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Old Jul 9, 2004, 7:32 PM   #1
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This question is for adding a telephoto multiplier to large zoom camera's. Either 3 or 4MP cams with 10 or 12X zoom or 8 meg camera with 7 or 8X zoom.

Do they cause a loss of clarity?

Is it just better to use a small % of digital zoom ?

Why don't these 8Mp cameras have bigger zooms ?

Is it because you can crop the raw image to gain zoom and still have a decent picture ?

My guess to the last question:

They want to sell the 8 MP camera with 12X optical zoom next year.
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Old Jul 10, 2004, 2:26 AM   #2
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A large zoom camera with a (good) teleconverter lens will be better than using digital zoom.

Here's an example of the Olympus C-750 comparing maximum zoom (380mm) and with the Raynox DCR-2020Pro 2.2x teleconverter (giving 836mm):

http://www.raynox.co.jp/comparison/d...tm#dcr-2020pro

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Old Jul 11, 2004, 3:47 AM   #3
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I agree with Mike. However lots of MP's can justify a good digital zoom to a certain levels and for "ordinary" use, the loss of quality isn't visible. But as Mike said - optical zoom is what you need. (look out for bad quality teleconverters!).
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Old Jul 11, 2004, 9:12 AM   #4
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to restate my question

if i buy a 8 MP camera with 7x optical and use 2x digital i get 14x. Assuming no cropping is need you really only need 3MP to produce a good 8 x 10. So you resize the image to 8 x 10 and print. (i assume a 8MP camera produces an intial image size larger than 8 x 10)

so do the extra MP's (8-3) in this casehelp the loss of resolution with digital zoom ?(maybe the zoom has better interpolation)

OR

you shoot with 7X optical, no digital zoom and create the extra zoom by cropping later, then do the extra MP's help the resolution of the final product ? (assuming your cropped picture still has 3MP left to produce a good 8 x 10)

Thanks
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Old Jul 14, 2004, 5:15 PM   #5
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obrien040362 wrote:
Quote:
to restate my question

if i buy a 8 MP camera with 7x optical and use 2x digital i get 14x. Assuming no cropping is need you really only need 3MP to produce a good 8 x 10. So you resize the image to 8 x 10 and print. (i assume a 8MP camera produces an intial image size larger than 8 x 10)

so do the extra MP's (8-3) in this casehelp the loss of resolution with digital zoom ?(maybe the zoom has better interpolation)

OR

you shoot with 7X optical, no digital zoom and create the extra zoom by cropping later, then do the extra MP's help the resolution of the final product ? (assuming your cropped picture still has 3MP left to produce a good 8 x 10)

Thanks
1) In general it will be better to do the interpolation after shooting without using the digital zoom. The reason is that you can use a bunch of different algorithms and pick the one that matches the picture you are shooting best. The camera is only going to use one algorithm on-the-fly on a processor that is not as fast/powerful as your home PC.

2) The resolution of the print you make will depend on the input resolution (from your camera) and the output resolution (of the printer). 3MP makes a good 8x10 but a better 8x10 can be made with 6MP. The way to figure it out is to divide the resolution by the print size to get the ppi (pixels per inch). In general 150ppi is the minimum acceptable number and 300ppi is considered photographic quality. Somewhere around 360ppi the printers are hitting the end of their capabilities.

Numbers between those will produce better and better pictures. This applies to 8x10 only when pictures get bigger you look at them from longer distances (usually) so the acceptable number goes down. The strange thing is a poster sized 2MP image may be more acceptable to our eyes than an 8x10 of the same image.

3) The bigger the focal plane the more glass (diameter)you need to make a lens out of. The more glass (in diameter) the harder it is to control the surface (look at all the PF discussions) so after a certain size you need to reduce the range or add another correction stage just to make it mechanically viable to use.The more glass you add the less light transmission. This is really important with 8MP cameras. The problems of adding more glass also adds weight, power (for the motor controls), andspeed (focusing)issues.

When you get really big the cost really goes up. Look at the kit lens with the D70 nice optics but $300 for 18-70mm (4x range). In the 35mm world a 28-200mm f2.8/3.5 would be a pretty good lens.

You can get an amazing range out of the 8MP cameras with some add ons. For example for less than $200 you can add on to the A2 a .25 Phoenix fisheye and an Olympus 1.5x adapter. This extends the camera to 7-300 giving you a range of 43x at the high end this magnifies almost as well as the 4MP superzooms. And yes I do have both I haveowned a Kodak Dx6490 for about 8 months andrecently upgraded to Minolta A2 that I have had for about a month.

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Old Jul 21, 2004, 7:16 AM   #6
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I've been crawling the net looking at the sony f717 and f828, looking for a similar answer.

If I decide to go with one of em. Is it worth my wild to invest the extra money off the bat, or is the zoom on it sufficient.

Does anyone know the effective range of the zoom on either of those cameras?
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Old Jul 21, 2004, 8:16 AM   #7
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The Sony 717 is 38-190mm (35mm equivalent)

The Sony 828 is28-200mm

So the zoom in value is pretty good for both. A teleconverter is available from Sony and is pretty high quality but pricy (About $200). People have reported sucess in using the TCON-14B (Olympus) for extending the zoom on both you can pick one of them up for about $99 on Ebay.

The 717 is a nice camera, the 828 is a little bulky feeling to me. I would advise checking out the other 8MP cameras with similar specs. The Minolta A2 and Canon - Pro 1 are the same price lens as the 828 but seem to better cameras (IMHO).

The Nikon (both the 5700 and 8700) both have 38-280mm Zooms. It's not very ergonomic (again IMHO) but a nice camera.
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Old Jul 21, 2004, 8:42 PM   #8
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I'm kinda leaning towards the sony. Because I can share my batteries from my camcorder. And my memory sticks I already have from my dsc-p32. Which by the way, I think is an excelent cam. It just doesn't have the capabilities I desire nowadays.

I don't mind the bulk so much. That's what your tripods for. :| lol. But I'll definitely look at the cameras you suggested.

Oh yeah, any suggestions fot other 5mp's?

Sorry, just have to.
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Old Jul 21, 2004, 9:09 PM   #9
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Of course all of this is IMHO but:

I actually like the Sony 717 for 5MP next down (but very close) is the Minolta A1.

But if you are willing to go down to 5MP how about expanding to the4MP cameras.

There are a bunch of super zooms out right now Kodak, Olympus, Panasonic and Minolta. I own an A2 but also own a Kodak 6490. The difference between 4 and 5MP is not that much.

Panasonic just announced the FZ20 which will have a 36-432mm lense (by Leica) and 5MP. It is going to have an adapter that will give you up to 648mm at f2.8. If they do it right this could be an amazing camera.
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Old Jul 21, 2004, 11:34 PM   #10
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Well I'm not enthusiatic about dropping to 5 mp, but I did get to spend a weekend toying with the f717 at a friends house. And I was impressed with he camera's abilities personally. I used it from broad daylight to pitch black in the house at night. And got some real good results.
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