Sigma 14-24 f2.8 "flicker" issue

M

markfpv

Veteran
Hello,
This is more curiosity on my part - trying to gain some knowledge. Just purchased the Sigma Art 14-28 lens in E mount. I know it's a still lens, not a cinema lens. But I've never had any other still lens do this, when using for video.

When shooting video with it and zooming "in" - manually adjusting the zoom ring - there's very odd strobing or flickering that happens. Doesn't happen when zooming out - or at least it doesn't do it continuously and as often on the zoom out. Happens on both small mirrorless cameras as well as when on the Sony FS7. I can see it on waveform and doesn't matter what shutter rate camera is set to...

I’ve uploaded 3 shots to show it happening (less than 1 min long).
https://vimeo.com/477411880
Password: 1424

Just a bad zoom ring on this lens? Or if I return this copy and get another one - will I find the same thing? Has anyone had other lens' that do this?

Thanks in advance.

Mark
 
I'd say that's not normal.

Initially I thought you might be talking about minor ramping (which happens sometimes even with a constant aperture), but the above isn't it.
 
Yes, I've seen ramping and/or breathing as well as a difference in advertised f stop - but never anything like this.
 
Maybe check the cameras if there is some kind of correction happening and/or if there is a FW update for the lens.

Spitballing...but if it happens on 3 cameras, it's most likely a bad copy.
 
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