Worth noting is that both a classical mechanical focal plane shutter (as is in the A6000 and most other ILCE and DSLR types camera) and the electronic shutter practically works the same way.
However, the speed of the mechanical shutter at, say what @TB_RTK says, 1/300s is much faster that the electronic read-out of the electronic “shutter”. On some cameras, that readout can take up 1/20 of a second. And so, while you don’t any motion-blur from this, you will see a rolling shutter effect.
What can fix all this ? A leaf-shutter, as @TB_RTK says (though a global shutter can also be implemented as an electronic shutter, which is still not as good as a leaf-shutter).
Thats why photographers love to truly freeze objects with flash. Its way faster then a shutter.
So… maybe your fix to the problem is mounting a humongous flash on your drone?..
I just realized, because my partner flies the phantom, and I prossess the data, that phantom flies during the mission with 2 m/sec. My error is mostly in y direction and a little bit in x and really small in h. This looks Logic as the flight direction is 344 degrees.
If you have a systematic y-axis error, which seems to be parallel to vector of travel, of 25 cm, that is easy to correct, and easy to explain.
On another note, you are trying to use a camera for something for which it was not designed. All sorts of issues could arise with such a camera in an aerial use-case. Something a photographer would potentially never see.
Simple production-variances, or firmware changes could be a cause of several centimeters of error.
I know that this camera was never designed for photogrammetry. And I can understand the limitations. The question in which I still not have an answer is how others seems to use the same combination with faster speeds and better results. If they can then maybe my set up has a problem.
Maybe they applies correctios like an average time shift.
I am just very curious to see what results aquire others using reach m+ and with what setup.
I forgot to mention that yesterday i measure with my geodetic GPS the talysman antenna, and i compare the results with the ppk value from the same base. All values is in 1 cm difference.
My partner make today 3 flights with the phantom. One with 2-3 m/sec, one with 7/m/sec and one with 9 m/sec. I will come back with results.
I’ve checked raw data from Reach M+ you shared and tried to post-process them. The results seem to be fine.
As far as I know, the Phantom’s camera is installed with a gimbal that allows it to be directed perpendicularly during the flight. That’s might be one of the reasons why you get this offset, as you don’t use a gimbal for Sony camera.
So, It’d be nice to compare your results of flights with different speed values to say something more certain.
[quote=“TB_RTK, post:63, topic:16298, full:true”]
The reason for my point is the true speed of the shutter leaf. Exposure is one thing, but the speed of the shutter leaf crossing the sensor is just 1/300 ish of a seconds (for most modern mechanical shutters).
This must not be confused with shutterspeed (exposure time).
You would be thinking, hey! I is just use 1/2000, that should do the trick and freeze the image. Errh… That is not entirely true, cus its exposure time, not motion time.
You camera is actually “freezing” images at about 1/300 of a second which with your speed at about 7-8ms would give you an error of 20-25cm
Thats is why a global shutter is sometimes better, it opens and closes all pixels at once, but not as fast as 1/8000 sec.
Blockquote
i know its a bit late but i red again the discussion and i must say that even if the shutter true speed is 1/300 with 8 m/sec is (1/300)8 = 0.027 so 2.7 cm
** and not 20-25 cm*
