Which ISO has lowest noise on Canon 1Ds?

[robertprice]

With any digital camera, cool temperatures and low ISO setting produce the least noise.  The inverse, higher air temperatures and higher ISO settings produce more noise.  On a cool day, you can shoot a higher ISO setting and still minimize noise, etc..

doc

[robertprice]

Henry,

I've not found that to be true for the type of shooting I do.  However, I'm too old to consider my experience the only valid experience (grin).  It is pretty well determined that high ISO and high ambient temperatures exaggerate noise, and I have proven that to my satisfaction with the 1Ds.    

I shoot primarily wildlife and landscapes, and have not shot any ISO 50.  However, I'll give it a try and get back with you.

doc

[Paul Caldwell]

50 on the 1ds is a tad cleaner that 100, but you do lose considerable dynamic range.  You will see this in shadows more than highlights, at least with my camera.

Most times I use 100, but like the previous poster, sometimes will go to 50 in place of a ND filter.  

No sure why anyone would be getting more noise in the lower ISO's on a 1ds, or any camera for that matter as the lower the ISO, the less noise, thats a general rule.

Paul Caldwell

[Jonathan Wienke]

Using ISO 50 reduces dynamic range. Noise may be lower than ISO 100, but I haven't really noticed much difference--100 is pretty low-noise to begin with. I use 50 mainly when I want a slower shutter speed than I can get with 100 and the loss of dynamic range is not an issue.

[hdomke]

I hear conflicting answers to the question of which ISO has the lowest noise on the Canon 1Ds.
With conventional film lower ISO usually results in less noise (grain).
What ISO will give me the least noise?

Does the Dnyamic Range of the image vary with the ISO? If so, which is the optimal ISO for the greatest Dynamic Range?

Thanks!
Henry

[hdomke]

Robert,
I have had several people tell me that the Noise level of the Canon 1Ds is higher at ISO 50 than at ISO 100. Apparently that is why Canon has hidden ISO 50 in a custom function.

Any ideas about that?

Thanks,
Henry

[sergio]

I haven't seen any difference between ISO 50 and 100 except that it is one stop slower. I use it as a substitute for a ND filter. Anyway @ ISO 100 the EOS1Ds has NO noise or whatever. Probably it can't be better.

[BJL]

I am trying to understand the special "use at your own risk" status of ISO 50 on the 1Ds, and my only guesses so far are
(a) ISO 50 is below the natural ISO of the sensor, meaning that even a full photosite is producing digital output at less than the highest level. Hence the dynamic range loss etc.
( the (on-chip) analogue amplifier is optimized for the higher gain levels used at more often used higher ISO's, and at its extreme low gain setting it works noticably less than optimally; more nonlinearity, worse S/N in later analogue stages due to the lower signal levels, or whatever.

There seem to be some old time audiophiles in this group who might be able to comment on analogue semi-conductor IC amplifier issues!