Senseless megapixels

The image above is a sunset I took recently looking west across the railway tracks at Blackheath. As displayed here, the image measures 408x274 pixels (111,792 pixels in all).

Ken Rockwell is a blogger who is well worth a read. He got to be well known by making controversial statements and expressing over-the-top opinions. Why not? Doing the latter has made him very successful. Check out this article entitled "Your Camera Doesn't Matter" at http://www.kenrockwell.com/tech/notcamera.htm

One of the things that makes Ken annoying for many people is that very often his seemingly outrageous views are spot on. "Your Camera Doesn't Matter" is a case in point. For potentially serious photographers, the message is clear. Beyond a certain easily reached point, for all the things that REALLY matter in a great image, the alleged differences between cameras and lenses don't matter.

I'll go further. Despite what the pixel peepers will tell you, for most display purposes, under optimum conditions, there will be no real noticeable difference in image quality, no matter what modern camera you buy. If you are obsessed with finding out the truth about which of those shiny new cameras in the Harvey Norman display case is actually the BEST, forget it. There IS no BEST camera. Almost ANY new digital camera will be capable of providing terrific image quality .... end of story.

This is not to say that all cameras are created equal. Each device is optimized for use under particular conditions and for specific purposes. But the REAL quality differences between images invariably come about because of non equipment factors such as lighting, composition and a photographer's technical skill.

A lot of new photographers (and even some photographers who should know better) have been led to believe in the universal digital camera "goodness" factor. Manufacturers would love you to believe that "the more megapixels, the better quality the image". That keeps everything nice and simple does it not? If one succeeds in convincing new camera purchasers that "more megapixel good - less megapixel bad" it then becomes simple to massively increase sales of one's product by just increasing megapixels. What could be easier? Yet another triumph for the marketing department.

Here are a few facts to help explode the megapixel myth. Go to this address: http://www.pbase.com/yp8/image/22187488

This is one of the beautiful images to be found on Yves Pinsonneault's wonderful galleries. It may prove useful to explore his website and let yourself become inspired. In any event the image I asked you to find looks good on your computer screen does it not? That image, as displayed measures 800x554 pixels and could theoretically have been shot by a digital camera with a 443,200 pixel sensor i.e. a little less than HALF a megapixel. When you consider that most images are now viewed on computer screens, it seems almost ridiculous to be obsessing over 15 megapixel sensors (30 times the resolution), doesn't it?

What on earth, therefore, is the benefit of all those megapixels so often gushed over by the salesmen at the counter? The answer, as always, is .... it depends. One thing in particular needs to be emphasized. Increasing the number of pixels in an image (beyond a point reached several years ago) has little or nothing to do with improving image quality. It IS for the purpose of increasing an image's potential display size.

In the interests of saving time here are some sweeping (but accurate statements) about resolution.

If all you want to produce are lovely images on a computer screen and sharp 8x6 inch prints, a 3 (that's right! 3!) megapixel camera is as much as you will ever need. You will not see any increase in image quality for those display purposes on the basis of higher resolution alone.

If you want to produce A4 or (say) 12x8 inch prints, 6 megapixels is more than enough. NO visible increase in image quality for those display purposes can be obtained using higher resolution sensors. In fact I have often produced beautiful 18x12 inch prints from 6 megapixel images which were effectively indistinguishable from the same subject shot with a 10 megapixel camera. For computer display, email sharing and such you will need to actually REDUCE the size of 6 megapixel images.

If you start with a solid noise free image, I find that you can interpolate an image by up to 50% without any loss of picture quality that yours truly can detect. Thus a 6 megapixel image is really a 9 megapixel image and an 8 megapixel image is really a 12 megapixel image in any event.

Here is an excellent article by Thom Hogan about the relationship between megapixels and image size: http://www.bythom.com/printsizes.htm

The point I am making is that for the vast majority of us, 6-10 megapixels is MORE than enough to produce breathtaking images for most display applications we are likely to encounter. Certainly the 15-24 megapixels offered by the latest models is (for most of us) decidedly overkill. The pity is that as we rush headlong into ever higher resolutions, picture quality starts to DETERIORATE rather than improve. I'll show you why in the next article.

See my work at: www.pbase.com/davidhobbs