Having read much about megapixels and reaching a point of diminishingreturns with P&S cameras at 10, 11 or 12 megapixels as opposed topictures shot at 6 or 7 mp, I'm not entirely clear if that means orimplies use of a camera with 6 or 7 mp versus one with more, orpossibly using a higher mp camera at lower res. It seems that amongthe current P&S cameras on the market, the more full featured onesare in the 10 to 12 mp range, but I can understand where shooting at10 or 12 means much larger files and not necessarily better pics..
Can somebody give me a little help?.
You are quite right; cramming more MP onto a sensor the size of a small fingernail accomplishes nothing in terms of improving image quality, as any nominal increase in resolution is cancelled out by the higher noise. It is a marketing trick to fool the gullible (obviously, 12MP is twice as good as 6MP, right?). The recently-dicsontinued Fuji F31D had an excellent reputation for low-light image quality as it had only 6MP on a relatively large sensor..
If you have a 12Mp camera there is nothing to be gained by shooting at lower resolution as your camera will simply not use some of the pixels (or, it will combine them by interpolation which you could do afterwards in photoshop anyway)..
If you are after a new compact, get one with as large a sensor as possible; that is ultimately what determines image quality. The number of MP is irrelevant these days, and a ridiculously large number is the price you have to pay for getting a fully-featured camera..
For good sound scientific reasons a 6Mp small sensor is about as far as you should sensibly go. The main limit is 'diffraction'. The term 'airy disk' is one to research if you are interested..
For poor and misleading marketing reasons companies seem to feel the need to make wild claims about 10+ Mp small sensor cameras. Unfortunately they are not making the 6Mp cameras any more and seem determined to force these silly cameras on people..
You will note that entry level DSLRs and pro level DSLRs seem to be quite happy at 6Mp and 10Mp. Very few pros need more than this in practice, so you have to wonder why an ordinary person would..
As for using a lower resolution than the sensor's own resolution it gets a little complicated..
With one exception ( Sigma's Foveon sensors ) all digital camera sensors use sensors that record only one primary color at each sensor pixel. Using messy maths they then try and reconstruct the missing primary colors and then deliver you a full color image. The term you want is "Bayer Array"..
This means a 6Mp sensor is really recording about 3 million green pixels, and 1.5 million each of red and blue, distributed evenly over the sensor. From this it generates 6 million each of reg, green and blue levels. This is the mysterious 'interpolation' you will hear spoken of..
Although that's artificial, it at least has a mathematical 'naturalness' to it..
If you then record a smaller image you are doing an additional scaling step to reduce the size and this, of course, looses information. For this reason I generally recommend you avoid it. It is better to use a lower quality setting ( e.g. use fine not 'super fine' ). This records the full resolution but at a higher compression ration which looses some data, but is not going to loose as much as using the lower resolution..
Pentax K100DFuji S5200Fuji E900PCLinuxOS..
And generally slower shot to shot, storage and dowload speed. And if you shoot RAW.... very slow..
All the replies thus far make good sense..
I'll add that many of the new features that today's P&S have aren't useful anyway. In fact, many of today's P&S cameras are, IMO, inferior in nearly every aspect to the ones released a few years ago..
Most lack view finders, they have ridiculously high MP for which the embedded lens lacks sufficient resolving power, are so chock-a-block with worthless features that you may find yourself hamstrung in an important moment if you inadvertently touch the wrong button or choose the wrong menu item thus putting the camera into some weird mode..
No, today's P&S compacts have little to recommend them. Some of the prosumer models are a different story..
If you want a compact P&S, I would look thoroughly at the reviews on this web site for highly rated models that are 3-4 years old. Look for models with 4-6 MP max and larger sensors..
When you find a model that looks promising, head right on over to ebay, where you are bound to find 437 of them for sale..
This might be of interest. It's a brief intro to the concept of diffraction and how it relates to resolving power..
Pentax K100DFuji S5200Fuji E900PCLinuxOS..