A lot of people, specially first time buyers of Digital SLR Cameras, ask the question in the title of this blog post. Here is my take on this. I have used a lot of Digital Cameras mostly from Canon and Sony. My short answer would be: Pick any one brand and you won't be disappointed. Due to technological advances in recent years, Digital Cameras have come a long way and even the low end Digital SLRs can produce excellent results given that you have a lens capable of the same. We will talk about lenses in a separate article.

If you are going to do a lot of photography in a variety of situations then the answer gets a little bit complicated. In this case a lot of factors come into picture. Please note that Olympus, Pentax and Panasonic also make Digital SLR Cameras but I am only comparing the big boys Canon, Nikon and Sony here as they are the most popular in the US market.

• Existing lens collection: Do you have an existing film or an older Digital SLR camera and one or more lenses? If so you can very likely use those lenses if you get a same brand Digital SLR camera. Old Canon EF lenses will still work on newer Canon SLR cameras and same goes for Nikon Lenses except in some cases. See this chart for details. Similarly old Minolta AF lenses will work on newer Sony Alpha SLR cameras.
• Lens and accessories available for a brand: At the time of writing this article, there are around 180 lenses available for Canon EOS cameras. For Nikon there are approximately 176 and for Sony only 108. This is no surprise since Canon and Nikon are producing Cameras and Lenses for many decades now. Sony jumped into this game late around 2006 when they bought Minolta another big name optical producer but failing in the digital arena.
• Materials used in the body: Another important factor to consider is the materials that are used and whether the camera has weather sealing or not. Most lower end DSLRs are made of plastics - tough plastics - but plastics none the less. The Canon EOS XXD series (e.g. EOS 50D) and Nikon DXX series is made of magnesium alloy. This gives some ruggedness to cameras which gives it a long life when used in outdoor conditions. At the time of writing this, only a full frame Sony Alpha A900 and A850 series has a magnesium alloy body. The higher end Canon XD (for e.g. 1D MK IV etc) and Nikon D3 etc have rubber sealing which makes them water resistant (not water proof).
• Frames Per Second (FPS) and buffer: Some cameras like the Canon 7D, Nikon D300s, Sony A55 can give anywhere from 7FPS to 10FPS continuous shooting. This feature is great for taking sports / action / kids pictures.
• Full Frame Sensor: Most lower end DSLRs have a 23mm APS-C (Film SLRs have a 35mm) sensor which means that a portion of the image will be cut off. Therefore a APS-C sensor is not ideal for Landscape pictures. A much wider lens is required to get the same wide angle effect as a full frame camera. Canon, Nikon and Sony all have full frame models namely Canon 5D Mark II, Canon 1DS Mark III, Nikon D3X, Nikon D700, Sony Alpha A850 and Sony Alpha A900. Due to a larger sensor and other added features, the price will also be high on these models.
• HD Video: Full HD (1080p) video is quickly becoming a standard feature now a days. Among all the different consumer models, the Sony SLT-A55 cameras shine in video capture as its translucent camera allows continuous auto-focus.  Many video professionals are using cameras like the Canon 5D Mark II for video production.
• Other features: Other essential and fancy features to look for in a DSLRs are:
  • Optical Viewfinder (OVF) vs Electronic Viewfinder (EVF): This is a matter of taste. OVF show the actual picture of the subject where as EVFs project a electronic image of the actual subject along with settings information. Most people like OVF as the picture is clear however nowadays EVFs have  improved in resolution and provide more information while composing a picture. It might effect battery life negatively though. A viewfinder in a low end consumer camera is much smaller than say a fully professional version.

    

  • Live View LCD: If you have never used a DSLR before then you will be surprised to know that you cannot normally use the LCD to compose the picture. However recently many Digital SLRs provide a full live view LCD. Many cameras also have a articulating (rotating) LCD Screen. For e.g. Sony A55, Canon D60, Nikon D5100 have rotating LCDs. A Live View LCD will eat more battery power and this is something to be considered while buying a camera.
  • Anti-Shake System: A built in anti-shake (image stabilizer) is great to have specially when taking low light or telephoto zoom pictures. It might save a blurry picture. A body that has built-in stabilizer will save you money from buying separate lenses with stabilizer. At the time of writing this, only Sony, Olympus and Panasonic series of SLRs have built in image stabilization.
  • Dust Cleaning System: Some DSLRs also have a dust cleaning mechanism that will remote dust particles from the sensor which otherwise can be a pain to remove manually. If you change lenses quite a lot outside then dust on the sensor might accumulate more often than otherwise.