Information about the types of zoom on Digital Cameras
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More zoomy than a zoomy thing that zooms!
If you are just getting started in digital photography or upgrading your digital camera then you may have noticed that one of the main things almost all of them boast about is zoom. Zoom allows you to get closer to distant objects, which is a really great thing, but you do have to be careful.
There are three main types of zoom on digital cameras that they will talk about: optical, digital and total zoom.
Camera A: 3 x optical zoom and 10 x digital zoom = 30 x total zoom
Camera B: 5 x optical zoom and 5 x digital zoom = 25 x total zoom
Camera C: 10 x optical zoom and 2 x digital zoom = 20 x total zoom
Looking at the total zooms on those three cameras the first one sounds the best doesn’t it? Its not, its actually the worst!
Optical zoom is zoomed in using bits of curved glass, the same as when looking through binoculars, normally very good quality, but it can depend on the quality of the glass in the lens.
Digital zoom is zoomed in by resizing the picture in the camera using software.
The thing with digital photos is that they are made up of millions of dots called pixels and when you zoom in digitally it guesses the missing information! It does use educated guesses, so if two pixels next to each other are black and it needs to put one in the middle then it adds a black one and it should look great. The problem is that if they are not the same then it mixes the two colours together, so if a black square was next to a white one and it needed to add one in the middle it would add a grey one, so with a 10 times digital zoom it actually guesses at nine pixels in between the two it does know, but it stretches it both ways, its actually guessesing 106 pixels, based on just four!!!
I have edited the original of this photo down to this size to start as it shows the effect better.
This Pygmy Marmoset was taken by me with a 10 times optical zoom
If I had been using a 5 times optical zoom and 2 times digital zoom then this is how it would look up close. Not too bad.
10 times digital and no optical would be like this up close!
The 10 times digital zoom would only actually photograph this:
Then try to guess all the missing pixels.
Digital zoom does have its uses, if you only want to use the pictures as small ones on the net and are going to shrink them down then they will probably be fine. Photos printed out small that have small amounts of digital zoom would also probably be fine, but if you want high quality photos then digital zoom really is worth avoiding at all costs!
Lets have a look at that list again:
Camera A: 3 x optical zoom and 10 x digital zoom = 30 x total zoom
Camera B: 5 x optical zoom and 5 x digital zoom = 25 x total zoom
Camera C: 10 x optical zoom and 2 x digital zoom = 20 x total zoom
Now ignore the digital zoom and the total zoom (as that’s worked out using the digital times the optical), the best camera is actually the one that originally looked worst!
Why do they advertise like that?
Digital zoom is a LOT cheaper to make than optical zoom, so looking at that list, the cheapest to make would be Camera A, but it sounds the best and a lot of people would buy it. A lot of big companies do this and some of them do have slightly better quality digital zoom. It’s the cheap virtually unknown companies you have to watch as they often plaster the size of the digital zoom all over the box or advert to make it sound like a great camera, when its not!
Do I really need a zoom anyway?
A lot of people do not think they will ever need zoom, but believe me, its something that you will use most of the time and one of the most important things to think about when buying a new camera. Virtually anything you can photograph looks better with a bit of zoom.
Alternatives to zoom on the camera.
Digital zoom can easily be replicated using an art package such as Paint Shop Pro, just crop the image down to a smaller size. If its to be used on a web site or somewhere else that does not need to be high resolution then you can often get the effect of 5 or even 10 times zoom without loosing quality! If you go to print them then you will get the same problem as the examples above, so be warned! A old friend of mine did some great work messing around with her photos and they looked great on the screen, but she had cut them down so much that they could not be printed more than 2 inches (about 5cm) square without looking dreadful!
Please note: When I refer to looking at the photos up close, I mean viewing them with the zoom on the computer set to 100%, that’s the best way of seeing exactly what happens when using digital zoom. If you view your photos on the computer zoomed right out then the effect will not look as bad, but its just hiding it from you! All of the zooms, apart from the 10 times optical zoom were simulated using Paint Shop Pro.
Copyright
This guide was 100% created by Dean Thorpe of Aspex Design, so please feel free to link to it if you think it is useful, but PLEASE do not copy it and use it on your own site, it took a lot of work to create. If you want to print it out for educational reasons then that is fine, just don't claim you created it or make profit out of it. Sorry to sound negative, but I have had a few bad experiences with people selling my creations on eBay!