Tuesday, November 29, 2011

Digital Zoom vs Optical Zoom

Most point & shoot cameras came with digital zoom feature, you might even been impressed by the "extra pull" that the digital zoom on your P&S can do; what exactly is digital zoom?

Wikipedia explained...

"Digital zoom is a method of decreasing (narrowing) the apparent angle of view of a digital photographic or video image. Digital zoom is accomplished by cropping an image down to a centered area with the same aspect ratio as the original, and usually also interpolating the result back up to the pixel dimensions of the original. It is accomplished electronically, with no adjustment of the camera's optics, and no optical resolution is gained in the process."

Huh?  A bit too much for you?  ;)

What it meant was digital zoom is actually taking your picture with the optical zoom at it's longest focal length, then electronically enlarged the centered area, in camera; to give an impression that your zoom lens is much longer!
The digital zoom of my Canon G9 made it look like I was right behind the photographer, I was actually so far away that these tourists don't even know I snapped this shot :)

About photography dot com advised...

"If you are using a digital point and shoot camera you may have something called "digital zoom". In order to preserve maximum image quality you should avoid digital zoom whenever possible. If it is your only option, use it. If you have the option of optical zoom, use that instead."

Is the quality of digital zoom really that bad?

That candid shot outside the Colosseum look pretty decent for a A4 print, as a matter of fact; it still look pretty good when pushed to A3!

A 300% cut from the JPEG file that was shot in digital zoom mode
The Birds Return...

Not that kind of birds, duh!  I am talking about the gregarious Tuis that visit the huge NZ flax plant outside my dinner room window.

I did write about my obsession on this native NZ birds :)

I decided to try the digital zoom of the G12 on this active bird.

Active was the understatement, the way my Tui boobed about made it really tough to get a decent frame!  Here are three of the best ;)

They all look pretty decent images but can the quality withstand more blow-up?
This is a 300% cut of the first picture, not great but passable; I was surprise how well the G12 pixels hold up!  After being blow-up by the digital zoom, I expected worst!

To find out how much better an optical zoom can do, I took out my E-P2 and my old faithful; the 25 year old Nikkor 80-200 f4 zoom.  These are the best two. Both were shot at 200 mm, on the E-P2 M4/3 format; that was a 400 mm FOV!

I will blow-up the second picture and you can see for yourself how much better is optical zoom.
The quality of a top optics, 25 years old and still deliver top notch result!
How about a prime lens?  Can a 25 year old Summicron 90/2 perform in this situation? Here are the best three. Since the Summicron have a 180 mm FOV on the E-P2, the image of the bird is much smaller than those shot with the 80-200.

The image of the bird taken by the 90 mm might be small but take a look at the blow-up!
May be now you understand why a Leica prime lens cost an arm and a leg ;) And mine is 25+ year old!

Famous Last Words:

I discovered there are such a lot of paranoid advice on digital zoom!

One site advice...

"Do me a favor. If your digital camera offers a digital zoom option, go get your camera right now and turn this option off! Don't use it... ever"


My advice?

If you need it, use it! And only by using can you find out the good and bad (it is NOT all bad) of this pseudo zoom!

You Might Also Like
The Bird and The Lens
Tui Obsession!
f2 Short Teles On E-P2

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