Sometimes camera has a few specks of dust on the sensor from a production line. It's also possible that the dust is on the mirror or in the chamber and later migrates on the sensor. Zoom lens can also pump dust in the chamber. I suspect mine also had some dust but haven't check at that time. After few 1000 shots I just used a blower, a cosmetic brush and a Lenspen loupe. Then I've used SensorKlear pen with a loupe to remove a couple of stubborn dust spots. Not a big deal. Now I use a blower and brush once in a while when I'm in the mood. Dust on sensor is somehow normal for DSLR cameras and sooner or later you'll have to buy some sort of cleaning kit. First just give it a few blows with a blower to remove as much dust you can.
I will try the blower. Never had good luck with it cleaning by d7000 though. But who knows.
I just found that feature on LR5 that makes it easier to spot the dust. I don't think it's worth me wet cleaning it for the one or two spots. Never done it before. But when I get a few more I will learn how to.
>I'm curious if it's abnormal to have dust on the sensor on a >week old d7100? I changed the lens a few times but in a >relatively clean area. I noticed about 3 last night when >editing some sunset shots. > >My main question is, is it worth cleaning it at this time or >just use spot removal tool in Lightroom? > >Thanks.
...each to his own but, unless there is a lot, the spot-removal tool is pretty fast and painless; the LR feature makes it even easier to find dust. I've never tried to do this, but if you are processing a lot of photos, I wonder if you could make this an Action and batch process?
Back before I lost interest in photography a few years ago I remember reading in LR 3 that it could be a batch process. At the very least you can select all and sync. I really only noticed it it sky shots.
I had the same issue with my new D7100. In my case I just did the -- exposure function next to Bulb setting. The first press of the shutter button lifted the mirror, and the second press opened the shutter exposing the CMOS sensor. I then used compressed air to gently blow off the sensor. This not only cleaned the sensor, but removed any residual manufacturing particles from the sensor, shutter and mirror box. Third press of the shutter then closes the shutter and lowers the mirror.