GH5 Footage wobbling / jumping / pulsing...

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Dave Draper

Well-known member
We just started doing some random tests with the GH5, and noticed in one shot -- in particular -- the footage wobbles, jumps, or pulses, about 3 times.

Check out the link below:


https://vimeo.com/233550693

Password: 12345

Rec format is MP4 (LPCM). Rec quality is 4K DCI, 23.98fps, 422 / 10bit / LongGOP, 150Mbps.

E-Stabilization is off, but IBIS is on.

Lens used is a Sigma Art 35mm mounted to a Metabones CINE Speed Booster.

And we're using a Lexar 1800x 128GB Class 10 Micro SD card.

Any thoughts?
 
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Looks very much to me like the IS on your lens playing up. Was the camera handheld on that shot or on a tripod? If it was on sticks, its best practice to switch off any stabilisation of any sort, as the gyros used in IS systems is known to sometimes get 'confused' by the lack of motion to counteract, and so end up introducing the 'swilling around' look that your video exhibits.

Hope that sheds some light on things for you!

Cheers, jason
 
jasonbrooks said:
Looks very much to me like the IS on your lens playing up. Was the camera handheld on that shot or on a tripod? If it was on sticks, its best practice to switch off any stabilisation of any sort, as the gyros used in IS systems is known to sometimes get 'confused' by the lack of motion to counteract, and so end up introducing the 'swilling around' look that your video exhibits.

Hope that sheds some light on things for you!

Cheers, jason
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Hi Jason. Thanks for your informative reply.

As far as I'm aware, there is no IS on the Sigma Art 35mm.

The shot was handheld.

What was concerning us, is that there might be technical issues with the GH5's IBIS.
 
Dave Draper said:
Hi Jason. Thanks for your informative reply.

As far as I'm aware, there is no IS on the Sigma Art 35mm.

The shot was handheld.

What was concerning us, is that there might be technical issues with the GH5's IBIS.
Click to expand...

What FL did you enter in the IBIS FL dialog? With a Speedbooster, it should be the reduced FL, not the native 35mm. Def. makes a difference.
 
Peter Berry said:
What FL did you enter in the IBIS FL dialog? With a Speedbooster, it should be the reduced FL, not the native 35mm. Def. makes a difference.
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I've seen a Focal Length prompt pop up when you turn on the camera, but only when you have the Speed Booster mounted, and no lens.

The Focal Length option seems to be greyed out in the menu if you mount the lens to the Speed Booster before switching the camera on.

We literally just mounted the Speed Booster to the GH5, and before switching it on, mounted our Sigma 35mm to it, so were never prompted to input any Focal Length settings.

What is the proper set up procedure when using a Speed Booster with a GH5 and EF lenses?
 
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I've noticed the same thing, I was never prompted until I turned the camera on with just the Speedbooster installed. I've made a mental note to always turn it on without a lens attached from now on. I would recommend referring to this chart for conversions.
 
ParagonFilmworks said:
I've noticed the same thing, I was never prompted until I turned the camera on with just the Speedbooster installed. I've made a mental note to always turn it on without a lens attached from now on. I would recommend referring to this chart for conversions.
Click to expand...

Many thanks for the link.

What does the camera think the lens is if you don't input the Focal Length settings?
 
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It appears to default to 35mm instead of the 24.85mm that should be input with the conversion etc., on a side note the Cine adapter only allows one decimal place. I wonder if that matters?
 
I would imagine it's the same with the Cine adapter, but all other EF Speed Boosters I've used with the GH5, accurately communicate the adjusted focal length to the camera. The focal length prompt is displayed and the menu option is enabled when no focal length is communicated to the camera, which is why the prompt is shown with manual lenses, passive adapters, or when no lens is attached to an active adapter such as the EF Speed Booster.

You should not need to enter the focal length manually when using the EF Speed Booster. To confirm that the Cine model properly adjusts the focal length, look at the EXIF focal length metadata embedded in stills or MOV/MP4 video clips shot with the GH5.

As for the pulsing, it does looks like overcompensating IBIS. However, while I've seen this quite a bit with cameras like the Sony a7S II, I've yet to see it in any footage I've shot with the GH5. I'd recommend testing with a couple lenses, ideally native lenses or ones that use a different adapter to rule out the adapter causing an issue.
 
Sol M. said:
look at the EXIF focal length metadata embedded in stills or MOV/MP4 video clips shot with the GH5.
Click to expand...

Just shot a test clip but can't find this information in Premiere Pro for the MP4 video file,I don't see any extra data written except for the video files either. I must not be looking in the correct place.
 
Someone else posted a thread about IBIS artifacts a while back.

I think it may just be a consequence of the feature. More visible at certain times depending on the situation.
 
That is an issue with the electronic SB and sigma lens I think. Vintage glass shot on dummy adaptors with the proper adjusted focal length don't do any of that jumping around. I vaguely remember a post about updating the firmware on the SB to solve some thing like this. In any case the firmware for the SB might be of help, but in general, IBIS has been spectacular for me with passive SB and vintage glass.

Cheers,
Pete
 
On GH5 when you press play, and then DISP repeatedly until the small thumbnail with lots of info shows, the focal length of the clip is shown on the 5th information tab. That is the focal length that the adapter told the camera and is the best way to verify if the adapter is reporting the focal length properly. You cannot set the focal length yourself when an electronic lens is attached. Setting the focal length before attaching the lens is both unnecessary and ineffectual. If DISP shows the correct focal length it is correct.

The simplest A/B test is to partially dismount the lens to severe all electronic connections, and then setting the focal length manually. This way you can compare having the electronics do its work versus manually entering the same data and see if you get a different result. You actually would - because most recent lenses report distance information and with the electronics you get the full benefit of 5-axis whereas a manual lens with no distance information gets you only 3-axis.

Whether you like the aesthetics of 5-axis is debatable, however. 5-axis appears to be a subject floating in front of a stationary background in a very three-dimensional manner. 3-axis never does that, it always degrades gracefully when its limits are stretched. If I am not mistaken, this could be the reason of dissatisfaction of the original poster.
 
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