Interval very unstable in LRTtimelaspse mode (iOS 8.1, Nikon d5200)

[AndyC]

I've just done a couple of test runs with the software and I'm finding the the intervals to be all over the map (set at 7 secs with a max exposure of 4 secs). I was getting intervals between zero and 78 seconds. I'm using an iphone 5S connecting via the Nikon wi fi accessory. Any suggestions?

[hubaiz]

Intervals are always performed at the defined interval.
qDD will send the capture command to the connected DSLR, if the DSLR can't perform the capture while it is busy it will skip the capture.
Probably a 3 sec is to small, try using 4-5 sec.

[AndyC]

Hi Zoltan, thanks for the response. Just to be clear, in my experiment yesterday although the shutter max was set to 4 secs my slowest actual shutter speed was around 1/125th sec so the camera had more than 6 secs to read the histogram (and I was using RAW + smallest jpeg setting). Anyhow, I updated the iOS version on my phone from 8.1 to 8.3 and experimented with the intervals below, recording the percentage of frames that were 2 seconds or more off the set interval. The slowest shutter speed was 1/30th sec. Most of the errors were small and this is a huge improvement on yesterday (where at 7 secs the intervals were almost 100% out by several seconds) but this still seems slower than your guidelines recommend.

interval (secs) % errors (2 secs or more from interval)
10 4%
8 9%
7 12%
5 7%
4 24%

There seem to be several possible explanations and I'm curious to here your opinion as to what is going on here.
1) some part of my card/camera/wi fi connector/iphone chain is slower than average
2) updating the iOS made a difference at the 7 second comparison

Regardless, my advice is for people to experiment with their intervals in case their combination of devices needs more than the largest exposure + 4-5 seconds.

Andy

[hubaiz]

You are using the Nikon WU-1a/1b adapter?

[AndyC]

Yes

[hubaiz]

I think the problem is with it, I just did a quick test with the WU-1a + D7100 and at 5sec I also had some skipped frames.
The problem is the WU-1a is a tiny adapter and the wireless signal is weak and there are some slowdowns (you can see that in live view).
The command is sent to the camera but if the wireless signal is weak or the communication speed is lowered the command might be delivered delayed to the camera.

[AndyC]

Thanks for narrowing down the issue. Presumably one option for shorter intervals would be to use a separate intervalometer on the shutter release port and just use dslrdash to adjust exposure via wi fi? Or would the micro USB port block the shutter release if it's uploading a JPEG while the intervalometer fires?

[AndyC]

Experimenting some more I realized that though I had RAW + basic I hadn't in fact set the jpeg size to the smallest. Doing this and repeating I have no misfires at 6 secs, 6% misfires at 5 secs and 8% misfires at 4 secs (all exposures less than 0.5 secs). I would say for my setup (Nikon d5200 + Wu1a wi fi + iPhone) interval should be longest exposure + 6 secs to avoid misfires.

[hubaiz]

External interval timer will work as long the camera is not in 'Host mode'

[AndyC]

thx