Digital Photography ISO

[Ysarex]

As you might know Joe, I am still learning with both my Fuji X cameras, the socks image is great as if I am right you have exposed it bang on with no noise at all ?

The socks image was taken indoors in low light and the camera ISO is set to 12,800. I did put the camera on a tripod and what I did to keep the noise down was to expose as much as possible.

There's the exposure triangle problem and the connection of noise to ISO. Noise in your photos, especially with your Fuji camera, is going to be a function of exposure. Exposure is how much physical light strikes the sensor and ISO is NOT part of that -- just shutter speed, f/stop and image brightness. I deliberately picked the socks scene because it had a low dynamic range (low contrast) and what I did was expose as much as the sensor would tolerate -- like a +2.3 EC. I knew something about ISO and Fuji. ISO is not a rating of the sensor sensitivity and Fuji hedges the sensor by a good solid stop. In other words when you get a good exposure JPEG from a Fuji camera odds are the sensor could have handled at least a stop more exposure. Given a low contrast scene even more exposure was possible without clipping the sensor and I pushed for all of it. The camera JPEG I got was overexposed badly but the raw file was not and because noise is a function of exposure the exposure increase I applied reduced the noise even at ISO 12K.

By the way in those two sets above all three exposures in SET A are the same whereas the last exposure in SET B is less.

Joe

 

[Ysarex]

I will try and dig out a photo, but last week using the X-T2 + XF 35mm f2 in a pub. Lighting was turned right down and it waas dark out side even though I was in side, had to put the iso up to 800 and deleted them all as they were terrible when I got them in LR6 and hit the exposure slider, then I went again but this time same sort of lighting turned down, iso 640 and the shots were not to bad.

Odds are you were making the exact same mistake my students make because the "exposure triangle" has taught them to be afraid of ISO. So what they'll typically do is resist raising the ISO and at the same time not expose enough thinking that's better than raising the ISO even more. If the circumstance requires it RAISE THE ISO so that if anything you seem to be exposing too much for that ISO -- doing the opposite is what clobbers you.

Joe

 

[Fujidave]

I have checked but deleted the shots, but what I remember was. Full Manual mode iso 800 shutter speed think was 1/100 and aperture was f7.1 I think. Lens was the XF 18-55mm.

 

[Fujidave]

First shot is of Abi, 1/100 ss, iso 640 f4.5 lens was XF18-55mm and it was evening time out side so dark.

2nd shot is Marilyn du Sax. f2 1/100 ss and iso 640 lens was XF 35mm. Camera used on both was the X-T2.

 

[Ysarex]

First shot is of Abi, 1/100 ss, iso 640 f4.5 lens was XF18-55mm and it was evening time out side so dark.

View attachment 161917


2nd shot is Marilyn du Sax. f2 1/100 ss and iso 640 lens was XF 35mm. Camera used on both was the X-T2.

View attachment 161918

So if these are JPEGs from the camera you have the potential to increase the quality and reduce the noise by 1. (best) increase the exposure (shutter/aperture) or 2. (not quite as good) increase the ISO and in either case process a raw file. The question remains by how much can you do either 1. or 2. and the answer is likely a stop or more but testing first is the best practice.

Joe

 

[Fujidave]

First shot is of Abi, 1/100 ss, iso 640 f4.5 lens was XF18-55mm and it was evening time out side so dark.

View attachment 161917


2nd shot is Marilyn du Sax. f2 1/100 ss and iso 640 lens was XF 35mm. Camera used on both was the X-T2.

View attachment 161918

So if these are JPEGs from the camera you have the potential to increase the quality and reduce the noise by 1. (best) increase the exposure (shutter/aperture) or 2. (not quite as good) increase the ISO and in either case process a raw file. The question remains by how much can you do either 1. or 2. and the answer is likely a stop or more but testing first is the best practice.

Joe

So I need to get as much practice as I possibly can then.

 

[Fujidave]

Hi Joe, if this is the book you were talking about. Would it help me if I bought it ?


https://www.amazon.co.uk/Manual-Pho...862&sr=1-1&keywords=The+Manual+of+Photography

 

[john.margetts]

I'm not going to engage with you on this because you are clearly crazy.

OK -- let's just leave it at everything you said is technically way wrong but you prefer a model of error and ignorance because it helps you understand stuff.

Joe

The thing is, Joe, it does help. It can ease a snap-shooter into being a more considered photography. The down side is that eventually the photographer comes up against a brick wall and can proceed no further as the incorrect but useful stuff is now incorrect and a hinderance.

Learning the technicalities is best and for those of us with a technical background that is rather easy. For people who left school with nothing, the technicalities might as well be written in ancient Sanskrit as they will understand nothing. Your students - by virtue of being students - have already demonstrated both a willingness and an ability to learn new stuff so teach them correctly. Those that are going to progress a bit and no further need something and if that something is a dead-end, it will not matter to them.

 

[Ysarex]

Hi Joe, if this is the book you were talking about. Would it help me if I bought it ?


https://www.amazon.co.uk/Manual-Pho...862&sr=1-1&keywords=The+Manual+of+Photography

Think of it as a technical reference when you want to look something up rather than an instructional read. So save some $$ and buy the previous edition: https://www.amazon.co.uk/Manual-Pho..._rd_t=40701&psc=1&refRID=P7R9WDN0ZPE9W8YMGRKD

Joe

 

[smoke665]

deliberately picked the socks scene because it had a low dynamic range (low contrast) and what I did was expose as much as the sensor would tolerate -- like a +2.3 EC. I

I haven't really dived into the way it works, but could this be how the "High ISO Noise Reduction" setting on my Pentax works? Doing it automatically?

 

[vin88]

WOW ! ISO guys, give it a rest.

 

[Ysarex]

I'm not going to engage with you on this because you are clearly crazy.

OK -- let's just leave it at everything you said is technically way wrong but you prefer a model of error and ignorance because it helps you understand stuff.

Joe

The thing is, Joe, it does help. It can ease a snap-shooter into being a more considered photography. The down side is that eventually the photographer comes up against a brick wall and can proceed no further as the incorrect but useful stuff is now incorrect and a hinderance.

Learning the technicalities is best and for those of us with a technical background that is rather easy. For people who left school with nothing, the technicalities might as well be written in ancient Sanskrit as they will understand nothing. Your students - by virtue of being students - have already demonstrated both a willingness and an ability to learn new stuff so teach them correctly. Those that are going to progress a bit and no further need something and if that something is a dead-end, it will not matter to them.

When you say "it does help" I'm not entirely sure what "it" is. Are you talking about the "exposure triangle" or the misconception that ISO alters sensor light sensitivity or the misconception that ISO alters exposure or the misconception that ISO causes noise or the misconception that digital ISO is the same as film ISO or all of the above? I understand that the "exposure triangle" can be helpful and I acknowledged that:

The Exposure Triangle can be initially helpful but it does lead to confusion.

In my class notes that I hand out to students I also acknowledge that: "It's a simple illustration that can admittedly help beginners get a grasp of the concepts that 1. correct exposure of film or a digital sensor is in fact a fixed constant -- the same total quantity of light is always required for a specific ISO value, and 2. the controls on the camera for shutter and aperture can be (must be) reciprocally adjusted for exposure while independently altering the rendition of motion and depth of field. Those are two important concepts to grasp and beginners seem to catch on with this illustration so why am I complaining." I acknowledge it again in the last paragraph of the same notes: "Unfortunately it's too late to fix it, this genie isn't going back in the bottle. And that does mean that a lot of people derive value from learning with this model misunderstanding or not. It's popular for a reason. They can learn to use their cameras pretty effectively even though maintaining misconceptions about how they function. This isn't the worst popular misconception about photography. But this is a college class so when you get this wrong on the test I'm still getting out the red pen."

So what we have in this thread is precisely what you note; an OP hitting a brick wall as the useful stuff just got revealed as incorrect and is now a hindrance. VidThreeNorth just encountered a technical article You probably don't know what ISO means – and that's a problem and is struggling to process that information. Do we tell him, "Don't look behind that curtain, just close the curtain and back away -- forget what you saw? If you lift the hood the hamsters will run away!" This is a thread where the OP specifically asked for some help understanding what's behind the curtain.

Joe

 

[Ysarex]

deliberately picked the socks scene because it had a low dynamic range (low contrast) and what I did was expose as much as the sensor would tolerate -- like a +2.3 EC. I

I haven't really dived into the way it works, but could this be how the "High ISO Noise Reduction" setting on my Pentax works? Doing it automatically?

No, High ISO Noise Reduction in your camera is a noise filter that's applied to the camera's JPEG output. In camera noise filters tend to generate weaker results than the noise filtering we can apply during processing. The problem the camera manufacturers face is the requirement to generate JPEG results very quickly. Your K3 has to be able to output JPEGs at a multiple frames per second rate and that typically dictates some corner cutting in the processing software. A computer hosted noise filter like DX0's Prime or DeNoise can be pretty processor intensive.

Noise filtering helps a lot and I use it all the time, but the real bottom line is exposure. The noise we all see in our photos that we don't like is shot noise and shot noise is a function of exposure. We raise the ISO on our cameras when we don't have enough light to either achieve a hand-holdable shutter speed or the f/stop we want for DOF. Without enough light we start to reduce exposure and that's the cause of the noise. Unfortunately a lot of photographers and especially beginners reduce exposure more than necessary and they complicate the problem by resisting raising the ISO. Contrary to popular misunderstanding, the electronics behind ISO typically suppress the noise caused by the exposure reduction. In the case of the example I posted, I took advantage of the fact that the camera's tend to hedge the tuning of their metering systems toward reduced exposure -- given a choice between possibly blowing highlights versus a stop less exposure they opt for what they see as the lesser evil and adjust their camera's meters to generate a good JPEG from a sensor exposure that is less than the sensor can tolerate. By pushing to the sensor's real limit I can increase exposure by more than double what the camera meter suggests and I get a lot less noise for it.

I'm enjoying my new P&S compact camera (Canon G7xii) which has a 1 inch sensor. I use it at ISO 12,800 if needed but I expose to keep the noise as low as possible. I posted this image a couple weeks ago: Gruesome Assault and if you look at the exif data you'll see I have a +1 EC set. The camera meter would have applied only 1/2 the exposure that I did. Yes it's noise filtered and I use good tools but the real bottom line is I applied twice as much exposure as the camera would have. That gave me a blown out JPEG and the requirement that I process the raw file -- that's how this game works.

Joe

 

[Fujidave]

WOW ! ISO guys, give it a rest.

For me and only me all this iso is big, I want to be able to up my iso and not worry at all when in the pubs and clubs shooting

 

[Grandpa Ron]

Nothing mysterious here, in the old days you controlled the shutter speed and aperture and loaded your camera with the film speed (ISO) you thought you would need. Maybe you could push it or pull it in the darkroom a bit.

With digital you still control the shutter speed, aperture and now you can also change the film speed between shots.

You still have the same issues however. the faster you push the ISO the "grainer", it called noise these days, the picture.

As always, good photography requires knowledge of all the effects of the camera's variables. With digital you have many more right at your fingertips.