Discussion
Am looking to buy a new camera soon, I have my eye on a Nikon coolpix 5700. I have read the article on Dpreview and found it informative. One question though can someone give me a description of what they mean by Noise?? I have read the feedback section and a few users have experienced problems with this. I know it is something to do with picture distortion but can anyone give me a better explanation (in english!)
Think of Digital Grain like film grain, an ISO 50 film will have far less grain that an ISO 400 film.
There is more to it, than that, but that's a simple way of looking at it.
Here's a link to a good explanation:
www.phototechmag.com/sample/sharma.pdf
Here's an example of noise on a mocked-up Photoshop file, the rhs has had noise artifically added to the original image.
I hope this is of some help, no doubt other people will come in and expand on my brief description.
Tim
There is more to it, than that, but that's a simple way of looking at it.
Here's a link to a good explanation:
www.phototechmag.com/sample/sharma.pdf
Here's an example of noise on a mocked-up Photoshop file, the rhs has had noise artifically added to the original image.
I hope this is of some help, no doubt other people will come in and expand on my brief description.
Tim
Not at all actually although both have a similar effect. Noise can be thought of as pixels going off randomly when they aren't supposed to, but grain is an artifact of film itself. The more sensitive your film (higher speed), the bigger grains of silver compound it must have. If they're big enough, you can see the texture of them.
I'm not sure about this. I've used film for 25 years and know exactly the effect zetec means. However his question implies that if he then took a photo in normal light, it would be OK, ie no visible grain. Hence the problem it can't be a silver grain thing, as that's a function of the ASA rating when the film is made.
I wonder if it's the film being 'forced' at the processors, or linked to reciprocity failure?
Not sure myself, but the laws of physics must have an answer!
I wonder if it's the film being 'forced' at the processors, or linked to reciprocity failure?
Not sure myself, but the laws of physics must have an answer!
simpo two said:
I wonder if it's the film being 'forced' at the processors, or linked to reciprocity failure?
Not sure myself, but the laws of physics must have an answer!
It's unlikely to be the processors 'forcing' or pushing the film. If the film is going through a machine and not being hand processed, the only way to do this is to physically turn the machines drive off, stopping the film in the dev. Colour neg film isn't processed by time/ISO like B&W, all ISO's have the same time. You do notice grain more if the image in underexposed, so maybe this is what zetec has experienced. Not sure why grain shows up more in an underexposed image though!
Out partying with page 3 girls.
When talking about film grain, you are asking me about something which is no longer relevant to me, so I am a bit rusty on the subject. I had to reach for Langford's 'Advanced Photography' off the top shelf to remind myself. There was more dust on it than Miss Haversham's dinning table.
Put simply, grain shows up more in underexposed, soft focus and low contrast areas of a picture simply because your eye has nothing else to look at. Compare that to a high contrast, sharp detailed view photographed outside in bright sunny conditions and the grain is 'hidden' in the detail. You can do things to reduce grain like over expose and under develop but then you have to compensate for the low contrast caused by under development my using more contrasty lighting in your scene..... not always possible. Or you could save your self the trouble and shoot digitally.
Digital, however, suffers with noise. Came across this little piece which, very basically explains, it:
www.betterdigitalonline.com/HTML%20Files/isocontrol.html
One bit says:
"Though all digital cameras have variable ISO settings, they actually only have one 'real' factory-rated ISO setting. This is usually the lowest figure in the range available. The higher numbers are created by increasing the electrical gain in the CCD - this gives a similar effect as actually having a higher ISO number CCD - but because the chip is literally being 'boosted', it also produces a nasty side effect called noise -"
In other words, the chip heats up and causes noise. Professional digital backs employ chip cooling to keep the noise down. Another way is to only take pictures in winter.
Another solution is to use software such as Quantum Mechanic:
www.camerabits.com/QM2.html
If you choose to scan film you are not immune from the affects of noise which can be introduced at the scanning stage. Double whammy, grain and noise, which again usually shows up in the low contrast, shadow areas of the scan. Depends on the quality of your scanner and software. If it allows you to do multi-pass scanning this will help or, failing that, use Quantum Mechanic.
HTH
When talking about film grain, you are asking me about something which is no longer relevant to me, so I am a bit rusty on the subject. I had to reach for Langford's 'Advanced Photography' off the top shelf to remind myself. There was more dust on it than Miss Haversham's dinning table.
Put simply, grain shows up more in underexposed, soft focus and low contrast areas of a picture simply because your eye has nothing else to look at. Compare that to a high contrast, sharp detailed view photographed outside in bright sunny conditions and the grain is 'hidden' in the detail. You can do things to reduce grain like over expose and under develop but then you have to compensate for the low contrast caused by under development my using more contrasty lighting in your scene..... not always possible. Or you could save your self the trouble and shoot digitally.
Digital, however, suffers with noise. Came across this little piece which, very basically explains, it:
www.betterdigitalonline.com/HTML%20Files/isocontrol.html
One bit says:
"Though all digital cameras have variable ISO settings, they actually only have one 'real' factory-rated ISO setting. This is usually the lowest figure in the range available. The higher numbers are created by increasing the electrical gain in the CCD - this gives a similar effect as actually having a higher ISO number CCD - but because the chip is literally being 'boosted', it also produces a nasty side effect called noise -"
In other words, the chip heats up and causes noise. Professional digital backs employ chip cooling to keep the noise down. Another way is to only take pictures in winter.
Another solution is to use software such as Quantum Mechanic:
www.camerabits.com/QM2.html
If you choose to scan film you are not immune from the affects of noise which can be introduced at the scanning stage. Double whammy, grain and noise, which again usually shows up in the low contrast, shadow areas of the scan. Depends on the quality of your scanner and software. If it allows you to do multi-pass scanning this will help or, failing that, use Quantum Mechanic.
HTH
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