[OT] Digital camara

[John Summerfield]

Konstantin Svist wrote:
> Martin Marques wrote:
>> Hi all, sorry for the OT, but as many people here have more knowledge 
>> then me on this topic I'll just ask.
>>
>> I'm about to by a digital camara and I was looking at a Panasonic 
>> Lumix with 5MP and 6x optical zoom.
>>
>> I tend to see the 6x zoom more interesting then having 7 or more MP, 
>> but I'd like to know if I should go for more MP or stay with the good 
>> zoom.
>>
>> Once againg, sorry for the OT.
>>
> There's a 10x zoom point-and-click camera that was recently released 
> (Kodak, I think). It uses 2 lenses to accomplish the high zoom ratio.

Canon's had a 10x for a while, my cousin Elaine has one. I found it hard 
to hold at the extremity, I tend to shake too much.

> 
> As for optical zoom vs. number of megapixels: optical zoom is definitely 
> better.

There is no relationship between zoom of any kind and megapixels, except 
more megapixels and better optical zoom both add to cost.

The more pixels does translate to better printed images, and my local 
camera vendor assured me 3.2 Mp is good to about A4. Which probably 
translates to marginal to the trained eye.

More pixels also translates to more scope for cropping later; a digital 
(3.2 Mp) image that prints well at 6x4 from a full frame will probably 
not give you a good picture of that tiny flower in the corner.


> Although it's not really a comparison because number of megapixels 
> doesn't correspond... but if you think in terms of digital zoom vs 
> optical zoom: digital zoom is just a crop of the image (followed by 
> algorithmic stretching - which can really be done after downloading the 
> image into your computer). Ignoring the cropped area, a 2x optical zoom 
> is very approximately similar to a jump from 6MP to 25MP (or 11MP from 
> 3MP, etc.)

The use of zoom affects what's in the focussed image inside the 
camera.It does not affect the size of that image. That's true of both 
film and digital, and the larger focussed image afforded by medium and 
large-format cameras goes to explain why the yield bigger, better pictures.

> The real comparison comes from the printed copy - as others mentioned 
> already, 4"x5" will look great at as little as 3MP.

Someone on the radio here recently said that 15 Mp is about where film 
sits (though I suspect that depends on the film; when I was shooting 
file regularly (and I mostly didn't use colour), I went for slower, 
preferably professional film).


-- 

Cheers
John

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