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Resulting day to night holy grail footage increasing speed.

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#1 CHristophrPaul
Hello all and thank you Gunther for your continued work.

I'm sure this issue has happened to everyone on their first try at a holy grail, "day to night" time lapse so i hope you don't mind the question and subsequently, i hope i find a solution.

As you can gather by the title of this thread, I accomplished, what i thought was a good first attempt at a holy grail scenario but as the output video starts, the footage (clouds etc) are moving at certain speed and then when the stars come out, everything speeds up quickly.

Equipment used was Nikon D750, 14-24mm, Vello external intrevalometer (wired), qDslrDashboard (auto holy grail setting)
Editing: LRTimelapse, Lightroom

The resulting video starts off in the "daylight" portion at a certain speed then increases the more night falls and tapers off once night has completely fallen into darkness and stars are fully out.

I absolutely acknowledge what is happening here.

At first, the shots are at 1/60 of sec with 2 second intervals and then, by the time night falls and qDslrDashboard has ramped the exposure down to my maximum preset of 25 second exposure (still with 2 second intervals), the frequency between shots has slowed, resulting in an accelerating speed in video play back.

When i realised what had happened, i decided to painstakingly use key frames in Adobe Premiere to try to slow down the gradually faster night fall sections of the video. Brutal..

It was horrendous to try to get the speed to adjust so that the whole time lapse was the same speed. The result was less than perfect to say the least and i don't want to have to go through that every time in post.

Is there any solution to get the speed right "during" the initial capture of the time lapse? I've read of something called Interval ramping. I'm not sure the Vello can be programmed to ramp the intervals and it would be very hard to ramp the vello manually during the time lapse

I'd be interested to hear of how others have overcome this with similar equipment listed rather than purchasing yet another gadget to adjust the intervals on the fly.

Keep in mind that later at night, i want to capture as much of the night sky as possible so i want my exposure to be 25 seconds with a 2 second interval. (approx. 27 second total)


I thought about setting my intrevalometer to 25 second intervals at 1/60 during the daylight captures in the beginning but then that only eventually becomes 25 second exposures with a 25 second interval once night falls (equalling over 50 seconds)!

Thanks in advance and i can't wait to go out and try again with some new advice/techniques.

Chris
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#2 Bobu
Chris, what I normally do in this situation is to start with the same intervall as used in the night. In your example 27 seconds. You could probably shoot at longer shutter-speeds than 1/60th at the beginning by adjusting the apperture (for example by using qDSLRDashboard) in addition to exposure time and ISO during the sequence. Whether this makes sense or not depends on the situation (recommended with water in the foreground or moving people, not recommended with the sun directly in the image and/or a subject sensitive to DOF changes due to apperture changes).
Another alternative is an intervall ramping for example by using the Pro-Timer. I rarely do intervall-ramping, but it can further improve the result.
Boris
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#3 Ralph
Hello Chris,
I think you've got a little thought mistake. The interval consists of exposure time + black time. 3sec exposure time + 2sec black time = 5 sec interval.
If you start with a 27 sec interval, the camera will trigger every 27 sec whether you expose with 1/60 or 25 sec. At 1/60 you have a very long black time, which shortens with increasing exposure time. To extend the exposure time during the day, I would close the aperture, as Boris suggests. Alternatively you can test the interval ramping of qDDB. However, it would be better if you did this with an external interval trigger, such as the Pro Timer.
I have uploaded an example of a time lapse with interval ramping to Vimeo. https://vimeo.com/341901100
I started with a 15 sec interval with 1/20 shutter speed, f/16 and ISO 100. At the end I was at a 25 sec interval, 20 sec shutter speed, f/4 and ISO 3200.

Greeting, Ralph
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#4 CHristophrPaul
Thank you Bobu and Ralph for taking time to respond with some suggestions.
Since the Pro-Timer is not available for shipping here in canada, (frown) i will have to check out the interval ramping of qDDB.
I assume your preference to use the external Pro-Timer is based on the fact that qDDB is "wireless" so there may be connection or delay issues of qDDB triggering the intervals for the Nikon D750.

Ralph, nice example video, thanks. Did you use the Pro-Timer here or qDDB or manual ramping.
Here is my first try on Instagram: https://www.instagram.com/p/Bygiv_agVmy/...hare_sheet

I used key frames in Premiere to try to slow down the acceleration of the longer shutter as night fell.

Bobu, thanks for the suggestion of using longer intervals during the start (daylight portion) of the time lapse. I had thought of that too but wondered how to control the ramping as nightfall came.


chris
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#5 Ralph
Hi Chris,
in my example I used the interval ramping of qDDB. The Pro Timer didn't exist at the time.
There are two reasons why I recommend an external interval trigger. If you use qDDB to trigger the camera and the connection to the camera is lost, you will lose some of your shots and you can't use the time lapse. If the camera is triggered by an external interval shutter release, only a few shots may be incorrectly exposed, but this could be corrected in post-processing.
But with the Nikons, the connection is very stable. You could also make the connection using a USB cable. All you need is an OTG adapter.
Another reason why I recommend an external interval trigger is that the interval times of qDDB are not exactly adhered to.
Why do you think the time lapse would accelerate when you change the shutter speed but leave the interval the same? In your example the clouds would be faster at the beginning, if you had worked with a very short shutter speed (1/60) and a very long interval (27sec).
Generally, it's better to do two time laps anyway and add them together in PP to one movie.
So you could run the daytime lapse, with ND filter, until the end of sunset and then, from the blue hour, without filter, record the rise of the stars.

...also check out: