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100% crops at ISO 1600 of sensor pitches 3.3µm², 4.9µm², 34.5µm² and 67µm². See the difference?
What's going on out there?
In the preceding pages I discussed the theory behind the functioning of digital cameras and their inherent inefficiencies and limitations, in particular the limitations on resolution, both spatial and dynamic. Now I wish to talk about what manufacturers are actually doing with respect to resolution and look at the models they are releasing.
The tail wagging the dog
The modern market-driven approach to design means that manufacturers produce the goods that customers BUY. This works fine when the customer is knowledgeable and experienced but sadly, most of the time the customer is an ignorant novice who buys whatever the salesperson can sell them. This problem occurs throughout the modern world, from motorcars to fast food, but it is especially tragic when it comes to cameras. The fact is that digital cameras are COMPLEX beasts, and it takes a lot of effort and intelligence to fully understand them. The average user just wants to point and shoot. They don't want to know about quantum effects and demosaicing. They want to be able to compare cameras with a simple number. Unfortunately the number they have latched onto is MEGAPIXELS. The ignorant consumer thinks more Megapixels is better so the manufacturers give them more Megapixels. Unfortunately this has destroyed the ability of these cameras to produce good quality images.
The manufacturers don't care
The manufacturers are not ignorant. They know what they are doing. They know that their small cameras are not producing the quality that they ought to. But THEY DON'T CARE! Modern businesses are morally bankrupt. They have no ideology beyond maximising their profit and gaining market share. They have no love of their own product. They might just as well be in detergents. It's all about marketing theory, efficient management and fiscal practice. It was not always so: Once the products of these companies were the pride and joy and life's work of driven men, like Kumao Kajiwara, Takeshi Mitarai and Johann Voigtländer, now they are merely corporate assets in the global share market. Sad, is it not.
Digital Camera Resolution At A Glance
Here is a table of pixel pitches for a number of different camera models and sensor formats in order of increasing pixel pitch:
| Camera Model | Sensor Format |
Sensor Dimensions (mm x mm) |
Sensor Area (mm²) |
Mega Pixels |
Pixel Pitch (µm²) |
Comment |
| Sony IMX060PQ | 1/2.5" | 5.8 x 4.3 | 25 | 12.5 | 2.0 | Cell phone camera chip with 1.4µm pixels and 12MP. Sony have no morals. |
| Omnivision OV08810-AL9A | 1/3.2" | 4.6 x 3.4 | 15.6 | 8 | 2.0 | Another crap cell phone chip. |
| Nikon Coolpix P90 | 1/2.3" | 6.1 x 4.6 | 28.1 | 12.7 | 2.2 | No excuses for the worst camera Nikon. Horrendous! Shame, shame, shame. |
| Canon SX200 IS | 1/2.3" | 6.2 x 4.6 | 28.5 | 12.1 | 2.4 | And Canon are nearly as bad.. |
| Canon SD870 IS | 1/2.5" | 5.8 x 4.3 | 25 | 8.3 | 3.0 | Standard rubbish compact of today. |
| Sony DSC-H10 | 1/2.5" | 5.8 x 4.3 | 25 | 8.3 | 3.0 | |
| Omnivision OV05620-C03A | 1/2.5" | 5.8 x 4.3 | 25 | 5 | 4.8 | Almost reasonable cell phone camera chip. |
| Fuji S5600 | 1/2.5" | 5.8 x 4.3 | 25 | 5 | 4.9 | I thought this was poor when it came out. Things are much worse now. |
| Fuji F10 | 1/1.7" | 7.6 x 5.7 | 43 | 6.3 | 6.8 | People acclaimed this at the time. It's all in the pixel pitch. |
| Canon A610 | 1/1.8" | 7.2 x 5.3 | 38 | 5 | 7.6 | My beloved and lamented A610. One of the best compacts ever made. |
| Canon G5 | 1/1.8" | 7.2 x 5.3 | 38 | 5 | 7.6 | Based on specs the best compact ever made. If only they would remake this... |
| Aptina MT9D011D00STC | 1/3" | 4.8 x 3.6 | 17.3 | 2 | 7.8 | Super-spec cellphone camera chip. |
| Kodak DX3600 | 1/2" | 6.4 x 4.0 | 26 | 2.2 | 11.6 | 2001. Who'da thought it. Pixels were bigger in those days. |
| Panasonic DMC-G1 | 4/3" | 18.0 x 13.5 | 243 | 13.1 | 18.5 | This is the problem with 4/3, they can't compete with APS. |
| Olympus E420/E3 | 4/3" | 18.0 x 13.5 | 243 | 11.8 | 20.6 | Ok, but not as good as an APS. |
| Pentax K20D | APS | 23.4 x 15.6 | 365 | 15.1 | 24.2 | Here we see APS sliding into the abyss. You've lost your way Pentax! |
| Sony A350 | APS | 23.6 x 15.8 | 373 | 14.9 | 25 | Sony have no morals |
| Canon 450D | APS | 22.2 x 14.8 | 329 | 12.4 | 26.5 | |
| Sony A700 | APS | 23.5 x 15.6 | 367 | 13 | 28.2 | |
| Nikon D5000/D300/D90 | APS | 23.6 x 15.8 | 373 | 13.1 | 28.5 | The APS King! Thanks to the CMOS sensor and Nikon quality. |
| Canon EOS 400D/40D | APS | 22.2 x 14.8 | 329 | 10.5 | 31.3 | If only they focused properly... |
| Sony A900 | 35 mm | 36 x 24 | 861 | 25.7 | 33.5 | Stop right there Sony. You've got your fat cam, now where's your fast cam? |
| Nikon D3x | 35 mm | 36 x 24 | 861 | 25.7 | 33.5 | Copying Sony are we Nikon? But you've got a fat cam AND a fast cam. |
| Pentax K200D/K10D | APS | 23.5 x 15.7 | 369 | 10.7 | 34.5 | This is about where the APS should sit. The perfect size for most of us. |
| Sony A100/A200/A300 | APS | 23.6 x 15.8 | 373 | 10.8 | 34.5 | |
| Nikon D3000/D60/D40X | APS | 23.6 x 15.8 | 373 | 10.8 | 34.5 | My beloved D60! |
| Canon 5D Mk2 | 35 mm | 36 x 24 | 864 | 22 | 39.3 | Bad move Canon. You turned your King into a fat cam. You've already got a fat cam: the 1Ds |
| Canon EOS 1Ds Mk3 | 35 mm | 36 x 24 | 864 | 21.9 | 39.5 | Canon's fat cam. Now what lens can I use? |
| Canon EOS 1D Mark III | APS+ | 28.7 x 18.7 | 537 | 10.7 | 50.2 | What is the point of this format? Might as well be 35mm. Dumb! |
| Canon EOS 1Ds Mk 2 | 35 mm | 36 x 24 | 864 | 17.2 | 50.2 | A good blend of high resolution and sensitivity. |
| Nikon D40 | APS | 23.5 x 15.5 | 364 | 6.3 | 57.8 | Some regard this as one of the best cameras ever made. Cheap too! |
| Canon 5D Mk1 | 35 mm | 36 x 24 | 864 | 13.3 | 65 | The old low-light King! |
| Nikon D3/D700 | 35 mm | 36 x 24 | 864 | 12.9 | 67 | Hail to the King Baby! |
| Mamiya ZD | Medium | 48 x 36 | 1728 | 21.8 | 79.3 | Just put this in for interest, not hugely better than 35mm actually. |
| Hasselblad H3D 22 | Medium | 49 x 37 | 1813 | 22 | 82.4 | Who uses medium format anyway? |
How much resolution do you need anyway?
Your 24" computer monitor might be 1920 x 1200 pixels. I bet you think that's fantastically detailed. Your best pictures look stunningly sharp don't they. Well such a monitor has a display width of 20.4". Divide 1920 by 20.4 and you get a display resolution of 94 pixels to the inch. Check out your high definition TV. Say you have a 46" LCD HDTV, I bet you think your Blue Ray images are beautifully sharp. If you use it to display computer images at full HD I bet you reckon they look great! It has a display width of 40" which gives a display resolution of 48 pixels per inch.
My old 5MP camera produced images 2592 x 1944 pixels in size. This is considerably more than you can squeeze onto your high def screen at a time. Bear in mind, YOUR HIGH DEF SCREEN IS ONLY 2 MEGAPIXELS! My 10MP SLR produces images at 3888 x 2592. That is more than double the display resolution in each dimension! Why do you need pictures bigger than the screen?
Yes it's nice to be able to zoom in on an image and surf around for a while but how often do you do that? I bet most of the time you just page through them at full screen.
Wikipedia assures me that the maximum resolving power of the human eye is 50 lines per subtended degree. This equates to 146 lines per inch at a distance of ½ meter, which is a typical viewing distance. But that is a best case scenario, with a high contrast test image. The real world requirement is rather different as the TV and monitor examples demonstrate. In fact, unless you get as close as your eye can focus, 100 pixels to the inch is plenty.
At 100 pixels to the inch, your 5MP image will be 26" x 19.5" in size and you will need to look VERY closely before you will see individual pixels. That is a small poster! At 10MP you can blow your image up to 39" x 26". That IS a poster!!! Do you print your photos at poster size?
I have done 50% crops on 5MP images and printed them out at 6" x 4" and they are perfect! You only need 2MP for snaps. And what is overwhelmingly the size that people print out? You know it: 6x4! Are you happy with your 6x4s?
It's nice to be able to crop an image down to exclude distracting elements or to magnify the subject. But even a 5MP image can be halved and still make a perfect 6x4. How much extraneous image do you want? Do you crop your photos down ruthlessly, by 80%? Perhaps you should spend more time on composing the image correctly to start with.
Yes there are reasons why you might need more than 5MP, but unless you are making professional high res posters, or cropping the bejesus out of the image, or spending all your time surfing around in the image, they don't apply to you... do they? Certainly the happy snapper does not have any use for 10MP images. All they do is slow the process down, take up too much room and produce a rubbish result. Back to 6MP with you!
Lens problems
OK, in the upper reaches of sensor size it is possible to get resolutions over 20 MPs whilst still maintaining good image quality, but can the lens take it? Perhaps some of the best primes, but I doubt the zooms are able to resolve to that level. Remember folks: "There is no point in a sensor that has greater resolving power than the lens!"
So what's to be done?
What must be done is that the manufacturers must be forced to concentrate on image quality, that is: the quality of each pixel, which will involve adopting a sensible approach to pixel pitch and resolution over a range of categories. Since they are never going to work this out themselves I have gone to the trouble of setting it all out in the following page, entitled: "The Martian Digital Camera Categorisation Scheme". It will then be up to the companies and independent reviewers and websites to educate the public and sales staff that "More Megapixels" is bad and "The Martian Scheme" is good. Pick your category from the The Martian Scheme and, so long as the camera is well made, you will get a camera that will make you happy.
Simple as that!