Spot The Difference

Professionals please pass further down the car. Amateurs and enthusiasts and first-time point and shooters please take note.

When you bring your camera in for cleaning, there can be several levels of cleaning needed - you might be able to recognise which ones you need by looking into the viewfinder and at the images on your computer screen.

1. If you have black spots and hairs and insect legs showing up when you look through the viewfinder they are most likely to be on the focusing screen inside the head of he camera. If they do not show up on " live view " at the back screen you can be sure they are up in the head. Here's hoping they are not too far into the pentaprism or porroprism as this needs dismantling to get to.

2. If you see vague grey-ish balloons on your images as they come up in the computer - and they are always at the same spot in each image - these are dust motes on your sensor. Needs professional cleaning here at the workshop. If the spots are not just grey balloons but have a definite shape they might be actual dirt fragments on the sensor. If they look like KFC spoons or rifle bullets you are well overdue for a clean.

3. If the rest of the camera looks like a pig's opinion, you need to consider having it cleaned before they open up to clean the inside. This means lenses as well as the outer body. If they get to the point up in the workshop where they are hosing out the card slot with a Kärcher you might consider giving the motocross a miss for the rest of the season.

Not to make too coarse a point of it, if you carry your gear in a filthy old camera bag that is leftover from the 70's, you can expect to do a lot of cleaning. Invest in a new one, and look for one that can be kept clean itself. The KATA range are lovely bright yellow inside and this shows up any dirt that falls in. They are spongeable so you can keep ahead of the game.