# Effect of megapixels on print size



## Bokeh (Nov 23, 2004)

What is the effect of megapixel count on the maximum size print one can make from a picture?

I'm trying to decide between a used EOS-1D and a new 20d, and I'm concerned with the small pixel count on the 1D. I have a rebel now which of course is 6.3  Thanks


----------



## mavrik (Nov 23, 2004)

It depends on the sensor.  I've heard that you can get just as good of pix from the 1D as from the 20D, but I'm not convinced.  If it were me, I'd either get the 1D MK II or the 20D.  Not the 1D itself.  

M


----------



## Digital Matt (Nov 23, 2004)

Megapixels directly affect print size.  If you want a high res 16x20 print, it's 4800 x 6000 pixels at 300dpi.  An 8 mp camera won't have to stretch as far to get those dimensions.

However, if a 6.3mp jpg has less noise and is sharper than an 8mp one, it will look better at a bigger size.

A lot of it will be specific to what you are shooting, but in general, more megapixels make larger prints easier.


----------



## Bokeh (Nov 23, 2004)

Digital Matt said:
			
		

> Megapixels directly affect print size.  If you want a high res 16x20 print, it's 4800 x 6000 pixels at 300dpi.  An 8 mp camera won't have to stretch as far to get those dimensions.
> 
> However, if a 6.3mp jpg has less noise and is sharper than an 8mp one, it will look better at a bigger size.
> 
> A lot of it will be specific to what you are shooting, but in general, more megapixels make larger prints easier.



Matt,

That was my understanding as well.  I wish I could afford an mkII but alas even on an IT salary that is out of reach    Looks like the 20d is my best bet. I have read it's pretty good for sports, but not what most of the pros use.  One step at a time I guess, thanks


----------



## Digital Matt (Nov 23, 2004)

Ryan Gracie said:
			
		

> Matt,
> 
> That was my understanding as well.  I wish I could afford an mkII but alas even on an IT salary that is out of reach    Looks like the 20d is my best bet. I have read it's pretty good for sports, but not what most of the pros use.  One step at a time I guess, thanks



Ryan,

I suspect that pros do use a 20D, and the only reason that they wouldn't is because they already have a 1D, or 1D MKII.  I'd still be willing to be that a lot of them bought one as backup.


----------



## DocFrankenstein (Nov 23, 2004)

How big are you gonna print?

I've done 13*19 prints from the rebel.


----------



## Bokeh (Nov 24, 2004)

DocFrankenstein said:
			
		

> How big are you gonna print?
> 
> I've done 13*19 prints from the rebel.



How did they look?


----------



## Digital Matt (Nov 24, 2004)

I've printed 20x30s that look amazing.


----------



## jadin (Nov 24, 2004)

Digital Matt said:
			
		

> However, if a 6.3mp jpg has less noise and is sharper than an 8mp one, it will look better at a bigger size.



That's only true if the sensor sizes are the same dimensions but different pixel counts. If the actual sensor of the 8mp is larger, than it can be just as clear and noise free as the 6.3mp one.

You can look up actual sensor sizes for your camera at dpreview.com. The bigger the pixel the better.


----------



## Corry (Nov 24, 2004)

My boyfriend printed a 20x30 from his rebel that looked awesome too.  It's of Chicago from the Sears Tower...really awesome stuff.


----------



## Jeff Canes (Nov 24, 2004)

The only real avenge of the 1D MKII 8mp or 1D 4mp (old model) is speed, they both shot at 8fps, on the 1D MKII the bursts is 40 frames, good for sports or models on the runway. D20 is basically just slower and about 2000 dollars less. The older 1D is still a good option for sport reporting, because the 4mp is fine for newspapers

Now 1Ds MKII is hold differ story 16.7mp, 4fps, burst 36 frames

Personally I would like a 1D MKII for shooting baseball.


----------



## Digital Matt (Nov 24, 2004)

jadin said:
			
		

> Digital Matt said:
> 
> 
> 
> ...



I'm talking on a picture to picture basis.  An 8mp shot at ISO 800 and 4 seconds will not look as good at 20x30 as a 6mp shot at 1/200 and ISO 100.  Or if the the 6.3mp is just a sharper image.  90% of getting good large prints is having a tack sharp (tripod sharp) image that is very clean.


----------



## jadin (Nov 24, 2004)

I don't understand why you'd even compare the two like that. It's apples to oranges.

I could also say an 8mp 1/200s at ISO 100 will look better than a 6.3mp 4s at ISO 800. But it doesn't prove that the 8mp camera is cleaner or sharper. I don't get what you're trying to prove. Are you trying to justify your 6.3mp purchase?!?


----------



## Big Mike (Nov 24, 2004)

I think he's trying to say that mega pixel count does not matter as much as picture sharpness.  You can get better prints with a clean & sharp photo from a 6 MP camera than you can with not so sharp photos from an 8 MP camera.

The point is...using a tripod and other techniques for optimal sharpness can outweigh MP count when you are making large prints.


----------



## jadin (Nov 24, 2004)

But implying that the 8mp camera will by default do worse, is quite simply not true. Given equal setups (same tripod, same lens, things like that) megapixel count has no bearing whatsoever on how clear a photo will be. Sensor size on the other hand does.


----------



## Big Mike (Nov 24, 2004)

jadin said:
			
		

> But implying that the 8mp camera will by default do worse, is quite simply not true. Given equal setups (same tripod, same lens, things like that) mega pixel count has no bearing whatsoever on how clear a photo will be. Sensor size on the other hand does.



I don't think he is implying that at all.  Given equal set ups...you are correct, but he is saying that the set up that you use is more important that the number of MP you are recording...and possibly the size of the sensor (within reason).

So when someone asks how big of a print (acceptable quality) they can make...it depends on the file size (MP count), noise levels (Sensor size) and sharpness (technique, lens, software etc.).

That's how I see it anyway.


----------



## voodoocat (Nov 24, 2004)

I'd put megapixel count lowest on the list of factors required for a good large print.  Sensor size and sharpness (lens and tripod) are far more important.


----------



## Jeff Canes (Nov 24, 2004)

voodoocat said:
			
		

> I'd put megapixel count lowest on the list of factors required for a good large print.  Sensor size and sharpness (lens and tripod) are far more important.



Ditto, but of those I would but the lens as the most important


----------



## DocFrankenstein (Nov 24, 2004)

Ryan Gracie said:
			
		

> DocFrankenstein said:
> 
> 
> 
> ...


They looked really good. I upsized them in the photoshop, so that you can't see individual pixels... etc... But it's nice and sharp

Of course, if you look at it from 8 cm and get really anal.... You could say that the detail is "smooth" or something...

But the rebel produces 3000 by 2000 file... 19 inches... 

3000/19=157 dpi 

If you consider that most of the color magazines print at 75 dpi and I think the maximum is 150 DPI...

You should be ok with the rebel sensor. Just don't shoot with 24-300 zoom


----------



## voodoocat (Nov 24, 2004)

> If you consider that most of the color magazines print at 75 dpi and I think the maximum is 150 DPI...


where'd you get that # from?
Magazines print between 200-399 dpi for the most part.  Digital and 35mm usually doesn't get printed higher than maybe a half page in magazines.  For full page prints the quality magazines require medium format and larger.


----------



## DocFrankenstein (Nov 24, 2004)

voodoocat said:
			
		

> > If you consider that most of the color magazines print at 75 dpi and I think the maximum is 150 DPI...
> 
> 
> where'd you get that # from?
> Magazines print between 200-399 dpi for the most part.  Digital and 35mm usually doesn't get printed higher than maybe a half page in magazines.  For full page prints the quality magazines require medium format and larger.


I may be wrong, but I remember seeing figures of that order somewhere on luminous landscape and an offset printing book I read 2 years ago. 

I can't find any quotes. Again... I may be wrong, but I do remember the 150 DPI for "quality glossy magazines" from some professional book about printing.

But it may be 300 dpi too...

Most of the physiology books claim that the human eye by itself can't distinguish detail finer than .1 mm.

It doesn't make sense to print at more than 230? LPI or something like that...

And considering the viewing distance for 13*19 poster... I think 157 DPI is adequate. IMHO


----------



## Digital Matt (Nov 24, 2004)

jadin said:
			
		

> I don't understand why you'd even compare the two like that. It's apples to oranges.
> 
> I could also say an 8mp 1/200s at ISO 100 will look better than a 6.3mp 4s at ISO 800. But it doesn't prove that the 8mp camera is cleaner or sharper. I don't get what you're trying to prove. Are you trying to justify your 6.3mp purchase?!?



I made a comparison to illustrate the fact that resolution does not = sharpness, and that getting large prints is not solely dependant on megapixels.  I never said, or implied that an 8mp camera will default to worse.  As Big Mike and others said, megapixels are really not the most important thing, and I'd hate to see someone buy a large mp camera and automatically expect to get good enlargements.

As far as 75 DPI, be careful when you say DPI.  There are two terms involved in printing.  Dots per inch, and LINES per inch.  Printers use lines per inch, and DPI.  75 LPI is 150 PPI.  Pixels  are for your screen.   75 LPI, or 150 DPI may be fine for newspapers, but high res photo prints are done at 150 LPI, 300 PPI, and no less, when quality is a must.  My 20x30s from my Rebel print at 200 DPI and look good, but you are viewing them typically from a few feet away.  All of our prints at work ( I work for a photo digital photo studio) are done at 300 PPI.


----------



## jadin (Nov 24, 2004)

Digital Matt said:
			
		

> I made a comparison to illustrate the fact that resolution does not = sharpness, and that getting large prints is not solely dependant on megapixels.  I never said, or implied that an 8mp camera will default to worse.  As Big Mike and others said, megapixels are really not the most important thing, and I'd hate to see someone buy a large mp camera and automatically expect to get good enlargements.



Roger that. To me it sounded like you trying to imply that the 6mp would be automatically better, which wouldn't add up. Looks like we're both arguing for the same thing.


----------



## TomRussell (Dec 20, 2004)

sorry to resurrect an old subject but..

i've personally seen 20x30 prints (off true photographic stuff) made from a 3 megapixel camera. that look absolutely amazing. Obviously the image was resampled upwards so the final print is at about 150-300 dpi, but that doesn't change the fact that the image that was there in the beginning was from a 3 megapixel camera.

Once you reach above 8x10/8x12, the ball game changes - resolution doesn't come into it so much. You don't eye something that large close up with a magnifying glass, if you do, sure you'll see a loss of clarity, but you don't normally look at something like that up close - it's to be viewed from, say, a pace back while the photo is hanging on a wall. There, a 3 or 4 megapixel camera, so long as you resample the image upwards, can look absolutely stellar.

If you've got a good picture, print it.

You have no excuses.


----------



## hlasso (Dec 21, 2004)

DocFrankenstein said:
			
		

> ...
> You should be ok with the rebel sensor. Just don't shoot with 24-300 zoom


Interesting...

I just bought a Canon Digital Rebel and attached it my Canon 75-300 USM lens. I can clearly see that shots with this lens are less sharp than those with the one enclosed with the camera.

Is this due to the lens (too slow) or something else?

Should I shoot a higher speeds? (e.g. 1/480 with 300mm focal length)

I'm about to shoot some portraits of my family and friends, so I'd use a 135mm or so focal length, but I also want to print the pictures in a reasonable size... Am I missing something?


----------



## Big Mike (Dec 21, 2004)

hlasso said:
			
		

> DocFrankenstein said:
> 
> 
> 
> ...



I think that lens is known for being a little soft...especially at full zoom.

If you are shooting hand held...you should keep the shutter speed (denominator) close to or over the focal length.  I think the 1.6 crop factor applies for this rule of thumb.  So when shooting at full zoom, you would want the shutter speed to be 1/500.  To get that speed in less than bright sun light you will probably have to jack up the ISO because opening up the aperture will not be enough.  A nice fast lens would help too.

To get around this, you can use a tripod &amp; remote release (or self timer).  This is always a good idea if you want to make enlargements anyway.


----------



## voodoocat (Dec 21, 2004)

The crop factor shouldn't have an effect on the 1/focal length rule.  The image isn't being magnified any more than a 300mm so you would still go with 1/300 as a safe handheld shutter speed.


----------



## DocFrankenstein (Dec 21, 2004)

voodoocat said:
			
		

> The crop factor shouldn't have an effect on the 1/focal length rule.  The image isn't being magnified any more than a 300mm so you would still go with 1/300 as a safe handheld shutter speed.


If you want to make a print of the same size, then you have to multipy by 1.6



> Interesting...
> 
> I just bought a Canon Digital Rebel and attached it my Canon 75-300 USM lens. I can clearly see that shots with this lens are less sharp than those with the one enclosed with the camera.


18-55 you mean?



> Is this due to the lens (too slow) or something else?


It's a "cheap" consumer lens. It's not designed to give sharp pictures or to focus quickly.


> Should I shoot a higher speeds? (e.g. 1/480 with 300mm focal length)


I think 1/300th would be ok if you hold your cam steady.



> I'm about to shoot some portraits of my family and friends, so I'd use a 135mm or so focal length, but I also want to print the pictures in a reasonable size... Am I missing something?


It's only sharp when you stop it down to f/8, but then you'd lose the bokeh. If you open it up all the way, you have an OK bokeh, but you lose the sharpness...

You need a better lens. Try 50/1.8... it's a good lens and costs 70 bucks. Good for portraits too. 

Then you'll see the difference between a good lens and a bad lens


----------



## voodoocat (Dec 21, 2004)

DocFrankenstein said:
			
		

> voodoocat said:
> 
> 
> 
> ...


I was talking about the rule for getting a sharp photo without the aid of a tripod or stabilizing device.  The focal length never changes with the crop factor so it's the same exact magnification regardless of film format.  A 300 lens would require ~1/300 shutterspeed when shooting handheld.


----------



## DocFrankenstein (Dec 22, 2004)

voodoocat said:
			
		

> I was talking about the rule for getting a sharp photo without the aid of a tripod or stabilizing device.  The focal length never changes with the crop factor so it's the same exact magnification regardless of film format.  A 300 lens would require ~1/300 shutterspeed when shooting handheld.


Would you like to extend this rule to small sensor digicams?

For example: Canon S1 IS has a sensor of around 3*3 mm. The lens built into the camera has focal length from around 4.5 mm to 38mm or something like that, which is an equivalent to 300mm at the telephoto end. If applied the same terminology as DSLR, it has a crop factor of (let's say) 10...

Now, by your rule, I should consistently be getting sharp pictures handheld at 1/30th of a second, even though the equivalent focal length for full frame is 300 mm. 

Good luck with that!

Therefore, you'd have to multiply the focal length of the lens by 1.6...


----------



## jadin (Dec 22, 2004)

No, no, you're missing the point.

The crop factor changes how much of the lens is captured. The crop factor does not change the focal length. Therefore the rule of 1/focal length therefore remains the same.

Does that make sense?


----------



## hlasso (Dec 22, 2004)

To all of those who replied: Thank you very much.

I was afraid the problem would be the lens. Now I'm sure.

DocFrankestein: Yes, the camera ships with an 18-55mm lens. What I meant is that I attached a lens I had from my previous EOS camera, a 75-300 USM.

I'll try taking pictures with a tripod and/or with fast shutter speeds (1/500). I'll also try getting a faster lens such as the EF 135mm f/2L.

BTW, is it a rule (or technical issue) that zoom lenses are slower than fixed focal length lenses? Most fast lenses I have seen have fixed focal lengths...

Thank you again


----------

