Better noise control

Duckys54

I remember hearing an analogy of how to get high ISO without noise; please correct me if I'm wrong in believing this:

On digital cameras, to expose for all the ranges of ISO the bucekts that capture the light need to be big enough to fil for ISO 100. Now, because of this when you get up to ISO 1600 the buckets don't fill up completely and you get noise. To solve this, if someone needs to shoot higher ISO with better noise control, a camera's "buckets" size should be made for higher ISOs such as 800 or 1600.

What do you guys think?

ziggy53

The "bucket analogy" is not very useful in describing the technological difficulties of designing more sensitive photographic imaging capture devices.

Trust me, the manufacturers are going to extraordinary measures to insure that today's cameras are as resistant to random noise effects as is possible.

The camera that my previous employer purchased in 1995 was a crop 1.3x size and produced 6 MPix worth of image. It was limited to ISO 80. It recorded onto very expensive PCMCIA cards and hard-drives or by tether into a computer. It also cost a very real $16,000 in 1995 dollars.

Pretty much any current dSLR from any manufacturer will beat that camera by any measure, and any current camera will cost a lot less as well.

Just thank your lucky stars that you live in this age of digital photographic plenty.

Tee Why

Duckys54 wrote:

I remember hearing an analogy of how to get high ISO without noise; please correct me if I'm wrong in believing this:

On digital cameras, to expose for all the ranges of ISO the bucekts that capture the light need to be big enough to fil for ISO 100. Now, because of this when you get up to ISO 1600 the buckets don't fill up completely and you get noise. To solve this, if someone needs to shoot higher ISO with better noise control, a camera's "buckets" size should be made for higher ISOs such as 800 or 1600.

What do you guys think?

I've heard the bucket analogy when describing the rationale for exposing to the right but not in terms of ISO. I'm not sure the analogy is that clear for me. It sounds like you are saying for higher ISO, the buckets should be bigger, which does go with traditional thinking, given all else being equal.

Duckys54

Tee Why wrote:

I've heard the bucket analogy when describing the rationale for exposing to the right but not in terms of ISO. I'm not sure the analogy is that clear for me. It sounds like you are saying for higher ISO, the buckets should be bigger, which does go with traditional thinking, given all else being equal.

I'm saying that currently you have big buckets for ISO 100 and the buckets don't get filled completely for ISO 1600 which creates noise (?). So, to solve this you make a camera with buckets designed for ISO 800 and up only to get better noise control.

ziggy53

Duckys54 wrote:

I'm saying that currently you have big buckets for ISO 100 and the buckets don't get filled completely for ISO 1600 which creates noise (?). So, to solve this you make a camera with buckets designed for ISO 800 and up only to get better noise control.

Fuji does do something similar to what you describe to add more dynamic range. The Fuji Super CCD SR Pro sensor used in the FinePix S5 Pro has a dynamic range of around 12 EV. Unfortunately having different sized photo-sites does not help resolution and complicates image processing, so you trade one problem for another.

The Nikon D3 (and D700) has a combination of modern imager design and relatively low pixel density with large micro-lenses and it does indeed produce spectacular high-ISO, low-noise results.

Then again the Canon 5D MKII has a higher pixel density than the Nikon D3 and still produces relatively low-noise at high-ISO.

It would be interesting to see what could be done with a modern 6 MPix sensor in full-frame configuration with suitably large micro-lenses and modern image processing, but it would be awfully hard to market and I think it would ultimately fail as a product.

jonh68

It would be interesting to see what could be done with a modern 6 MPix sensor in full-frame configuration with suitably large micro-lenses and modern image processing, but it would be awfully hard to market and I think it would ultimately fail as a product.

I would love to have a camera like that. Like you said, it would be hard to market. It's sad, though, when most people only need 6mp. Lower noise would help image quality over more resolution.

Art Scott

jonh68 wrote:

I would love to have a camera like that. Like you said, it would be hard to market. It's sad, though, when most people only need 6mp. Lower noise would help image quality over more resolution.

Even with 6mp and the fine uprezing software like GF5 you can get really huuuge photos to print..........I had been using a trial version of GF4 and recently upgraded from GF3 to 5 and love it....1 step uprezing and it works like a dream......now if I had a 6mp cam with the low noise capabilities of the D700 and D3 I would be in heaven.......

LiquidAir

Sensors are like arrays of buckets, more or less. Photons hitting the sensor get converted to electrons which are stored on the photosite until the sensor is read. So part of a photosite could be described as an electron bucket. However, the signal to noise level is not determined by the size of the bucket. Rather the S/N level for a pixel is determined by the total number of electrons in the bucket. Making the bucket larger doesn't help unless you have more to fill it with. What bigger buckets (along with a higher precision A/D) do give you is higher dynamic range and the recent transition from 12-bit to 14-bit A/Ds probably does reflect the fact that new sensors have somewhat larger buckets than the ones of a few years ago.

The two primary strategies for reducing noise (simplifying things greatly here) are to increase the efficiency of light gathering and to lower the electronic noise in the amplifiers and A/D. Advances in these areas have been quite dramatic over the last few years with the latest crop of sensors having as much as 3 stops lower noise than the prior generation.

ziggy53

LiquidAir wrote:

... The two primary strategies for reducing noise (simplifying things greatly here) are to increase the efficiency of light gathering and to lower the electronic noise in the amplifiers and A/D. Advances in these areas have been quite dramatic over the last few years with the latest crop of sensors having as much as 3 stops lower noise than the prior generation.

In addition to reducing noise at the chip level the latest cameras also have more sophisticated image processors to further reduce visible noise, similar to what can be done with dedicated noise reduction software.

It's all pretty amazing.