jerrypoller Loc: Huntington, NY

I watched a Steve Perry video yesterday about shooting in manual mode with Auto ISO turned on. I liked the idea of being able to quickly adjust aperture and shutter speed with the dials without having to worry about also figuring the ISO. I've been taking digital snap shots of my family for about 10 years now, and progressed from a D80, to a D90, to my current D7100. For most of the past 10 years I shot in Auto mode or Program mode, letting the camera make all/most of the decisions. When I got the D7100 a month ago, I decided to start making some of the "shooting triangle" (ISO/A/S) decisions myself. So, I set up my Auto ISO with 100 for the lowest setting and 6400 the highest (the full range of my camera). Yesterday I shot a family gathering indoors with only window and indoor light. I used my Nikkor 35-80 F2.8 lens with the aperture set at 2.8 and the shutter speed at between 90-125th sec. I assumed the camera would select the perfect ISO to accommodate these two settings and the ambient light in the room (I was shooting during the day in a room with a large picture window). What I found was that under the different light conditions in the large living room, I was getting some underexposed shots- even when the ISO had not "automatically" maxed out. I had to lower the shutter speed below 90 to allow enough light onto the sensor to make the exposure satisfactory. I'd like to understand why the camera didn't push the ISO up more - I was using center only and center weighted metering to allow for the varying light in the room. As I said in the beginning, I'm still pretty new at this, and the theory of getting all three elements to work together correctly is still a work in progress.

Apaflo Loc: Anchorage, Alaska

If you post a specific picture and ask about why it is what it is (and be sure to click on the "(store original)" button to include Exif data) we can probably give you some good help.

Absent that, who can tell what happened or why? There are many possible causes, we'd bore you to death with discussions of each and every way that can be...

That said, realize that your light meter is just a dumb machine. It does what you tell it to, and it can't read your mind. It tells you how much light is reflected from the scene. That is not necessarily a good indication of the right exposure. Point your camera at a black dog in a snow bank, as an example, and you get an underexposed dog. Point it at the full moon on a dark night and you'll get an over exposed moon. That is why there is an "Exposure Compensation" adjustment.

AutoISO with Manual Exposure mode works very nicely. There are tricks... Always set ISO manually to the lowest ISO. Always set the upper limit to ISO one step farther than you ever want it to go. Then set the image review display to show image data, and be sure to watch the ISO that is being used. If it is automatically set to the lowest ISO, check to make sure you aren't over exposing. If is gets set to that highest ISO, you know you want to adjust either the aperture or the shutter speed for more exposure.

MtnMan Loc: ID

Use matrix metering.

I don't think spot metering on the D7100 is"center only". On Nikons it follows the chosen focus spot (in contrast to some other camera types). So if you put the spot on a brighter than average spot it will underexpose.

While I normally use spot focus I usually use matrix metering.

There is another recent thread on using Manual exposure with auto ISO. I have tried it and find it to be OK in some instances. I don't think I'll use it much though.

I usually use A mode. My D800 has a setting for "Easy ISO". You might check if the D7100 has it...I don't recall it on my D7000 but that doesn't mean it wasn't there. It enables the thumbwheel for ISO in P, A, and S mode. The front wheel does the other thing. So you can get anything you want without pushing a button. I prefer that most of the time.

But if I feel a need to use M mode I do think using auto ISO is a good way to make use of the camera you paid for as compared to putting your thumb and brain into the loop to match up a needle.

Ched49 Loc: Pittsburgh, Pa.

Yes, post a picture. The D7100 is a good low light shooter.