rotormota 20:22 28 May 2003

My digital camera is 2.1 megapixels.

It has 3 modes Fine (1600x1200), normal (1280x960) & basic (640x480).

I have a number of photo editor programmes where I can alter the number of pixels per inch to improve quality. Some programmes increase/decrease the photo size depending on pixel amount but one, ULEAD, I can keep the size the same but also increase pixel quality which is ideal.

Can someone explain how all these elements work together. I mean if the camera takes photos with a certain amount of pixels/mega pixels (are these two different?)how is it I can alter amounts/quality in editing programmes for instance?


  accord 20:29 28 May 2003

i think its called "interpolation". Fuji use it one their digicams stating a 6Mp camera with a 3Mp CCD. Basically its as you say above, it increases the quality via software instead of by the CCD in the camera.

click here

hope this helps

  rotormota 20:59 28 May 2003

Ultimately, is the final photo print quality determined by the dots per inch values of the printer?

Thanks for info.

  Patr100 21:12 28 May 2003

Anything in 1280x960 will print well up to around 7 by 5. Anything 640 by 480 will look fine on a montor screen but will look too grainy when printe. Go more by the resolution of the orignal image you are printing than the resolution of the printer itself. That more that anything determines actual print quality.

  Niff 22:09 28 May 2003

I am looking to purchase a 4megapixal digital camera which is compatible with my iMac. i want space for some video recording. Is there anything better than the SonyDSC-P9 for the money- £389.76?

  accord 22:13 28 May 2003


create a new thread if you want this one to be answered properly.

  DieSse 00:07 29 May 2003

This is an excellent (but long) primer click here on the relaionship between pixels, dots per inch and quality. Don't be put off by the "Scanning" in the title, or by it's length.

You're a little confused (and it's easy to be, I was for a long time) between number of pixels and dots (or pixels) per inch. Dots per inch only has a meaning when you take into account the viewing size, and many programs confuse by zooming pictures in and out to fit them on the screen. Ulead photo Express is actually doing nothing that any half decent photo manipulator can't do.

A golden rule is that you can never add more "quality" into a picture after you've taken it. Adding more pixels only calculates what the program thinks the extra pixels may be - there are different ways of doing this, which produce different results. Interpolating extra pixels does mean that you can enlarge a picture more without it looking "blocky" - but it may look worse, not better.

  DieSse 00:09 29 May 2003

It's much more complex that dpi on the printer - have a look at the above link for an excellent discussion on this.

  woodchip 00:15 29 May 2003

Basically if you take or scan an image at any given Resolution you cannot improve it's Resolution. You can alter the size but the Resolution moves with it if you increase it the picture will be blocky just as if you zoomed in

  Kyomii 00:41 29 May 2003

As a rule of thumb, for the average photo, photos altered and saved to 200 dpi generally give the best results without fuzzing or blurring, although that is not to say a little experimenting won't go amiss.

The printer and its capabilities definately has an effect on the overall picture quality when printed - this is because printers use a dpi system - dots per inch - the more dots per inch, the finer and less scaley the finished picture.

Its useless printing high quality picture out with a 600dpi printer!

Other factors come into play for the end result too, such as quality and wieght of photo paper, the max dpi the photo paper is capbable of, the way the original picture has been saved and edited (if any original quality is lost) and good quality ink cartridges.

As for megapixels - the higher the megapixel the camera is capable of, the larger you can print the photo out (assuming printer and settings are correct) without losing any quality.

This is great if you want to chose just a small section of the original photo and enlarge it - because you can do so without losing any quality if the camera is capable (3 mp upwards)

Your fine mode is the highest pixel mode that your camera can achieve. So, for example, if you took a picture in fine mode, you could crop it, or take the section out that you want, and enlarge it somewhat (to around 7 X 5) (a 4 megapixel would allow you to enlarge the chosen section more, and a 6 megapixel more than the 4 etc)

If you took the same picture at basic (640 mode) then chose a specific section of the photo and cropped it, you would be very limited with what you could do with it, and you would not be able to enlarge it without losing any detail - and if you enlarged the section to say 10 x 12, the picture would look abismal and very, very poor.

So, to sum up:

Amount of pixels a camera can take the higher the number will allow you more editing and enlarging techniques without losing quality (assuming the original is saved correctly and decompressed as little as possible)

Amount of pixels per inch - this is refining the photo, is as native to the photo as dot per inch is to printing - a general setting to 200 ppi (pixels per inch) is a good rule of thumb to follow.

Dots per inch - these are native to printing - and it depends on your printer capabilities. Each inch square is made up of tiny dots - the higher the dots, the more refined and detailed the picture/object, photo etc (any print)

A 2.1 MP camera and a 2400/2800 dpi printer with correct paper and carts can produce very good results.

  anchor 09:41 29 May 2003

To recap what Kyomii says: I
have been a digital photographer for quite some time, I advise taking your pictures at the highest resolution. This will give you more scope to obtain the best results, particularly if you want to enlarge, and use, only a portion of the picture.

Interpolation is no substitute for the fine detail being there in the first place. I had a Fuji 2.3Mp camera, and could print an excellent A4 picture on a Epson 700 ,(1400dpi), with glossy photo paper.

I store my many hundreds of pictures, in their original size/format, on CD-R.

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