Digital Question

[Severn Wolf]

Don`t quite know how to ask this because I don`t really know what i`m asking!

 

Had a call from my father last night. He`s after a new camera and has decided to come into the modern age so is looking for a digital. Now, the guy has years and years of experience in photography and can be a bit meticulous when it comes to specs etc of new gear. Just because I own a digital he thought I would know the answer to his question but I was totally blank.

 

Here goes, I really hope this makes sense to someone.

 

On the spec sheet of a Canaon camera there is a `sensor size` line. Now, we`re aware that the sensor is, well the sensor but next to this title are numbers which one would assume are the sizes:

 

1/2.5 inch (5.3Mp).

 

What actually does the 1/2.5 measure? Why would a larger one be of benefit?

 

What is the size measuring?

 

HELP

[Steve Randles]

I missed this one..sorry 'bout that.

 

As I understand it the sensor size relates to the resolution of the picture, the size.

 

A bigger sensor than you have posted will give a bigger picture size, therefore contain more pixels and would be a bigger file size, so it might be a 6,8 or more megapixel camera.

 

This is the real simplistic explanation, you can google for the real heavy stuff as its beyond my knowledge to explain or fully understand but it goes into lens size used with the camera, and the angle the sensor allows the camera to take the picture at, and then some!

 

Steve

[Severn Wolf]

Cheers Steve!

 

Makes absolutely no sense to me but I`ll pass it on!

 

Thanks

[poledark]

Good link here..

 

http://www.photo.net/equipment/digital/basics/

 

 

Den

[Steve Burke]

See also http://www.dpreview.com/learn/?/Glossary/C...or_Sizes_01.htm

 

In the final analysis sensor size is just one of the many factors in determining image quality. This is why I always look at test reports before buying rather than just technical specifications.

 

Steve Randles has got together a load of links in the "Link Vault". The one on test reports and price comparison sites is at http://www.anglersnet.co.uk/forums/index.php?showtopic=58897

[Guest franticfisherman2]

Excellent info in those links chaps. I can add another practical example - from my video camera. The chip size is rated at one sixth of an inch and contains 800,000 pixels. The effective diagonal size of the chip is actually only 2.7 mm! This is obviously very small compared to most still cameras but you don't notice the shortcomings in a moving image since it is showing 25 frames per second. If you capture and display a still image at this resolution you see a lot of jagged edges!

 

The one-sixth inch chip has become very popular in consumer camcorders because they use less power and need smaller lenses so overall camcorders have become very small and light - pocket sized in fact. The downside is that the focal length of the lens is only about one-tenth of an inch so everything is in sharp focus nearly all of the time and you don't get a sharply focussed subject with a nice out-of-focus background.

In addition you get a huge depth of field which sounds good until you start noticing dust and crud on the lens on top of your lovely video footage!

[Steve Burke]

The downside is that the focal length of the lens is only about one-tenth of an inch so everything is in sharp focus nearly all of the time and you don't get a sharply focussed subject with a nice out-of-focus background.

 

Obviously it's not so bad as in a video camera but the sensor on my Canon S2 IS is a 1/2.5. The result at a zoo park was that I couldn't get the bars of a big cat enclosure completely out of focus and thus invisible even at full aperture. This was easy to do with my 35mm camera.

 

Of course the upside is that images even at maximum 12x zoom (equivalent to a focal length of 432mm) still have a nice amount of depth of field. It's also a lot smaller and lighter than an SLR, plus the image stabilisation means that I seldom need to cart a tripod around!

[Severn Wolf]

Sorry to bump this back up but I have to say a big thanks to all who answered. The information and links were great and just what was needed