A7Sii help sought. Low light video very very noisy

[pms151]

Hi all,
New to the forum and an amateur photographer/videographer. Looking for some help with video of the northern lights here while I'm in Canada. I shot some footage last night and am extremely underwhelmed by the quality , I must be doing something very very wrong. The footage is blurry (out of focus? )even on a tripod and lots of noise in the dark spots and blurring/streaking when the camera moves. I tried various ISO settings and shutter speeds and it looked like optimal image on the LCD, but when I play back the footage in VLC its as bad of a quality as the associated mp4.
I am awaiting my rokinon f1.5 24mm but in the meantime could only acquire a sony 16mm f2.8 . Shooting in XAVC S 4K 30p 60m on 64gb 150mbs SDXC II 1000X card , manual focus, ISO 12800 (different ones tried) ,PP7, HIGH ISO NR normal, steadyshot on, auto slow shutter on, SS 1/4 (others tried).
My focus was at infinity , and I even checked in zoom and the stars seemed to be in focus.
Is it the lens that is making the footage so bad? Large file size seems right.
I have attached a screenshot to illustrate . Thanks in advance for any help..

[Jay]

Hello there

I have never worked with the Northern Lights, but from what you are saying it appears like the exposure is significantly to dark. I think most folks do time-lapse photography in order order to create video footage of the lights. I could be wrong though of course, because I have not re-searched it in detail. As far as video goes, I would suggest using a slower shutter speed in order to lower the ISO and get a brighter exposure. I'm not sure how fast the lights actually move, but from the videos I've seen over the years, it always looks speed up to me. This is what leads me to believe time-lapse photography is being used to create the video. Focusing is often very difficult in these situations, and I have been hearing more and more that infinity focus is not working correctly. I never use infinity focus, because I prefer to do it manually case by case to insure accuracy. Infinity focus should work though if the aperture is stopped down a little I would think.

I don't think your doing anything wrong here, I just think the lighting is so super low, that capturing footage is going to be extremely difficult and trial and error based.

Here are a couple of links for you to check out that should really help get you going in the right direction, and I'm sorry I am not more knowledgeable in this area... From what I'm seeing, time-lapse photography appears to be used:

https://www.dpreview.com/forums/thread/3259420

http://digital-photography-school.co...melapse-video/

This last link goes into really good detail about the camera and settings if you scroll down a bit:

https://fstoppers.com/landscapes/fil...ime-film-48904

I hope that helps and thanks for sharing the image and asking the excellent questions!

Jay

[Obelix]

Welcome to the forum!
You said you are using Sony 16mm f2.8 lens, this is APS-C lens and you would have heavy vignetting if not completely dark corners on A7SII.
Optimal shutter speed for any video is 2X your fps rate, so in your case 1/60 or 1/50, for slow moving lights you could go even lower.
Are you sure your video is in 4K? If you have auto crop for APS-C lens turned on, your camera would automatically adjust to crop mode and 1080 video.
Did you render your video and see final results? Some video editors (I assume VLC is video editor) will show you low quality preview for ease and speed of editing, and you will get full quality only after rendering final product.

[Jay]

Excellent points on all accounts Obelix!! I over looked the 16mm f/2.8 pancake lens crop factor issue, and that is certainly causing some of the vignette issue I would think Low quality before render is also totally possible as I have seen this myself. If recording in 4k, the lens is working in full frame mode for sure, otherwise the 4k would not work. The camera might not switch to crop factor mode automatically when having that quality setting I'm thinking.

Thank you very much for the help,

Jay

[Steve]

Jay was also right a lot of camera guys do time lapse on Northern lights also.

[pms151]

Youre all right. I used zoom to crop sensor and get rid if vignette. Looks like my real problem was the shutter speed. Bumped to 1/25 it's way better footage. Thanks for your help

[Jay]

Awesome news and thanks for the update!!

Jay

[Obelix]

Youre all right. I used zoom to crop sensor and get rid if vignette. Looks like my real problem was the shutter speed. Bumped to 1/25 it's way better footage. Thanks for your help

Let me see if I understand final product.
You shot in FF mode, and cropped in post processing.
Did you render for 4K or 1080?
If 4K, you could end up with soft image and more noise from upscaling