How Many Pixels?
A reasoned approach to digicam specifications
(And a minor rant by Dave in defense of the "happy
snapper.")
Why this article?
As we write this article, much of the digital camera world is
breathlessly awaiting the imminent arrival of the 2 megapixel
("2MP" hereafter) digital cameras: Those having more
than 2,000,000 pixels on their CCD sensors. In the newsgroups
and discussion forums, and in our own email correspondence, these
new devices appear to be assuming the significance of the Holy
Grail to digital photography: Many, many photographers appear
to be holding off on their purchases, wanting to get the very
latest technology, convinced that the only cameras they should
be considering are those with 2MP or more in their sensors.
This is certainly understandable, given the rapid pace at
which the whole digital camera marketplace is evolving: Today's
hot technology is next week's bargain-bin throwaway, or at least
so it's seemed over the course of the last year. With technology
moving so fast, it certainly makes sense to buy only the very
latest, in order to get the maximum return on your investment...
Or does it?
While our early tests with the Nikon CoolPix 950 and Olympus
C-2000 Zoom certainly suggest that the 2MP digital cameras hold
great things in store for the digital photography community,
we feel that many people are being caught up by a whirl of specmanship,
fueled by the manufacturers continual search for an "edge"
to propel their sales ahead of their competitors. In the process,
we think many excellent bargains in the marketplace are being
overlooked, to the consumers' detriment. Hence this article,
intended to focus attention more clearly on various reasons for
buying a new digicam, and to help bring some perspective to the
issue of resolution.
It's not just about resolution
There are many reasons to choose one digital camera
over another, only one of which is the resolution and level of
detail each is capable of capturing. This may seem obvious, but
as we'll see, it's important to separate-out the various factors
influencing your purchase.
Besides resolution, you should be looking at other image-quality
aspects, such as color rendition, noise, and tonal range. To
an even greater extent, you need to look at other features and
factors that will affect your use of the camera: Do you want
lots of control over the picture-taking process, or would you
prefer the camera to attend to details of exposure, shutter speed,
etc? How big a factor is the physical size of the camera? (A
big, bulky camera that gets left in a drawer at home may not
be as suitable as a more compact one with fewer features, but
that goes everywhere with you.) Then of course, there are all
the other issues, such as the software bundle that accompanies
the camera, how it connects to your computer system to transfer
images, etc.
High-end, "Creative Control"
may be a valid reason to wait
One characteristic that's prominent in some of the
latest offerings is the dramatic increase in the level of photographic
control offered by the new 2MP designs: Both the Olympus C-2000
Zoom and Nikon CoolPix 950 offer significantly greater control
over the picture-taking process than their predecessors, including
features such as shutter- and aperture-priority metering, and
extended ISO (light sensitivity) capabilities. But then, so do
at least some other recent, non-2MP entries in the market, notably
the Canon PowerShot Pro70, and the Sony D700, with 1.7 and 1.3
megapixel sensors, respectively. Overall, we're seeing a general
trend for digital cameras to provide greater levels of creative
control than has previously been the case. As noted though, there
are products already on the market that offer some of this, and
not all users need or want this level of sophistication
Take note of that last comment: Not everybody wants
or needs the level of control offered by some of the newer camera
models. Snobbish photo buffs look down their collective
noses at the "happy snapper" who's content to let the
camera handle the exposure and shutter speed, but nobody need
feel any shame at including themselves in this category: Getting
decent-looking pictures without spending a lot of time fiddling
with knobs, menus, and buttons is an entirely valid photographic
objective! If that's your primary interest, then why should you
spend hundreds of dollars more for a camera model sporting multiple
exposure modes and menu options that you'll never use? Some may
argue that it's limiting to buy a camera without manual control
options, but the fact is, I personally know many people who derive
great pleasure from their picture-taking, yet have very little
idea of the effect of different lens apertures and shutter speeds
on the images they capture. More power to them! If they're enjoying
their hobby, then far be it from me to insist that they "really
ought" to learn more about basic exposure principles, to
expand their creative options!
Cramming in a few more pixels may not be...
- A reason to wait, that is. Here's the big secret:
2 million pixels really isn't such a huge step beyond 1.5 or
even 1.3 million pixels! Think about it: At the upper end of
the sub-2MP cameras on the market, we have devices with image
sizes of 1536x1024. Relative to the 1600x1200 image size of most
forthcoming 2MP designs, that's only 64 pixels less horizontally,
and 166 pixels vertically! Clearly, this isn't much of a difference!
Even at the common 1.3 MP size of 1280x960, the difference is
less than you might expect.
The proof is in the pictures:
See for yourself: Here are some sanity-inducing sample
images, courtesy of the Imaging Resource. We could argue the
theoretical merits of this issue all day, but in the case of
digital cameras, a picture is really worth a lot more than a
thousand words. To that end, we've prepared a set of sample images
that our readers may find instructive in evaluating the differences
between the new 2MP designs and previous generations of digicams
What we wanted to do here was to eliminate the variables of
optical design, color quality, and other non-resolution issues
that will exist between different digital cameras. In order to
focus solely on the pixel-count issue, we've prepared some sample
images from high-resolution PhotoCD Pro scans of a 35mm slide.
The sample images below were created by down-sampling a high-resolution
PhotoCD scan of a 35mm slide to four common digital camera resolution
levels: 1600 x 1200 pixels, 1280 x 960 pixels, 1024 x 768 pixels,
and 800 x 600 pixels. The resampling was performed in Photoshop,
using bicubic spline interpolation. (No arguments allowed about
the relative merits of bicubic splines vs. Mitchell interpolation,
etc!) Since it's beastly hard to accurately judge relative resolution
in images of different sizes, we then re-sampled all of the test
images back UP to 1600 x 1200, to provide a consistent basis
for comparison. We then took identical slices of each image,
and arranged them in the table below. Take a look at these: How
big a difference do you actually see between the slices from
the 1600 x 1200 and 1280 x 960 images? Surprisingly little difference,
isn't there?
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Printing is Believing
Throughout this site, we encourage people to download our sample
images, and output them on their own printers: This is the truest
test of what an image will look like in your own environment.
Here, we provide links to two different sets of images. On the
top row of the table below, you'll find links to the images which
were re-sampled back up to 1600x1200 pixels, from whatever resolution
level they were originally reduced to. (These are the images
from which the clips above were taken.) The second row of the
table contains the "original" images at the resolutions
listed above. (For instructions on printing these images at a
consistent size for comparison purposes, see the "Choosing a Camera"
article by Barbara Coultry.) We encourage you to download the
images and print them out, to see the magnitude of differences
you may (or may not) find between many current digicam models
and the new 2MP designs.
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1600x1200 (524k) |
Resampled up to 1600x1200 (508k) |
Resampled up to 1600x1200 (480k) |
Resampled up to 1600x1200 (452k) |
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1280x960 (444k) |
1024x768 (304k) |
800x600, (208k) |
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The Bottom Line
While the new 2MP digital camera models in many cases
offer a host of new and exciting features (as well as marginally
improved resolution), we're convinced that many buyers are missing
some great bargains in the marketplace: Older digicam models
have had a longer trip down the manufacturing learning curve,
and are often available at drastically lower prices than the
latest designs. By settling for a fairly minor reduction in maximum
resolution, you could end up saving literally hundreds of dollars
relative to the very latest 2MP camera designs!
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