Canon 70D noise issues

If you want a nicely exposed sky as well as a nicely exposed dark castle wall then you should use the HDR feature or take a bunch of bracketed shots and merge them into HDR later :)
 
Ferj said:
Why can you not use those ISO settings? What will happen?
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Canon cameras apply ISO adjustments in two stages. ISO values which double up from 100 use only analogue gain from the sensor, which is good.

ISO values which double up from 125 actually take the shot at a true multiple of the ISO value below and then apply a digital multiplier to increase the brightness of the file before you see it. This gains you nothing you could not do yourself in post with more finesse and risks wasting 1/3 stop of dynamic range. It is actually a deliberate 1/3 stop underexposure and then a digital fix. This is bad.

ISO values which double up from 160 actually overexpose by shooting at the next higher ISO value above and then digitally darken the file by 1/3 of a stop. Where noise is concerned this can actually be beneficial, but the cost is the risk of clipping highlights in camera before you get to see the file.

If you stick to doubling multiples of 100 only then you avoid the digital trickery completely and get exactly the exposure you should do. All my cameras are set to only use the ISO values without digital manipulation.

If you enable HTP the camera actually underexposes by 1 stop and then through software either in camera(JPEG) or post(raw) adjusts the file to brighten the shadows and mid tones without also pushing the highlights. This is a recipe for extra noise.

Please note that these issues are quite subtle and possibly of little concern for many who shoot "normal" scenes and don't expect to heavily edit, but if you want to extract the best file possible from the camera before you set to work on it these tips should help.

Note that this advice applies specifically to Canon DSLRs. I can't speak for other brands or compact/bridge camera.
 
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Ferj said:
Why can you not use those ISO settings? What will happen?
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They are not native ISOs so the sensor is pushed or pulled digitally which increases noise.

Enabled full stop ISOs in the custom functions so those ISO choices aren't available.
 
Sharky said:
They are not native ISOs so the sensor is pushed or pulled digitally which increases noise.

Enabled full stop ISOs in the custom functions so those ISO choices aren't available.
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I accept that the fact is that ISOs are best in multiples of 100. What I can't understand therefore is how the way the electronics work. I assumed (incorrectly it seems) that the ISO on digital cameras was purely a sensitivity setting on the sensor amplification. There's obviously more to it than I thought.
 
Ickle97116084 said:
Flickr account created.

Here is the untouched JPEG (exported from RAW with no PP applied):

https://www.flickr.com/photos/127507724@N04/15132374955/in/photostream/

Here is the retouched JPEG with a sharpening of 30 and luminance of 50, I adjusted to remove clipping from whites and blacks.

https://www.flickr.com/photos/127507724@N04/14945837757/in/photostream/

Thanks,

Ickle
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If you're trying to push out the shadows of a JPEG from a cropped sensor, I'm not surprised you're seeing noise!

Edit - I think I misunderstood, I see you're using raw files. I think you are expecting too much from ISO 100, the parts causing noise are drastically under exposed. A lot of people think if they have their camera on a tripod they can stick to ISO 100 which isn't always the case. You should happily be able to increase the ISO a bit more to expose properly.
 
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DerekL said:
I did not post it for critique. You are right it was shot in jpeg and is a small file save for a web site. Bearing in mind this was taken under the floodlights of a lower league football team a couple of 100 watt bulbs would have been brighter.

But considering it was shot at 10000 ISO there is not much noise. I previously had a 500D and shot the same ground (I do all their matches) and gave up on night games in the end.
Perhaps I bought the good 70D but have had no issues with noise or focusing.

Just as an aside you can see the shin pads through the black sock so it is not that bad. IMO
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Fair enough, I wasn't however trying to criticise the photo in itself, but merely indicate that the processing looks (to me) to make any discussion about noise rather moot as it looks highly processed and any detail/noise smoothed out.
 
DizMatt said:
Fair enough, I wasn't however trying to criticise the photo in itself, but merely indicate that the processing looks (to me) to make any discussion about noise rather moot as it looks highly processed and any detail/noise smoothed out.
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I think a look at the absent detail in the grass is a strong indication of overall IQ. Its also amazing just how smooth the skin is on those middle aged men. When I can make out individual blades of grass then I shall be impressed.
 
drounding said:
I accept that the fact is that ISOs are best in multiples of 100. What I can't understand therefore is how the way the electronics work. I assumed (incorrectly it seems) that the ISO on digital cameras was purely a sensitivity setting on the sensor amplification. There's obviously more to it than I thought.
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The sensor produces a voltage from each pixel as an analogue signal. This can be amplified just as an audio amplifier might amplify sound. This is the analogue part of amplification which is used for ISO 100,200,400 etc.. As a digital device the analogue signal is then converted to a digital output - numbers. To obtain the intermediate ISO values the camera simply multiplies each of these numbers by 1.25 or divides by 1.25 in order to brighten or dim the image to simulate the intermediate ISO sensitivity value you set. No extra information is created or retained in this process and, for raw shooters, it is a process better left until you sit down at your computer when you can decide exactly what multiplier (if any) you think the image needs.

So, when you take a signal from the sensor and then apply digital amplification within the camera you end up amplifying (brightening) the noise along with the rest of the signal. This s a poor approach to maximising image fidelity. Conversely when you digitally reduce the signal the noise also gets dimmed along with everything else. In this latter case the noise does diminish slightly, but the initial analogue capture was overexposed by 1/3 stop, which might put your highlight details at risk before the digital reduction lowers their brightness. This would be especially likely if you seek to maximise ETTR. For these reasons the intermediate ISOs are best forgotten completely. You will have the most complete and least compromised raw file as your starting point if you stick to the main ISO values.
 
Thanks for the explanation Tim.

It seems the sensor output may not be linear across the full range of sensitivity, the output would therefore have to be linearised/adjusted at break points within the full range, those break points being the 100 ISO divisions and then extrapolated in between.

Sorry for taking the thread off topic somewhat.
 
tdodd said:
I think a look at the absent detail in the grass is a strong indication of overall IQ. Its also amazing just how smooth the skin is on those middle aged men. When I can make out individual blades of grass then I shall be impressed.
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Middle aged men?? These are finely tuned young athletes, The pitch at the mighty Droylsden FC stadium is akin to Wembley,:):)
 
Why can you not use those ISO settings? What will happen?
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I've heard of this for other cameras as well as Canon. I suspect the reason is that the camera exposes for the next multiple of 100 or 160 then adjusts the brightness downwards if the selected iso lies between them. By doing so you may be introducing more noise than is absolutely necessary.
 
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Droylsden FC, kingdom of Mr Pace
They were involved in the strangest match I have ever watched

My lot were losing 0-2 with 12 minutes left to Droylsden in the FA cup. We ended up winning 8-2 aet with both sides down to 9 players. Mr Pace was also sent to the stands, started off taunting the home fans then totally lost it when he got some stick back
 
tijuana taxi said:
Droylsden FC, kingdom of Mr Pace
They were involved in the strangest match I have ever watched

My lot were losing 0-2 with 12 minutes left to Droylsden in the FA cup. We ended up winning 8-2 aet with both sides down to 9 players. Mr Pace was also sent to the stands, started off taunting the home fans then totally lost it when he got some stick back
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This was against Leyton Orient if I am not mistaken. Dave Pace is always getting sent to the stands. As you know lower league floodlights are not up to much but IMHO the 70D stands up admirably regarding noise.
 
[QUOTEThis was against Leyton Orient if I am not mistaken. Dave Pace is always getting sent to the stands. As you know lower league floodlights are not up to much but IMHO the 70D stands up admirably regarding noise.][/QUOTE]

That is correct, freezing cold December night and not surprised Mr Pace is often asked to leave the field of play

Some good photos you have there especially considering how poor lighting is at many non league grounds
 
I have an interesting problem with one of my cameras (Canon 70D) in both Video and Photo modes, attached is a brief video showing excessive noise only on black;


I cant figure this out as it just appeared one day after using the camera for 12 months with no issue??????

Any suggestions? Thank you!
 
No, no sensors or transmitters in that room. We thought the same thing also so we changed room and shot this clip.

Thanks for your questions thought!
 
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I have the Canon 70D also and have been plagued with noise problems also. I am careful not to underexpose images as I know the noise will be severe. I shoot mostly in raw, and mostly fast exposures, wildlife primarily. I have have several good images made unusable by the noise. Frustrating!
 
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