Why so noisey?

[ruffdog64]

I took some macro shots today and found them a bit on the noisey side, my set up is 1d mk2, sigma105 2.8 macros lens, cheapo macro flash mounted on the lens, iso 160 ap 6.3 1/125 shutter speed can any see why and what i`m doing wrong please

Macro on a sunday 005 by Harvey Young, on Flickr

 

[u8myufo]

To be honest Harvey I am struggling to see a noise issue, if anything I would say the image was underexposed slightly. Perhaps you could elaberate a bit more on the problem you think you have.

 

[ruffdog64]

To be honest Harvey I am struggling to see a noise issue, if anything I would say the image was underexposed slightly. Perhaps you could elaberate a bit more on the problem you think you have.

Thanks for the reply, on my monitor it looks grainey Harvey

 

[Pookeyhead]

I can see noise.. terrible noise, and it's that awful colour noise too.. and banding.

Was this under exposed? That has all the halmarks of a underexposed image shot in JPG then rescued post process. If that was a correctly exposed RAW, there's something hugely wrong for a shot at ISO160

 

[Yellowbelly]

Looking at the original on Flickr, you've nowt to worry about. It is a little under exposed, but there is no noise to concern you. Bear in mind that if printed, you would see even less noise.

 

[ruffdog64]

I can see noise.. terrible noise, and it's that awful colour noise too.. and banding.

Was this under exposed? That has all the halmarks of a underexposed image shot in JPG then rescued post process. If that was a correctly exposed RAW, there's something hugely wrong for a shot at ISO160

it was shot in raw and your correct it was underexposed I never thought that would be a problem

 

[u8myufo]

I can see noise.. terrible noise, and it's that awful colour noise too.. and banding.

Was this under exposed? That has all the halmarks of a underexposed image shot in JPG then rescued post process. If that was a correctly exposed RAW, there's something hugely wrong for a shot at ISO160

Well you have taken almost the top quarter of the darkest part of the image and cropped it, and then produced a file of 1188 x 677. Of coarse you will see noise. Zoom in a bit further and you will see out the other side of it

 

[Nick_1981]

Well you have taken almost the top quarter of the darkest part of the image and cropped it, and then produced a file of 1188 x 677. Of coarse you will see noise. Zoom in a bit further and you will see out the other side of it

 

[Pookeyhead]

Of course I have. I've not enlarged it though... that's a crop from the full resolution file he uploaded to Flickr. It's noisy. He's already admitted it was underexposed, and that's the reason why. Shadow detail will always become noisy if you under expose. That WILL be noticeable on a print. Why wouldn't it be? Depends how bit you print it. 6x4? No, of course not. A3? Damned straight you'll see it.

If it was correctly exposed, the noise levels in the dark areas should be no worse than they are in the light areas. Are you suggesting it's OK to under expose and have noisy shadow detail? Call me old fashioned but I'd say it's not. Seeing as the OP wanted to know why his images were noisy, I think it's fair to advise him that they ARE noisy, because it WAS underexposed.

The OP had noticed it.. I noticed it. It shouldn't be like that


It's not just the darkest shadows either. Look at the noise and vertical banding in the green.

You're cool with that? I'm not.

To the OP. It's an exposure issue. You can't rescue an underexposed image without paying a price... as you can see.

 

[ruffdog64]

Of course I have. I've not enlarged it though... that's a crop from the full resolution file he uploaded to Flickr. It's noisy. He's already admitted it was underexposed, and that's the reason why. Shadow detail will always become noisy if you under expose. That WILL be noticeable on a print. Why wouldn't it be? Depends how bit you print it. 6x4? No, of course not. A3? Damned straight you'll see it.

If it was correctly exposed, the noise levels in the dark areas should be no worse than they are in the light areas. Are you suggesting it's OK to under expose and have noisy shadow detail? Call me old fashioned but I'd say it's not. Seeing as the OP wanted to know why his images were noisy, I think it's fair to advise him that they ARE noisy, because it WAS underexposed.

The OP had noticed it.. I noticed it. It shouldn't be like that


It's not just the darkest shadows either. Look at the noise and vertical banding in the green.

You're cool with that? I'm not.

To the OP. It's an exposure issue. You can't rescue an underexposed image without paying a price... as you can see.

Thanks for that i`ll be more careful next time

 

[u8myufo]

Of course I have. I've not enlarged it though... that's a crop from the full resolution file he uploaded to Flickr. It's noisy. He's already admitted it was underexposed, and that's the reason why. Shadow detail will always become noisy if you under expose. That WILL be noticeable on a print. Why wouldn't it be? Depends how bit you print it. 6x4? No, of course not. A3? Damned straight you'll see it.

If it was correctly exposed, the noise levels in the dark areas should be no worse than they are in the light areas. Are you suggesting it's OK to under expose and have noisy shadow detail? Call me old fashioned but I'd say it's not. Seeing as the OP wanted to know why his images were noisy, I think it's fair to advise him that they ARE noisy, because it WAS underexposed.

The OP had noticed it.. I noticed it. It shouldn't be like that


It's not just the darkest shadows either. Look at the noise and vertical banding in the green.

You're cool with that? I'm not.

To the OP. It's an exposure issue. You can't rescue an underexposed image without paying a price... as you can see.

I think you will find I mentioned it was underexposed in my first reply. The image the op posted up looked fine, I seen no mention of him wanting to print it, so for web it looked ok. in fact the 1024 underneath looks quite acceptable for web imo. Do you think I do not realise that shadows become noisy if underexposed? Or perhaps you are trying to teach me something I dont know :shrug:another point is that there is a big chunk of wasted space on the right, so sometimes underexposing can have its advantages as it makes the flowers satnd out a little more, even if at a small price. Depends what kind of effect the op wants really.

 

[Pookeyhead]

I agree with the dark space, and darkness making the flowers pop out, but it should still be exposed correctly in camera even if that is your intent, or.. well.. the shadows will be noisy

Just seemed to me there was a general opinion that there was nothing really wrong with this image, and that is not really helpful to the OP, as there IS a problem with it. It's around 2 stops under I reckon, and that's caused the noise in the shadows. You can't under expose without paying a price.

There were some decidedly poor posts in here.. "Looking at the original on Flickr, you've nowt to worry about.".... for instance. I'm sorry, since when has under exposing been nothing to worry about?

Sorry... I just feel that giving correct advice is important. Yes, you did notice it was under exposed, but you also said "To be honest Harvey I am struggling to see a noise issue" when there is a blatant noise issue here. Not seeing it at 1024 doesn't mean there's not a noise issue. Print small enough and nothing will have a noise issue

"Bear in mind that if printed, you would see even less noise"

Which is only true if printed small. Print large, and it will exaggerate the problem.

Call me old fashioned but a thread where the general consensus was that he's got nothing to worry about just bothered me. His camera is more than capable of producing much higher quality than that and it is important that he understands the value of accurate exposure. You're resize looks acceptable for web, yes. Is that the new benchmark? Looks ok at 1024 so sod it, that will do? Since when has "It looks ok for the web" been acceptable? He uploaded it up to a Flickr Pro account at full camera resolution... so clearly it's not "acceptable for the web" at all. So what if he didn't mention wanting to print it. So if I don't want to print something, it's OK to get my exposure wrong and and degrade the image? I don't know about you but I shoot everything as if it's being printed as big as possible. You can always make things smaller, but if the quality is not there.. you can't make it bigger.

Just to put things back into prespective.. the original question was

can any see why and what i`m doing wrong please

He's under exposing.

 

[woof woof]

If the problem is caused by boosting an underexposed shot...

If you are using evaluative maybe when the subject and the background differ quite a bit you could switch to spot or centre weighted? Other than that I often try to ETTR and than back it off in post capture which I find is often better than boosting an image.

 

[allanmacdonald]

Yes, I'd say that's a problem with underexposure, too and quality can quickly get worse, if you try to adjust the exposure to a higher level in Photoshop.

I was having a look at the EXIF info, and it says that the copyright info is 'Stuart Franklin / Getty Images'. Not sure if that's supposed to be like that, as your name's Harvey. It can be easily changed if not, though, just by connecting the camera to your computer and opening EOS Utility.

 

[ruffdog64]

Yes, I'd say that's a problem with underexposure, too and quality can quickly get worse, if you try to adjust the exposure to a higher level in Photoshop.

I was having a look at the EXIF info, and it says that the copyright info is 'Stuart Franklin / Getty Images'. Not sure if that's supposed to be like that, as your name's Harvey. It can be easily changed if not, though, just by connecting the camera to your computer and opening EOS Utility.

The getty image thing has always puzzled me ,i assume it a flickr thing and something id like to sort out,with regards to my underexposing thats due to me using6.3 app to try and get a greater dof but i guess withflash im going to underexpose

 

[allanmacdonald]

The getty image thing has always puzzled me ,i assume it a flickr thing and something id like to sort out,with regards to my underexposing thats due to me using6.3 app to try and get a greater dof but i guess withflash im going to underexpose

Perhaps you bought the camera second hand, and it belonged to Stuart Franklin before? Let me know if you need help in sorting it out.

 

[u8myufo]

I agree with the dark space, and darkness making the flowers pop out, but it should still be exposed correctly in camera even if that is your intent, or.. well.. the shadows will be noisy

Just seemed to me there was a general opinion that there was nothing really wrong with this image, and that is not really helpful to the OP, as there IS a problem with it. It's around 2 stops under I reckon, and that's caused the noise in the shadows. You can't under expose without paying a price.

There were some decidedly poor posts in here.. "Looking at the original on Flickr, you've nowt to worry about.".... for instance. I'm sorry, since when has under exposing been nothing to worry about?

Sorry... I just feel that giving correct advice is important. Yes, you did notice it was under exposed, but you also said "To be honest Harvey I am struggling to see a noise issue" when there is a blatant noise issue here. Not seeing it at 1024 doesn't mean there's not a noise issue. Print small enough and nothing will have a noise issue

"Bear in mind that if printed, you would see even less noise"

Which is only true if printed small. Print large, and it will exaggerate the problem.

Call me old fashioned but a thread where the general consensus was that he's got nothing to worry about just bothered me. His camera is more than capable of producing much higher quality than that and it is important that he understands the value of accurate exposure. You're resize looks acceptable for web, yes. Is that the new benchmark? Looks ok at 1024 so sod it, that will do? Since when has "It looks ok for the web" been acceptable? He uploaded it up to a Flickr Pro account at full camera resolution... so clearly it's not "acceptable for the web" at all. So what if he didn't mention wanting to print it. So if I don't want to print something, it's OK to get my exposure wrong and and degrade the image? I don't know about you but I shoot everything as if it's being printed as big as possible. You can always make things smaller, but if the quality is not there.. you can't make it bigger.

Just to put things back into prespective.. the original question was

He's under exposing.

Yes and no really.Since when has under exposing been nothing to worry about? Depends what you are photographing really I suppose :shrug: I do it on a regular basis, check the exif on these and these feel free to tell me I am wrong by doing it, but I would be more than happy to get a decent sized print done from the originals.

 

[Pookeyhead]

But you know what you are doing. There's always a case for over riding the meter's suggestion, as you well know, but advising a beginner that it's OK to under expose is not really a great idea, particularly on an image with so much shadow area, and no really bright highlights.

The OP is clearly not happy with his results, hence him posting on here. The noise in his images IS because he under exposed. This isn't a case of under exposing a bit to retain highlight detail in the feathers as you have done, because his image is predominantly dark to begin with. I'm sure you know all this, and are just arguing to save face though.

 

[Gary Coyle]

There are the odd occasions when underexposing is required, mainly for effect, BUT if noise is important then its far better to expose to the right and even over expose a smidgen but to underexpose and try to pull back in PP will just cause trouble.

 

[u8myufo]

But you know what you are doing. There's always a case for over riding the meter's suggestion, as you well know, but advising a beginner that it's OK to under expose is not really a great idea, particularly on an image with so much shadow area, and no really bright highlights.

The OP is clearly not happy with his results, hence him posting on here. The noise in his images IS because he under exposed. This isn't a case of under exposing a bit to retain highlight detail in the feathers as you have done, because his image is predominantly dark to begin with. I'm sure you know all this, and are just arguing to save face though.

"And are just arguing to save face though" Now why go and spoil a perfectly good reply with that comment? Looking at a lot of your replies on TP you seem to have an annoying trait, mainly accusing people of saying and thinking things they clearly have not, you really need to make your mind up. You blatently suggest in one of your replies that you dont underexpose, yet here you are saying " But you know what you are doing" so which is it to be? Yes I agree that in the perfect scenario correct exposure is needed and overexposing is ok, all I am saying is that underexposing is not as bad as some would like others to believe. Ok, getting back to the OP, and I say this in a constructive way. Looking at all of his Flickr images I see nothing much that stands out, this makes me believe and I could be wrong :shrug: that the problem also may have something to do with his editing skills. I know very little myself so will decline telling him what he should or should not be doing with respect to that, but I would not mind betting that as far as the flower picture is concerned, something a bit better could have been produced from the RAW file. Yes I know it goes against what should and should not be done in your books, but if you have a little bit of knowleadge when it comes to PP then sometimes things are not as bad as you first thought.

 

[Pookeyhead]

"And are just arguing to save face though" Now why go and spoil a perfectly good reply with that comment?

Because I can genuinely see no other reason for you arguing about this. The image IS under exposed, and that IS why it's noisy... the end.

You blatently suggest in one of your replies that you dont underexpose, yet here you are saying " But you know what you are doing" so which is it to be?

Do you live in a black and white world of absolutes or something? I'm saying that to just tell people it's OK to under expose as a general piece of advice is not a good idea, no, but there are certain occasions when it may be a good idea to stop down from your meter's suggestion.. snow as an example. However, as you well know, the OP's image is simply NOT one of those cases, and there is no logical reason to under expose a shot with all those dark tones. In fact, there's a strong argument to over expose a little if anything, so yes, I'm left wondering exactly why you are arguing with me.

Yes I agree that in the perfect scenario correct exposure is needed and overexposing is ok, all I am saying is that underexposing is not as bad as some would like others to believe.

In the OP's case it is.. why else do you think the image is so noisy? Underexposing an image with all that detail at the left of the histogram is VERY bad If you do.. you'll.. err.. get noise. We seem to be going in circles now.

Ok, getting back to the OP, and I say this in a constructive way. Looking at all of his Flickr images I see nothing much that stands out, this makes me believe and I could be wrong :shrug: that the problem also may have something to do with his editing skills.

He's already said that it was under exposed.. Look at it! It's clearly under exposed. Why start confusing the poor guy by suggesting that? The only reason this is a product of PP is because he's had to rescue an under exposed image in the first place. LOL.. but carry on confusing people if it makes you happy.

Yes I know it goes against what should and should not be done in your books,

In my books? Find me ANY book that recommends under exposing an image full of shadows and few highlights. If ever there was a case for ETTR.. this is it!

but if you have a little bit of knowleadge when it comes to PP then sometimes things are not as bad as you first thought.

Or just get the exposure right... which is actually immeasurably easier than messing about in PP trying to rescue your shadow detail that isn't there.. and therefore just pull up the noise floor of the sensor instead. There's nothing in PP he's doing wrong... it's an under exposed image.

 

[POAH]

Because I can genuinely see no other reason for you arguing about this. The image IS under exposed, and that IS why it's noisy... the end.

Do you live in a black and white world of absolutes or something? I'm saying that to just tell people it's OK to under expose as a general piece of advice is not a good idea, no, but there are certain occasions when it may be a good idea to stop down from your meter's suggestion.. snow as an example. However, as you well know, the OP's image is simply NOT one of those cases, and there is no logical reason to under expose a shot with all those dark tones. In fact, there's a strong argument to over expose a little if anything, so yes, I'm left wondering exactly why you are arguing with me.

In the OP's case it is.. why else do you think the image is so noisy? Underexposing an image with all that detail at the left of the histogram is VERY bad If you do.. you'll.. err.. get noise. We seem to be going in circles now.

He's already said that it was under exposed.. Look at it! It's clearly under exposed. Why start confusing the poor guy by suggesting that? The only reason this is a product of PP is because he's had to rescue an under exposed image in the first place. LOL.. but carry on confusing people if it makes you happy.

In my books? Find me ANY book that recommends under exposing an image full of shadows and few highlights. If ever there was a case for ETTR.. this is it!

Or just get the exposure right... which is actually immeasurably easier than messing about in PP trying to rescue your shadow detail that isn't there.. and therefore just pull up the noise floor of the sensor instead. There's nothing in PP he's doing wrong... it's an under exposed image.

An underexposed image does not = noise

Recovering an underexposed image in RAW will make it noisy lol

 

[HoppyUK]

It's under-exposed, simple as. Trying to rescue an under-exposed image is guaranteed to create far more noise. You will also get a lot less noise by shooting at a higher ISO rather than under-exposing and trying to make it right in post processing.

Check the original histogram on the camera's LCD - there will be a a lot of unused area on the right, which is where the sensor records far more data. In round numbers, there is 16x more data - photons/light - recorded on the right hand side of the hostogram than on the left.

Photons are the life blood of exposure, the more the better, and they're the simple reason why larger sensors are less noisy than smaller ones - they simply collect more light. This is the basis of Expose To The Right technique (ETTR - see here http://en.wikipedia.org/wiki/Exposing_to_the_right and also here http://www.luminous-landscape.com/tutorials/expose-right.shtml ). In the OP, that image would take at least another two stops of exposure, maybe three or more as it's a particularly benign subject with no bright highlight areas. This would record far more light, dramatically reducing noise. The image would then be technically over-exposed, but with ETTR you then darken the image in post processing to restore the correct tones, but the noise is still reduced and there will also be far more detail in the darker areas with cleaner colours.

 

[u8myufo]

Because I can genuinely see no other reason for you arguing about this. The image IS under exposed, and that IS why it's noisy... the end.

Here we go again Who exactly is arguing? I am putting my points over in much the same way as yourself. The OP asked about the image he posted up, I said I could not really see that much noise in it, his reply was " Thanks for the reply, on my monitor it looks grainey " The image posted does not look grainy on my monitor hence my reply.


Do you live in a black and white world of absolutes or something? I'm
saying that to just tell people it's OK to under expose as a general piece of advice is not a good idea, no, but there are certain occasions when it may be a good idea to stop down from your meter's suggestion.. snow as an example. However, as you well know, the OP's image is simply NOT one of those cases, and there is no logical reason to under expose a shot with all those dark tones. In fact, there's a strong argument to over expose a little if anything, so yes, I'm left wondering exactly why you are arguing with me.

Point me to where I was advising people to underexpose? So now you are saying there are certain occasions (Note: Plural) to underexpose, and give Snow as one example. So do you mean there could be more? Who is going around in circles now?

In the OP's case it is.. why else do you think the image is so noisy? Underexposing an image with all that detail at the left of the histogram is VERY bad If you do.. you'll.. err.. get noise. We seem to be going in circles now.

When taking a shot like this you have to decide which is the most important part of the image, the wasted space on the right is not. The shot could have been composed or cropped better. You have given us all a fine example of how much noise there is by your cropped section from the full sized Jpeg, nowhere have I said to you that there is no noise in that example though. And to be honest grabbing a picture from Flickr, cropping it, uploading it again and then linking it here is not really the correct way to go about things is it?

He's already said that it was under exposed.. Look at it! It's clearly under exposed. Why start confusing the poor guy by suggesting that? The only reason this is a product of PP is because he's had to rescue an under exposed image in the first place. LOL.. but carry on confusing people if it makes you happy.

What exactly is it you are on? Once again, when did I state it was not underexposed?
Where do I mention that the picture is the end product of him having to rescue it in PP?


In my books? Find me ANY book that recommends under exposing an image full of shadows and few highlights. If ever there was a case for ETTR.. this is it!

In my books? As in your opinion Do you take everything people say to you at face value? :shake::shake:

Or just get the exposure right... which is actually immeasurably easier than messing about in PP trying to rescue your shadow detail that isn't there.. and therefore just pull up the noise floor of the sensor instead. There's nothing in PP he's doing wrong... it's an under exposed image.

It`s a macro shot with minimal dof if you look a bit closer, what sort of detail do you think will suddenly appear even if it was exposed correctly then?also once gain you seem hell bent on trying to tell me it is underexposed. Hello!! I have already told you I know that. So let us put that to one side for the moment.

 

[EOS_JD]

There are the odd occasions when underexposing is required, mainly for effect,

Correct but you would not be recovering that under exposure so you wouldn't see the noise. The noise and banding generally ocurs when you try to recover an under exposed shot. That would not be the case that you state above

 

[EOS_JD]

An underexposed image does not = noise

Recovering an underexposed image in RAW will make it noisy lol

Correct (whether it's RAW, jpg, tif etc) - Recovering shadow detail is actually very difficult to do well and will be a lot noisier than having shot at a higher ISO and gotten the eexposure right in the first place.

 

[Terrywoodenpic]

Under exposure always produces noise. the least noise and most even tonal range comes from using native ISO and exposing to the right ( maximum exposure with out clipping.

You then have a virtually noise free raw image, with which you can make the maximum processing changes, deepening and saturating tones, as in the OP shot, become easy and free of noise problems

 

[Terrywoodenpic]

Correct (whether it's RAW, jpg, tif etc) - Recovering shadow detail is actually very difficult to do well and will be a lot noisier than having shot at a higher ISO and gotten the eexposure right in the first place.

Not actually true as we have discussed before.
Higher ISO settings do nothing to the exposure on the sensor, they simply adjust for the under exposure that was captured. (Higher ISO settings are more a form of Raw processing in camera to combat under exposure. Or instructions in the raw file, that set the appropriate raw processing development externally.)

 

[Terrywoodenpic]

duplicate post

 

[EOS_JD]

Under exposure always produces noise. the least noise and most even tonal range comes from using native ISO and exposing to the right ( maximum exposure with out clipping.

You then have a virtually noise free raw image, with which you can make the maximum processing changes, deepening and saturating tones, as in the OP shot, become easy and free of noise problems

The act of under exposing does not produce the noise in the above image until you start to try to recover it.

Whilst there is is noise in the dark area of images you don't see it generally until you try to recover it but consider underexposing the background in a flash lit shot - There's actually very little visible noise in the underexposed part of the image - but try to recover that - that's a different story

I agree about ETTR but there are times when under exposure of an area is actually the correct exposure (if you see what I mean)

 

[EOS_JD]

Not actually true as we have discussed before.
Higher ISO settings do nothing to the exposure on the sensor, they simply adjust for the under exposure that was captured. (Higher ISO settings are more a form of Raw processing in camera to combat under exposure. Or instructions in the raw file, that set the appropriate raw processing development externally.)

It seems therefore the camera does a much better job at adjusting for that under exposure I see a lot more noise when trying to recover under exposure in the likes of Lr/Ps.

 

[Johnytuono]

HI
Wouldn't mind seeing the original completely unprocessed image just to see how much it's been adjusted. Must admit though, it doesn't look THAT bad to me (noise-wise) if I'm honest.
JohnyT

 

[EOS_JD]

HI
Must admit though, it doesn't look THAT bad to me (noise-wise) if I'm honest.
JohnyT

It does if you look at the full size image on Flickr

 

[Terrywoodenpic]

It seems therefore the camera does a much better job at adjusting for that under exposure I see a lot more noise when trying to recover under exposure in the likes of Lr/Ps.

Because you are doing it in addition to the corrections already made by the in camera processing or raw instructions.
Cameras do have excellent in camera strategies for dealing with under exposure noise.

 

[EOS_JD]

Because you are doing it in addition to the corrections already made by the in camera processing or raw instructions.
Cameras do have excellent in camera strategies for dealing with under exposure noise.

Perhaps we misunderstand each other.

I don't mean doing anything "in addition"

 

[u8myufo]

Well it is at least good to see some varying opinions, and the added bonus that a few of us including myself, can learn something from the technical side of things that are being pointed out to us by others. As I have said I underexpose quite a bit with my shots. And after all depending on the subject, lighting and a host of other factors, some shots will look far worse than others. All I was trying to point out is that if you got one that has been underexposed by accident then sometimes all is not lost. But if you think you are getting poor noisey shots each time you take a picture then obviously something needs to be done about it.

 

[EOS_JD]

Because you are doing it in addition to the corrections already made by the in camera processing or raw instructions.
Cameras do have excellent in camera strategies for dealing with under exposure noise.

Terry,

To explain. lets say you shoot a scene 3 stops under exposed but the subject itself (lit by flash) is correctly exposed.

There won't be very much noise visible in the under exposed part of the scene.

If you take another shot at 2 stops under, the image will be brighter but still the noise will not be very visible.

If however you try to recover that first image to make it look the same as the 2 stop under exposure, there will be much more noise in the shadow areas of the image visible than in the one taken by the camera at 2 stops under.

What you are suggesting is that both should be equal but they are not.

 

[EOS_JD]

Well it is at least good to see some varying opinions, and the added bonus that a few of us including myself, can learn something from the technical side of things that are being pointed out to us by others. As I have said I underexpose quite a bit with my shots. And after all depending on the subject, lighting and a host of other factors, some shots will look far worse than others. All I was trying to point out is that if you got one that has been underexposed by accident then sometimes all is not lost. But if you think you are getting poor noisey shots each time you take a picture then obviously something needs to be done about it.

I agree that all is not lost. I showed an image here a while back that was three stops under exposed and when recovered you wouldn't have known.

But the image didn't really contain much dark areas - that's where noise is generally visible.

I should add though it's a bad idea to deliberately under expose images. When your blinkies appear on the back of your camera all is not lost either.... the camera shows a jpg preview of the image and there's a lot more detail captured in the raw image so if there's a slight over exposure you should be able to hold the highlights using the extra data in the raw file (hoppy is more of an expert on the ETTR philosophy than me).

Under exposure will as has been discussed to death, introduce a lot of noise in your images particularly noticeable in the shadows when you recover that under exposure).

 

[u8myufo]

I agree that all is not lost. I showed an image here a while back that was three stops under exposed and when recovered you wouldn't have known.

But the image didn't really contain much dark areas - that's where noise is generally visible.

I should add though it's a bad idea to deliberately under expose images. When your blinkies appear on the back of your camera all is not lost either.... the camera shows a jpg preview of the image and there's a lot more detail captured in the raw image so if there's a slight over exposure you should be able to capture much more data (hoppy is more of an expert on the ETTR philosophy than me).

Under exposure will as has been discussed to death, introduce a lot of noise in your images particularly noticeable in the shadows when you recover that under exposure).

I think lighting is the key factor Jim but I could be wrong. I know very little with respect to mathematical equations,sensors etc. Here is one from a while ago shot @ -5/3 EV. About 2/3 minutes of my very basic PP skills applied, does it look that bad :shrug: Would I do anything different given the opportunity again more as likely I would do, as I am not a stickler for it has to be taken a certain way, my settings could be completely different


Magpie by Richard Venn, on Flickr

 

[Terrywoodenpic]

Terry,

To explain. lets say you shoot a scene 3 stops under exposed but the subject itself (lit by flash) is correctly exposed.

There won't be very much noise visible in the under exposed part of the scene.

If you take another shot at 2 stops under, the image will be brighter but still the noise will not be very visible.

If however you try to recover that first image to make it look the same as the 2 stop under exposure, there will be much more noise in the shadow areas of the image visible than in the one taken by the camera at 2 stops under.

What you are suggesting is that both should be equal but they are not.

"Correct" exposure based on ISO is a myth.
A sensor only has one native sensitivity.

The problem is you never see an unadulterated raw file, you would be shocked it you could.

When you set an exposure on a camera that has a native ISO of 100 and set the speed as ISO 200. It simply underexposes by one stop and adds the ISO information to the raw file. ( in the case of a Peg it does the same but processes it, to recover the stop under exposure.

When you later open the raw file in your raw processor It reads the ISO setting and automatically makes the required exposure adjustment.
( different raw processors give slightly different results and different levels of noise.)

However the camera may or may not do additional noise reduction procedures to reduce known noise issues, but it can do nothing to reduce the basic random shot noise (which is an Photon issue related to the actual exposure)

This is all true what ever the ISO set.
Noise is directly related to photons, exposure.

The ISO you set is used by the firmware or software to compensate for the under exposure of the sensor.