Thursday, April 11, 2013

That megapixel race...

A friend recently asked me my opinion about image quality differences between the three Canon 5D full frame camera models.  He seems to love an apparently vast improvement in clarity having moved from the first 5D to the MkII, and he wondered if there would be a similar improvement in moving to the MkIII.


The question deserved an answer as I think people in general might not appreciate or understand what's really going on with sensor sizes.

Camera manufacturers fuel discussions about mega-pixels and sensor qualities.  There are testing labs that compares camera sensors and lenses.  Large forums are devoted to discussing the minutia of every camera and lens ever made. Readers follow these sources of information very closely looking for an edge.  They seem to be looking for something that will add a bit of spark to their image making.  Or perhaps instead they feel the need for bragging rights in some kind of photographic horsepower competition?

Yet, if we were completely honest with each-other, everyone would fail to be able to tell you what camera, sensor size, and lens were used between one image and another without looking at the EXIF information.  So, to answer my friend's question, here is what I said:


Do you want the truth?  Here it goes.

Your 5D at 12 mega-pixels gives you image sizes of 4368x2912.

Your 5D MkII at 21 mega-pixels gives image sizes of 5616x3744.

A print at 300 DPI out-resolves the human eye.  Anything more than this is throwing away resolution and is completely and utterly useless. 

Dividing the long dimension of each image size, we find that:

5D 300dpi images print 14.5inches in the long dimension and with image quality exceeding the limit of human vision.

5D MkII 300DPI images print 18 inches in the long dimension with the same resolution limitations.

Can you really tell any difference between 3.5inches worth of resolution?  I doubt it.  Seriously. If we think we see a difference, it's in our mind's eye and desire to believe something is better than another.

That's just the way it is.


Which is why I'm not ready to move to another camera unless I break one or Canon comes out with an affordable 50+mpixel image monster and insanity gets the better of me.

After replying to my friend, I remembered a short conversation I had with Kerik Kouklis.  He pointed out that some of his best work had been made using a 12 megapixel Canon 5D.  Up to that point, he'd been using (and I believe he still does use) very large format film cameras.  The digital negative 5D images contact printed to 20x24inches pleased him.  He told me it was difficult to tell the difference between an original film contacts and his digital contact prints.

That was way back when 12 megapixels were the most affordable thing in Full Frame digital.  Oh, yes, that was only six years ago.  Whew! time flies.

OK.  So I continue to beat the Cameras are Tools drum.  Sorry.