Friends and family often ask me for advice when buying a new camera.  Now that SLRs in the consumer range are so good, many people are moving from simple point and shoots (P&S) to the bigger cameras. There are a slew of web articles out there that attempt to answer that question, often with mixed results.  I think a lot of the answers are too technical.  I’m going to try to answer this as simply as possible.  My answer might be too technical, but heck I’ll give it a try.  

The only thing you have to really know about photography before jumping in is that it’s all about capturing light.  The more light that you want to the capture, the more money you’ll likely need to spend.  Everything is governed by light.  It’s as simple as that. 

When making the decision to go to an SLR, the most common desires I hear are:

1.  I want to take better pictures
2.  I want to take pictures of my kids playing sports
3.  I want to take pictures at night or in low light without using a flash
4.  I don’t want to spend too much money

These desires can be fundamentally aligned with the basics of photography.  The desires above are governed primarily by these concepts.

1. Aperture
2. Shutter Speed, Aperture
3.  ISO, Shutter Speed, Aperture
4. The cost of camera equipment is often but not always directly related to how much control you have over the above three factors so by association, the more control, the more the cost. 

I want to take better pictures

Although both SLRs and P&S take photos, the first and most visible differentiator between pictures taken by each is depth of field.  Depth of field (DOF) describes how much is in focus vs. out of focus in a picture.  With P&S cameras, the depth of field is very deep which means everything is in focus.  This translates to a very flat picture.  With SLRs, the depth of field is often shallower, which means that the subject is isolated and separated from the background.  This creates depth (3D effect) and makes the picture more pleasing to the eye.  When people say, “better pictures” this is often what I interpret them to mean.  The DOF is governed by the camera lens’ aperture or how big the size of the hole is that lets light into the camera.  The larger the hole, the shallower the depth of field.  The size also controls how much light enters the camera.  Simply put, the bigger the hole, the more light you get, the shallower the depth of field, the more expensive the lens, and the more money you need to spend.    

I want to take pictures of fast moving object and sports

Imagine that you’re standing on a street corner watching cars drive by.  A yellow cab is driving past you on the street.  You close your eyes for 2 seconds and then open them.  What happened?  The cab is likely gone because it has already driven past you.  Now what happens if you just blink?  The cab is likely still there but has just moved to a slightly different place from before you blinked.  A camera captures movement just like your eyes do.  The camera’s equivalent of blinking/closing your eyes is called the shutter speed.  The faster the shutter (faster you blink), the more of the speeding object you can capture.  Most cameras allow a fast enough shutter speed to capture all fast movement.  The problem comes from light.  The faster the shutter, the less the amount of light is allowed to enter the camera.  Without light, you can’t capture movement so this means that while you can take sports shots during the day you can’t doing nearly as well at night.  So what do you need? More light!  How do you get more light?  You need a lens with a bigger aperture.  This mean you need to spend more money on a better lens.  

I want to take pictures at night or low light without using a flash

In case you haven’t heard, it’s all about the light.  The more light you want to capture, the bigger the aperture, the more expensive the lens.  There’s one other aspect to light capture and that’s ISO.  ISO describes how sensitive the camera is to capturing light and is a function of the sensor.  Typically, the better the sensor, the more expensive the camera will be. 

I get it, I need more light.  So how does that affect my buying decision?

As you now know, the aperture controls how much light gets into the camera, controls DOF, and is the primary driver of the cost.  The aperture is a function of the lens.  A lens is described by its focal length and aperture.  So, when you see 18-55mm f3.5-56, this means that the focal length is 18-55mm and the aperture is sized 3.5-5.6.  It’s a range because on zoom lens, the hole gets bigger or smaller as you zoom.  The “f” number tells you how big the hole is and can range from 1.2 to 32.  The scale is also backwards.  1.2 is very big.  32 is very small.  Ok, now that you know all that, I’ll give it to you straight.  When you don’t spend a lot of money, you won’t get a lens with a very large hole, which means that your depth of field won’t be that shallow, you can’t take fast moving pictures when it gets too dark, and you can’t take pictures at night very well.  There will be a limit to what you can or can’t do.

Ok, I still only have so much money.  What do I typically get for my money?

SLRs typically come in the form of a kit or body only.  The standard kit usually includes a midrange zoom lens 18-55mm.  A deluxe kit will include an 18-55mm and a 55-200mm lens.  This in effect gives you a 10x zoom range.  The longer the focal length of the lens the farther the image you can capture.  Kit lens typically satisfy the needs of most consumers which is why they are included with the camera.  However, once you become more advanced in photography, the lens will limit or impede what you can or can’t capture.  I say limit because almost all pictures can be achieved to a certain extent with any lens.  However, the EASE with which you can capture an image can be dependent on the lens.  Additionally there are some images that are not achievable without a specific lens. .   With a kit lens, pictures of kids playing soccer outside when it’s sunny are probably not a problem but pictures of kids playing basketball inside dark gymnasium will likely be difficult. 

OK, I get it that kits are limiting but I don’t need to get too fancy right now, what camera should I get?

So now that we’ve gone through all the basics, we’re back to the original question.  As you can see, there’s a lot of information needed to make an informed decision because it depends on what you want to achieve and how much you’re willing to spend. 

So assuming you’re not going to go all in when you don’t even know if photography will be your thing, here’s what I recommend:

Between $0 - $1000

Get either a Nikon D3100 or Canon Rebel T3I with a kit lens or kit lens deluxe.  Keep in mind that if you get real serious, you’ll probably dump the whole rig and buy a new camera and new lenses.  

Between $1000 - $2000

Get a Nikon D5100, D7000 or Canon 60 D, 7D and skip the kit lens.  Buy the body only and purchase a higher quality lens. 

Between $2000 - $5000

Get either Nikon D700 and a few good lenses or a Canon 5D2 and a few good lenses

$5000 or more

Clearly money is not a problem so just buy the best stuff.

Why Nikon or Canon, what about some other brand?

Although I shoot Nikon, I personally think that both Nikon and Canon make fantastic consumer entry level cameras.  I choose Nikon over Canon because I think the lenses are better and the cameras are more rugged.  That’s it.  Canon has more lenses and camera selections.  Canon is also a much bigger company and they make a lot more products.  I have nothing against other companies like Pentax, Sony, Olympus, or anyone else.  I think they make great products.  However, the two biggest players in consumer SLRs are Nikon and Canon.  

Other Stuff

If you’ve read all the way to the bottom then it’s only fair to let you that I’ve left some stuff out that would make other photographers jump straight at my throat. It shouldn’t in my opinion affect your buying decision but just in case, full disclosure.

1. There are cheap lenses with large apertures.  50 1.8, 35 1.8, etc.  These lenses are fixed and do not zoom.  They are often the first large aperture lenses that people get when they realize they need more light.  But they don’t zoom and if you’re going from a P&S that zooms at the touch of a button, its going to make learning pretty difficult.  Maybe you took photography in High School and a fixed 35mm lens is exactly what you’re looking for.  By all means, go forth and conquer.  Otherwise, I don’t recommend that as a first purchase.
2. There are even cheaper slrs than what I’ve listed that will allow you to buy better glass. 
3. Like, nice watches and cars, expensive lenses has the potential to retain their value or even appreciate.  So spending $2,000 dollars on a lens might seem outrageous but keep in mind that you could probably use it for 3 years and sell it for $1800.  Second or third hand doesn’t really affect the price that much.  Think of it as purchasing an asset instead of thinking of it as a sunk cost.  
4. I’d like to think that I’m not propagating any false information but make sure you do more research.

That’s all I got.  Hope this helps.