Hi,

My Pro Timer is working very well with NMX motion control in slave mode, slewing a Nikon D750 camera.

However I just lost several frames of a Milky Way sequence set up as follows:

D750, NMX Saphire with two dof, Pro Timer firing the NMX as slave, QDSLR dashboard on Android tablet, USB directly to camera. No wifi. 30 second interval, 25 sec exposure, move set to -3 seconds. 750 frames. 6 lost. Release time 200msecs.

I have tested many combinations to try to find the guilty party, all runs well without Qdslr so I imagine there may be a control conflict as data is read to the tablet ?

Any thoughts on what to do to make this combination a reliable system ? Is the dark time just too short maybe?

You should do some tests dutring daylight to narrow down, what's going on. It's difficult to give an advice.
Normally, the setup sounds legit.
Make sure to have the Raw+Smallest JPGs set in camera, you might try to increase the release time to 250ms just to be on the safe side (and exclude the LRT PT from the equation) - make also sure that the screen of the table stays on to prevent sleeping.
Then do some tests begfor you go out for a real shooting next time.
You can shoot totally overexposed test sequences during the day - LRT will tell you later via the interval column, if you missed shots.

Hi Gunther

Yes, I have already doing that; I always have Largest Raw/Worst jpeg set in the camera and have just shifted release time to 250ms. Android screen is always on.

My suspicion falls on the Android tablet and app; I have found that the pictures folder is full. Maybe I downloaded an entire sequence from the card into the tablet? not sure; but I have cleared it out and will restart today. This eliminates one variable.

The LRT interval is always good, the D750 always fires on time but the NMX does not it does not illuminate its blue 'move' lights for one or two frames, so the stars 'move' for a frame or two, then do not as the NMX tracks the sky.

Full moon and high humidity means no dark nights so I have some time to resolve this.

so I will shoot long exposures in the day to try to replicate/eliminate the problem.

I will let you know the outcome. Many thanks for the response.

Set qDDB to not store any images locally on the tablet!

... sent mobile ...

OK, success.

I have set release at 230ms and slave delay at -2.0secs.

I set NMX to slave mode using the three taps on the switch, slave mode is confirmed by the app slider.
Previously I set it to slave mode using the app slider only, maybe here is the cause ?

Either way I am back in business with the outstanding Pro Timer

Good to hear that! Enjoy!

Just to finish this, and for anyone else with same problem.

I believed that I had resolved my NMX problem, but I was wrong.

What happens is that the ProTimer sends a 'move' signal to the NMX, you can see the two middle green lights flash when the signal arrives, but the Sapphire fails to move on some occasions. Usually it does not move when you are not looking :-)

So with 500 frames sequence say, total slew of 30 degrees clockwise, shutter 1/1000, move sent 3 seconds before shutter and 10 seconds interval, some maybe 2% of frames have no slew motion. Prolonged study proves that there are no cable snags and that the signal is received at the NMX.

The cure is the last variable, the release time, which I have further extended now to 400ms.
With success. Now the move signal is registered and the head moves directly after, every frame.

I very much hope I have got to end !!

congrats on solving your problem, I'll keep the release time fix in mind as I start working through slaving moco kit myself.

I have very similar moco hardware setup to you (SapphirePro and a StageOne slider), but I have replaced my NMX with a Blackforest Motion "Pine" controller, which I can highly recommend. I originally bought the Pine because:

1) the NMX's bluetooth chip fails when it's cold (I lost a lot of shooting opportunities on a trip to Iceland because of that problem, my fault for not bringing a suitable USB cable to be able to control the NMX from a direct connection)
2) the NMX's app is pretty old (it doesn't allow full control over anything but 2 keyframes).
3) the NMX can only control 3 motors: I've added a 4th motor to my setup (I already was controlling pan/tilt/slide with both the NMX and the Pine, but now I can control focus or zoom, opening up extra creative opportunities!).

I'm very happy with the Pine, and no, I don't incentives from Blackforest for evangelising it ;-)