ISO 200 - Why so much noise?

FlyTVR

FlyTVR

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Took some shots of my friends lad today.

Using my Canon 400D, AV Mode, 50mm F1.8.

Settings:

ISO 400
F9
1/4000 sec

No flash, in bright light (sun into face).

So, why is the shot so grainy?

wendy-jack-2.jpg
 
Hard to tell in mono as I expect to see grain by default :lol:

Could we see it in colour, maybe with a 100% crop too? :)
 
Depends on the processing afterwards. What processing to get the image into mono? Changes to up the contrast or tweak with the exposure can exaggerate noise, even at ISO200.

Doesn't look that grainy from here though? :shrug:
 
I guess it's difficult to see from the image I have uploaded.

Thinking more about it, the original shot is under exposed. I've tried to correct the exposure in PSE (shot RAW). I think it is this that has introduced the grain.

So, I guess my investigation now needs to move towards why the camera underexposed in the first place using AV mode.

In an ideal world I would have taken more time, but the little chappy was not going to hang round for long :)
 
because it is under exposed and then pushed in the processing?
 
The shot is probably well underexposed even on a sunny day like we've been having. Whilst shooting RAW will help there is only so much that can be done, and what you are seeing is noise. The way data is captured digitally is that less information is recorded in the shadow areas.It's not spread evenly over the exposure range. Emphasis is put into the highlights where much of the information exists. When you have an underexposed image the majority of the information is in the "shadow" areas, due to the underexposure. When you try to stretch the exposure back there just isn't the data available hence the noise giving the "grainy" effect.
 
Perfect exposure at ISO 400 with an aperture at f/9 ought to be 1/800th second - 1/1000th second

research: "sunny 16 rule"
 
1/4000th sec, ISO 400

Is this a lesson to check your settings before shooting or to remember to reset them to a norm after a shoot?
 
EdBray said:
???



?

I would suggest 'acceptable exposure', as the sunny 16 rule is a rule of thumb to get you by only.
Click to expand...

Its a good starting point though - it ought to let you know if you are "way off"
 
Byker28i said:
1/4000th sec, ISO 400

Is this a lesson to check your settings before shooting or to remember to reset them to a norm after a shoot?
Click to expand...

In all fairness, I would normally shoot in Manual mode, but as the little chap (i.e. the subject) wouldn't exactly stay still I thought I'd let AV mode sort out the shutter speed. Whilst taking the shot I didn't even notice what shutter speed the camera had selected.

So, if AV allows me to pick the DOF and in theory sorts out the shutter speed, why did things go wrong? Could it have been the bright white vest, or the Cotswold stone wall that thew the camera?

Just to clarify there were several shots, some at ISO 200 and some at 400.
 
FlyTVR said:
In all fairness, I would normally shoot in Manual mode, but as the little chap (i.e. the subject) wouldn't exactly stay still I thought I'd let AV mode sort out the shutter speed. Whilst taking the shot I didn't even notice what shutter speed the camera had selected.

So, if AV allows me to pick the DOF and in theory sorts out the shutter speed, why did things go wrong? Could it have been the bright white vest, or the Cotswold stone wall that thew the camera?

Just to clarify there were several shots, some at ISO 200 and some at 400.
Click to expand...

Should have approached this the other way around and shot in shutter priority mode and let the shutter sort out the aperture. You could have chosen a shutter speed fast enough to keep the little fella in focus and the aperture wouldnt have really mattered as theres not much to consider in the background anyway.
 
Studio16 said:
Should have approached this the other way around and shot in shutter priority mode and let the shutter sort out the aperture. You could have chosen a shutter speed fast enough to keep the little fella in focus and the aperture wouldnt have really mattered as theres not much to consider in the background anyway.
Click to expand...

Possibly. Hindsight is a wonderful thing.

However, why did the camera select such a fast shutter speed? This has never happened before. I'd like to know why.
 
Flash In The Pan said:
Because you were shooting in bright sunlight at iso 400...
Click to expand...

Thanks - can you expand on that?

I suppose ISO-400 and bright light would explain such a fast shutter speed! Have to be honest however, I've never used ISO-100 outside - only indoors using studio lighting. 200/400 on sunny days has never really caused me headaches before :(
 
FlyTVR said:
Thanks - can you expand on that?

I suppose ISO-400 and bright light would explain such a fast shutter speed! Have to be honest however, I've never used ISO-100 outside - only indoors using studio lighting. 200/400 on sunny days has never really caused me headaches before :(
Click to expand...

Looks like the kid is wearing white too, I surprised the camera's meter didn't have smoke pouring out it :lol:
 
FlyTVR said:
Possibly. Hindsight is a wonderful thing.

However, why did the camera select such a fast shutter speed? This has never happened before. I'd like to know why.
Click to expand...

If you were using EVALUATIVE metering the camera places more emphasis on the meter reading at/near the active focus point. Untanned caucasian skin is approx +1.3 stops brighter than "middle grey". A white top is more like +2.3 stops above middle grey, and the brightest, sunlit part should be at approx +3 stops. If you focused on any part of the child's skin, or the white top, then the camera would have reduced the exposure to get those areas nearer to "middle grey" while still factoring in the rest of the scene. Even with any other metering mode, which places emphasis on the centre of the frame rather than the focus point area, with that bright area in the centre of the frame the camera was still going to underexpose the scene as a whole.

I personally prefer to use manual exposure and find the "Sunny 16" rule to be a most excellent starting point for shooting in bright sunshine. It will make sure you hold detail in the brightest areas of reflected light, such as the sunlit white top, while putting everything else in the scene right where it belongs. With a manual exposure set you are then free to focus where you like and compose as you wish without worrying that the exposure will wander all over the place.

Another great technique, especially when shooting people and wanting an accurate exposure for skin tones, is to (spot/partial) meter from the palm of your hand when it is in the same light as your subject and then set an exposure at +1.3 stops for your palm. This works well for sunny conditions and pretty much any other conditions too. If your palm is exposed correctly (at +1.3 stops) then so should any other human skin, regardless of colour. You use your palm because it does not tan and is thus a constant reference all year round. This is much like setting an exposure from a "grey card" but with an adjustment because your palm is more reflective than a standard "grey card". The great thing about using your palm is that it costs nothing and you always have it with you (I hope).

The guidelines above work well when you have important highlight detail (the white top in this case, or a swan, white car, or a bride in a white dress etc..) that you want to protect from clipping. When your subject/scene is devoid of important highlight areas you may prefer to increase your exposure, perhaps by up to 1 stop, in order to capture more detail in the shadow areas. e.g. when I shoot my black dog against a backdrop of grass I normally expose at 1 stop over the "normal" exposure value for that scene. As soon as anything white and important enters the scene then I back off my exposure.

p.s. if this was underexposed by 2 stops then shooting at 400 ISO and corercting in post is somewhat like shooting at 1600 ISO and exposing correctly, but perhaps a little worse. A more suitable "Sunny 16" exposure for this shot might have been 100 ISO, f/4, 1/1600.
 
Well after all the picture was taken with a Canon !!! ( hides and waits for the flack :p )

Realspeed (Nikon Owner)
 
tdodd said:
If you were using EVALUATIVE metering the camera places more emphasis on the meter reading at/near the active focus point. Untanned caucasian skin is approx +1.3 stops brighter than "middle grey". A white top is more like +2.3 stops above middle grey, and the brightest, sunlit part should be at approx +3 stops. If you focused on any part of the child's skin, or the white top, then the camera would have reduced the exposure to get those areas nearer to "middle grey" while still factoring in the rest of the scene. Even with any other metering mode, which places emphasis on the centre of the frame rather than the focus point area, with that bright area in the centre of the frame the camera was still going to underexpose the scene as a whole.

I personally prefer to use manual exposure and find the "Sunny 16" rule to be a most excellent starting point for shooting in bright sunshine. It will make sure you hold detail in the brightest areas of reflected light, such as the sunlit white top, while putting everything else in the scene right where it belongs. With a manual exposure set you are then free to focus where you like and compose as you wish without worrying that the exposure will wander all over the place.

Another great technique, especially when shooting people and wanting an accurate exposure for skin tones, is to (spot/partial) meter from the palm of your hand when it is in the same light as your subject and then set an exposure at +1.3 stops for your palm. This works well for sunny conditions and pretty much any other conditions too. If your palm is exposed correctly (at +1.3 stops) then so should any other human skin, regardless of colour. You use your palm because it does not tan and is thus a constant reference all year round. This is much like setting an exposure from a "grey card" but with an adjustment because your palm is more reflective than a standard "grey card". The great thing about using your palm is that it costs nothing and you always have it with you (I hope).

The guidelines above work well when you have important highlight detail (the white top in this case, or a swan, white car, or a bride in a white dress etc..) that you want to protect from clipping. When your subject/scene is devoid of important highlight areas you may prefer to increase your exposure, perhaps by up to 1 stop, in order to capture more detail in the shadow areas. e.g. when I shoot my black dog against a backdrop of grass I normally expose at 1 stop over the "normal" exposure value for that scene. As soon as anything white and important enters the scene then I back off my exposure.

p.s. if this was underexposed by 2 stops then shooting at 400 ISO and corercting in post is somewhat like shooting at 1600 ISO and exposing correctly, but perhaps a little worse. A more suitable "Sunny 16" exposure for this shot might have been 100 ISO, f/4, 1/1600.
Click to expand...

Being new to the sunny 16 rule - very new :)

Sunny 16 says

ISO 100, F16 = 1/100
ISO 400, F/16 = 1/400

Can you explain your suggestion - ISO 100, F4 = 1/1600

Thanks
 
No problem. The "Rule" (more of a guideline really) says that in bright sunshine, at f/16 (that's where the rule gets its name) your shutter speed will always be the reciprocal of your ISO. So if you stick with f/16 as your aperture you could use any combination of ISO and shutter speed such as....

100 ISO, 1/100;
200 ISO, 1/200;
400 ISO, 1/400;
800 ISO, 1/800

and so on. You can also (if you insist) use intermediate ISO values and the rule still applies. So you might choose....

125 ISO and 1/125;
160 ISO and 1/160 etc..

The point is that you can change one of the settings and so long as you change something else to compensate you still end up with the same exposure.

So, I recommended f/4 as an aperture value instead of f/16. "Why?" you may ask. Well, the choice of aperture affects the Depth of Field (DOF) or how much of the scene is in focus from front to back. Your subject is the child and, frankly, the wall behind is not really of much interest. It might be better if it was a bit blurry and less distinct, and that would make the child stand out more. By choosing a wider aperture setting, such as f/4, it will make the DOF shallower, and thus make the wall look a bit softer.

But f/4 is 4 stops brighter than f/16. You go from f/16 -> f/11 -> f/8 -> f/5.6 -> f/4 = 4 stops. So by making that adjustment to the aperture you need to change something else in order to achieve the same "Sunny 16" exposure. I suggested 100 ISO because it will give the best IQ and no visible noise. With a well lit scene and a static subject I just know there is no need for a higher ISO. So with the ISO at 100 and the aperture at f/4 (4 stops brighter than f/16) I need to chose a shutter speed that is 4 stops dimmer than 1/100 (1/ISO). Well the progression in shutter speed to get to 4 stops is - 1/100 -> 1/200 -> 1/400 -> 1/800 -> 1/1600.

And Bob's your uncle.

If your lens only opens to f/5.6 at the focal length you require, rather than f/4, then try f/5.6 (3 stops brighter than f/16) and 1/800 (3 stops dimmer than 1/100), still with the 100 ISO.
 
tdodd said:
No problem. The "Rule" (more of a guideline really) says that in bright sunshine, at f/16 (that's where the rule gets its name) your shutter speed will always be the reciprocal of your ISO. So if you stick with f/16 as your aperture you could use any combination of ISO and shutter speed such as....

100 ISO, 1/100;
200 ISO, 1/200;
400 ISO, 1/400;
800 ISO, 1/800

and so on. You can also (if you insist) use intermediate ISO values and the rule still applies. So you might choose....

125 ISO and 1/125;
160 ISO and 1/160 etc..

The point is that you can change one of the settings and so long as you change something else to compensate you still end up with the same exposure.

So, I recommended f/4 as an aperture value instead of f/16. "Why?" you may ask. Well, the choice of aperture affects the Depth of Field (DOF) or how much of the scene is in focus from front to back. Your subject is the child and, frankly, the wall behind is not really of much interest. It might be better if it was a bit blurry and less distinct, and that would make the child stand out more. By choosing a wider aperture setting, such as f/4, it will make the DOF shallower, and thus make the wall look a bit softer.

But f/4 is 4 stops faster than f/16. You go from f/16 -> f/11 -> f/8 -> f/5.6 -> f/4 = 4 stops. So by making that adjustment you need to change something else in order to achieve the same "Sunny 16" exposure. I suggested 100 ISO because it will give the best IQ and no visible noise. With a well lit scene and a static subject I just know there is no need for a higher ISO. So with the ISO at 100 and the aperture at f/4 (4 stops brighter than f/16) I need to chose a shutter speed that is 4 stops dimmer than 1/100 (1/ISO). Well the progression in shutter speed to get to 4 stops is - 1/100 -> 1/200 -> 1/400 -> 1/800 -> 1/1600.

And Bob's your uncle.
Click to expand...

Excellent! Thanks.

You see, I was thinking multiples.

ie. F16 ISO 100 = 1/100
F4 ISO 100 = 4 / 100 X WRONG

Instead (as you said), I would need to compensate 4 stops of shutter speed.
 
"Sunny 16" and manual exposure is one of those things I wish I'd known about three years ago when I got my first DSLR. Sunny 16 is a very useful guideline and manual exposure can simplify things no end when you have constant lighting such as continual sunshine (or even cloud cover). Broken cloud or things moving in and out of shade is a bit of a killjoy for manual exposure though.
 
I think this has highlighted to myself that i do not understand aperture as well as i thought. Why is f16 > f11 one stop? What happened to f14 and f13?
Same with shutter speed, why is 1/100 > 1/200 one stop? Where did 1/125 and 1/160 go?

I know the relationship is the same so the idea of one up one down stays the same, just wondering why your number of stops is different?
 
Too much fuss on exposure. This is why digital cameras have screens for reviewing after. Ooooh, and the wonders of RAW :)
 
bass_junkie83 said:
I think this has highlighted to myself that i do not understand aperture as well as i thought. Why is f16 > f11 one stop? What happened to f14 and f13?
Same with shutter speed, why is 1/100 > 1/200 one stop? Where did 1/125 and 1/160 go?

I know the relationship is the same so the idea of one up one down stays the same, just wondering why your number of stops is different?
Click to expand...

One stop is either a doubling or halving of the total amount of light hitting the sensor (or thereabouts). Doubling the shutter speed obviously doubles the total amount of light and vice versa for halving. As regards aperture, the physical aperture would have to be half (or double) the area. The f/stop number gives an indication of the diameter of the aperture. Doubling or halving this would quadruple or quarter the area, so a multiplier of square root of two (approx 1.4) is used.Hence the progression of f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16.....
 
1 stop is a halving or doubling of the light. 200 ISO is double the sensitivity of 100 ISO. 125 ISO and 160 ISO are 1/3 stop intermediate values.

It's the same with shutter speed. 1/200 is twice as fast as 1/100 and so it only captures half as much light. Shutter speeds of 1/125 and 1/160 are 1/3 stop intermediate values. The full sequence would be 1/100, 1/125, 1/160, 1/200 to get you to 1 whole stop faster.

The sequence for apertures looks a bit weird because, while a 1 stop change does imply a halving or doubling of light, the aperture values only change by a factor of 1.4X instead of 2X. The reason for that is that the aperture value relates to the diameter of the aperture relative to the focal length of the lens. However, when you double the diameter of the aperture you actually allow in 4X as much light because the area of the aperture increases in relation to the square of the radius. 1.4 is ~SQRT(2).
 
bass_junkie83 said:
I think this has highlighted to myself that i do not understand aperture as well as i thought. Why is f16 > f11 one stop? What happened to f14 and f13?
Same with shutter speed, why is 1/100 > 1/200 one stop? Where did 1/125 and 1/160 go?

I know the relationship is the same so the idea of one up one down stays the same, just wondering why your number of stops is different?
Click to expand...

The F No is a mathematical relationship between the focal length of the lens and the actual diameter of the iris. This ensures that different focal length lenses when set to the same F No transmit the same amount of light.

Why the sequence, I'm not sure. I can only speculate, that in the distance past someone came up with the sequence, starting at F1

F1, F1.4, F2, F2.8, F4, F5.6, F8, F11, F16, etc. Each number in the sequence reducing the light by half.

Of course there are also sub divisions within the sequence, such as those between F 5.6 and F8, those being F6.3, F7. These reduce the intensity by 1/3 stop.

Naturally if you reduce the intensity you need to compensate by increasing the time of exposure. Hence an exposure of 1/200 @ F11, needs to be 1/100 if the aperture is changed to F16. If we change the aperture by 1/3 stop we will need to use and exposure which is changes the exposure accordingly, i.e 1/160 0r 1/125

You might find this link helpful

http://www.luminous-landscape.com/tutorials/understanding-series/understandexposure.shtml
 
voodoochild said:
Too much fuss on exposure. This is why digital cameras have screens for reviewing after. Ooooh, and the wonders of RAW :)
Click to expand...

Some truth in that. However, things were so bright yesterday i could hardly see the screen!
 
Cheers for explaining that guys. I know i could fudge it back in most cases with PP, but i would much prefer to get it right with the camera.
 
FlyTVR said:
Some truth in that. However, things were so bright yesterday i could hardly see the screen!
Click to expand...
Be warned that it is not advisable to use the preview image on the screen to judge your exposure. Use the histogram. You can use the image to look for blinking warnings of highlight clipping but do not judge the exposure from the overall appearance of the image itself. It can be very misleading as your eyes adjust to differing levels of ambient light. I know. I've made that mistake.


bass_junkie83 said:
Cheers for explaining that guys. I know i could fudge it back in most cases with PP, but i would much prefer to get it right with the camera.
Click to expand...

That's the spirit :) :thumbs:
 
tdodd you have a fantastic way of explaining things to make it easier for folk to understand :clap::clap::clap: I already understood :D But i must commend you for the way you explain things and the time you put into your posts. A true gentleman and a very good member of this forum:notworthy: When it comes to giving out the talk photography oscars i know where my votes going:thumbs:

Dave
 
Studio16 said:
tdodd you have a fantastic way of explaining things to make it easier for folk to understand :clap::clap::clap: I already understood :D But i must commend you for the way you explain things and the time you put into your posts. A true gentleman and a very good member of this forum:notworthy: When it comes to giving out the talk photography oscars i know where my votes going:thumbs:

Dave
Click to expand...

I agree, he is a gentleman :clap:
 
Chappers said:
The F No is a mathematical relationship between the focal length of the lens and the actual diameter of the iris. This ensures that different focal length lenses when set to the same F No transmit the same amount of light.

Why the sequence, I'm not sure. I can only speculate, that in the distance past someone came up with the sequence, starting at F1

F1, F1.4, F2, F2.8, F4, F5.6, F8, F11, F16, etc. Each number in the sequence reducing the light by half.

Of course there are also sub divisions within the sequence, such as those between F 5.6 and F8, those being F6.3, F7. These reduce the intensity by 1/3 stop.

Naturally if you reduce the intensity you need to compensate by increasing the time of exposure. Hence an exposure of 1/200 @ F11, needs to be 1/100 if the aperture is changed to F16. If we change the aperture by 1/3 stop we will need to use and exposure which is changes the exposure accordingly, i.e 1/160 0r 1/125

You might find this link helpful

http://www.luminous-landscape.com/tutorials/understanding-series/understandexposure.shtml
Click to expand...

the area of a circle goes as r^2 so to halve the light from F1. the radius of the aperture needs to be square root of two which is 1.4 (ish) , sqare root of 4 is 2 which gives quarter the light, square root of 8 is 2.8 which lets through only an 1/8th of the light as F1 ,etc etc

sid
 
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