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Old May 26, 2004, 12:33 AM   #1
KSS
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What is the easiest way to convert resolution to megapixels? Do I just multiply the two resolution numbers? So as an example 1200x2000 would be 2.4 megapixels? Thanks!
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Old May 26, 2004, 8:15 AM   #2
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yes, and you will see by doing so, that your megapixel gets exponentially bigger as your resolution increases which falsely leads you to believe that a 4 megapixel camera is much bigger than a 3.2 for example. A 3.2 megapixel camera is 2072 by 1536, where as a 4 megapiel is about 2272 by 1704 which is only 200 pixels more in the width, which is less than an inch if you print at 300 dpi. A camera with double the width of a 3.2 megapixel would be a 12.8 megapixel, not 6.4 like some would think. Even a 5 megapixel camera is around 2592 by 1944 whcih would result in picture with less than 2 inches wider than a 3.2 mp camera

But there is a bright side to all this upsetting math;



1. - when you print bigger, you do not need to print at 300 dpi, 200 will suffice, so 200 extra pixels is one full inch.

2.- even if you do not print bigger sizes, a higher megapixel camera will allow you to crop tighter in the picture, if your composition was not good to start with.




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Old May 26, 2004, 11:39 AM   #3
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AMG,

Thank you very much for the information. The reason I asked is that I have an Olympus C-8080 and would like to shoot in the 5-6 megapixel ranges. It appears that I can only choose 5mg in the SQ1 and Tiff modes only? And there appears not to be a range for a 6mg shot?I have includedthe resolution ranges. Any ideas? Am I missing something? Another newbie question if I may? What does the 3:2 mean? Thanks again.

KSS


RAW 3264 x 2448

TIFF 3264 x 2448

3264 x 2176 (3:2)

2592 x 1944

2288 x 1712

2048 x 1536

1600 x 1200

1280 x 960

1024 x 768

640 x 480

SHQ 3264 x 2448

3264 x 2176 (3:2)

HQ 3264 x 2448

3264 x 2176 (3:2)

SQ1 - High 2592 x 1944

2288 x 1712

2048 x 1536

SQ1 - Normal 2592 x 1944

2288 x 1712

2048 x 1536

SQ2 - High 1600 x 1200

1280 x 960

1024 x 768

640 x 480

SQ2 - Normal 1600 x 1200

1280 x 960

1024 x 768

640 x 480

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Old May 26, 2004, 12:59 PM   #4
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Why not use the full resolution capability of your camera instead of dropping back to 5 or 6 MP? Are you trying to save space on your memory card? Most folks recommend using the highest resolution your camera will allow. After all, it's relatively easy to down size a picture but impossible to regainunused resolution.

3:2 is the ratio of width (w)to height (h)of your image. 35mm film cameras use this format and photo labs print out pictures in this sameratio, for example 6"(w) x 4"(h) prints . Most digital cameras, for some reason (anyone know why?), use a 4:3 ratio.If a lab prints your pictures and uses the standard size, 1/2" of the height of your image willnot be printed. (4:3 format would yield a 6" x 4.5" picture).

The fact that your camera allows a 3:2 format is a nice feature, especially if you are going to utilize photo labs to print your pictures. You don't have to worry about cropping them first to make surethe labdoesn't cut off the important 1/2"! I've takenportrait shots where I had the top of the head a little too close to the top of the frame. They looked fine on my monitor but when I let a lab print them, they cut off the top of the head!


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Old May 26, 2004, 1:15 PM   #5
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Hey Puck, first of all I agree, always take at full rez and downsize later. I have a theory of why dig cameras are 4:3 but have no proof. FIrst of all, a televison screen is 4:3, so when you hook up your camera to your tv, the frame is filled with pic with no chopping or distorting, secondly, your average computer monitor is 4:3, so these pics when you zoom out to fit on screen, they fit perfectly. But thirdly, and most importantly, I'm sure the powers that be that decided on this standard said to them selves, if it is a 3:2 ratio, anyone wanting to print 5x7 or 8x10 will have to crop anyway, so let's just stick to the digital computer reality of 4:3.

And puck, I use an automated function that allows me to resize all my pictures at once depending on what size I want to print. So the lab receives exactly 4x6 or 5x7, etc. I suggest you do the same, no surprises. I actually have 3 presets because some pics you don't want the same place trimmed, so I have center, top and bottom. And for you very advanced readers out there, sometimes you don't want to lose anything, so extend the sides of the canvas and re-create the rest of the pic manually. But this is another topic altogether that requires you have good software.
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Old May 26, 2004, 1:56 PM   #6
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AMG wrote:
Quote:
I have a theory of why dig cameras are 4:3 but have no proof......
Quote:
And puck, I use an automated function that allows me to resize all my pictures at once depending on what size I want to print. So the lab receives exactly 4x6 or 5x7, etc. I suggest you do the same, no surprises. I actually have 3 presets because some pics you don't want the same place trimmed, so I have center, top and bottom. And for you very advanced readers out there, sometimes you don't want to lose anything, so extend the sides of the canvas and re-create the rest of the pic manually. But this is another topic altogether that requires you have good software.
I think you have a pretty good theory about the 4:3 convention- sounds good to me!

I'm sure I have a program that will automate the resize for printing job. I'll just have to figure out how to use it! Normally I print my own pictures,four to a sheet. I don't lose anything but the pictures are not as big as 4x6 prints. This isfine even with my slow printerbecause I'm usually only printing 16 to 20 pictures. After a recent Alaska cruise I came back with over 300 pictures. My printer would still be printing! I took them to the a photo lab and took my chances. Most were O.K. but some tightly framed shotsgot chopped in all the wrong places!


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Old May 26, 2004, 7:50 PM   #7
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Quote:
The reason I asked is that I have an Olympus C-8080 and would like to shoot in the 5-6 megapixel ranges. It appears that I can only choose 5mg in the SQ1 and Tiff modes only? And there appears not to be a range for a 6mg shot?


Megapixels is a pretty useless number except when buying a camera. Graphics are done in pixels and resolution. I'm curious how you arrived at the 5-6Mp range you want to shoot in.

Quote:
yes, and you will see by doing so, that your megapixel gets exponentially bigger as your resolution increases which falsely leads you to believe that a 4 megapixel camera is much bigger than a 3.2 for example. A 3.2 megapixel camera is 2072 by 1536, where as a 4 megapiel is about 2272 by 1704 which is only 200 pixels more in the width, which is less than an inch if you print at 300 dpi. A camera with double the width of a 3.2 megapixel would be a 12.8 megapixel, not 6.4 like some would think. Even a 5 megapixel camera is around 2592 by 1944 whcih would result in picture with less than 2 inches wider than a 3.2 mp camera


If a 16 X 20 only looks twice the size of an 8 X 10 hanging on your wall I can't argue with your perceptions. But it is 4 times the area and looks 4 times as large to me.

If you print a 3.2Mp image and a 4Mp image at 200 PPI the 4Mp image will be 25% larger in area than the 3.2 image. Conversely if you print them at the same size the 4Mp image will have 25% more pixel density in pixels/sq in. That is a direct and not exponential relationship.

By your logic it is silly to pay twice as much for an 18 inch tile than for a 12 inch tile since one edge is only half again as long. Images are two dimensional and not one.

Quote:
1. - when you print bigger, you do not need to print at 300 dpi, 200 will suffice, so 200 extra pixels is one full inch.

2.- even if you do not print bigger sizes, a higher megapixel camera will allow you to crop tighter in the picture, if your composition was not good to start with.
I have a good photo printer and can't see improvement over 200 PPI. You see some ridiculously high recommendations for printing resolutions but I agree with you.

And I agree with everyone about using the highest resolution when practical. If you are on vacation with limited storage or are shooting only for an e-mail or post it makes sense to use something other than the best resolution. I take everything at full resolution except for some 360 degree panorama shots to put in files that let you look around. People don't display them that large and it takes forever to stitch full size.

TIFF is an entirely impractical format for a camera IMO. Raw is better and takes half of the write time and storage space. If you want to save storage space on your card use SHQ as it is virtually impossible to tell from TIFF and takes a fraction of the space. An 8Mp SHQ image is better than a 5Mp TIFF and uses less storage and write time. Even HQ is good quality. You start picking up visible artifacts with standard JPG qualities.

I'm not a big fan of shooting 3:2 unless you are sure you will never want anything but a 4 X 6 print from the shot. You are just cropping off pixels from the top and bottom of the CCD, and it is the wrong ratio for other print sizes.




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Old May 27, 2004, 11:10 AM   #8
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look slipe, I don't need a geometry lecture from you. AMegapixel is one number, People don'tthink in terms of area. I am telling you, and I know this for a fact, that many people are under the impression that a 6 megapixel camera is double that of a 3 megapixel camera. Of coarse the area is double, all you did was repeat my point backwards. People don't realize that if a 3.2 is2072 by 1536, that a 4 is only 2272 by 1704 by comparison. That was my initial point. I never said a 16x20 is only double an 8x10
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Old May 28, 2004, 9:10 PM   #9
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Ulead photo impact will allow you to resize a image to any photo size. You select crop and it shows a box for you to select and lock the size of the image you want to create. Its a good feature if you want an exact crop before you print a particular image.
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Old May 28, 2004, 11:19 PM   #10
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Quote:
A Megapixel is one number, People don't think in terms of area. I am telling you, and I know this for a fact, that many people are under the impression that a 6 megapixel camera is double that of a 3 megapixel camera.
You can include me in that group that is under the impression that a 6 Mp is double that of a 3 Mp camera. In every way I know to see or measure it is double.
  • You obviously have twice the pixels.[/*]
  • If you display them at 100% onscreen the 6Mp image is twice as large as the 3Mp image.[/*]
  • If you print them both at say 200 PPI the 6Mp print is twice the size of the 3Mp print.[/*]
  • If you print them both the same size the 6Mp print has twice the resolution in pixel density.
[/*]
My tile simile seems to irritate you but it seems that is exactly what you are saying. An 18 inch tile looks twice as large as a 12 inch tile to me. A 16 X 20 print looks 4 times as large as an 8 X 10. You seem to think everyone shares your perception that the 16 X 20 is only twice as large because you only look at an edge, but I don't think that is universal. I think most people do see area.
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