Nikon time-lapse feature. Some thoughts / Interval consistency

[conceptics]

Hi everyone

I am new to this forum, but have been an avid reader for years. Anyway, let me get straight to the point.

I have been a Nikon Z7II shooter for some time (before that d800 for several years). I have now recently extended my collection of Nikon cameras by buying a Nikon Z30 with the 16-50mm kit lens to focus on one very simple use-case: time-lapse, or more specifically, drive-lapse videos for our upcoming trip to the US-westcoast, where we will be doing a lot of driving.

To create drive-lapse, I am using an ND64 filter on the kit lens and using the following settings for a 24fps video:

1.) 12x speed equivalent

Interval: 0.5s, mode: S (Shutter priority), shutter-speed: 1/4s, auto-ISO: enabled, exposure-smoothing: on, silent-photography: on

2.) 24x speed equivalent

Interval: 1.0s, mode: S (Shutter priority), shutter-speed: 1/2s, auto-ISO: enabled, exposure-smoothing: on, silent-photography: on

With these settings, you can achieve smooth motion blur that looks a lot nicer than what your typical GoPro camera can achieve that looks choppy and aesthetically unpleasing. By being in shutter-priority mode, the motion blur remains consistent throughout the recording. Varying lighting conditions are addressed with the variable aperture and auto-ISO.

This works well, however, there is a catch:

Using option 1 and the shortest available interval of 0.5s, the interval isn't consistent under certain circumstances. When the aperture closes beyond f/7.1 with silent-photography enabled (no mechanical shutter), the interval changes to 1.0s. This is an issue, as this ruins the drive-lapse recording, as in extremely bright conditions when the aperture closes to f/8 or beyond, the interval changes to 1.0s and the recording doubles in speed from 12x to 24x for these periods.

This can be tested rather easily by setting up the Nikon on a tripod with the above mentioned settings and pointing a flash light at it while looking at the aperture. When the aperture is close to wide open, the interval of 0.5s is met, however once light hits the lens and the aperture needs to close farther and beyond f/7.1, the interval slows to 1.0s.

There is one solution: Disable silent-photography and thus enable the mechanical shutter. This, for some reason, solves the problem entirely as then, even if the aperture closes beyond f/7.1 (i.e. f/11), the interval of 0.5s is maintained consistently. This unfortunately isn't feasible, as the wear & tear is too high. The mechanical shutter of a Z30 is rated at 150k, which would roughly equal 25 hours of drive lapse.

My observations thus conclude;

For consistent drive-lapse or time-lapses of any kind requiring a consistent shutter-speed and interval, you need to set an interval of at least 1.0s. If you absolutely require 0.5s, you need to have the camera in M-mode and limit the aperture to something wider than f/8 and work entirely with auto-ISO to counter variations in lighting (which to be fair, is probably not possible on a typical drive including varying weather conditions or tunnels). Perhaps using an ND1000 filter or stronger could provide a workable solution, wherein you keep the camera in shutter-priority and push the camera to use an almost wide-open aperture even in extreme bright conditions, however live with the compromise that for the most part, you will be pushing your ISO under normal conditions and beyond once it gets cloudy.

Has anyone made similar observations and/or found other solutions?

Also; does anyone have any idea why, when the aperture closes to f/8 or beyond, that the interval is pushed to 1.0s? One would assume that the aperture isn't fast enough, thus, that is the limiting factor, however when disabling silent photography, the camera is quick enough to engage the aperture within the interval. So what is the reason?

For the record, I have also tested different lenses to see if this behavior is lens-specific, but testing the 35mm f/1.8 on my Z30 revealed that it behaves identical. I have also tested the Z7II and the results are similar to identical.

And most importantly; Anyone know why the aperture changes constantly during such a recording? One would think/hope to reduce wear & tear, the aperture would stay and only adjust when the lighting changes? Is there a reason for this constant opening/closing?

 

[JasonMulvern]

Useful post, thanks.

And most importantly; Anyone know why the aperture changes constantly during such a recording? One would think/hope to reduce wear & tear, the aperture would stay and only adjust when the lighting changes? Is there a reason for this constant opening/closing?

It's the way Nikon does it, "London Viewpoints" on YouTube covered this because he was finding the constant opening/closing of the aperture for each shot even when in manual mode was causing flickering. He also said some of the later firmware on the Z8/9 fixed this for certain aperture settings, but otherwise, a partial dismount of the lens was the only way to physically fix the aperture in one place. I've not noticed flickering on my 16-50 lens using the Z50 though, so it might only be some lenses, and there's software options later to deflicker.

Like you I've found ND filters and reasonably long shutter times gives smooth results for this type of timelapse, though it's maybe more of a challenge on British roads due to how bad they are, so faster shutter speeds are needed, or it becomes a bit of a mess.

 

[Leswick II]

I found it easier adjusting Variable ND....allowing everything to click in "M". That would give me proper shutter, consistent F-stop and solid ISO. As you may know, good quality VND will cost....I'd go with Heliopan (if available) or B+W, but test for color alteration anyway. But, the downside of this would be that you'd have to pay attention to exposure when the light changes....that could be an issue...or not.

Your first job, however, is to determine how long you wish for this video to remain on the screen and set up your camera accordingly.

Oh, and I'm not criticizing (just a heads up thing)....if your camera triggers every 0.5 sec, you'll have 120 frames in the minute, 7200 in an hour and 57,600 over 8hr drive. I think the time lapse only goes to 9999 frames....and you might have to employ outside time lapse controller.

Best of luck.

 

[conceptics]

Thanks for the valuable input.

@JasonMulvern

Good reference to London Viewpoints channel. Would you happen to know which specific video he talks about the aperture mechanics?

I have not found much issue with flickering, but perhaps this is less visible during drive-lapses where everything is in constant motion. As you have noted, on bumpy roads with lots of corners and changing scenery close to the road, an interval of 24x is too fast and the long shutter speed makes the footage rather messy. However I have found 12x at 0.5s interval to be well suited for our roads here. The 1/4s exposure is quite important to me, as I want to achieve that 180° shutter angle, hence why I am trying to bend my brain around finding a way to get the interval of 0.5 consistent.

Perhaps for our upcoming road trip in the US, a 24x speed at an interval of 1s would be optimal, as I expect the roads there to be more straight with the scenic backdrop farther away. A 12x would perhaps be too slow. Since we only get one chance though at this trip and these recordings, I was operating under the assumption that it's easier to speed up the 12x footage in post rather than slowing down the 24x one.

@Leswick II

Good points, also on using a VND. I will look into that, if I choose to enforce the 0.5s interval and try to force the aperture to be wide-open most of the time. However, as we only get one chance, I'm not sure I'd be confident enough to change the VND during changing conditions while driving though....?

As you note, time-lapse is indeed limited to 9999 shots (or less, depending on settings I think). However, I was intending to use the video-feature ("time lapse video") that automatically creates a video without saving the RAW images on the SDcard.

Using this feature, at an interval of 0.5, it is limited to roughly 20min of footage in FullHD@24 (recording time 4 hours) or 3.45min of footage in 4k@24 (recording time of 45min ). This is sufficient enough.

Anyway, after doing some more tests and also checking some of London Viewpoints videos on YouTube, it seems there is an element of "how much time does the camera have to process X, Y, and Z and is the gap between shots sufficient to achieve that. If it isn't - the interval can not be consistently upheld and is skipped.

When setting the interval to 0.5s, obviously, there isn't a lot of time when setting the camera to a shutter-speed of 1/4s (which would achieve a 180° shutter angle). The camera then has time of 1/4s to process the image and prepare for the next shot at the next interval.

If you for example set the interval of 0.5s and the shutter-speed to 1/8s (90° shutter angle), the camera has an additional 1/8s more time to process and prepare for the next shot and indeed, it seems to be enough to not skip frames.

I have tried deactivating certain modes like auto whitebalance, vibration reduction or even using FullHD instead of 4k to free up processing power, however, this does not seem to make a difference. I could try a different SDcard, but given that it works with the mechanical shutter enabled, I don't think the SDcard is the limiting factor....

PS: On the Z30, I believe an external intervalometer is not possible as it lacks the interface for it?