So, as we spoke of last time, the only thing you really need to think about when looking at a new camera is the megapixel wars between manufacturers and different models?  Well, not really the other thing to think about is what sort of zoom does the camera have and what is better for you?

You’ll find most camera phones can also zoom, but they do this digitally not optically. Pocket cameras are often the same, many may have maybe a on average up to a 10 times optical zoom and then digitally zoom up to 20 times, but what does it really mean?

Optical zoom: this is where the lens moves back and forth externally, as you can see on some pocket cameras or internally as on many DSLR zoom lenses. This means is that the piece of glass at the back of the lens and the of glass at the front of the lens physically come closer together as its zooms out  (wider field of view) or further apart as a zoom in (concentrates on one part of the field of view) just like a telescope. This provides the actual image across the whole sensor of the camera.

Digital zoom: used in most mobile phone and the majority of pocket cameras, is a little bit different.  Sometimes it is also combined with a small optical zoom capability, the actual digital zooming part is not done by the lens at all. Digital zoom works by actually electronically enlarging a small portion of the captured image and expanding that to electronically fit the frame size and ignoring the rest of the image . This means that if you were to have your camera in the widest possible field of view such as goal posts with the posts on either side of the frame and you digitally zoom into a football in the middle all the information from football to those goal posts is then lost and your electronically enlarging the football alone.  This means is that the information other than the zoomed object is lost, the lesser football information is expanded to fit the frame, impacting the quality of that information in the image as it is a lot less than would be have if you optically zoomed and used the entire sensor and not just a small part of it.

Let’s try looking this way when you look at a printed image in a magazine nowadays you’re looking at the printer and the printing machine filling in the blanks and merging the colours to create a continuous change of colour as it flows across a page. In newspaper stop particularly the black-and-white photographs newspapers these to be made up of millions of little dots and when you looked at a distance all of his dots became a picture and the more dots there were the darker it was the less dots the lighter. This is the way it works well in the old film days with the silver oxide on the film emulsion creating light and dark and this was called grain but will talk about that later. Back to the point if you look at one of his old newspapers from a distance you consider picture of say a face if you were to get closer to the picture and put a magnifying glass to say the I see it turns into a mass of dots that sought to resemble the eye and all the other information in the picture is lost this is the same sort of thing that happens when use digital zoom you are focusing on a small part of the original image and ignoring the rest of information so digital zoom is simply expanding on a small part of the captured image. Optical zoom actually allows that small part to become the full image so there is no additional information to lose you’re looking at the raw information and the more information the better quality of the output.Putting all this together and when you start thinking about megapixels not being the same with the dependency on the size of the capturing cells on the sensor and then you think about optical versus digital zoon (if used in your camera) you can see all of this comes down to the quality of information being captured the better the quality the better the image and is not always the number of megapixels, although let’s be honest everyone wants more megapixels.

For most of us we will never really need the resolving power of a high-end professional flagship camera or a digital medium format camera, these are used by professional photographers for studio work paid advertising and so on the majority of us are happy with picture on our phones or standard photograph on an A4 size prints or maybe a A3 size poster and massive and many of us will never go near something like a six-foot white panorama but you never know.

The choice of the right camera from a megapixel perspective comes down to what are you going to use full and how are you going to use an image and this is again as mentioned before the trade-off in photography size versus use cost versus simplicity.

All right so now we have a basic understanding of megapixels and with thought about the sort of camera we might want and what we might want to use for. Of course there are more things that come into the decision in choosing a camera.  And this is just to give you a general when trying to make the decision. Hope this is given you some information and allows you a better understanding of things you need should maybe think about.

That’s enough for now, next time let’s look at the things that make up an image and then we can move on to taking the image and what to think about or consider when taking a photograph rather than just a snapshot but that’s for a later episode. Until then keep on shooting and I’ll talk to you later.