CHKD, Canon Hack Development Kit

A non-destructive modification for Canon PowerShot cameras.  This adds functionality normally only found on higher spec cameras to the whole range, such as histograms, ROT grids, RAW files, scripting, c.f. CHDK wiki.

chromatic aberation

This is colour distortion caused when a lens focuses different colours in different planes, which leads to colour fringing.  Expensive lenses will attempt to eliminate it, cheaper lenses try to minimise it.  It is easy to correct in a simple lens with a slight increase in manufacturing cost.  It is more difficult in a multi-element lens, particularly if it adjusts the spacing of the elements when zoomed or has a macro facility.

Colour cast

This is where an image displays an unnatural tinge to the colours rendered in the image.   It is the effect you would get if you lit your subject with a coloured light instead of a white light.   Indeed, this is often the cause, but it can also occur for other reasons, notably the fading of dyes in old photographs, particularly if exposed to sunlight (containing a high UV component).   When the colour cast is uniform it can often be corrected in an image editor by increasing the amount of the complementary colour.   When the effect is only on a portion of the image it can be more problematical to correct, although a selection may help.   One area where this can show up is deep shadows on a bright sunny day often have a blue cast.   This can be pleasing and add to the image or it can be distracting in which case some Photoshop work might be needed.   The wikipedia article does not add much to this but it may get expanded later, so I have included the link.

Colour Space

This is a complicated technical subject beyond what most photographers understand, let alone beginners.   For an introduction to the subject, if you are interested, you could refer to the wikipedia article, but this only scratches the surface.   The subject is important when it comes to calibration.   What beginners do need to know is that equipment does need calibration.   What you see on your laptop screen may not be the same as is projected at the club or as is printed by your printer unless they are using the correct profiles.

Compact camera

See also Bridge Camera and DSLR.   As its name implies the essence of a compact camera is its small size and low weight, easily slipped in to the handbag or shirt pocket, so always ready to hand. Nowadays you can get remarkable quality from a compact and they can be very good at Macro photography.   Some top of the range compacts compete with Bridge cameras.

contrast

Contrast is how we perceive a scene or an image of it.   Some parts are darker then others and it is this contrast between the highlights and the shadows that allows our brain to interpret what we see as a scene in 3 dimensions. If everything lacked contrast it would be a uniform grey and look flat (like some skies).   The range from the darkest to the lightest part of a scene is the contrast ratio or dynamic range.   Cameras can only handle a limited dynamic range so we have to bring the dynamic range of a scene within a range that the camera can handle by controlling our exposure settings.   As usual what starts out as a simple concept soon gets complicated as you can see here.