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Tourist
Posts: 10

Risoluzione video non soddisfacente

Buongiorno, di recente ho acquistato una Hero 8. Ho provato a fare delle riprese kart indoor, con scarsi risultati. La camera l'ho impostata su 2.7k 50Hz, ma il risultato lascia a desiderare.

Ho cercato di togliere eventuali impostazioni automatiche, con ISO dai 100 agli 800. L'immagine appare quasi "flat", decidento di usare Premiere per il post editing.

Data la scarsa luminosità durante il video, dovuto al white balancing e ISO, durante la post produzione il filmato"sgrana", perdendo qualità.

Inoltre, ho visto utenti online pubblicare dei test in 4K e l'immagine non appare "nitida" e fluida come mi aspettavo. Non necessito video da professionisti, in quanto è per puro piacere personale la ripresa, l'edit e la visione del filmato.

Come posso fare per incrementare ulteriormente la qualità in post produzione? 

Highlighted
Backpacker
Posts: 1,003

Re: Risoluzione video non soddisfacente

hi,

 

low light does not mean no light.

 

in this early firmware, noise reduction is not still solved. will be, as was in h6, h7.

 

keep in mind;

- it is a small sensor, as a fingernail compared with a DSLR that has a sensor as big as our camera.

- therefore the pixels are small

- because of the small pixels, when ISO is higher (1600-3200), the electronics noise is higher which give you noise in the image

- DSLR with huge range ISO 50-256000 have special sensors and special noise reduction to make photos even in dark.

 

some advice:

 

- use the entire sensor 4K

- otherwise, you use  a crop on the sensor, the pixels will be fewer, will "appear" larger, the noise area is larger

- ISO 800 or 400 or lower

- 25fps to have a better exposure in low light

- in this case the gopro will push the shutter to 1/25, which maybe can give you jelly frames because of moving

- avoid using hypersmooth - in low light the frame does not have enough information and the image will be jelly, the lights will bounce

- if you want still to use hypersmooth, block the shutter to 1/(2xfps) or 1/(4xfps), in this case, 1/50 or 1/100 for a better image with hypersmooth, but the image will be darker.

 

hope this helps,

robert

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Tourist
Posts: 10

Re: Risoluzione video non soddisfacente

Thanks Robert, I've written my first topic in Italian and I've realised that it translate automatically in the language of your country! Yes I understand perfectly what you mean with the DSLR sensor (I've recently upgraded to a full frame because of the low light condition). But, I've two issues from your answer to understand: the first one is "use entire sensor of 4K", what do you mean? And the second one is about the shutter speed "1 / (2xfps) o 1 / (4xfps)". I've recently bought the h8, my last one was the h4 black, so you understand that all these new features are new for me (and I have more difficulty using the shutter speed in video instead shooting photos).

 

I appreciated your answer because very explanatory.

 

I wish that my english is understandable,

 

best regards.

 

 

Mattia

 

 

Highlighted
Backpacker
Posts: 1,003

Re: Risoluzione video non soddisfacente

[ Edited ]

hi Mattia @zuchi13 ,

 

do not worry about the language, your English is fine.... Smiley Wink

and the forum software translates perfectly whatever language you use... 

 

the beautiful of latest Hero camera is the manual control of settings...

 

about "frame per second" (fps) and "shutter speed".

 

gopro will adapt to brightness exactly how DSLR is doing, but f-stop.

but the GoPro aperture is fixed, f/2.8 - here is the first clue Gopro is not so good in low light, due to aperture.

the second is the sensor size....

(I used 50mm f/1.4 lens for a night walk in the town ---- years ago, I sold all my Nikon D850 gear when I discovered GoPro H5)

 

an example of photo exif will gave you the f-stop

 

exif.JPG

 

as DSLR does, GoPro will measure the entire sensor or the square you set in "exposure control" (page 65 in English manual).

(same as DSLR in metering matrix or centre-weighted )

         exp.JPG

 

let's say you are filming outside bright light.

- at 50fps camera will take 50 frames (50 still images) in one second

- for each frame (image) GoPro apply what the DSLR does for one photo (only ISO and shutter speed as f-stop is fixed)

- will use ISO at minimum, 100 (if ISO 100 is the minimum set)  

- the exposure will be let;'s say 1/1000 sec 

you will get for 1 second 50 crisp images ("frozen" images) each with 1/1000s shutter speed 

that played at 50 fps will give you nice smooth footage.  

 

if you use hypersmooth, hypersmooth will have at 1/1000 shutter speed for his algorithm crisp actual and previous images (frame)  that can be successfully used in the stabilization algorithm.

so the stabilization has all the chances to do what he has to do.

 

now let's move in low light.

let's say you film at 25fps.

- because of the low light ISO will be pushed to a higher value (let's say you set max 800)

- but as well the shutter speed will be higher

- the shutter speed cannot go higher than 1/fps so the maximum will be 1/25s

- so you will get in one second 25 frames each with shutter speed 1/25

- as you know from photo, at 1/25s your picture may have blur if a slight movement of the subject or camera

- in photo we use shutter speed around 1/25s (and to compensate bright light close the aperture f stop) to catch movement - that technique named panning

 

       pann.JPG

 

- as the background looks in this panning taken picture, the same will look a frame taken by GoPro in low light when pushes the shutter to max (1/25)

- he frames will have blur, jerky, noisy image.

- now, if you use hypersmooth, the algorithm will have blurred images imposible to "stabilize"

- to have crisp images, the shutter in this situation have to be limited to 1/50 and for best results 1/100 - of course image will be darker, underexposed...

 

test, test, test......

 

hope this helps a bit.

enjoy you GoPro and the moment you capture with.

 

robert

 

 

 

 

 

 

 

 

 

Highlighted
Tourist
Posts: 10

Re: Risoluzione video non soddisfacente

Thank you for the reply, as the first one, this is very explanatory. BUT, the most important advise that you gave me is about testing. Today I've started to test video recording in 4K 30FPS while the weather was cloudy with some snow falling down. I've tried many setting test, starting with these two format:

 

4K 30FPS

ISO: 100-400

Sharpeness: the lowest set

Color: FLAT

Shutter: auto

WB: auto.

 

The second format:

Same as the first, but sharpeness was set on the higher set and color in "GoPro".

 

There is a huge difference between the two videos, even in post-editing. The "RAW" one can be edited without losing sharpeness, while the second format is difficult to edit because of the native software in the GoPro.

 

 

So, next test we'll be about shutter speed, using only flat color and the lowest sharpeness set. After that, I'll start to use the withe balance (is the only one that I use in auto-mode in my DSRL).

 

It takes some time to understand how to potentially use this little guy, but once you've understand, post-edit we'll be easier and better. Thank Robert for all your advices.

 

 

Best regards,

 

 

Mattia