Chopping a 3 Megapixel chunk out of an 8 Megapixel photo

I am looking at a buying a new camera that has more pixels but a shorter
zoom. The original camera, Olympyus 730, can do 2048 x 1536 at 380 mm

The new camera, Konica Minilta A200, can do 3264 x 2488 at 200 mm. If I
chop a 2088 x 1536 chunk out of this, what would be the equivent xxx mm?

--
Alan

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No Smaller area yes but not the same compression of perspective. It the
same as using the digital zoom fills the frame as a longer lens would but
has the perspective still of the 200m focal length. But dont forget the
Minolta tele converter ACT 100 If you need it.

Though it might suit the effect you want . At least you have enough pixels
left for a good print after you have cropped a Lot of space out of the
image. But the good point is the 28mm wide angle, that you cant cheat.

 

312mm

Not quite as long. The actual effect will be comparable. 'Perspective'
is irrelevant at these distances as it is a factor of lens to film plane
distance/lens to subject distance(s), and these cameras are so tiny and
the lenses so long that they equal optical perspective without
photographic optics coming into it.

David

 

On Mon, 8 Aug 2005, David Kilpatrick wrote:

DK> > I am looking at a buying a new camera that has more pixels but a shorter
DK> > zoom. The original camera, Olympyus 730, can do 2048 x 1536 at 380 mm
DK> >
DK> > The new camera, Konica Minilta A200, can do 3264 x 2488 at 200 mm. If I
DK> > chop a 2088 x 1536 chunk out of this, what would be the equivent xxx mm?
DK>
DK> 312mm
DK>
DK> Not quite as long. The actual effect will be comparable.

The reason behind this thought is depth of field at the shorter end.
Whilst not losing the telephoto at 3 Megapixel, the camera has a larger
ccd. This means that the lens will be physically larger so that the
perfect depth of field from in front of my nose to infinity, inherent with
the small lenses, mught be reducted a tad.

--
Alan

( If replying by mail, please note that all "sardines" are canned.
There is also a password autoresponder but, unless this a very
old message, a "tuna" will swim right through. )

 

There are some other quite complex factors at work with the A200/A2
lens. It is, in effect, a longer zoom with a negative converter group at
the very rear linking it to the CCD. This enables the lens to have a
reasonable range of 'real' apertures down to f9.5 at 7.2mm focal length
without using waterhouse stops - it has a true variable aperture, but
it's not positioned traditionally.

As a result, the actual pictures from the '28-200mm' zoom have rather
less depth of field than might be possible - you can get pretty good
differential focus effects even at 7.2mm.

The same goes for a few similar digital camera designs. They would look
very odd indeed if scaled up to 35mm size (the A200 lens would, if made
to cover 35mm, have a 192mm front filter thread!)

David