Cleaning oil spots… off a D7000

As I was out taking some of the pictures I shared yesterday, I wound up with a few shots that highlighted the one part of D7000 ownership that’s been pretty negative – recurring dust/oil spots on the sensor. I’ve already sent my camera back to Nikon twice to have them removed under warranty (losing my use of the camera on both occasions, though I did have the D3 as a “backup” during one repair).  I don’t even have that option now that I’ve moved to the U.S., since I’d have to send it for service in Canada which would be quite a pain with customs and shipping.  I mostly just ignored the problem, until hitting conditions yesterday that greatly exacerbate it – narrow apertures.  Here’s a few pictures that I kept just to highlight the issue.  First, at f/4.5, this looks like a pretty normal picture:

When stopping down to f/8.0, though, something became a lot more visible:

See all the little dots along the right, especially towards the bottom? That’s caused by the oil spots on the sensor.  They’re in the same place in every frame, regardless of what I’m shooting.  Their appearance does change with aperture and even by lens, but they are really annoying.  At f/11, they get even more “well formed”:

Those tiny little branches, just one drop of water wide, are the same ones in that shot from yesterday, in which more than an inch of snow somehow stacked nicely on these narrow branches!

Although the branch looks bigger in successive shots, that’s just because I’m getting closer to the branch; focusing is changing, but the lens isn’t (105mm f/2.8 micro). As I got closer, I needed more depth of field and that’s why I was stopping down, revealing the extent of the issue. Once I realized this, it was trivial to check for dust spots – indoors where it’s not super-bright, at ISO 100 (or 200), use a wide aperture (f/11 or higher), and take a shot of something like a wall while moving your camera around. The shutter speed will be low enough to make everything out of focus. Except the oil spots!

Since Nikon service was no longer a real option, I looked for information on whether I could clean this up myself.  A few interesting discoveries along the way:

1. This is a fairly widespread issue with the D7000, even though Nikon hasn’t acknowledged it.  It seems to be oil, not dust, because air blowers rarely remove the spots (they didn’t for me), and the spots always appear on the right side of the frame whereas dust would be a little more random.
2. There’s a menu option on the D7000 to lock up your mirror and shutter for cleaning.  Sometimes, it seems like it doesn’t work because the option is grayed out. On a past attempt, I set the camera to manual, exposure to bulb, and held down the shutter button while blowing air inside!  It turns out that you need to be at 75% battery or higher, or that function will get disabled.  So charge up, it’s much better than trying to hold down the shutter release!
3. Touching the surface of the sensor seems super-scary, but while you won’t want to be scratching at it with a knife, it’s surface isn’t made of an unstable jelly either, and there is a layer over the sensor.  The risk of making the sensor dirtier seemed to be greater than the risk of scratching it from what I read.

There are various wet cleaning solutions that were recommended by various forum-goers as being effective – but to my great benefit, one of the recommended cleaning tools that worked for many turned out to be something I already had, by pure chance:

Pictured above is a Visible Dust Arctic Butterfly 724 that my friend Herman and I got when buying a big batch of camera equipment about 8 months ago. The front of the brush goes in a plastic cover, which then goes into a styrofoam + plastic case, which then goes into a leather-like case. There’s a button to make the front of the brush spin around. When it was explained to us (as an option we could buy), the seller said it used some kind of electrostatic mechanism to rid the fibers of the brush from any dust. Though the seller was a really honest guy, I was thinking of this as an enormously unnecessary tool for cleaning lenses when microfiber cloths and a $10 blower work just fine. I mean, the thing came in more cases than you’d expect for Dolce & Gabanna sunglasses. We said no to buying this particular item – but the seller just threw it in anyways at the end. It sat on a shelf (and in a box) since then, and wasn’t used once, till Googling for sensor cleaning revealed that this tool was not in fact an overpriced cloth, it was specifically design to clean sensors!

Sadly, it was only after successfully cleaning the sensor and putting things away that I found a piece of paper in the case that said “do not spin brush while cleaning the sensor”. I thought that was the point, but actually, you’re supposed to spin it outside the camera to get all the dust off, then use the brush to clean the sensor. Fortunately, my D7000 sensor is now clean, and I won’t fret too much if I see oil spots cropping up again.

Finally, the above is what worked for me, but it is not professional advice on how to clean your sensor and I’m not advising you to do what I did. In other words, I don’t want you to try and hold me responsible if you try this and it doesn’t work for you.

And no, that dot in the top right of this last picture is not an oil spot on my sensor, it’s a spot on my carpet which will require something other than an Visible Dust Arctic Butterfly 724 to remove!