On Jun 14, 2018, Ken Hart wrote
(in article ):

On 06/14/2018 03:29 PM, Savageduck wrote:

Snip

Any given sensor will have a base sensitivety, or ISO. Typically ISO 200, or
ISO 100 depending on manufacturer.

Really? I've never looked into that, but I would have thought that the
base sensitivity would be closer to the mid-point of the camera's ISO
setting range. But that's just electronics design practice.

Yup!

Take the Nikon D800 which has a base of ISO 100, and the D810 which has been
reduced to ISO 64. Any increase in ISO is an increase of signal gain from the
sensor. Both of those cameras are capable of dealing with very high ISO
settings without producing noticeable noise.

In the APS-C world the D500 has a base of ISO 100, and can be cranked up to
ISO 51,200, and extended to an unthinkable ISO 1,640,000.

My APS-C Fujifilm X-T2 on the other hand can shoot from a base ISO 200 to ISO
12800, and can be extended down to ISO 160, 125, & 100, or up to ISO 25,600,
and ISO 51,200.

These are worth a read:

https://www.bhphotovideo.com/explora...aphy/tips-and-
solutions/understanding-exposure-part-4-iso

https://www.jmpeltier.com/2018/02/13/what-is-extended-iso-native-iso/

This one is a real simplification:

https://photographylife.com/what-is-iso-in-photography
--

Regards,
Savageduck