Ringed Splotches on DSLR photographs

Question

I'm a new user so I don't have a lot of technical knowledge yet, would appreciate some help on this. I'm seeing these splotches and spots on the photos in my DSLR camera.

I'm stumped on the source of the big ugly splotch in the centre and its 2 siblings to the left. I've cleaned both ends of the lens; unfortunately, I only have the one lens so I can't swap it out to see if the splotches remain. Position of splotches is constant in all photos.

Thanks in advance for the assist! Camera is the Nikon D7200, lens is 18-105mm.

EDITED TO ADD: A couple of close-ups of the splotch. These are both of the central splotch from a couple of different photographs.

Answer 1

The ringed splotches are unlikely to be dust. I suspect water spots. Tim Campbell suggests oil. If you really want to know what they are, you should examine the sensor with a loupe. Regardless, you will likely need to clean the sensor with wet swabs.

I disagree with having someone at a camera shop clean the sensor for you because it's such a simple process. However, you might have to visit a shop to buy the swabs and solution.

1. Obtain a sensor cleaning kit. Consider one that uses a low-alcohol solution.
2. Read the instructions that came with the kit.

3. Read the instructions again.

4. Enable sensor cleaning mode to lock the mirror and open the shutter. Consider using a room that has had an air purifier running for several hours.

5. Use a dust blower to remove any free dust.
6. Read (again) and follow the instructions that came with the sensor cleaning kit.
7. If your kit has dry swabs, you may use distilled water in the final pass. This is usually unnecessary. Also, please refrain from serving large amounts of liquid to your camera.
8. Turn off sensor-cleaning mode.
9. Check for remaining dust with a plain, diffuse background and lens set to F22-32. It's normal to have a few small spots left, and it's a losing battle to attempt to remove every single spot, especially if all that's left is a single spot a corner. Most dust spots will not appear in photos taken with apertures larger than F8.

Answer 2

One thing everyone agrees on, which is important to understand so I'll say it again later:

If you aren't 100% comfortable cleaning your sensor, take it to a camera shop!

The sensor is the most expensive, and the most delicate component of a camera. Therefore, trying to clean it with a cheap kit yourself may cause irreparable damage to your sensor.

These are just tiny specks of dust, on (/on top of) your sensor. To prevent them, be very careful when you switch lenses:

1. Point your camera body downward when swapping lenses.
2. Always keep a dust cap on the camera body (without a lens, even when swapping straight to another one) and a back cap on the lenses you're not using. This is a really good habit to get into.
3. (Obviously) Try to avoid changing lenses anywhere with a lot of particulates (dust) in the air, or on surfaces.
4. Don't swap lenses unnecessarily, and try not to do so "in the field" (see #3).

I used to get these little buggers all the time. Now I can no longer afford glass, so it's not a problem (no extra lenses = no swapping).

You can also clean your sensor, but be aware that the more you do this the shorter your sensor's life will be and it must be done properly with the utmost care! Pixels die surprisingly fast with excessive cleaning, and sometimes (if you are in a dusty environment) you will attract new dust even as you remove the old dust.

Professional cleanings are advisable unless you know what you're doing (there plenty of tuts available online though, and it's not rocket surgery). Another way to deal with this is to use a "dust map" with software that will let you use it. This was more applicable to older cameras, and some newer ones actually do this "behind the scenes".

To check for dust after a cleaning You will need:

1. a consistent white (or very light gray 50%-) surface
2. a lens with a focal length of 50mm+

Then you will need to:

1. Set the lens focal length at 50mm or longer. You want the white surface to completely fill the frame.
2. Switch the camera to manual focusing (either a switch on the lens, on the camera, or in a menu).
3. Set focus to infinity (turn focusing ring counterclockwise until it reaches the farthest end of it's focal range).
4. Hold the camera about 8-12 inches from the surface.
5. Take a picture.

This should show you any dust/debris on your sensor (invert the image to increase visibility). It is also the method used to create a "dust delete" image if your camera supports them. Also, of course, you can remove these in post-processing with Photoshop.

Here's an article on sensor dust, and how to deal with it from Digital Photography School. ...and here's one from "dummies.com" (specifically about a Canon 60D, but most of the advice is universally applicable).