Iso 100


Senior Member
I have read many threads about ISO settings. Most recommend using ISO 200 and if you want to use some of the D90's auto ISO features, have it adjust the ISO based on a minimum shutter speed and then set a maximum ISO setting. All this makes sense as the low ISO minimizes noise on the photo. Now the question. Since the D90 will shoot at ISO 100, is there a reason not to use 100 other than the obvious need for a higher setting due to lighting? It would seem based on the premise that lower ISO's mean a sharper image, in bright daylight an ISO setting of 100 would be better.


Senior Member
[FONT=Arial, Helvetica, sans-serif]This is one of the strongest reasons I prefer my Nikons to my Canons, which lack this critical feature.[/FONT]
[FONT=Arial, Helvetica, sans-serif]ISO Auto Increases sensitivity (ISO) in dim light automatically to prevent blur from slow shutter speeds.[/FONT]
[FONT=Arial, Helvetica, sans-serif]I use this all of the time, unless I'm using manual exposure mode. Auto ISO is a crucial component of Modern Exposure Technique.[/FONT]
[FONT=Arial, Helvetica, sans-serif]Today I adjust the Auto ISO's minimum shutter speed as I change lenses and conditions. I no longer adjust ISO directly, as we did in the old days before 2004. This is a time-saving step towards the future, just as program exposure was a step ahead of aperture priority in the 1970s.[/FONT]
[FONT=Arial, Helvetica, sans-serif]You can choose the highest ISO to which the Auto ISO will go (Max sensitivity). I let my D80 go all the way to to ISO 1,600, since it looks fine at ISO 1,600 and any small amount of grain is better than a blurry photo. If you prefer blur to grain, feel free to limit the D80 to ISO 800 or 400. Try ISO 1,600: the D80 is better at high ISOs than film ever was, and far better than any compact digital camera at these speeds.[/FONT]
[FONT=Arial, Helvetica, sans-serif]You also may set the minimum shutter speed (Min Shutter Speed) below which the D80 starts raising the ISO. Select the slowest shutter speed at which you'll get sharp images under your present shooting conditions.[/FONT]
[FONT=Arial, Helvetica, sans-serif]I wish this function was smart enough to recognize which lens I'm using and adjust accordingly, but it's not.[/FONT]​


Senior Member
Taken directly from Ken Rockwell, not my worrds. But I thought you would find it interesting. I use this Auto setting all the time. I like to think the results are great. Check my gallery, if you like.

Ruidoso Bill

Senior Member
I pretty much keep mine at 400 which seems to work best with my lenses giving me the most flexibility with DOF etc. Picture quality is completely acceptable to me. I do crank it up more for some lower light situations. I also thought I would have to keep the iso low like 100 or 200 to get quality shots but I no longer ascribe to that.


New member
Shoot at the base when possible. With my shots, I've never detected a difference between, say, a 1/1000 sec exposure at ISO 200 and a 1/500 sec exposure at ISO 100 (with all other variables remaining constant), but then I've never actively put such images side by side. I've read that one loses dynamic range by pulling ISO to one of the "lo" settings.

As for work, I do basically what Curt said: Auto ISO with a set minimum shutter speed and maximum ISO, and those depend on what's going on. If it's a band, for instance, I might need 1/400 or even 1/500 to stop the action, setting the aperture as I please and trusting the auto ISO to work its magic.