Strange dirt problem

Archived from groups: rec.photo.digital (More info?)

I have a D70, about 2 weeks old.

At very high f-stops, there are 5 or 6 dirt specks on the images, which
become blurred at lower f-stops. (specks are always in the same place)
Replacing the lens made no difference, but there is no obvious dirt on
the sensor, and taking a shot with no lens gives no dirt. Also, if the
dirt were on the sensor, it would look the same no matter what the
f-stop, right?

So it's not the body, and it's not the lens...

Any ideas???

Archived from groups: rec.photo.digital (More info?)

google.20.jbloggs@xoxy.net wrote:
> I have a D70, about 2 weeks old.
>
> At very high f-stops, there are 5 or 6 dirt specks on the images, which
> become blurred at lower f-stops. (specks are always in the same place)
> Replacing the lens made no difference, but there is no obvious dirt on
> the sensor, and taking a shot with no lens gives no dirt. Also, if the
> dirt were on the sensor, it would look the same no matter what the
> f-stop, right?
>
> So it's not the body, and it's not the lens...
>
> Any ideas???

It happens. The dirt is actually on the sensor - or just above it, on
the filter. There are several ways to clean it, some scarier than
others. I have had good success by holding the camera face-down, doing
the mirror lock-up through the menu, and then giving it a few puffs with
a Giotto Rocket air bulb. A little puff or two of gentle air will
usually get the larger dust strands off the sensor.

You'll see them a lot more clearly at high f-stops than low f-stops
because the angle of the incoming light is less. It's the same reason
you can blur distance at low f-stops.

To make sure you've got it clean, put a lens on, set it to the smallest
aperture, point it at a white wall, and take a photo (flash will do).
Then look at the resulting all-white shot.