Is it a bird? a plane? a blob? a digital dust spot?
Ever noticed strange looking dark blobs (spots that are usually small) in only some of your photos? They don’t show up in every image – only when the camera is optimized to reveal them (for me this is usually when using a higher aperture and close to a hyper-focal distance focus setting.) The image below shows some ‘real’ spots on a image from a camera that needs a sensor cleaning – if you notice similar spots in many or most of your images then a dirty sensor may be the problem.
'Spots' on a digital camera sensor.
Older digital SLR cameras are more susceptible to this problem – according to manufacturer’s descriptions of their newer model cameras with self-cleaning sensors.
Eventually, you will need this information: the process of changing lenses on DSLRs provides ample opportunities for dust to contaminate your ‘low-pass filter’ and/or image sensor. After months of shooting I noticed a ‘consistent dark spot’ on my images – sure enough a quick check revealed a ‘blob’ on the low-pass filter – cleaning was required. A few weeks later I noticed that I seemed to be experiencing some lens ‘vignetting’ – another review for ‘dust spots’ revealed a concentration of dust-like pixels in the corners of my images – another cleaning was in order.
Your camera manual should provide some information on ’sensor’ or ‘filter’ cleaning – the link below is for the brave folks who like to handle this themselves – otherwise you should see your camera dealer or seek an authorized repair facility for your camera. While it is possible to ‘clean images’ in editing software I think everyone happier if the images don’t need such tweaking. If you only have small ‘dust spots’ then your photo editing software may have simple tools to assist you in removing such spots, i.e. the ‘healing brush’ in Adobe Lightroom or Adobe Photoshop.
How do you prevent such digital image spots?
- Only change your lenses in a ‘clean’ environment (in-doors, away from dust, sand, dirt, wind, etc.)
- Clean your camera lens mounts prior to changing them.
- Clean your camera lenses.
- Have your digital camera professionally cleaned by an authorized service center.
- Do your own cleaning with one of the kits available for this purpose (visit the link below or search for ‘digital sensor cleaner’ or similar terms.)
How do you fix or clean dust spots in an image?
- Use digital photo editing software to remove or replace the spots, i.e. use the healing brush tool found in Adobe Products like Adobe Photoshop CS4, Adobe Photoshop Lightroom 2, Bibble Labs or other tools. In many cases it as simple as red-eye-removal: a) select the tool, b) set your brush/tool size to be slightly larger than the spot and c) click on the spot to remove it.
- Use your camera options that provide a somewhat automated image cleaning process, i.e. some Nikon camera models and software provide a multi-step process where you create a ’spot mask’ image which you use as a filter with the Nikon software and the end result is that the spots are removed.
Cleaning Digital Camera Sensors – this is a link to an external site devoted to this topic. The site appears to offer a comprehensive review of solutions and approaches for cleaning your digital camera sensor.
