[rollsman4]

I am trying to use ISO 100 but when I select the ISO button I can only get 200. How can I get 100? Thanks

[Rondec]

Do you have highlight correction on? I don't own a 645D, but that is the the setting that usually puts your base iso up to 200.

[Alex645]

I am trying to use ISO 100 but when I select the ISO button I can only get 200. How can I get 100? Thanks

Straight out of page 46 of the owner's manual:

"You can expand the sensitivity setting to ISO 100 to 1600 with [3. Expand Sensitivity.] in the [C1] menu.

http://www.ricoh-imaging.co.jp/english/support/man-pdf/645d.pdf

[Adam]

I am trying to use ISO 100 but when I select the ISO button I can only get 200. How can I get 100? Thanks

Enable expanded ISO in the menu as described above, and make sure highlight correction is disabled.

Adam
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[rollsman4]

Thank you for your help. Dennis

[rolfo]

Is ISO 100 on this camera better than 200, or better asked what is the base iso? On Canon cameras if you expand iso-settings things get worse 50Iso on a 5D is much worse than 100.

[672]

100 is expanded iso, mushier compressed highlights being the compromise.......

[hausen]

As far as I remember, the photographic dynamic range is basically the same as iso 200. However, you can notice the difference in their highlight restoration. 645D seems to have less headroom for highlight. This happens in particular if you use iso 100. You can notice the less smooth transition of the brightness in a cloud if you use it in the daytime. But that's not a big issue in general. I recommend exposure bracketing so you can pick the best exposure (without using HDR).

[rolfo]

thanks all