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Old Mar 12, 2003, 1:22 PM   #1
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Default Zoom ?

Can anyone tell me the difference between an optical zoom and a digital zoom. If there even is a difference.
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Old Mar 12, 2003, 1:33 PM   #2
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A world of difference. Optical is useful and uses the lens like a pair of binouculars to magnify the image with virtually no loss of quality.

All digital does is effectively crop the image removing the outer pixels. You end up with a lower res image.

You can do this better (usually) in post processing and especially with something like Genuine Fractals.

So forget digi zooms - worthless in my opinion
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Old Mar 12, 2003, 2:20 PM   #3
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Digital zoom is no substitute for optical zoom. Iíd never buy a camera with no optical zoom at all and the description above explains why.


steve6 - I have done some tests comparing my C-730ís interpolation (when taking pictures at 3200◊2400 and also when using digital zoom) with outputs from Photo Editors (when performing the same operations). I tested Photo Shop, PhotoImpact and Fireworks, and believe it or not, my C-730 did a significantly better job than any of them!

I think itís a bit harsh to say that digital zoom is worthless, I quite like having the convenience of digital zoom on my camera, it is quicker than doing it in post production and like I said above, it also seems to be slightly better quality. And with a 10◊ zoom as well you can reach to extraordinary depths. For example: http://photos.edjeavons.co.uk/albums/oly_zoom.htm. Obviously itís a feature you donít use on really special photos, but IMHO it has itís uses for many people.

Ed
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Old Mar 12, 2003, 3:07 PM   #4
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Quote:
I think itís a bit harsh to say that digital zoom is worthless
Don't forget folks, that digital zoom in post is often done on the compressed jpeg, whereas if it's done in the cam, it benefits from the RAW output and noise reduction, before the JPEG compression is applied.

However, I'm in general agreement with its inferiority over optical, and if I was a frequent zoom user, I'd go with optical. But for convenience and occasional touch of digital zoom to get compactness I'm happy with that. In both cases, zoom can be pretty useless without stabilisation, so for serious stuff a tripod is essential.

I wonder how the anti digital zoom users would feel about it in the future, with more pixels on the ccd and digital image stabilisation to work on a compact handheld cam, versus the BIG lens and tripod?
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Old Mar 12, 2003, 10:48 PM   #5
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I agree with Eddie J. A few days ago, I compared the 2, using my D40/C40, and a tripod, on a sunny day with bright light. Opened them in Photoshop side by side. had to set the optical zoom at 125% to look similar to the digital zoom at 100%. Guess what? The digital zoom shot was sharper. No jaggies, blotches or other noise artifacts. Color saturation was the same. I don't see why so many people put digital zoom down. I'm going to use it.
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Old Mar 13, 2003, 6:19 AM   #6
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I've tried digital and optical zoom on my CP4500. The digital zoom is now switched off for normal purposes, as I didn't like the quality.

However it can still be used for checking photos in the camera if you need to do some "in the field" editing, which as a Digiscoper I often do (despite a 128MB card).
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Old Mar 13, 2003, 7:03 AM   #7
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I've wondered about the usefulness of in field cam editing. E.g if simple cropping is on the saved JPEG it might not be lossless, and I could't understand it's benefit, unless it's to save on a bit of memory. Perhaps if you were on the road putting cards into Walmart it might have a use.
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Old Mar 13, 2003, 7:13 AM   #8
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My in the field editing is simply protecting the decent shots and deleting the rest (if I run out of memory - which I usually do).
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Old Mar 13, 2003, 12:41 PM   #9
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Quote:
steve6 - I have done some tests comparing my C-730’s interpolation (when taking pictures at 3200◊2400 and also when using digital zoom) with outputs from Photo Editors (when performing the same operations). I tested Photo Shop, PhotoImpact and Fireworks, and believe it or not, my C-730 did a significantly better job than any of them!
You have to compare to something like Genuine Fractals. The ones in photoshop etc (bi-cubic etc) are a waste of time in my opinion.

I compared an image taken at 640x480 after interpolation and not with a magnifying glass (printed)- wasn't worth the effort. However with GF it was superb. Trouble is I've run out of my 20 trials.

I reckon digi zooms result in MUSHY looking pictures.
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Old Mar 13, 2003, 1:58 PM   #10
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So what do you choose when your optical zoom is just not long enough (no pun intented) and you know you will crop the image anyway?
This may change your mind about the uselesness of digital zoom: my 5050 will shoot (at highest rez) a file one third the original size at full digital zoom. When i shoot sports in a remote location (mainly mountain bike and rodeo kayak events) i can shoot at full digizoom about 40% more shots than taking the whole photo with useless data in it. And we are still talking close to the resolution of a 2.1 mp.
And,no, a teleconverter is not the better alternative as it steps down the lens too much for shaded areas. And, also, no a flash (even a METZ hammer) will not reach a paddler at 30 feet.
Digizoom is not a good solution to everyday use, but far from useless.
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