Hello,

I use another USB device to ramp the exposures while LRT timer is running. I got some missing shots when I ramped the exposure thru this USB device. The gap btw my shutter speed and interval is around 2~3 seconds. So it's hard to change the exposure setting exactly after the shutter is closed, which I think had caused the issue. It seems like the shutter is blocked when I make a change from the USB device.

Please see attached screen shot. Most of the missing shots occurs before the exposure is changed. I remember I tried multiple times before the setting was applied. Sometimes the change was not carried out as the app will block any operation if the shutter is open.

There's no issue if I made the changes manually thru the camera dials while LRT timer is running.

I don't want to touch/shake the camera during a TL sequence for exposure ramping. Do you have any recommendation of other app that can pair/synchronize with LRT timer so that I can change the exposure manually without missing shots? I heard qdslrdashboard can do exposure ramping automatically, but I really want to ramp the exposure manually by myself.

Thank you!
Zoom

It seems that your USB trigger blocks the camera, that's quite often the case.
qDslrDashboard is one of the few exceptions that is able to control cameras and still give you the freedom to operate them. Holy Grail can either be shot automatically with qDDB or also of course manually, if you want.
I also started manually and then created the concept on how to automate what I was doing - that's the "Auto Holy Grail" in qDDB today. Just check it out.
Here's my video where I show it. https://lrtimelapse.com/gear/dslrdashboard/

Wonderful, thanks!

I will try manual ramping with qDDB paired with the LRT timer.

I'm not sure how the auto holy grail works when the TL sequence starts from sunset all the way to the milky way, when the exposure is around -7EV. Most camera meters cannot measure below 0EV. But definitely I will check out your video.

Cheers,

The qDDB auto holy grail does not use the camera metering, that's why you can ramp all the way to the milky way. The Auto NTC feature will even consider your location and the dusk and dawn times. Give it a try, you'll be surprised how well it works!

Sent mobile...

Today, I tried again with my USB device (Unleashed) after discussing with Oliver, the company owner. He said Unleashed wont block the camera operations.

I replaced my SD card with a faster CF card, and kept the gap between LRT interval and shutter speed around 2~3 seconds. Tried 200 shots twice with frequent exposure adjustments thru Unleashed, there was no missing shot.

Unleashed will not allow me to make any change when the camera is busy, so I just kept trying. I don't know if a CF card will fix the issue in the real world with thousands of shots.

I guess qDDB should work similarly to Unleashed in regard to the exposure adjustments. If unleashed has missing shots, then qDDB or Canon's own remote "Camera Connect" App would have missing shots in the same situation. Camera itself should have some multi tasks synchronization mechanism. Please correct me if I'm is wrong.

Thank you!

Well, I went back to the slower SD card and tried again (Oliver suspected the buffer writing is too slow), but I cannot reproduce the issue with 200 test shots.

This section <attached> has 5 missing shots. As you can see, the shutter speed (1/100) is pretty fast compared with the interval (4.5 sec), and I did not make any adjustment during this period. I suspect those missing shots might not be caused by the USB controller.

Could it be related to LRT interval ramping? I lost 15 shots totally among the 4k photos. All of them are during interval ramping.

Now I am confused which part might have contributed to those missing shots and why.

Is your LRT PRO Timer on the latest firmware? If not, please update. Then make a test with the same settings and shooting with the PT only (without unleashed). This will help to isolate, where the issues come from.

Sent mobile...

This post was last modified: 2021-05-17, 10:06 by Gunther.

Thanks, Gunther.

Mine was on v24. I just updated the firmware. I read the release notes,

2.5 r15
- When stopping the interval ramping, sometimes instead of continuing the shooting stopped for a while. Fixed.

2.5 r10
- Fixed an anoying bug, where after the interval ramping finished, wrong intervals were used. Sorry for that.

These issues might be related, but I am not sure. It's really hard for me to reproduce the issue, as I only missed 15 shots among 4,000 photos. I tried several times with 200 test shots with Unleashed, I was not able to see any missing shot at home.

I hope the firmware update will fix the issue. I will report back whether the issue is gone or not in my next couple of long shootings.

Cheers,
Zoom

Those changes do not apply to your firmware update, they happened in firmware 10 and 15. You went from 24 to 25. :-)
Let me know, if you still get the issues with firmware 25 and if so try to find a scenario of settings, that is reproducible.

This post was last modified: 2021-05-18, 06:09 by zoom.

Oops, my bad. I thought 2.5 (25) is the version number.

Sure, I will report back if I see the issue again and will try to reproduce it.

Thank you!