Billedstøj
© Anil Öztas, CC BY 4.0
Billedstøj er et udtryk anvendt i forbindelse med digital fotografering, populært en benævnelse for flere eller få korn i det endelige resultat af fremkaldte billede.
Støj opstår oftest i forbindelse med fotografering i svagt lys med en høj ISO-værdi.
Vejledende ISO-værdier for støjreduktion
Vejledende ISO-værdier, 2009, afhængig af kameratype og billedchip, opstår synlig støj på billederne ved værdier større end:
- Mobiltelefon: > ISO 100
- Kompaktkamera: > ISO 400
- Spejlrefleks, begynderkamera: > ISO 800
- Spejlrefleks, halvprofessionelt: > ISO 1600
- Spejlrefleks, professionelt: > ISO 3200
Hovedgrupper af støj
- Lys- eller luminansstøj, opstår på grund af små variationer i den målte lysstyrke
- Farvestøj, opstår på grund af billedchippens evne til at behandle de røde, grønne og blå pixels.
- Banding, opstår fordi de elektroniske kredsløb afgiver varierende mængder af støj, hvilket kan ses som misfarvede striber på billedet.
- Hot pixels, opstår som regel ved lange eksponeringstider, hvilket medfører falske lysgengivelser.
Eksterne henvisninger
- Adobe, reducere billedstøj (Webside ikke længere tilgængelig)
- Compact Camera High ISO modes, Separating the facts from the hype Arkiveret 5. april 2008 hos Wayback Machine
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Emoji u1f509.svg
Forfatter/Opretter: Google, Licens: Apache License 2.0
A colored Emoji from Noto project, released under Apache license
Forfatter/Opretter: Google, Licens: Apache License 2.0
A colored Emoji from Noto project, released under Apache license
Unicode name: Speaker with one sound wave
Annotations: Low, Sound, Speaker, Volume, Wave
Sony Alpha 9 II, ISO 50-204800 -- 2024 -- 0001-37C.jpg
© Anil Öztas, CC BY 4.0
This image was composed from all the shots of an ISO series with the Sony Alpha 9 II. The shutter speed for all photos in the series is 1/125 seconds, the manual white balance was set to 5500 K. The camera body was in a darkened room with a mounted housing cover during the shoot. The shutter was released mechanically. The room temperature was 19 °C. The camera was switched on 50 minutes before the first image was taken. RAW images were taken at ISO 50-204,800 and developed in Capture One 23 in five versions (EV 0, +1, +2, +3, +4 and EV 0 with tone correction/balance) with minimal JPEG compression.
© Anil Öztas, CC BY 4.0
This image was composed from all the shots of an ISO series with the Sony Alpha 9 II. The shutter speed for all photos in the series is 1/125 seconds, the manual white balance was set to 5500 K. The camera body was in a darkened room with a mounted housing cover during the shoot. The shutter was released mechanically. The room temperature was 19 °C. The camera was switched on 50 minutes before the first image was taken. RAW images were taken at ISO 50-204,800 and developed in Capture One 23 in five versions (EV 0, +1, +2, +3, +4 and EV 0 with tone correction/balance) with minimal JPEG compression.
Highimgnoise.jpg
Noise clearly seen in this photo.
Noise clearly seen in this photo.