Is Auto-Focus Motor in DSLR camera important?

I don't have a DSLR camera and i'm looking for one and something new that i can afford until these past few days i finally deeply dig with "Nikon D5100" for previews and stuff and it seems its a good camera for its price with "18-55mm Kit Lens" however there's only one thing that i didn't understand it doesn't have "Auto-Focus Motor" i seen many price and features comparisons range for this camera some old DSLR are more expensive and i realize all those expensive ones does have Auto-Focus while D5100 is less price for missing AF matter so can anyone give me some advice here this should be my first DSLR camera and my only aim is for quality of the picture.

If your camera doesn't have an autofocus motor (like the D40 & 80 I used to have) you're limited to lenses that have said motor built into the lens. My D200 has the AF motor, so I can use almost any lens Nikon made since 1959.

No motor = no autofocus.

Nikon reduced the cost of the D3000/D5000 series by removing the motor from the body. Sony and Pentax always have the motor in the body (a few lenses have motors too), Canon have never used body motors, always placing them in the lens.

If you want autofocus with your D5100, you'll have to buy AF-S (lens motor) Nikkors, or their third-party equivalents because you need a motor to move the focus train and allow AF to work.

A D5100 can autofocus any AF-S lens as those lenses have the motor built into them.

The older style (but still made) AF lenses do not have a motor in the lens, so it requires a motor in the camera body. So you have to go beyond the entry level cameras to get that option (D7000, D90, etc).

As you said, they are more expensive - but they have more features than just the autofocus motor.

You can thank Canon for this - as they have undercut Nikon in the low end DSLR market, so Nikon had to follow suit and remove the motor from the entry level cameras. Canon does not have autofocus motors, but all of their lenses have the motors in them.

So buying an entry level Nikon with an AF-S lens is equivalent. It is just that you will not be able to take advantage of the wide selection of AF lenses.

To save money and make their entry-level DSLR cameras more attractive price-wise Nikon left out a focusing motor on the D3100, D3200, D5100 models. This forces users who want auto focus to buy Nikon's more expensive AF-S lenses which is where they really make their money. Its kind of a Nikon "Gotcha!" moment. Of course the D90 and D7000 models have a focusing motor in the camera body but just look at the price difference between them and the lesser models.

So if you buy the D5100 plan on buying the AF-S lenses if you want auto focus.