David Hughes124436
Veteran Member
I would say that the quality of the lens is most important of all. Everything else depends on it. As for megapixels, I'd say that 5 mp is more than enough for most people who are, lets face facts, mostly viewing on screen or else printing to A5 (about 8¼" by about 6") and sometimes, but not too often, printing to A4 size (about 8¼" by about 11¾"). For everyday use a good 3 or 4 mp camera will approach the quality of the 5 mps ones. Just look at the picture I mentioned earlierto see what I mean - it's from a 2 mp camera. The link is in the second of my two adjacent posts.
Pay attention at the back - there may be questions on this later... ;-)
We'll start with WB; your brain and eyes are very good at post production processing and so most scenes that you see appear to you to be "shot" in identical lighting. But really you brain is adjusting what you see and standardising it. So you usually always see white and white. Mechanical things will see the yellowish-red light from (say) a normal light bulb as yellowish-red and white things will appear yellowish-red and other colours will be distorted too. WB adjusts the colours and shifts the balance slightly to make white look white and so on. Most people and camera are set to "Auto-WB" and do it automatically. In some cameras you can over ride the auto-settings and set the colour temperature (as it is called) to whatever you like - though it is best to set it to whatever your colour temperature meter tells you... Also, on some cameras you can wave a bit of white paper (Kleenex tissues are a good example) in front of the lens and capture that as the standard white, but only for that shot and under that lighting. (E-10 and E-20 owners use Pringle lids for this but this is a very specialised art - almost witchcraft... )
Compression: a 5 megapixel picture, for example, will generate a file of about 14 MB size and this can be compressed by various processes to a much smaller file but, this is the important bit, it does it by getting rid of the subtleties; the more it removes the more the file is compressed. The most popular compression device is the JPEG* file (or jpg) but there are many others.
When you view the file it is uncompressed but will not be as subtle nor as detailed. If you edit the file and then save it, it will be compressed again and more will be lost. So a lot of people are happy to save their pictures as TIFF's, which are about full sized ('though some can be compressed). Other save the pictures as the RAW data from the CCD but this needs a "plug-in" (usually) to get it into a managable version for your viewer and editor. (Asking about RAW usually generates a huge post on this forum - why not do a search on it and TIFF and JPEG?)
In some cameras you have a wide choice: these are usually serious (means expensive here) cameras and you might have a choice of saving pictures are RAW data, TIFF's and a variety of JPEG's depending on the compression rate you use. (I use 1:2·7 and have no complaints but I seldom go beyond A3 size: experiment if unsure.)
Aside: jpeg's and others also/sometimes give you a little thumbnail and then the EXIF data and then the picture. These can (and do) get lost in some editors. Use the brilliant freeware "EXIF Image Viewer" to see it, BTW.
Some cameras give you no choice and so you get compression ratios of 1:18 or so - it all depends. High compression can limit the print size and the editing that is possible. So it pays to get the picture right before squeezing the shutter release. OK?
It is also why you should save the original picture and copy to CD-R later and another copy for viewing and editing.
Regards, David
- Joint Photographic Expert Group