Hi all, I’ve run into an issue when attempting to change the Reference Value in qDSLRDashboard when attempting a Sunset Holy Grail. To describe what I’m doing:

(I recently decided that it was time to get back into timelapse - particularly the Holy Grail sunset/sunrise. I purchased an Android tablet (S7) to use qDSLRDashboard in the process.)

I set my Canon 70D camera (wide lens with RAW+small jpeg), intervalometer, and qDSLRDashboard up and working: 30 second interval on the intervalometer, qDSLRDashboard with: auto holy grail, maximum 20 second exposure, max ISO 1600, 1.8 to 16 aperture.

The reference photo was working well, exposures were good, histogram was good - no clipping. Set it going and watched for a while then went out to dinner with family. (This was basically a test.)

Come back and checked - the exposure was way too high. qDSLRDashboard showed EV 1.33 (plus, not minus). Okay, I figured it was a good test anyway - pressed the “-“ button beside the “Reset Reference Value” button and waited a few shots.

Nothing changed.

A few more presses, waiting 4-5 shots between, the EV stayed at 1.33 and the histogram was still clipped highlights.

I’ve packed things up for the night, however it’s nagging me as to what I’ve done wrong. Should I have turned off the Auto Holy Grail and then adjusted? Was I simply too impatient and should have waited for 9-10 shots to see how the adjustment went?

Tips are very much appreciated.

Cheers,
William

If you change the reference it will take time for the camera to adjust.
In your scenario with the very long interval of 30 secs (quite unusual for holy grail), qDDB would adjust by 1/3 stop only every 3 shots which is 90 secs in your scenario.
In a real shooting you would rather work with intervals of 5-10 secs which would then also adjust much faster.

Another thing: Double check the Aperture setting (I'd not recommend to do Aperture ramping, if you don't know exactly what your are doing. Aperture ramping might cause weird changes in vignetting.
Also in your scenario the direction 1.8 to 16 would be wrong, in Sunset mode id would need be from the larger value to the smaller.

I'd recommend to do some more tests and practicing before going out for a real shooting.

This post was last modified: 2023-06-21, 00:51 by WilliamD.

Ah, a combination of misconfiguration and me being impatient. Thank you Gunther, I will practice more.