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Old Dec 19, 2002, 8:40 AM   #1
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Default A LOGICAL QUESTION. . . .I think

Have a fairly easy question for those who know.

How much better (sharper) is a 3mp photo (seen on a monitor), then a 4mp?. . .Heck, how about a 5mp for that matter.

As I understand it, the more MP are used, the larger the photo is. So by that reasoning, what good is a 4 or 5mp camera if a person must reduce the pic to fit the monitor???

As you've noticed, I'm really new at this. . .but I'm trying. :?
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Old Dec 19, 2002, 9:20 AM   #2
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1mp will be fine for a PC screen. it's prints that mean you need the biiger MP. I find 3MP is MORe than enough.
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Old Dec 19, 2002, 9:36 AM   #3
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You can't see more than the detail resolution of your output device. Monitor res. is generally 72 dpi. Higher resolution modes are possible but crt's suffer brightness/contrast decreases. So why shoot more? Well edge detail is not just about whether a single pixel is there or not, on or off, Edges are really 3 dimensional so the improvement you might see is not easy to define with simple 2D arithmetic. BUT put 2 pictures side by side and the difference can be visible to the point where pics 'look & feel' more real and better quality.

Monitors are fairly easy to scale res. for, but most photographers are interested in hard copy, where size and resolution become more important. Photo capture and editing usually involves file compression so the more detail you start with - the better will be the result after decoding. Editing often involves cropping so having more pixels to start with is important.

Your question is quite valid at the moment whilst cam makers are moving incrementally in pixel count from 1-5Mpix, and at each increment the discernible benefits get less, if all you want are 6x4 prints. Ideally, we'd have bought our first 1mpix cam, then a 5Mpix cam a couple of years later for the same money, and never need another cam for 10 years!

However, many high pix cams offer more sensitivity/res options which make a difference between getting a pic and none at all!

Next year we'll be putting our pics on 50 inch HD plasmas, viewing 3ft away, and 10Mpix wo'nt be good enough!
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Old Dec 19, 2002, 1:12 PM   #4
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A CRT monitor capable of 1024x768 pixel resolution displays 786,432 pixels total - that's 0.786 megapixels. In theory therefore a one magapixel camera is all you ever need if you never intend to produce hard copy prints which is another issue altogether.
The big advantage of higher resolution cameras - 3, 4 or even 5 megapixels, is the ability to crop the photos and achieve the same result as would otherwise require big and expensive zoom lenses and a lot more photographic talent!
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Old Dec 19, 2002, 3:13 PM   #5
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More megapizels alone won't get you anything. However, its possible that a 5 MP camera might have better optics than a 2 MP camera, so you could see a difference. But it's *not* due to the number of pixels.

When shooting for the a web page or email, you have to conisder two things. Dimensions of image and byte size of the actual file. Remember that not every one has a computer with a 19 inch monitor running 1280x1204. Not everyone has highspeed connections. Even if they did, people still like imgages to load quickly, and you may also have to pay to get more sotrage space on the web server and you may also have some sort of data transmission quota. For email, people typically have quotas on how large the inbox can be.
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Old Dec 20, 2002, 1:39 PM   #6
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From what I've seen reviewing sample photos from various cameras that have been posted on the Web, any camera from 1.3MP and above with a well made focussing lens creates a sharp image when viewed at 100% of actual image size on any size monitor (15-19"). Where the higher MP images shine is when you go into "Slide Show" or create a full frame 'desktop' image, where the whole image is reduced to fit the displayable area. This makes the larger file sizes 'appear' sharper cause each detail is REDUCED in size to fit the display (same as with a print). It's like standing farther away from a TV set: the picture 'appears' sharper as the apparent size of the details (and flaws) have been reduced at your new vantage point. So for prints and slide shows, more MP is better. How much has to be determined by each viewer as a personal quality issue.
As a personal example: I have 1.3 and 2.0 MP Fuji's. The 1.3 is fixed focus: the 2.0 is autofocus. If I set my 15" monitor to 1280x960, and view full frame images (slide show), the 2.0 appears obviously sharper. If I view them both at 100% original size, it becomes a more daunting task to determine which is sharper. The more obvious difference is that the 2MP compression has slightly fewer JPEG artifacts than the 1.3, not that it is much sharper (except at infinity).
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Old Dec 20, 2002, 2:05 PM   #7
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MentorRon...you just made the other important point (which I drew attention to in my post) that 2 cams of similar Mpix source don't necessarily use the same degree or quality of compression, so the differences at 1-2Mpix between cams, becomes more obvious on a monitor.

If you shot 1-2Mpix uncompressed, then there should be plenty of detail sharpness for a crt monitor.

Alternatively, shooting with more pix, compressed and down sampling for a monitor, produces similar resolution but pics can look sharper because there is less JPEG 'dirty windows' artefacts in edge detail.

So we're probably saying, for a monitor, if you have a 1-2Mpix cam which does uncompressed, you'll be doing not a lot better than a new cam with more pix (All other benefits of new cams apart).
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