Z6 II video glitch?

I'm wondering if anyone else has encountered the following phenomenon. I was trying to record video of the approach of a steam train to the station. As it was a bright sunny day and I didn't have any ND filter with me (not good), I set the camera to record 4K 50 at 1/100s, f/16, ISO 100 which kept detail in the white clouds and blue sky was correctly rendered. Now as I was shooting into the light, to preserve detail in the black train and carriages, I turned on D-Lighting (Normal). I had 24-70 E with FTZ mounted.

I tested the settings by recording some video of regular trains passing by, this worked fine. But as the steam train approached, when the engine was in sight, the camera back and top LCD went blank and this didn't seem right so I turned it quickly off and on, and pressed record. It recovered and started to record again but I mostly missed the engine passing by. I inspected the clips and it indeed seemed to have stopped recording right as the train came into the field of view.

Now I know the 4K 50 fps feature was added to the Z6 II in firmware and it must be processor-intensive. I had a bunch of processing on including vignetting correction and the D-Lighting, which added to the workload of the camera. I'm wondering what would be the best course of action if I want to avoid this shutdown happening again at a critical moment. Should I just stick to 4K 25 fps and use ND filter to get away from having to stop down to f/22? I could alternatively use FullHD and this would allow me higher frame rates and correspondingly faster shutter speeds without stressing the camera too much. I would like to use D-Lighting as an easy way to manage high-dynamic-range scenes in video, but if it is the reason for the camera crash then I'd have to find a workaround.

I'll try to write a bug report to Nikon and send them the clip.

The quality of the successfully captured videos was very nice, so I don't want to give up so easily on this camera. The clouds and sky and the carriages were perfectly rendered without any post-processing, which was more than I had expected in such a high-contrast situation.

But as the steam train approached, when the engine was in sight, the camera back and top LCD went blank and this didn't seem right so I turned it quickly off and on, and pressed record. It recovered and started to record again but I mostly missed the engine passing by. I inspected the clips and it indeed seemed to have stopped recording right as the train came into the field of view.

Had anything similar happened before or after?

I had incidents of Z cameras stopped switching between LCD and viewfinder. Came to find out that the contact needed cleaning. This never happened in other cameras.

It has happened only once. Do you mean the electrical contacts between body, adapter and lens, or some other contacts? Thanks.

Not electrical, apparently something blocked the sensitivity of the switch. This happened with both my Z6 and Z7 on that trip - something I had not experienced with other cameras, including Olympus mirrorless. It turns out this is quite a common problem with Z cameras. See this thread:

Passing along a tip - Z6 and Z7 Automatic Monitor Switch Problem

Should I just stick to 4K 25 fps and use ND filter to get away from having to stop down to f/22?

Surely the shutter time is independent of the frame-rate (providing it's shorter)?

Even in pro film movie cameras this was implemented by varying the sector angle of the rotating shutter. Have we not moved on from there?

Whatever. It's difficult to see how the lens aperture would cause a CPU overload - if that's what it was.

Did you have the camera running for a long time prior to the train coming into shot? Maybe it overheated at a critical moment?

WRT the eye-sensor issue. Could mascara have rubbed off on the sensor window? And FWIW my Sony is overly sensitive to a shadow passing over the sensor and switching the rear LCD off. The first few times it happened, I thought the battery had suddenly gone dead.

I had recorded a couple of short clips of roughly 1 min in duration before starting the one that shut down the camera. It only took two seconds of recording the clip before the camera went dark.

I can choose the shutter speed but I am trying to maintain 180 degree shutter angle so at 25 fps I would use 1/50 s and at 50 fps, 1/100 s.

I noticed that my PC doesn't play back 4K 50 fps videos smoothly so, for the time being, I will stick to 4K 25 fps.

Today I was able to record the train departing at 4K 25 fps and the result looks OK although the more cloudy conditions didn't result in as lively a result as yesterday's attempts in more contrasty lighting. I'll need to get at least one additional ND filter.

Did you use approved CFexpress or QXD cards?

I have had gliches like that when writing to the the SD slot, not the CFexpress slot, but I use approved cards.

I used a Sony G-series XQD 64 GB card (QD-G64E) which is on the approved list.

Hmm. The card's nominal (on the card) write speed is listed as 400 MB/s and Nikon says that for the 4K50 and 4K60 modes, a card with max write speed of 250 MB/s or higher is recommended. My card is on the right side of the latter figure but there is not that much margin for error.

In Premiere, the 4K 50 footage does run almost smoothly, there is a slight jitter in it but I suppose this could be resolved by getting an accessory GPU card (probably). I am currently using just the GPU on the main processor.

I can choose the shutter speed but I am trying to maintain 180 degree shutter angle so at 25 fps I would use 1/50 s and at 50 fps, 1/100 s.

Why?

A high shutter speed can look a bit weird in rain or with other fast-moving stuff in shot, but a steam train? That's hardly going to look 'stuttery'.

The technology is there; why not use it?

As an experiment I just shot some 4K video indoors at 1/400th shutter speed and f/5.6, zooming fast and panning the camera about fairly vigourously. The result looked fine, despite the auto-ISO reaching stupidly high figures.

Incidentally, does an in-camera playback look smooth? If so then you need more editing power in your computer.

Why?

A high shutter speed can look a bit weird in rain or with other fast-moving stuff in shot, but a steam train? That's hardly going to look 'stuttery'.

I don't have a lot of experience in video and try to follow general guidance which I've read to be 1/50s for 25 fps and either 1/50s or 1/100s for 50 fps. So far I've been happy watching 4K in 25 fps. Since my computer seems slightly underpowered to play 4K 50 fps I am not going to pursue that further for now. It's likely that if I publish something in 4K 50 fps then some viewers might have the same difficulty and although the movement looks more smooth in 50 fps (smaller steps between frames) I am comfortable with the result in 25 fps. I can get ND filters to get to larger apertures in sunlight.

The technology is there; why not use it?

A lot of people say they do not like faster shutter speeds in video as it becomes a bit like "staccato" in playing music. I try to follow general guidance until I have a better eye to form a personal opinion on the topic.

As an experiment I just shot some 4K video indoors at 1/400th shutter speed and f/5.6, zooming fast and panning the camera about fairly vigourously. The result looked fine, despite the auto-ISO reaching stupidly high figures.

I tried zooming also and it looked quite bad as the image scale changed in steps. It looked really jarring. I think for zooming during video recording, it should happen quite slowly to not disturb the viewer. This would require some gearing to implement in my current lenses. Unfortunately Nikon do not make a power zoom for Z, though they did make one (10-100 mm) for the 1 system. I imagine a powered zoom for Z will be at some point on their agenda.

Incidentally, does an in-camera playback look smooth? If so then you need more editing power in your computer.

Yes, it does. However, my PC is only two years old and it has some features which are unusual today (e.g. it has one PCI slot which I can use for old cards that are needed to operate old peripheral devices) and I don't plan on upgrading it for a number of years. I could get a GPU card but from past experience that tends to increase the fan noise quite a bit and it doesn't seem necessary for now for my purposes. I will consider it but it's not at the moment near the top of the list.

I have a very (!) vague recollection of something similar happening on my second ever video shoot where I guessed I'd nudged something.

Being very unfamiliar with the feel and controls of my Z6ii, I put it down to user error which it may well have been.

I did have to 'cycle' the power switch and all things were good.

I was trying FHD at 120fps to get 'auto slo-mo' of a fishing eagle.

It's never happened again.

A lot of people say they do not like faster shutter speeds in video as it becomes a bit like "staccato" in playing music.

Yet a 'lot of people' also watch sport on TV, which is invariably shot using a fast video shutter (for stop-action replay). With almost no complaint from those millions of viewers.

I'd take no notice of a few vociferous dissenters. I believe they've got their own video channel now, called newtube isn't it?

I've often wondered about the 'old' twice the frame rate idea for the shutter speed.

If you tried extracting a single frame from old video of some modestly fast action it would have considerable motion blur.

I haven't tried using 1/2000 @ 120fps just to see what it's like. Might make ND's unnecessary.....;)

I've often wondered about the 'old' twice the frame rate idea for the shutter speed.

 

If you tried extracting a single frame from old video of some modestly fast action it would have considerable motion blur.

Yes, this is true, but I just want to create a video which is pleasant to watch and conveys the feeling of the sounds and functioning of the engine (or another subject) to the viewer in a way that a still photograph can not. The fast shutter speed or Nd filter is needed here mainly if one wants to shoot in bright sunlight. I don't want to take still frames from the video and present them as individual photographs, as better-quality images can be obtained in still photography mode.

I haven't tried using 1/2000 @ 120fps just to see what it's like. Might make ND's unnecessary.....;)

Or it might be jarring and unpleasant to watch.

Yet a 'lot of people' also watch sport on TV, which is invariably shot using a fast video shutter (for stop-action replay). With almost no complaint from those millions of viewers.

I believe that usually the slow-motion is shot separately from the main coverage. At least in figure skating TV coverage, usually the overall footage is shot with a wide view, and the slow-motion shots are shown with a narrow field of view covering the athlete very tightly. Different settings, different focal lengths and separate cameras.

When I bought my Lumix GH-1 about 12 years ago, there was an initiative to hack the firmware driven primarily by filmmakers that in the GH-1 saw a camera with crippled potential.

I followed these discussions, not because of the video part, but because a hack would allow me to change the menu language of my Japanese market model.

What I noticed from browsing these discussions was their desire to shoot close to the frame-rate of 35mm film (24-25 fps) and with a similar shutter speed - as it would appear more cinematic and pleasing to the eye.

I am not sure if "pleasing" is a "fact" or if it is just because we were used to that look and if so, if the past 10 years of digital video advances have changed our preferences?

Does anyone know what frame rate the digital cinemas are projecting at?

24 fps is standard in cinema while high frame rate (HFR) projectors can do, e.g., 48 or 60 fps.

Here is some discussion on high resolution, high frame rate movies and audience reactions to it:

The Hobbit’s vision for the future of cinema looks awful, but it just might work

I think the technical quality of video and TV has improved noticeably over the past several decades (in particular, there is more detail) and when picking up a 30-year-old movie on DVD, I can immediately notice there is less detail compared to newer productions. However, after a few minutes of watching, I get used to it and don't pay any further attention to the technical quality of the image if the movie is really good in its cinematography, acting and plot. I think for the purposes of making a movie, the resolution or technical details such as frame rate may not be so important compared to the quality of the camera work or the content. The resolution may even distract from the more important things. However, no doubt we'll get used to it.

Here is some discussion on high resolution, high frame rate movies and audience reactions to it:

 

The Hobbit’s vision for the future of cinema looks awful, but it just might work

One rather biased and uninformed article is hardly a discussion. Especially when it centres on a movie that mainly consists of CGI footage.

Where was all this 'flicker, blur' etc. in traditionally shot movies? Cine projectors have always used a shutter that doubles the flicker-rate to twice the frame rate (48/s), making it invisible to the vast majority of viewers. And as previously stated, most advanced amateur and professional cine cameras allow wide control over the shutter duration, disconnecting it from the frame rate. The two are not the same, nor inextricably linked.

I had another go at shooting 4k video using the same fast pans and zooms at a variety of shutter speeds. To be honest I could see very little difference between using 1/400th, 1/250th and 1/100th shutter speeds. It was only stepping through the individual freeze frames that the difference in trailing blur was visible. Even then the 1/250th and 1/100th motion-blur trails weren't vastly different.

I even tried shooting at 1/20th second shutter speed - amazed that the camera even let me do that, and don't ask me how that works with a fixed 50FPS! But regardless, there finally was some stuttering visible at that setting.

My conclusion is that either my old eyes aren't too sensitive to flicker, or other people are deluding themselves over how persistence-of-vision works, and are determined to see individual frames 50 or 60 times in a second.

how persistence-of-vision works

Like HD or 4K monitors with a 'refresh rate' of 200Hz...and/or referred to as 1ms screens designed for gaming?

;)

An electronic shutter is not limited to a 180 deg angle. I record at 1/60 at 60 fps without difficulty. Since most of my videos are of musicians, shutter speeds faster than 1/100 produce obviously stroboscopic effects. Shutter speed has little effect on things like cars and scenery. I would think the reciprocating parts of a steam locomotive would fall somewhere in between, but mitigated by using an higher frame rate.

Shooting in sunny daylight presents an exposure problem. I am loathe to use an aperture smaller than f/8 for best image quality and bokeh, and strive for f/5.6 to f/6.3. The ISO setting is often at the lowest value. Your best choice for pleasing results is to use a neutral density filter. While expensive, a variable ND filter is the best choice for action photography (including trains). If you're willing to build a rig with a matte box, the filter rings usually rotate. You can create a variable ND filter using two polarizers. The advantage of a matte box is that one size fits all lenses, up to the typical 95-105 mm objective of cinematic lenses.

A digital video camera can use a shutter angle exceeding 360 degrees by keeping the shutter open across frame boundaries, basically independent of the fixed fps. The most obvious application is the "low light" option.

It seems now that I am using CFexpress for storing the video, 4K 50 fps works reliably. It could have been due to the XQD card not quite being reliable enough at the required write speed. Also Premiere can play it back smoothly, it was just NX Studio which had jerky playback on the high frame rate video on my computer.

I'm now recording with two microphones (a stereo microphone on the Zoom H6 and a shotgun on-camera microphone). This seems to create quite a good sound landscape after mixing the two sources. At least for my inexperienced taste. :) Now, if I could learn to plan my movements during the takes (and not do any unnecessary ones), things would be going pretty smoothly.