Mavic 2 Pro Automatic Light-based Speed Adjustment very slow

I was testing out a new Mavic 2 Pro yesterday. I was mapping a golf course. Even though it was a fairly sunny day the speed was adjusting down to between 4-7 mph on each flight... Everything was set to auto, no special lens filters. I was flying at 325' tying to get about a 1"/pixel resolution. 80%/80% overlap.

In comparison I flew the same missions right after each other using my Phantom 3 Pro, which I have been using for a couple years. its typical speed was 13-16 mph. It was flying at 205', 80%/80% overlap also trying to achieve 1"/pixel resolution.

All settings were the same, except for the "model" of course. Has anyone else noticed this? I assume it mat be related to the higher resolution on the M2P camera and so it blurs at slower speeds. If that is the case is there a way to change settings on the camera manually to get similar results to the P3P?

We have been very happy with the results of the P3P in the past, but wanted to get a more compact unit to use when our projects involve air travel to the site. Any suggestions would be much appreciate. Thanks!

Thomas W Campbell 2019년 11월 07일 13:51

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It is starting to get a lot darker at this time of year. It also depends on what the camera was seeing on the way from the takeoff point to the green dot. The estimation is made during the first 70% of that leg and if it is darker than the rest of the area then it will be set to a slower value.

Also... The Mavic 2 Pro has a much narrower field of view than the Phantom 3 Pro which means its images are closer together. The speed is basically limited by the speed at which images can be written to the SD card.

To fix this... The comparison should be made with equal GSDs. At the same height with the same overlap the M2P is getting smaller GSD. To make it even you can fly the Mavic higher and the numbers will likely even out.

Zane 2019년 11월 07일 17:18

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As I mentioned, I was already flying the M2P at 325', 120' higher than the P3P. The predicted mission times and number of images worked out to be about the same... so would that mean the the GSDs were close to the same?

Thomas W Campbell 2019년 11월 07일 17:35 0 표

You would have to check the altitude slider which will tell you the GSD. Also, you could check the Aperture of the M2P and make sure it is set to the largest available value. This means selecting the smallest number. f1/2.7 is a much larger aperture than f1/4.6. A larger aperture will let in more light and allow the aircraft to fly faster.

Zane 2019년 11월 07일 17:45 0 표

The aperture is your solution. I have exactly the same experience with P4A. Compared to P4 which have aperture f1/2.8 MapPilot let the AC fly with smaller shutter speed and therefore no slow downs due to light adjustment.

With P4A in auto camera mode during a sunny day I had shutter speeds 1/320 because it tried to keep aperture value to f5.6. So I had also those slowdowns.

The solution is to put the camera in shutter priority and fix the shutter speed to 1/800 or smaller e.g. 1/1000. No more slowdowns for whatever reason.

The P4A camera problem from my experience is with overexposed images. For example I have one GCP in 20 images and some of them are washed out. I don't know if the same is with Mavic 2 Pro but I think that this is a problem for a moving camera anyways..

George 2019년 11월 07일 18:17 0 표

Thank you for the responses...

As i mentioned in the original post, I had them both set to achieve a 1"/pixel resolution on the altitude slider. so that would mean the GSDs were the same.

As for the aperture setting, I just checked the EXIF tag and sure enough the M2P was set to f/5 while the P3P was f/2.8. Excuse my ignorance on this subject, but we our irrigation consultants, not photography people... I had everything set to Auto, like we have always done on the P3P. Is this part of the Auto camera settings? If not do, I set it in Map Pilot or DJI Go4? If it is autoset, is there a way to force it into f/2.8 while having all the other entries auto like ISO and shutter Speed?

Thanks again

Thomas W Campbell 2019년 11월 07일 18:26 0 표

The P3P like P4 has fixed lens with aperture f2.8.

You can set the settings of the camera in MapPilot. Read here

https://support.dronesmadeeasy.com/hc/en-us/articles/207392056-Exposure-Mode-and-Exposure-Time

Do some tests and you will understand how it works.

George 2019년 11월 07일 18:31 0 표

4.1.0 introduced a Aperture priority mode. If you select that and pick the largest aperture possible you will be getting the most light possible. Leave everything else on auto if you aren't sure what to do.

Zane 2019년 11월 07일 18:34 0 표

George,

Thanks for the info. Like I put in the response to Zane, we are irrigation consultants, not photography people, We just use the process to create a good base map to design the irrigation system.

So with that in mind do you know of a resource for inexperienced people to decide the various camera settings?

Thomas W Campbell 2019년 11월 07일 18:34 0 표

Zane,

Thanks, that's awesome, just what we were looking for!

Weather is bad here today, but hopefully better tomorrow so we can give it a try.

I really appreciate the timely responses!

Thomas W Campbell 2019년 11월 07일 18:45 0 표

Zane,

does larger aperture e.g. f2.8 results in lower quality/accuracy maps compared to f5.6 or other value?

George 2019년 11월 08일 07:51 0 표

A larger aperture collects light from wider angles to the sensor and will result in a narrower focus band when working in close but at aerial mapping ranges it doesn't matter as much. But as a general rule, larger aperture means more light but harder to focus, smaller aperture means less light but easier to focus.

Zane 2019년 11월 10일 14:40 0 표