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Old Jan 15, 2005, 10:45 AM   #1
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Sorry if it's a silly question:

If I take a zoom shot with the 4 mp, 10x optical Olympus C-765, how would it compare to the 7 mp, 4x optical Sony DSC-V3 equivalent photo, if I were to use software to blow the Sonyimage up on my PC?

Thanks
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Old Jan 15, 2005, 10:59 AM   #2
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Because resolution is computed by multiplying width x height (like area), if you crop a photo to make it look like you used twice as much optical zoom, it takes 4 times the resolution to maintain the same amount of detail in pixels per inch. In other words, you end up with 1/4 the pixels captured by the camera representing your subject.

You can interpolate it to enlarge it again (like using digital zoom), but this only adds pixels based on the values of adjacent pixels, and does not increase the detail captured by the camera.

Basically, there's no substitute for Optical Zoom, if you really need to bring a subject in closer. For example, even a 2 Megapixel Camera with a 200mm lens, can capture just as much detail (real pixels representing your subject)as an 8 Megapixel Camera with a 100mm lens.


Here is a table of popular "long zoom" models that compares their resolving ability:

http://www.geocities.com/digital_ray_of_light/zoomzoomv6.html

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Old Jan 15, 2005, 11:43 AM   #3
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P.S. -- a lot depends on what you want to do with the images, too. For example, if you're not going to be printing a larger sizes, then the amount of pixels per inch in detail representing your subject not be very important. The type of subject also impacts how well an image enlarges later.

Also, you may not take that many photos at longer focal lengths (I take most of my photos at the wide angle end of the lens). I'd suggest comparing other features, too (you may find some things are much better on the V3 -- autofocus speed/reliability, cycle times between photos, etc., versusa longer zoom model).

So, don't look at optical zoom alone when comparing cameras.


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Old Jan 15, 2005, 12:13 PM   #4
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Thanks for the advice.

The problem is I like the idea of a big zoom, but don't know how often I'd actually use it.

Plus having seen the V3 in the shop, I'vre kind of got my heart set on it, but now need to convince myself I don't neefd the zoom and that I can part with all that cash.

Cheers.
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Old Jan 15, 2005, 3:25 PM   #5
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u_luv_it wrote:
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Plus having seen the V3 in the shop, I'vre kind of got my heart set on it, but now need to convince myself I don't neefd the zoom and that I can part with all that cash.
How often do you think you will use zoom? Try to estimate the percentage of time you spend in different type of pics (eg. family pics (wide angle), sporting events (telephoto), landscapes (wide angle), "normal" pics such as a tree or house (wide angle), etc). If you think you will spend more than 25% of the time for telephoto pics then I think you should go for a zoom. But if it is, say, only 10%, then I would probably lean towards a low zoom camera. Don't forget that you can get telephoto lens for low-zoom cameras (although they are not as good); conversely, you can buy an ultra-zoom camera and use a wide-angle lens add-on (although it won't be as good). BUT do keep in mind that buying extra add-on converters and stuff costs quite a bit and may not be worth it (is it worth spending $100 on an add-on lens when the camera costs $450? I don't think so)...

Since you are looking at one of the top low-zoom cameras (the other I like is the Canon G6), I think you should also look at the top end ultra-zoom such as Panasonic FZ20. FZ20 vs V3 (or Canon G6) is a better comparison in terms of features/quality/etc IMO...
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Old Jan 15, 2005, 8:17 PM   #6
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Way back when the old Sony Mavica FD91 had a 14x optical zoom but less than 1Mp resolution, there was always the question about whether a large zoom could deliver a better shot than a smaller zoom on a higher resolution camera.

The answer was that the optical zoom always wins. If you crop the higher resolution image to cover the same scene area as the large zoom camera provided, there would be more pixels in the image from the camera with the larger optical zoom.

But that was ONLY at the maximum zoom, as youzoomed out...the camera with higher resolution eventually wins out.

At msximum zoom, the C-765 can cover an area with 4x as many pixels as the V3 can when the V3 image is cropped. But ONLY at maximum zoom.
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