Hello.
I have two reach m+ units.
One have been purchased from Topodrone with a modified camera as a kit for phantom 4 pro.
The other have been purchased directly from emlid in previous integeo 2018. But I didn’t have an appropriate camera to use it.
I have really good results from the phantom 4 pro kit.
Last week I purchased a Sony A6000 and I installed the second emlid. I have seen a lot of users use this camera and I thought that it would be a proven solution.
The problems start from the beginning. I wasn’t able to trigger the camera. After searching in the forum I discovered that it was a hot shoe problem. Sony has paint it Black and the connection wasn’t good. After following the instructions, I sant the hot shoe and I have solved this problem.
But after making my first test flight in a site with 20 check points I have found a systematic error over 25 cm in y direction. I have much much better results with the other kit with phantom. I have installed the talisman antenna directly over the camera.
After checking the camera settings I found that I have set the camera flash mode in fill mode. Is that correct? I think I have a delay in synchronization and course this problem. Anyone who’s using this camera with reach m+ can help me?
If that is the problem, you should not have a systematic error on only one axis. Are you flying with the drone facing the same direction all the time ?
i use pixhawk and i make the mission with heading hold. So the drone hold the yaw direction.
But the slope of the drone is max 7 degrees and the antenna is 15 cm over the camera so that must cause max 2.5 cm error
Are the checkpoints and the M+ derived points corrected with the same base?
same base and i produce coordinates in the same system outside of photogrammetry software.
With the phantom the results are perfect.
So i think the problem is in the camera. I choose this camera because i have seen many people to use it and i thought it would be a proven solution.
is it possible to have electronic shutter enable? I don’t found any setting for that. But i can hear the shutter noise
Does flash mode play any role in reach Synchronisation?
You don’t want that for photogrammetry. Will like create issues with rolling shutter.
Yes, you have to choose some kind of manual setting.l, where the camera does not expect to communicate with flash. You also have to stay away from the rear curtain sync mode, as that would then give you the pulse at the end of the exposure.
I was hoping rear sync to be the solution.
Sony A6000 has only 3 Mode available. Fill Flash (which I have already tried), slow sync, and Rear sync.
I know that I don’t want rolling shutter, I am just can’t find an option for that in A6000
Fill flash may fire prior to the shutter for measuring the scene, this might trigger a fals signal for GNSS timestamp.
Rear sync causes the flash sync to wait, and not to trigger the flash until the end of the shutter duration, as the second curtain is about to start closing.
So what to use? Slow sync?
Is this camera not good for synchronization?
I have seen a lot of people used this with gps modules.
Rear sync sound right to me. But how each flash modes work is different from camera to camera.
Also use manual, that should give the control to what ever setting you set and not let the camera start autodialing on you
Edit: In the menu you should turn off red Eye function, also check what options you have in the flash mode settings.
Rear sync would, as mentioned, send the trigger signal just before exposure ends, not what you want.
However, if it works, it would be easy to take into account the shutter-time as adjust accordingly.
Are you using reach M+? If yes with what camera? I am doing a lot of research on the internet and I have seen that all brands have almost the same flash modes. Accordingly is not ok. I thought hot shoe should give perfect sync. I am testing it right now at my Hexa at a speed of 8 m/sec but at the end, I want to place it in a plane with a speed of 20 m/sec.
I read in " Reach in action" Tuffwing using a sony nex 5N. I have also this camera but the hot shoe is an extra part which I ordered from china. I saw also 3DroneMapping which use A6000 with excellent results. Also in this forum, I have seen other people also with A6000. So i thought A6000 should be ok
Perfect sync is not possible to obtain without knowing the exposure time, and being able to trust that the camera sends the sync-signal consistently. For a perfect sync, you need mid-exposure syncing, and you can only find the middle of something of you know its overall length.
For normal cameras, you want the trigger the flash as early as possible, to make sure you get the full effect of the flash discharge.
So the best way is to take the exposure time into account when computing the events and pos-file. Especially if flying with 20 m/s.
Or, bite the bullet, and get a camera/platform that supports mid-exposure syncing (Phase One IXM, teokit, and most other dedicated aerial solutions) and so on)
3DroneMapping completes PPK trials
Have you seen this in emlid reach M+ page? they fly with A6000 and 19 m/sec and the results is similar with what i get with pantom 4 pro and the topodrone kit which include reach m+ and a modified camera
What happens if you let place the drone on a groundpoint with known coordinates? Does M+ also report 25 cm off ?
Good question. I am going to try this. I will place my Trimle R8 antenna in top of emlid antenna and i will solve both from the same base. But i find it difficult to be that the problem.
But anyway i will try it.
Speed, that is what its almost all about . How fast are you flying and at what shutterspeed.
With shutterpseed of 1/500 the exposure would take 2ms from the start to the end and flying at 20m/s you would get a blurry image, in theory. You would fly 4cm for the time it took to take the picture.
With 1/1000 exposure it would be 2cm and so on.
If you can trigger the flash its usually not when during the exposure that is the problem, its either a pre firing flash or too long shutter. I should mention bad connection and other failure too, but lets say we have them ruled out for now.
Basically you need fast enough shutter (1/800 or faster when flying fixed wing) to get clear images which again should be enough to keep the delay between trigger and flash 1-2ms.
This is related to the front/rear sync and normal flash sync.
If you can manually change settings from rear to normal sync, that is ok too.
I know about that.
When flying with my hexa with 8 m/sec i use shutter speed 1/1000 or 1/1250.
As i wrote at the begging i also could not have events from reach m+ without having the internal flash extended.
But then i found this thread in the forum:
So i used sandpaper in the hotshoe and now i have events.
But as many searches i ve done none speak about flash settings with any camera.
It sounds like you need to manually override the flash, you have a pre firing signal issue.
What does your flash mode opitons looks like in the menu?