Notice anything weird about this picture (apart from the fact that it’s not in focus?)
Here, I’ll make it a bit easier to see…
Apparently I’ve gotten crud on the image sensor of my Nikon D50. This is an inherent problem with DSLRs, where changing lenses can allow particles to enter the chamber and collect on the sensor. With film cameras, this isn’t an issue. The "sensor" is the individual film frame, which then moves on as the film is advanced. However, with digital cameras, junk can build up.
The spots show up most often against the sky. With a wide aperture, they aren’t as noticeable. However, with smaller apertures, or at longer focal lengths, they can detract from the image. The best way to check for sensor spots is to set your DSLR at the smallest aperture, usually f/22, and point it at a light surface to take a reference image. Here’s what I got…
The latest models of Canon DSLRs have an automatic sensor cleaner. I haven’t seen anything like that in the works for Nikon. However, they do have a "dust reference" image mode. With this active, the raw images can automatically filter out the dust in post-processing. This uses an interpolation porcess similar to the bandage, or healing tool in Photoshop. If you have fine detail in your shot, it could create artifacts and anomolies. The best thing to do is to eliminate the dust, but it ain’t easy.
Nikon does not recommend cleaning the sensor. They suggest blowing the dust away with a squeeze bulb or something similar. Fortunately, Fort Pierce has an excellent photography store, and they were able to recommend a couple of products. I bought a device that uses compressed air to create a vacuum. This worked for some of the stubborn particles. I found that a cheap ear cleaner worked about as well to blow the rest of the particles away. I still have some specs on the sensor, but I’m just a bit worried about bringing anything into actual contact with it.
I think my photographic equipment was all conspiring against me. My Nikon S1 decided it was going to flake out, too. When I turned it on, it started randomly cycling through its various menu options. I’m not happy about this at all. I left it on recharge all night, just to see if a low battery might be the cause. I hope that’s all it is.