# Canon T5i (700d) noise issue?



## Jared L. (Feb 23, 2016)

Hey everyone. I think my camera is either having issues or I'm doing something wrong. I am a relatively experience photographer, but for video work, I'm having bad issues! 

Attached is a screenshot from a video I did. My face was mainly lit, however, anything that was not lit or was dark had serious noise! I've had issues with this since I got my camera used on Amazon last year, so I have no warranty. Is this an issue with my camera or do all T5is behave like this? During a Magic Lantern time-lapse, the darker spots were very noisy, even at ISO 100. When I see videos from other YouTubers, even the T3i seems fine. If this is a problem with my camera, is there a way to fix it?

Color profiel was neutral, 0, -4, -2, 0. 

Tl;dr Weird noise occurring in videos, in darker shades even in bright light. At low ISOs, this still occurs and it's driving me crazy.


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## DB_Cro (Feb 23, 2016)

I can't help with the specific issue, but your T5i has the same sensor and image quality as the T3i (and the T2i for that matter) so.. don't expect it to be
better because it's newer.


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## Jared L. (Feb 23, 2016)

DB_Cro said:


> I can't help with the specific issue, but your T5i has the same sensor and image quality as the T3i (and the T2i for that matter) so.. don't expect it to be
> better because it's newer.





Ok, if you shoot video, can you say if this occurs for you? I'm considering upgrading to the semi pro Canon line, or even a cheap 2nd body before a semi0-pro. Does this type of noise occur in your videos, especially at high apertures?


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## DB_Cro (Feb 23, 2016)

To be honest looking at the attached images I don't understand what the issue actually is.

The 18mpix sensor in those bodies is as bad as it gets re: noise.. and you're only making it worse if you're
using ISO that's too low so the video is underexposed.

Here's ISO3200 video from my T2i:





Aperture value has nothing to do with noise.


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## Jared L. (Feb 23, 2016)

DB_Cro said:


> To be honest looking at the attached images I don't understand what the issue actually is.
> 
> The 18mpix sensor in those bodies is as bad as it gets re: noise.. and you're only making it worse if you're
> using ISO that's too low so the video is underexposed.
> ...


Thanks for the reply. I know that aperture has nothing to do with noise, but I was just speculating that it was possible that I was underexposing. I was using FPS override, so in order to get a time-lapse straight from video I was changing the framerate which in turn introduced more light. 

Do you think I should just get an ND filter and see if it's any better then to keep wide open and use an ISO depending upon how dark the shot is? I've been wondering what this is now for several months but it never got to the point in which it's this bad, just shooting in daylight at trees.


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## DB_Cro (Feb 24, 2016)

Big aperture + ND and small aperture are 2 different looks, only you can decide what you want.
Either way, underexposing by a lot using any of the 2 methods will give the same noise since, again,
aperture doesn't matter. I don't do much video at all, but see that night time stuff isn't good with this
sensor, even with 2.8 glass.

If I needed to do more video, I'd get a few primes, maybe 18-35 1.8 sigma or something like that.


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## KmH (Feb 24, 2016)

Noise is always more visible in dark areas of an image.

That's just the way digital images work. The image sensor pixels in your camera are linear analog devices.
For example.
To keep it simple lets say the image sensor in your camera has a 6 stop dynamic range, and uses 12 bits to encode what the image sensor records.
12-bits can code 4096 levels. 
We'll also assume it takes 4096 photons of light to make the camera record level 4096, or to completely fill/saturate a pixel.

Half of the 4096 levels, 2048, get devoted to the brightest stop of dynamic range your camera has.
That only leaves 2048 levels for the remaining 5 stops of dynamic range.
The next brightest stop of dynamic range uses up 1024 levels, 1/2 of the remaining 2048 levels.
Leaving 1024 levels for the remaining 4 stops.
And so on until the darkest of your 6 stops of dynamic range, the darkest shadows only has 64 levels.

http://www.adobe.com/digitalimag/pdfs/linear_gamma.pdf


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## Jared L. (Feb 24, 2016)

KmH said:


> Noise is always more visible in dark areas of an image.
> 
> That's just the way digital images work. The image sensor pixels in your camera are linear analog devices.
> For example.
> ...


Nice detailed explanation. I've seen videos with the 70D which don't have grain in the video and it's more of a dark shadow with a curve in-between shades. Do you think that it has to do with the camera I'm using and the low-light performance?


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## DB_Cro (Feb 25, 2016)

70D does a bit better but not much (not even a full stop; your iso1600 would be a bit noisier then 2000 on 70D).
Maybe it's post-production/editing.


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## KmH (Feb 25, 2016)

Digital cameras don't have 'grain'. They have image noise.

How were those other 70D videos with less noise lit? Just outdoor ambient light, indoor ambient light, or outdoor/indoor ambient + supplemental constant lighting?
What exposure setting values were used?
What was the dynamic range of the scenes shot?

Do you use Manual mode to set the triad of exposure settings for video? 

FWIW - there are several kinds of image noise - read noise, dark noise, thermal noise, shot noise.
The dominant noise in the darker parts of an image is shot noise. Shot noise is caused by statistical quantum fluctuations - variation in the number of photons sensed at a given exposure level.


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## DB_Cro (Feb 25, 2016)

And I was trying to keep the 'chat' in English here.. @KmH 
T2i-T5i sensor has horrible color noise, those red dots..


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## beagle100 (Feb 25, 2016)

yes, you're really underexposing

that same 18MP sensor at *ISO 6400*



Untitled by c w, on Flickr


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## DB_Cro (Feb 25, 2016)

Heavy on the noise reduction I assume but that's actually very good.


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## Jared L. (Feb 25, 2016)

KmH said:


> Digital cameras don't have 'grain'. They have image noise.
> 
> How were those other 70D videos with less noise lit? Just outdoor ambient light, indoor ambient light, or outdoor/indoor ambient + supplemental constant lighting?
> What exposure setting values were used?
> ...



I believe most of them were indoor ambient light. However, if the room was well lit but the corners were dark, I didn't see any noise, just a curved band. However, when I do videos with this set up, the dark corners are very noisy without overexposing other portions. I think I could benefit from getting a soft box setup so that all the portions of the shot are equally lit.

Manual mode
For indoor shot, 1/50th of a second at 24 fps 1080, along with ISO 400. I don't see a real reason for this other than underexposure because if I use ISO 100, it's still very noisy in dark portions to the extent that it was this nasty pattern of red, blue and black. If I can find a video of it I'll take a screenshot. 

For other shots in daylight, I had to underexpose slightly to keep the sky correctly exposed. However, with the deep blue color came noise!


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