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Translate Megapixels to Print size

by itmatters2me / June 23, 2004 1:25 AM PDT

I know that the higher the megapixels you have the larger you can print. But I still need numbers. How many megapixels do you need to get 8X10, an 11X14, a 20X30, etc.?

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Re: Translate Megapixels to Print size
by absolut / June 23, 2004 3:17 AM PDT

i have a 4.0 mega pix and i can print 8x10 even with a couple inches cropped around the edges.

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Re: Translate Megapixels to Print size
by snapshot / June 23, 2004 6:51 AM PDT

It is not quite that simple.

First - Most cameras are not exactly 3, 4, 5, etc megapixels.
So you want to look at the Maximum Resolution.
The camera maker may state that max resolution for a 3 megapixel
camera is 2048 x 1536.

That means 2048 pixels x 1536 pixels

When you print a photo, you talk about dpi (dots per inch).
A printer set to print at 300 dpi will produce an excellent photo.
A printer set to print at 150 dpi will produce very good photos.

For this exercise you relate pixels and dpi as being the same thing.

Divide 2048 by 300 = 6.8 inches
Divide 1536 by 300 = 5.12 inches.

So you will get an excellent 6.8 x 5.12 inch print if you printer is set for 300 dpi.


Working backward - you want an excellent 8 x 10 photo.

That is a problem because that is a ratio of 4 x 5 (width to length ratio)
You digital camera most likely will produce a 3 x 4 ratio.

That means you will have to crop the picture to create a 4 x 5 ratio result.
If you don?t want to crop, you have to accept a 7.5 x 10 inch or 8 x 10.67 inch photo.

Lets choose the 7.5 x 10 inch photo.

Multiply each number by 300 and you get 2250 x 3000 (or 3000 x 2250).
So you need a camera that has a maximum resolution of 3000 x 2250

A six megapixel camera is 2816 x 2112
An eight megapixel camera is 3264 x 2448

So my guess is, you would need a seven megapixel camera (minimum), but I don?t think anyone makes a seven megapixel camera.


But reality is a bit more squishey that that:

Lets say you have a 3 megapixel camera - 2048 x1536 maximum resolution.
Now let us use Photoshop or some other digital photo manipulation software,
and resize/resample that 2048 x 1536 photo to a size of 3264 x 2448.

After you resize/resample the photo, you then use a software tool (unsharp-mask) to sharpen the photo.

You now have a photo file that you can print at 300 dpi and get an excellent 7.5 x 10 inch photo.


I?ll let you do the math for 11 x 14 and 20 x 30 inch photos.


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Re: Translate Megapixels to Print size
by itmatters2me / June 23, 2004 7:45 AM PDT

Thanks for your knowledge. That helps VERY much. Do most quality print shops print at 300 dpi?

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Re: Translate Megapixels to Print size
by snapshot / June 23, 2004 10:26 AM PDT

The large photo printing places use high speed digital printers that will equal or better the 300 dpi.

There are many companies that are building this type of printer and there are many types of printing processes.

So you are likely to see some differences, depending upon who processes your photos.

They want more customers, so they usually strive to produce a superior product.


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Re: Translate Megapixels to Print size
by JoePhandango / July 1, 2004 5:34 PM PDT

For a desktop postscript (ie: color laser) printer, you'll need about 200-220dpi for a decent photo. For an inkjet, you can still get great results with 150dpi photos.

This is because inkjets don't create halftone screens in the way PS printers do.

Commercial printers' imagesetters run on postscript, which converts
your pixel image into a halftone screen, typically 175 lpi (lines per inch). For commercial print, a good guide would be to think in terms of your resolution needing to be at least 1.5 times the printer's lpi.

So 175 x 1.5 = 263 - A lot of pre-press pros (me included) round that up to 300dpi when preparing our images, just so that we've got a bit of room scale if need be. Also, for very colorful and detailed images, a bit more resolution can (very marginally) improve the accuracy of the reproduction.

Generally, you really don't need to go to 300 dpi for home use, you really won't see much of a difference between a 200dpi and a 300dpi image printed on a modern inkjet a high quality setting.

I'd stay at 200dpi and keep those file sizes down!

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equipment that takes picutres and video
by cesar3710 / May 16, 2005 2:16 AM PDT

How can I use the same equipment for shooting video and taking commercial quality pictures?

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Video & pictures
by snapshot2 Forum moderator / May 16, 2005 8:13 AM PDT

I don't understand the question.

Almost all digital cameras can take photos and videos.


"commercial quality pictures"

At least 50% of all digital cameras can produce commercial quality pictures.

It depends upon your definition of commercial quality pictures.


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It's Not That Complicated Either
by Joe_the_Geek / September 20, 2010 11:07 AM PDT

While counting megapixels and translating this amount to what a print image can be printed at, it's not just a numbers game.

A 5 megapixel camera could theoretically produce a better looking image than a 10 megapixel camera at a given enlargement. The reason for this lies with several determining factors such as the quality of the camera lens, the quality of the light sensor, and the skill of the photographer in taking the shot.

Added to this is how the actual image is processed within the camera itself. Some cameras apply "filters" and "noise reducers" in processing the final image. This will also affect final print quality and sharpness.

So when all is said and done, the numbers game is only a guide to how large you can print a digital image; you may be able to go larger or smaller based upon the above factors.

Also, the human factor is at work here too. Some people will be satisfied with one level of quality whereas others won't be happy until they have a virtually perfect print. Large prints usually look better from a few feet if they aren't tack sharp, so consider this too.

So next time you want to print out a digital image/photo, take a little time out to access what sort of camera equipment and electronics you have inside. Read reviews or visit camera forums. They produce lots of useful info on what sort of quality a particular camera produces.

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Resolution, Poster Sizes
by ShannonF68 / April 6, 2012 1:32 PM PDT

I'm really confused, so I will keep reading but ask my question anyhow.

I have a Nikon D3100 which I am still learning about. However, I have taken some great shots with what I thought was great resolution, etc (at 14.2m, 4608x3072) only to have places such as Walgreens tell me that I am unable to have a 16x20 photo print of that size due to resolution. What am I doing wrong? Should I be shooting everything in RAW instead of jpg or does that have any impact or ?

I'm still really new to all the features on my camera, which I love, but am struggling with being able to have some of my work printed to poster size if desired. Help appreciated.
Shannon in Seattle WA

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Your choice it seems.
by R. Proffitt Forum moderator / April 6, 2012 1:47 PM PDT

That print would be about 180 dots per inch. A little short for some but as a picture if you are a few feet away it would be fine.

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Aspect Ratio
by snapshot2 Forum moderator / April 7, 2012 12:51 AM PDT

It is possible that the person at Walgreen is trying to tell you that there is an aspect ratio difference between your picture file and the shape of the paper (16x20).

The aspect ratio of an image is the proportional relationship between its width and its height.

Your picture file size (3072x4608) has an aspect ratio of 2:3
The paper (16x20) has an aspect ratio of 4:5

That means you cannot put your entire picture on 16x20 paper and completely fill the paper.

You have to decide if you want to loose some of the length of your picture
print the picture on the paper and have white space above/below the picture.
(i.e. the image on the 16x20 paper will be 13.3x20).

I suggest you consider cropping your picture image to the size of 3072x3840.
That has an aspect ratio of 4:5
That will fit perfectly on 16x20 paper.

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Re: Translate Megapixels to Print size
by viclud / July 1, 2004 6:02 PM PDT

There is no simple answer - it depends to a large extent on what quality you are looking for. Try putting "digital images" +"print quality" into Google - you will get a lot of guidance, such as that at
Good luck, viclud

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Re: Translate Megapixels to Print size
by jantolo / July 2, 2004 12:55 AM PDT

It is not just the number of megapixles. It also has to do with the size and type of sensor. The larger the sensor the better size of prints you can get. It is like comparing APS, 35mm or 120. You can have less megapixles in a large sensor and get better images.

Unfortunatelly it looks like it is cheaper to increase the megapixles than to increase the sensor size.

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Is there a formula????
by nycboy0156 / May 27, 2005 9:02 PM PDT

I print great 8X10's with a 2 megapixel canon. Depends on the camera you use and the lense it has. There is no secret formula and many idiots will tell you that you need more than 2mp for an 8X10.

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Megapixels and lenses and resolution...
by rpm60 / June 29, 2011 5:06 PM PDT
My question is similar, but I want to blow my picture up to one of those super-size Costco canvas prints. I have one particular picture I want to take for this image, and my Canon powershot (7.1) photo was dinged by Costco as too fuzzy.
I'm thinking about getting a Lumix 14.0 megapixel camera. But that's about all I want to spend for one picture to hang on my ridiculously high dining room wall.
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Photo Math
by snapshot2 Forum moderator / June 30, 2011 12:11 AM PDT

You have asked your question on a thread that was concluded in the year of 2005, so some statements you read above may have changed due to the advancements of digital cameras.

You failed to tell us what "super-size Costco Canvas Prints" means.
We would like to see that in Inches.
I am going to assume you mean 20 x 30 inches.

Also assuming that the printer used is capable of 300 dots per inch (dpi).

For the very best print quality you need a image size of 6000 x 9000 pixels. (multiply the size by 300).
Which means you need a camera that has 54 megapixels. (multiply 6000 x 9000)
Such a camera will cost you about $25,000.

So lets lower our expectations and ask for a print at 150 dpi. (not excellent but good).
We need an image of 3000 x 4500 which would be approx 13.5 megapixels.

You also need a sharp picture.

Here is a complete write-up on the subject:


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Not all the same
by PistonCupChampion / June 30, 2011 12:23 AM PDT
In reply to: Photo Math

Math aside, not all megapixels are equal. A 14 MP point & shoot camera is not going to have anywhere near the image quality of a 14 MP DSLR, or even one with fewer MP.

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by rpm60 / June 30, 2011 8:18 AM PDT
In reply to: Photo Math

I know this was an old thread, but took a chance.... The link is excellent for a layman like me.

The canvas print would be 40x60 (also available in 30x40 and 30x30).
It's a big, plain wall.

My picture is a still shot of a cobbled street in Sweden, and my last photo became significantly less sharp when blown up beyond 8x10.

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Blowing up a photo
by snapshot2 Forum moderator / June 30, 2011 8:59 AM PDT
In reply to: thanks!

Lets say you have a photo that is 3072 x 2304 (approx 7 meg).
It should give you a very good 8 x 10 photo.

If you print it larger several things can happen, depending upon who did the printing.
You could get a very sharp blocky looking print.
can get a photo that is printed at a lesser density (say 150 dpi).
a print from a resized photo.
If you just resized the photo to 4288 x 3216 (approx 14 meg) you will get a degraded image.
(because, just where did those extra pixels come from? They did not come from your camera.
They were generated by a software program that was making an educated guess.
That is called interpolation.

Some people claim that you should resize a picture (upward) by about 10%,
then do it again (10%), and do it again until you get to the size you want.
They claim that method produces a better result.
Maybe, but time consuming.


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