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Old May 31, 2009, 12:57 AM   #1
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Default Megapixel!!!???

i wanted to know the difference between a 8 megapixel and 10 megapixel
and how many mega pixels one require
and how much is too much
and how does it affect the picture quality
and can someone tell me whats the difference in
a canon's digic 3 processor and digic 4 processor
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Old May 31, 2009, 8:39 AM   #2
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A 10 Mp camera will allow an enlargement 9.5% (sqrt[10/8]) larger in linear dimension if all else is equal (it never is). Just about any other better feature would be worth more than that, e.g., faster lens, better autofocus, smaller size, nicer case color, ...

Having said that, there is no such thing as to many megapixels. The question really is what do you have to give up to get more? More money to buy? More noise? ...
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Old May 31, 2009, 12:49 PM   #3
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A lot of questions, and I think that Bill gave an excellent answer in terms of the final result. You get a bit more area. However, you have asked a lot of additional questions...

and how many mega pixels one require - This is the $64,000 question. The camera companies have been pushing more is better. However, packing more pixels into a small area produces cross talk (or leakage) between the pixels or what is known as "noise". P&S cameras have very small sensors so they pack around 30MP (actually 35 to 37) per square cm. dSLRs on the other hand have larger sensors. I have a Pentax K100 with a 6mp sensor (1.7 MP/cm^2) and a K20 with 14.6mp (4.0 MP/cm^2). More space between pixels thus less noise, and higher image quality (neglecting the lenses). The difference in density alone is a factor of 10. In general 6MP will produce great images of useful printable sizes. Here are a couple of good references on the topic...

http://www.clarkvision.com/imagedeta...els/index.html
http://www.clarkvision.com/imagedeta...l.size.matter/
http://www.tfpsoft.com/fun/digitalca...egapixels.html

I recently got a 52" HDTV, that is able to display JPG images off of a thumb drive. The ones from the K100 - 6mp were stunning (way beyond my wildest expectation). The K20 - 14mp, I expected to be stunning and were superb (but closer to my expectations). So to easily answer your question, 6mp and above does just fine.

I also have an old Canon sd500 - 7mp and a Panasonic LX3 - 10mp. Both provide excellent images. It all boils down to what you want to produce, and how you are going to look at the results. That will determine how many pixels you will need.

and how much is too much -This essentially goes to sensor size, which translates into semiconductor yield within the FABs. As the sensor size increases with megapixels, the yield decreases, thus driving up the costs. Also, the camera processor has substantially more pixels to process, so that needs to be either faster processing, or a longer time to process (time between shots, and or time to store to the memory). Quite a few folks want full frame (35mm) sensors which would run around 30MP+, for better image quality and resolution. There are a few dSLR cameras that currently provide this, but are expensive. So the bottom line is - how large is your check book? You can also go to medium format cameras 4x5s and 6x7s that sport around 45MP - but they are north of $15 - $20,000 (body only - lenses extra), and are very large and heavy. It all boils down to what the camera manufactures are able to design profitability and what the public can afford to purchase. Also, larger sensors need larger lenses, which need larger glass, of higher quality, which are heavier and cost much more.

and how does it affect the picture quality - Look at a fine magazine or a coffee table book. The pictures are 300dpi (dots per inch). Then look at a newspaper picture - lower quality, lower dpi. So in the quest for quality, everyone is looking for more pixels or megapixels, however to produce them cheaply and in large numbers, they squeeze more into a given area, this causes noise, which reduces overall quality. So right now your main two choices are P&S, or dSLRs. One has small sensors, relatively high noise and small lenses, while the other has larger sensors, lower noise and larger lenses. With the magic of digital image processing, and fast electronics, there has been a larger increase (faster rate of improvement) in image quality within the P&S segment in the last few years, than there has been in the dSLR world. The P&S quality has been rising up to near the level of the dSLRs. Will they ever be equal - probably not - due to the same advances are being applied to the dSLRs, and just the plain physics of larger sensors, lower noise and better lenses. You are also ignoring the lenses, which gather the light and get it to the sensor. Better lenses equate to better pictures. A superior lens coupled with a inferior sensor, will produce a better image than a superior sensor with a crappy lens in front of it. Also, a great photographer will probably take good pictures with crappy equipment, as compared to a bad photographer using the absolute best equipment. Translation, Tiger Woods using a shovel, rake and hoe will beat me (badly) any day of the year - even if I am using the absolute best clubs money can buy.

and can someone tell me whats the difference in a canon's digic 3 processor and digic 4 processor - http://en.wikipedia.org/wiki/DIGIC_II

hope that helps....

Last edited by interested_observer; May 31, 2009 at 1:23 PM.
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Old Jun 1, 2009, 9:46 AM   #4
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wow that was some information
thank you bill and interested observer

actually i am a new buyer, and a rookie in terms of using a camera
i first went and did a research on sony and canon
i found the picture quality of canon better ,
now the cameras which i checked out were sony's w210 the 12 megapix one
and the canon's ixus 80is which is 8 MPx, 95 is which 10 Mpx, i saw that canon's 80 is gave much brighter picture as compared to sony so finally i thought of buying a canon digicam now i got confused here which one to buy the 8mpx or the 10 Mpx
if i can get 10 Mpx for a few bucks more i can buy the ixus 95
but than i read the articles INTRESTED OBSERVER posted in his reply and i hought may be 8 MPx is better , but the article also says that larger the bucket the more rain you collect so that got me thinking again.
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Old Jun 1, 2009, 10:26 AM   #5
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Quote:
Originally Posted by zade View Post
..., i saw that canon's 80 is gave much brighter picture as compared to sony ...
Not sure what you mean by the Cannon's photo being "brighter", but you shouldn't take the sample photos in reviews to seriously. Those are pretty much always shot at the the camera's default settings (about the only a reasonable choice). Often that means the saturation and sharpening are cranked up for the less capable cameras to make them look better. Since stepping up saturation and sharpening introduce irreversible changes, higher level cameras tend to be more conservative.

Though it is counter intuitive, the verbal descriptions in reviews are more important than the sample photos.
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Old Jun 1, 2009, 11:31 PM   #6
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Hi Zade,

There are a lot of cameras available, all sizes, shapes, weight, colors, and specializations (superzoom, pocket, etc.). Overall, they all perform quite well and take good pictures. If you go to an extreme (size, weight, thinness, amount of zoom, megapixels, underwater, etc.), you are going to pay a premium. It sounds like you are looking for a good general digital camera, that for the most part - will take good pictures.

Steve's has a couple of lists for you here....

Here is a list of best cameras by category...
http://www.steves-digicams.com/best_cameras.html

Also, here you can filter by make, size, zoom, megapixels, price, etc and come up with a selection list...
http://steves-digicams.pgpartner.com...php/page_id=48

... and you can read the reviews, here....
http://www.steves-digicams.com/hardware_reviews.html

They are all available off the front page down the left hand side...
http://www.steves-digicams.com/

You do not have to go broke. Do not feel that you have to go to the absolute maximum extreme, or the absolute newest (a just discontinued model at a clearance discount can be a great bargain - what every you buy, a new model will always replace it - so do not worry about it). See what appeals to you, make a list, do a bit of reading of the reviews on the ones that make the list, filter it down to a hand full, go to a store and see them or a similar model, handle them as much as possible, you have to be happy with what your are going to use - or you will not use it. Make another posting and get some feed back and/or go to the search along the top menu bar and put in the camera name and get a list of posting about it (good, bad or indifferent). If you are going to buy off the internet, order from a good retailer that will take the camera back (B&H, buydig, beach, amazon, etc.) that offers a good price. .... and then take pictures - because that is what its all about.
  • 6MP is a good basic. 8 to 10MP is just fine - no use for paying for any more.
  • Figure out how much zoom you want.
  • What type of body style (small, normal, etc.)
  • Canon, Nikon, Panasonic, Sony, Pentax, Olympus, Fuji, Samsung, Kodak and Casio (in no particular order) are all good cameras and will provide good service.
Bill had some very good advice, the review sample photos may not be the best examples. In the store, I would take an SD card with me and take some test pictures, that way you can evaluate it yourself.

... hope that helps....
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Old Jun 2, 2009, 3:06 AM   #7
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wow. alot of technical stuff there. As alot do forget, the picture transfers someplace else to be seen. I went to HD on my custom pc just 2 years ago, to realize 5mp is beyond my wildest dreams, and didn't even need that much, so I spotted a 4mp nikon and grabbed that for 11x17 photo capable (I have never had a need for a poster). My dabbles asked the same question, years ago, and funny enough, I didn't forget the answer. It reminded me of bill gates claiming 640k was eonugh for everybody. "Beyond 3mp is impossible". In a way they were right, beyond it needs HD hardware to be very good to look at.if one doesn't know, they most likely haven't got the questions a machine may need to read them nicely. I found beyond 3mp needs HD computers...and that says alot about megapixel...from a regular person with a camera.
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Old Jun 6, 2009, 4:44 AM   #8
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thank you bill,bgd73, interested_observer
thank you all for your suggestion
after reading all the stuff you recommended
i think for a beginner i have decided on buying ixus 80
i even liked ixus 860 but because it has a wider lens but than it is costly
what do you all say
is it a good buy ...
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Old Jun 6, 2009, 6:34 AM   #9
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hi all

well i have just come back from the cam shop and the shopkeeper showed me another cam
canon's A1000
does anybody has a say on this model
and which one is better ixus 80is or A1000
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