thanks houghy. some good ideas there and using USB alone worked a bit smoother and has helped me trouble shoot what's going on with the shoestring adapter. i'd like to get it working though as having mirror lockup will help (but am going to do some testing to verify exactly how much). reducing the shutter press time to 50ms seems to have helped as well (fred and i had to experiment with that on his timelapse controller as well).
some results below.. bizarrely in each case it's the switch between the longer 1"-2"-4" exposures that start to break down first, rather than the gaps between the faster exposures.
- with just USB control, the sequences work fine with a spacing of 1.0 secs, and start to break down at anything less than that.
- using the shoestring DSUSB without mirror lockup, i get a similar result but actually need slightly longer than 1" for a reliable sequence.
- using the shoestring DSUSB and mirror lockup, i need closer to 2" exposure spacing to get a reliable result.
there are still two advantages to using the shoestring adapter though.. i get mirror lockup (of variable duration as needed) and when i'm running consecutive exposures of the same settings (eg 1/3000 sec for bailey's beads) i can run a few of those together with <1 sec spacing, which i can't do via USB alone.
so i'm leaning towards still using the shoestring adapter but it will take some hand coding of the scripts to optimise the result.
cheers
phil