Max ISO on 1Ds for printing to A4

I shoot at anything from ISO 100 to 400 with the 1Ds with hardly a thought as to image quality. 400 is so close to 100 that it's only on really learge prints that one can see the difference, and even then it's like the difference between Provia 100F and Kodak ISO 100 transparenciy film — small but visible.

I make 11X17" (A3) exhibition and sale prints from ISO 400 frames done with the 1Ds all the time.

Michael

[Ralph Eisenberg]

Sorry to raise this topic again, with so many variables in the equation (OS platform - in this case Mac 10.2.5 - hence determining for the moment RAW conversion options, etc), and I ask your forebearance. When printing to A4 (= 8.26 x 11.7 inches), and under natural, low-light conditions, hand-held, how high does your experience indicate one can go in regard to ISO settings to get a very pleasing print at this size? (I know, it's also in the eye of the beholder). It would seem that some who had proclaimed noise-free images up to ISO 400, which prompted concerns about sensor quality variability, have apparently indirectly retracted. Subjects are landscapes and people. Thanks in advance for your feedback.

[Ralph Eisenberg]

Thanks very much for your helpful reply, which I very much appreciate.