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Geoff Chandler
07-29-2005, 11:44 AM
First off let me state that I am not interested in digital zoom and don't particularly like it.
Just an observation recently made.
As you will see by my signature - I have at present 2 digital cameras.
The C-740 - a 38 - 380 ultra zoom with 3.2mp max resolution
- with a 3x Digital zoom (which I don't really use)
The A-200 - a 28 - 200 Zoom with 8mp max resolution
- with a 4x Digital zoom (which I have used a few times)
Can the A-200 totally replace the C-740?
Well I think possibly yes.! - With reservations
There will always be times when one camera will capture a scene in a more
pleasing way than another - this is true with my 2 - although most often I prefer the A-200 for it's natural presentation and resolution.
To get to the point: -
I recently did a controlled test.
I took a picture at 380mm on the C-740 and the same picture on the A-200 at 200mm with 2x Digital zoom (=400mm?)
If I recall I used 8mp on the A-200 (to be confirmed)
Anyway - the A-200 pic when cropped to show a tiny part of the pic - still resolved finer detail with less pixallation (must have been at 8mp)
I don't know the maths involved - but it would seem that I can equal, or
even better, the quality of the Ultra Zoom C-740 at max optical with the
A-200 at max optical with 2x Digital zoom.
Does anyone else have any observations/comment concerning this compromise/workround, if so I would be quite interested for some other points of view.
It may be worth consderation when purchasing a really decent camera with restricted zoom capability - although every fibre in me wants to reject digital zooming - it is maybe, sometimes, with a reasonably high mp count, a work around. Sure you can crop afterwards as well.

D70FAN
07-29-2005, 01:22 PM
First off let me state that I am not interested in digital zoom and don't particularly like it.
Just an observation recently made.
As you will see by my signature - I have at present 2 digital cameras.
The C-740 - a 38 - 380 ultra zoom with 3.2mp max resolution
- with a 3x Digital zoom (which I don't really use)
The A-200 - a 28 - 200 Zoom with 8mp max resolution
- with a 4x Digital zoom (which I have used a few times)
Can the A-200 totally replace the C-740?
Well I think possibly yes.! - With reservations
There will always be times when one camera will capture a scene in a more
pleasing way than another - this is true with my 2 - although most often I prefer the A-200 for it's natural presentation and resolution.
To get to the point: -
I recently did a controlled test.
I took a picture at 380mm on the C-740 and the same picture on the A-200 at 200mm with 2x Digital zoom (=400mm?)
If I recall I used 8mp on the A-200 (to be confirmed)
Anyway - the A-200 pic when cropped to show a tiny part of the pic - still resolved finer detail with less pixallation (must have been at 8mp)
I don't know the maths involved - but it would seem that I can equal, or
even better, the quality of the Ultra Zoom C-740 at max optical with the
A-200 at max optical with 2x Digital zoom.
Does anyone else have any observations/comment concerning this compromise/workround, if so I would be quite interested for some other points of view.
It may be worth consderation when purchasing a really decent camera with restricted zoom capability - although every fibre in me wants to reject digital zooming - it is maybe, sometimes, with a reasonably high mp count, a work around. Sure you can crop afterwards as well.

Nope. You are correct. It's really not much different than what Nikon is doing with the D2X. You can use the full 12MP APS-C sensor at 1.5X crop or a 7MP additional crop at 2X. This also allows continuous shooting at 5fps with 12MP and 8fps with 7MP. To bad that last part doesn't translate to your all-in-one.

The guys over on the Panasonic board were experimenting with slightly added digital zoom on the FZ20 and going from 5MP to 3MP by using digital zoom with good results.

With higher and higher resolutions available in all-in-ones (9MP!) there is no reason not to take advantage of a little digital zoom even though you could just crop in post processing. So consider it an in camera crop (which is what it is) and a possible time saver. ;)

Geoff Chandler
07-29-2005, 05:02 PM
Nope. You are correct. It's really not much different than what Nikon is doing with the D2X. You can use the full 12MP APS-C sensor at 1.5X crop or a 7MP additional crop at 2X. This also allows continuous shooting at 5fps with 12MP and 8fps with 7MP. To bad that last part doesn't translate to your all-in-one.

The guys over on the Panasonic board were experimenting with slightly added digital zoom on the FZ20 and going from 5MP to 3MP by using digital zoom with good results.

With higher and higher resolutions available in all-in-ones (9MP!) there is no reason not to take advantage of a little digital zoom even though you could just crop in post processing. So consider it an in camera crop (which is what it is) and a possible time saver. ;)
George - thanks for your quick confirmation.
I would add that things are not quite so good once you go further into the
dodgy digital zoom (ie 4x). But, as you say, a quick result and time saver
by effectively making an 'in camera' crop. Additionally, I believe mine is not the only one to make use of the available extra MP when using it at a lower res. - If I am shooting at 5mp, which I tend to do 90% of the time on
holidays, if I use the digital zoom it seems to interpolate (if that is the
correct term) to maintain 5mp quality as long as it can by using the
additional 3mp of unused capacity. Not sure any of my terminology is correct
or even if I am talking rubbish!! But that seems to be what is happening, I
think it is a selectable option in the menus.
I am well pleased with this camera for a non dSLR model, even my 10 year old daughter (minigini) and my 13year old Son say that it is really easy to use, and show a preference over my other camera. :rolleyes:

Rob vdKam
08-04-2005, 08:54 AM
This is an interesting thread. My wife and I are trying to choose between 12x 5MP P&S and the A200 with its wider angle and less zoom. The salesman told us we might just use the full 8 MP to crop out what the 5MP can shoot at max zoom. However, using digital zoom may be no different. (I must admit I really like the feel and quality (at first glance!) of the A200 but my wife likes the large LCD of the Sony H1.)

However, could I hear more please on how this translates into faster shooting. Did one of you say that you could get more fps doing something or other? Could you describe it in simple terms? Thx

Geoff Chandler
08-04-2005, 10:17 AM
I think George was refering to something on another camera with the faster shooting issue. (Nikon dSLR??)
It's up to you which you go for though - it should really depend on which does more of what YOU want and also which you prefer the feel and look of. Certainly the A-200 @200mm plus 2x digital zoom at 8mp is better resolution than my C-730 at 380mm at 3.2mp and I would guess it's close on the same quality as a 5mp camera at that point. After that, however, I think the quality via the digital zoom deteriorates rapidly - at 4x digital zoom it's not to special. 2x digital zoom on top of the 200mm is a usefull extra though.

D70FAN
08-04-2005, 11:32 AM
This is an interesting thread. My wife and I are trying to choose between 12x 5MP P&S and the A200 with its wider angle and less zoom. The salesman told us we might just use the full 8 MP to crop out what the 5MP can shoot at max zoom. However, using digital zoom may be no different. (I must admit I really like the feel and quality (at first glance!) of the A200 but my wife likes the large LCD of the Sony H1.)

However, could I hear more please on how this translates into faster shooting. Did one of you say that you could get more fps doing something or other? Could you describe it in simple terms? Thx

Rod, sorry for the confusion. The camera I was using for a reference is the Nikon D2X which is a professional dSLR in the $5000 range. Basically it can use the whole 12 Megapixel sensor and shoot at 5 frames per second, or it can crop the image to use about half of the actual sensor elements (7MP) and shoot at 8 frames per second (due to the smaller file size).

The D2X is unique in this capability, but there is no particular reason it couldn't be implemented on the next generation of consumer cameras.

While digital zoom was a no-no when cameras were limited to 2 or 3 Megapixels, there is no reason not to use it sparingly to maybe 1.5X on a 5MP camera and maybe 2X on a 7MP, or even 2.5X on 8MP and 9MP cameras. This would still maintain a decent 3-4MP image and eliminate having to crop later in post processing. So it turns out that there is a legitimate reason for more megapixels besides advertising hype.

Rob vdKam
08-04-2005, 11:38 AM
Alright! Thanks.

Now, I thought about what zoom that would be equivalent to. If my wife wants a 12x zoom, and the A200 (8MP) gives a 7x zoom, but I can increase that by 2x as you suggest below, does that give me approximately a 14x zoom? I hope it's that simple... :rolleyes:

Rob vdKam
08-04-2005, 11:42 AM
When I use manual zoom in the A200, the magnified image is quite blocky. I thought that was a limitation, but if I use a smaller picture size, can I get a nice, sharp zoomed image? Any details on this wouldl be appreciated.

D70FAN
08-04-2005, 01:02 PM
Alright! Thanks.

Now, I thought about what zoom that would be equivalent to. If my wife wants a 12x zoom, and the A200 (8MP) gives a 7x zoom, but I can increase that by 2x as you suggest below, does that give me approximately a 14x zoom? I hope it's that simple... :rolleyes:

Yup it is that simple. 2X digital zoom at 7X optical zoom = 14X total. For normal viewing size (like full screen) you shouldn't see the pixelization described in your following post. Only when you get up to about 80% to 100% crop. It' should be the same as taking the picture at 4MP setting.

Balrog
08-04-2005, 02:26 PM
Just to make a mathematical correction here - 2x digital zoom effectively reduces you to one FOURTH of the megapixels available, not half: you're using an area in the center of the sensor that is half the width and half the height, thus 1/4th the area.
So a 2x digital zoom on an 8mp sensor would leave you with 2mp quality.
Looking at it from the other end, to keep 4mp quality the maximum digital zoom you could use would be 1.44x (square root of 2).

D70FAN
08-04-2005, 02:49 PM
Just to make a mathematical correction here - 2x digital zoom effectively reduces you to one FOURTH of the megapixels available, not half: you're using an area in the center of the sensor that is half the width and half the height, thus 1/4th the area.
So a 2x digital zoom on an 8mp sensor would leave you with 2mp quality.
Looking at it from the other end, to keep 4mp quality the maximum digital zoom you could use would be 1.44x (square root of 2).

Balrog, Thanks for that correction as sometimes we (meaning me) loose sight of that fact, which is why I used 1.5X digital zoom as the base.

Hopefully even a 1.5 or 2 megapixel image will suffice, in a pinch, for most consumer 4 x 6 and 5 x 7 prints.

The bottom line is use digital zoom sparingly. ;) It is still a good option within limits.

Geoff Chandler
08-11-2005, 09:53 PM
Despite the clearly understood maths balrog has pointed out - I have still found that the A-200 @8mp using 200mm + 2x digital seems to resolve slightly better than the C-740 @3.2mp and 380mm ! I don't quite understand
why - and I shan't let it worry me. Suffice to say that if the chips are down - I am happy to push it as far as 2x digital to get the shot. :rolleyes:

Balrog
08-12-2005, 12:47 PM
I guess you'll have to chalk that one up to lens quality? Really can't think of any other reason...

Geoff Chandler
08-12-2005, 02:26 PM
Nope - not lens quality! - if you blow up the crops and look the Oly has much larger pixals, this is a crual comparison as this was a number on a boat in the water - - much cropped from the orig's just to make the point.
If you can view the image full screen without using a graphics package to enlarge (which changes this again) you will see larger pixal blocks from the OLY and smaller ones from the Minolta :cool:

Balrog
08-12-2005, 06:05 PM
Viewing a tiny image like that in fullscreen in an image editor still is a digital enlargement operation - the only reason the Oly pixels appear larger is because the original image is half the res (101*45 pixels as opposed to 201*92).
The only way to actually check how much each camera is REALLY resolving would be to take pictures of line-patterns, I think... the "E262" appears smooth enough on the digitally zoomed pic, but that can be achieved by the use of a good filter during the upsampling process.

Balrog
08-12-2005, 06:11 PM
To illustrate the point about the fullscreen viewing - I just grabbed the Oly crop image you posted and upsampled it to twice its size (to match the dimensions of the KM image). Try viewing this one at fullscreen and it'll have the same sized pixels as the KM one.

Geoff Chandler
08-14-2005, 04:10 PM
Balrog
Absolutely - I am with you - I was viewing these pics using ACDsee. When I used my usual Serif Photo Plus ( kind of like a Paint Shop Pro thing) the upsizing smoothed things out quite a bit.
The reason for the size difference is simple, and at the heart of my point anyway - The smaller image is cropped from an optically zoomed (only) 3.2 Olympus, whereas the other is from an 8mp Image that was subjected to 2x digital zoom ( which I expect ibnvolved a bit of in camera interpolation as well) - The point was that I could resolve more using the 8mp camera, including using the 2x digital zoom. Does that all make sense??
Bottom line - the KM A-200 can more than match the Oly at full Zoom - despite resorting to 2x Digital to achieve it. Obviously this experiment is performed with both at their respective max MP settings.
I tried upsampling the Oly crop, like you, and found the same. But simply enlarging it on a veiwer - or maybe printing it up HUGE would show the A-200 to be better.
Geoff

Balrog
08-15-2005, 05:22 AM
The point was that I could resolve more using the 8mp camera, including using the 2x digital zoom. Does that all make sense??

The problem here is the term 'resolve'. The picture has a larger resolution (8megapixels) -- but that doesn't mean there's 8 megapixels worth of detail in there .. it's just interpolated from the 2megapixels worth of real information available. The fact that it looks 'smoother' fullscreen (or printed out large) doesn't mean that smoothness contains any extra information - 'smoothness' and 'detail' are more or less opposites, in fact.

Think of it this way: a digital zoom is just a crop from the center of the image sensor, which is then upsampled to the full resolution. A 2x digital zoom from an 8MP sensor would mean you're only taking the central 2 megapixels (8 divided by the square of 2) - and then upsampling to 8MP. On the other hand, if you took the 3.2 megapixel Olympus image and then upsampled it to 8MP on your PC, it would have *more* detail than the A-200 pic, since you're starting from 3.2MP of real info instead of just 2.

How does that affect really large prints? well .. if you took the digital-zoom 8mp pic and printed it out, and then took the 3.2mp optical zoom pic and printed to the same size, it's possible the 8mp one would come out better because of the higher DPI .. however, if you upsampled the 3.2mp pic to 8mp and then printed it, it would have more detail than the 8mp digital-zoom one.

Geoff Chandler
08-15-2005, 11:53 AM
Balrog ~
Gotcha - inderstood.
I reckon the A-200 pic is fine though to use that as a last resort - as stated already - I don't really like digital zoom.
You can see chunks taken out of the numbers in both examples, whether upsampled or not. I did try upsampling the two both to the same size, from the small crop and felt the A-200 one was still marginally better - slightly less chunks I guess.
Not that it is really important - but it is interesting.
In the final analisis - what do you think of these two extreem crops?
Do you have a preference? - and did you ever see the 2 orig pics side by side that I posted somewhere a while back??
I will bear the Maths in mind though whenever I consider using the digital zoom.
Thanks

Balrog
08-18-2005, 03:52 PM
In the final analysis - I actually do prefer the KM crop .. it looks 'cleaner' to me. However, that could just be because the interpolation cleaned things up which were actually blotchy in real life. ;)

As far as last resorts go, I prefer not to use digital zoom ever. I figure I can always crop it tighter if I want in photoshop, and then upsample if needed for a large print. It'd probably even look better that way, since I have more processing power on hand and can try out different filters while upsampling to see which one looks nicest. The only time I'd use digital zoom would be if I was using my camera like a telescope - i.e. just to see what I was taking a picture of .. and even then, I'd back down to pure optical before actually taking the picture. But then, that's just me .. I know several people who don't hesitate to use a little digital zoom now and then.