have my money back. In my opinion 10-14 days seems appropriate for a repair/replacement.

An update and a question...

So I got this in email today and it's a little confusing :/ At the top it says "The product wll be covered under warranty." But then right after that there's an invoice for $309.00. Ah. What does that mean?

When I click on the " Payment Links " it says "order is invalid." But when I go to "track my repair" it says "waiting on payment."
Anyone have experience with this? Is this a bug or a feature?

Ah - so today I received a second "DJI Service Quotation" email that has another invoice that says I don't owe DJI anything. That's reassuring.

So I am in the same boat. Brand new mavic as of end of April and right side is massively blurred. And I thought that this problem was just at the beginning of the production last autumn

The story continues!

I have received the Mavic back 2 days ago. Despite the case stating "repair", what I got was a box with a brand new drone - stickers, film and everything. DJI threw in a new set of propellers too. Alas, no extra controller or batteries I just got around to doing a table test - same as described in the beginning of the thread, slightly different angle. So far, the results are much better.

Top left corner: focus left, focus center, focus right

TT top left

Bottom right corner: focus left, focus center, focus right

TT bottom right

I can't see a discernible differnece in the images. There's still a bit of blur - in the very corner - but no disparity based on where the focus is. I also tried a quick manual-focus-video test, again facing the floor - not seeing the unevenness that I saw before.

This was the repair timeline.  
1. Case open and label issued: March 22
2. Mope around for a few days
3. Mail Mavic to DJI: March 29
4. DJI Repair timeline as below:

Timeline

5. Mavic arrives back: May 2.

Overall, just slightly over 1 month. Will do a flight test soon and post results here.

poliakov Posted at 2017-5-4 18:55
The story continues!

I have received the Mavic back 2 days ago. Despite the case stating "repair", what I got was a box with a brand new drone - stickers, film and everything. DJI threw in a new set of propellers too. Alas, no extra controller or batteries  I just got around to doing a table test - same as described in the beginning of the thread, slightly different angle. So far, the results are much better.

What's the build date of your replacement? http://djiserialdecoder.x10host.com/

srg Posted at 2017-5-4 21:02
What's the build date of your replacement? http://djiserialdecoder.x10host.com/

Interesting. March 24 apparently.

I sent mine in for exactly the same problem, the left side of my pictures are blurry when I center focus. I hope they get it fixed up, I read a lot of reviews of the Mavic before buying it and never heard about the problem, but as soon as I noticed it i started searching specifically for that problem and then they started popping up all over the place. I saw so many nice photos and videos online done with Mavics that don't seem to have the same problem so I hope mine gets fixed quick. Other than that it's an awesome flying machine I love it.

So - yes - I can reproduce the problem on my replacement Mavic but I have to try a lot harder and it's more subtle. One example:


For example, for this set of 3 images, I can only see a disparity on one side, the right. There isn't a matching disparity on the left that I could find, for no lack of patterns or trying. Overall: not perfect but definitely much better.