The perfect Camera
The search for the “perfect camera” is as old as photography itself.
When you ask anyone what their opinion is on this topic, you will get as many answers as there are photographers.
Your best answer will come from your own head, after you resolve the same issues you would personally be facing when choosing a golf club, cricket bat or tennis racquet.
How do plan to use it? What is your ultimate goal? And (most important) How much money can I spend?
To begin with, there is no general "perfect" camera. Most serious photographers own more than one camera, because different circumstances require different tools. With all those cameras, some basic differences do exist, and these differences do in fact have a specific impact on handling, usefulness and results in taking pictures in specific situations.
The one issue that has the biggest impact on picture quality is the size of the camera sensor. Not megapixel numbers, just sensor size. In the “good old days of film” we had just one major format among most amateurs: the so-called 35 mm film (marked “135” on its box). The negative size of film is 24 x 36 mm and all indications of focal length on any lens was based on this standard size.
On digital cameras, a sensor with the good old size of 24 x 36 mm is called “full format” or “full size sensor”, or, as Nikon put it, just “FX”. You will find this sensor size on professional cameras only, like the Nikon D700, Nikon D3, Sony Alpha 900 or Canon EOS 5 Mark II. As of today (summer of 2009) FX sensors may house as few as 12 Megapixels or as many as 25. These are rather large numbers in comparison to the Megapixels available on most small point and shoot (P&S) cameras.
DX is the format most commonly used by amateurs in there DSLRs (digital single lens reflex cameras). The true revolution in photography started with this size, about 40% smaller than FX, with a sensor size of approx. 22.4 x 14.9 mm ( Canon) or 23.6 x 15.8 mm (Nikon). Smaller sensors are cheaper to produce and require smaller lenses (because they cover a smaller area).
Olympus and Panasonic started out with a format of their own, the 4/3 format. Instead of the 2:3 ratio of width to height as with 35 mm film or DX sensors, these DSLRs have a 3:4 ratio, similar to the small P&S cameras. Sensor size is about 50% of FX, a little smaller compared to DX.
Want a small point & shoot? Well, that’s where the small sensors start. In this area, sensor sizes are described by their diagonal dimension in inches, ranging from about 1/1.6” to about 1/2.5”. Maybe this does not sound as bad as 6 x 8 mm and smaller but it is just a fraction of the DX or FX sizes, smaller than your smallest finger nail.
Nonetheless these mini-sensors are cramped with 10 to 15 Megapixels. Now what’s wrong these small pixels? Imagine a pixel being a bucket, and light being raindrops. What happens? With large buckets, you will easily catch a raindrop even if only few of them keep flying towards you. And the ones you catch will stay in their bucket. With very small buckets, you will easily miss a drop. And the drop you are trying to catch will easily jump off into another bucket, filling buckets up in the wrong places.
In our camera, the buckets are our pixels, and the raindrops are the photons of light the pixel on the sensor has to catch. The smaller the pixel, the fewer photons end up in one, and the greater is the chance that neighbouring pixels get a hit, too. In addition, fewer photons create image information, leading to a higher risk of the sensor reading out false information (e.g. caused by static electricity or heat, both of which cause sensors to pass information on that’s not been caused by real light. That’s like catching raindrops with an already wet bucket and trying to figure out the difference between the raindrops and the water already in the bucket.
One basic principle applies here: larger sensors equal better image quality, especially in low light, where you only have a few photons (raindrops) to form the final image.
Remember film sensitivity? In the old days they called it ASA, and now we refer to it by the organization that sets the standards (International Organization for Standardization).
The standard film for sunny outdoor pictures was usually rated at ISO 100 or 200. With low light we used ISO 400, and in churches or other dark places ISO 800 was needed. In digital cameras, you can change ISO from picture to picture. Need to take a picture during a ceremony in church without using flash? Just turn the wheel (or push a button, whatever), put sensitivity to ISO 1600, and shoot on. If you happen to be using a modern DSLR like a you will get a near perfect picture. If however you happen to be using a small P&S camera, forget ISO 1600. Anything above ISO 400 will be harsh, grainy and full of noise. Some better, some worse. Most never reach ISO 1600.
Sensor size summary: if you need to take good pictures in low light without blinding everyone with a small, not very useful flash, get a DSLR. Period. If you stay on the sunny side, every camera available today will get you great pictures.
If you don’t like DSLR’s and need to take pictures in low light, there are just few exceptions to the rule, non by Nikon (sigh). New this summer: Olympus E-P1. This is a small, portable camera with a rather large sensor and interchangeable lenses. The dream of every photographer around. Sigma has been around with the DP1 and DP2 now for some time, but these two have fixed lenses without zoom. That may be interesting for some serious photographers, but perhaps not so much for dads’ hoping to get a good collection of family pictures.
Nikon D300s Sensor
File formats and the “digital lab”
Most pictures we see on our computer screen have been saved in a compressed file format called JPEG (with file names ending in “.jpg”). Just like the ISO, this name comes from the governing organization that sets the standards (Joint Photographic Experts Group). Most P&S cameras save pictures in this format on their memory cards. Handling is easy. Just copy the files onto your computer and print or mail them. That’s usually all there is to it. In fact, you can in most cases take the memory card out of your camera and place it in a printer at a department store (or at home) and print the images without ever touching your home computer.
As with most easy things in life, there is a downside: pictures in jpg format are difficult to modify. Your camera got the white balance wrong, your aunty is blue all over her face in the nice picture you shot in full daylight (provided she got enough oxygen)? With jpg files, you may correct the colour cast, but you cannot modify white balance (which would correct all colours in your picture at once). A jpg file contains colour information at pixel levels, that’s about all (plus some info about your camera, the date and time and so on, but nothing linked to the information in the picture itself). Plus picture quality deteriorates every time you save the jpg file, since jpg is a compressed format: compression means loosing little details your computer thinks you wan’t see anyway.
Want to modify everything there is in the picture, without losing quality in fine details? Want to be able to undo every modification you made? Easy: use RAW files. All DSLRs and some p&s cameras (e.g. Panasonic LX3, Canon G10, Nikon P6000) have this option. Instead of converting the sensor data to jpg files in the camera, the sensor data is saved. It is very much like the difference between having an original “negative” of an image or just a sample print. You can do so much more with that negative to correct any exposure problems. This also means that you need software on your computer to transform the RAW file into JPG (a RAW converter). Photoshop does this and many freeware programs like Picasa have the option, I would however advise photographers to use the software provided by the camera manufacturer, since they know best what data the RAW file contains.
Processing digital files is very similar to the process we had in old film days: using jpg files out of the camera is like sending the film canister to a commercial lab. You push the button, they do the rest. No trouble, but only limited control over the result. The lab people (or their computer) tried to make the best of your pictures, but they never saw the real thing, they can only guess.
Processing RAW files is indeed like processing your own negatives. You have full control. But you need to learn. It may be frustrating at the beginning, but it will be very rewarding once you find your way. There are lots of good books and helpful internet sites (especially us Nikonians), and many friendly people will be happy to help if you post questions here (but try to search the existing one first, your answer may be around already!).
File format summary: get a camera that has the option of saving files in RAW format, if you need or want full control and perfect results, but be prepared to learn. The necessity of RAW files will boil camera choice down to few models, especially if you want something small and portable.
Stick to JPG if you don’t like computers or need fast and easy results. Pictures will be good, but you will have to rely on your camera.