What is "Base ISO"? Yesterday I watched a video tutorial by a professional photographer who explaining that his Canon 7D was set up with ISO 640 for the current shoot. He went on to...

Jolly Roger Loc: Dorset. UK

Yesterday I watched a video tutorial by a professional photographer who explaining that his Canon 7D was set up with ISO 640 for the current shoot.
He went on to explain the 7D has a "Base ISO of 160" so reducing the ISO down to 100 will not improve the image quality. Also he increases his ISO in multiples of 160, hence his setting of 640.
Could anyone explain this "Base ISO" to me. Thanks

Bob Andrews Loc: Scotland

Canon believes - as other camera manufacturers believe - that you camera has the "best" quality at base iso. Personally I think he is wrong. Btw someone calling their selves professional doesn't automatically mean is a good photographer. Further reading.

http://www.rawdigger.com/howtouse

Searcher Loc: Kent, England

Jolly Roger wrote:

Yesterday I watched a video tutorial by a professional photographer who explaining that his Canon 7D was set up with ISO 640 for the current shoot.
He went on to explain the 7D has a "Base ISO of 160" so reducing the ISO down to 100 will not improve the image quality. Also he increases his ISO in multiples of 160, hence his setting of 640.
Could anyone explain this "Base ISO" to me. Thanks

The lowest ISO setting to attain the highest image quality (low noise) see http://photographylife.com/what-is-iso-in-photography

Jolly Roger Loc: Dorset. UK

Bob Andrews wrote:

Canon believes - as other camera manufacturers believe - that you camera has the "best" quality at base iso. Personally I think he is wrong. Btw someone calling their selves professional doesn't automatically mean is a good photographer. Further reading.

http://www.rawdigger.com/howtouse

Hi Bob. I will watch the link provided when I have a little more spare time. Thanks for the input.

Jolly Roger Loc: Dorset. UK

Searcher wrote:

The lowest ISO setting to attain the highest image quality (low noise) see http://photographylife.com/what-is-iso-in-photography

Hi Searcher. I have just read the article you posted, thanks.
So I can see that different camera's may have different base ISO's. The guy said that the Canon 7D is 160.
If 160 is the optimum for this camera I cannot follow the logic to increase the ISO in multiples of this, unless I am missing something???

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

Jolly Roger wrote:

Yesterday I watched a video tutorial by a professional photographer who explaining that his Canon 7D was set up with ISO 640 for the current shoot.
He went on to explain the 7D has a "Base ISO of 160" so reducing the ISO down to 100 will not improve the image quality. Also he increases his ISO in multiples of 160, hence his setting of 640.
Could anyone explain this "Base ISO" to me. Thanks

As I understand it ( could be wrong of course) there are 2 other settings that might effect IQ. Shutter speed and F-stop. Does a base ISO cover all settings regardless of the situation. For example- I seriously doubt that the change from base ISO from 160 to 200 other things being equal that any one could tell thaat there is a change in IQ Maybe with a 100 power microscope and and a wall size mural ther would be a difference. But I don't have a microscope in my bag.

Db7423 Loc: Pittsburgh, PA

Jolly Roger wrote:

Hi Searcher. I have just read the article you posted, thanks.
So I can see that different camera's may have different base ISO's. The guy said that the Canon 7D is 160.
If 160 is the optimum for this camera I cannot follow the logic to increase the ISO in multiples of this, unless I am missing something???

I'm not familiar with your camera but the base (optimum) ISO for Canon is generally considered to be 200 and for Nikon 100. If the base for your camera IS 160 you would want to keep it there when practical and increasing it in whatever multiple you choose when the available light requires it. There is no need or reason for increasing it in any specific multiple. ;)

Nic42 Loc: Cardiff, Wales

Jolly Roger wrote:

Hi Searcher. I have just read the article you posted, thanks.
So I can see that different camera's may have different base ISO's. The guy said that the Canon 7D is 160.
If 160 is the optimum for this camera I cannot follow the logic to increase the ISO in multiples of this, unless I am missing something???

ISO is a third part of the exposure triangle. Your aim is to keep it as low as possible to reduce 'noise' in your image. However, if you want to keep a specific aperture and your shutter speed is too slow to (for example) hand hold, then you will have to increase the ISO.

ISO, shutter speed and aperture are all inter-dependant.

Searcher Loc: Kent, England

My own understanding of this (subject to correction) is that there is an optimum setting of ISO to achieve the lowest amount of noise, and this is not necessarily the lowest ISO setting on the camera.

I have never felt the need to test this because if I get my exposures right, and if there is enough light to not need to increase ISO, I rarely have noise issues provide I keep ISO to 100 - 200. My DSLRS are both fairly old models and noise is significant at ISO's over 400. At ISO 1600 and over I call every image "Something in a Snowstorm"

From what I have read on the Hog, modern cameras have much less of a problem, and that would be the only reason for me to even think about upgrading from my beloved D200.

So knowing that a modern DSLR has a greater flexibility for shooting High ISO/low noise, does the "Optimum ISO setting" have a role to play?

Jolly Roger Loc: Dorset. UK

Db7423 wrote:

I'm not familiar with your camera but the base (optimum) ISO for Canon is generally considered to be 200 and for Nikon 100. If the base for your camera IS 160 you would want to keep it there when practical and increasing it in whatever multiple you choose when the available light requires it. There is no need or reason for increasing it in any specific multiple. ;)

This is the way that I see it. If you can achieve what you want at ISO 500 I don't see why I would wind it up to 640.

Jolly Roger Loc: Dorset. UK

Nic42 wrote:

ISO is a third part of the exposure triangle.
ISO, shutter speed and aperture are all inter-dependant.

Thanks. I'm aware of the above. My original post was about "Base ISO". Which Searcher has addressed.

amehta Loc: Boston

Jolly Roger wrote:

Yesterday I watched a video tutorial by a professional photographer who explaining that his Canon 7D was set up with ISO 640 for the current shoot.
He went on to explain the 7D has a "Base ISO of 160" so reducing the ISO down to 100 will not improve the image quality. Also he increases his ISO in multiples of 160, hence his setting of 640.
Could anyone explain this "Base ISO" to me. Thanks

If it is publicly available, could you please give a link to the tutorial?

G Brown Loc: Sunny Bognor Regis West Sussex UK

Lets go back a bit - if you double ISO you increase light sensitivity an equal amount.
100, 200,400,800 etc is the 'standard' and usually with most cameras cannot be altered beyond these set increments
if for your camera 160 is optimum to would make equal sense to double that
160 320,640,1280 etc if your camera allows 'odd' numerical increments. that way the triangle remains equal throughout the fstop and speed range

cheaper cameras have set wb expensive have kelvin numbers if you have got it use it.

seems a bit like expose to the right rule that some people swear by.

Jolly Roger Loc: Dorset. UK

amehta wrote:

If it is publicly available, could you please give a link to the tutorial?

www.youtube.com/watch?v=vq0oumkzkGw‎

Jolly Roger Loc: Dorset. UK

G Brown wrote:

Lets go back a bit - if you double ISO you increas... (show quote)

If 160 is the optimum for the 7D what would be the point of it having 125 and 100?
Surely you select the minimum ISO to achieve the desired result, thus keeping noise to a minimum. I still don't follow the logic to doubling up the "Base ISO" as being optimum.