if you really do need the larger apertures then the only good option is ND filters.

You're not gaining anything with ISO100. It shouldn't even be an option in camera imo. You can find posts on luminous landscape/dx0 about the ISO curves.

Brilliant photos, Gail! Thanks for sharing those sites and I hope you'll stick around on the forum. I'd love to see some of your work on the picture-a-day threads.

http://gailmontgomeryphotography.blogspot.com/ is a link to my photoblog, http://www.gailmontgomery.com is my website. Everything on the website was done with the D40X. I've only had the D90 since Christmas, so only the past couple posts on the blog were done with the D90. I was looking for the narrow depth of field with the wide aperture, but I do need to try turning the lights down first! I have been working with ISO 200, but figured I'd ask the experts about the low ISO settings. I'm glad I asked! I definately feel a little more educated, but know I need to keep practicing and experimenting. Now to get a willing model...

THANKS AGAIN!!!

lo 1 is ISO 100 and I use it all of the time. I have observed that kit, consumer, and crappy lenses lower the quality of the Iso on the D90 I shoot with.

Welcome to the forum Gail. Do you have any sample photos we could take a look at?

heartyfisher said:
on the D90 100 ISO is exactly like shooting at 200 ISO but exposing for 100 ISO and then adjusting the brightness. therefore you loose a bit of detail in the highlights compared to shooting at 200 ISO. For studio work just use 200ISO.

That is absolutely correct, and why insist on ISO 100? You could lower your aperture and shoot all the way down to 1/4000 ... or you could turn down the lighting in studio, use reflected and softened lighting ...

Gail, that's exactly what I use (well, sometimes three AB 400s). Don't be scared—you can just turn them down. I'm often living around 1/8 or 1/4 on my key light. ISO 200 is where you want to be, I think.
edit: Here's a shot taken at around 1/4 on the softbox and another AB400 above and behind his head at around 1/16.
edit: fixed broken link. Not sure what happened there.

Thanks everyone! I just want ISO 100 so I can lower my aperture - not that iso 100 is that much of a difference. I feel like I'm still learning my studio light set up and havn't ventured turning the lights down more (2 AB 400s). I'm really waiting for the new Pocketwizards to come out for Nikon so I can hypersynch them! Ugh - Photography is one expensive habit! Thanks again everyone!

on the D90 100 ISO is exactly like shooting at 200 ISO but exposing for 100 ISO and then adjusting the brightness. therefore you loose a bit of detail in the highlights compared to shooting at 200 ISO. For studio work just use 200ISO.

At ISO 200 my D90 is completely silent too. (no noise)

ISO100 is basically an EV adjustment anyway. It won't net you any less noise.

Gentoo said:
Jonny, you meant the D40X ;)

The D90 has virtually no noise at 200

right, you.

Jonny, you meant the D40X ;)

The D90 has virtually no noise at 200

Welcome, Gail. There are no stupid questions. I'm not sure exactly what the lo settings do, but I think it has to do with losing a little dynamic range, so it's not the best for holding detail in high contrast scenes. For studio stuff, it's probably fine to use, but I have to say I've done lots of studio shots at ISO 200 with no problems. I'll bet there's a lot less noise at 200 on the D90 than the D40 has at 100.

As PB said those are basically firmware tweaks. Generally (but perhaps not always), the cameras with higher ISO and/or better ISO performance start at a higher native setting. Many P&S's start at 64 or lower but many of these don't go past 1000 and often suck above 400! Those cameras less sensitive to light can and by necessity start lower. Some say this is good, others say it's not so good. The following posts will likely prove that.

The native ISO range on the D90 is ISO200-3200, with hi and lo being in camera adjustments, rather than actual ISO.

OK, so I made the jump from a D40X to a D90. I have been incredibly happy with my upgrade, but wanted to ask some Nikon experts a ? about ISO.

On the D40X, my lowest ISO was 100. Since I mainly do studio portraiture, that is perfect for me.

On the D90, the lowest ISO is 200, but then there is "lo" options. Are they even useable? Why are they termed "lo"? I'm still learning the ins and outs of my new gear, so please forgive this lurker if this question is lame. I just hear talk about useable high ISOs and was wondering about the low end too. Thoughts? Opinions? Educate me oh wise Nikon brothers and sisters!