Learn aboutLens focus motor

A camera's autofocus system requires a motor to physically move the lens to bring the subject into focus. Most modern DSLRs have these motors in the body of the camera, however there are exceptions, primarily in entry-level DSLR cameras.

The justification for not having a focus motor in the camera body is that most modern lenses have built-in autofocus motors already, so the size and cost of the camera body can be decreased by omitting a focus motor. Also, the focus motor in the lens is often faster and quieter than the camera's in-body focus motor.

One major drawback of not having an in-body focus motor is that you will have to manually focus when using leses that lack a built-in motor. Another drawback is that lenses with built-in motors are considerably more expensive than equivalent lenses without a motor.

Cameras lacking a focus motor

The following is a list of cameras lacking an in-body focus motor.

	Nikon D5100 from $497	Great image quality 80.0 Low noise at high ISO 1,183 ISO Flip-out screen Great for movies Learn more about the Nikon D5100
	Nikon D5200 from $697	Great image quality 84.0 Many focus points 39 High true resolution 24 MP Learn more about the Nikon D5200
	Nikon D3200 from $547	Great image quality 81.0 High true resolution 24.1 MP Really small Prosumer size 125x96x76 mm Learn more about the Nikon D3200
	Nikon D3100 from $373	Really small Prosumer size 124x96x73 mm Slightly more lenses available 169 lenses Movie continuous focus Makes it easy to get in-focus movies Learn more about the Nikon D3100
	Nikon D3000 from $436	Really small Prosumer size 126x97x64 mm Thin 2.5" Slightly more lenses available 169 lenses Learn more about the Nikon D3000

Discussion

Showing 17 comments

Syd (5:54 AM, May 27, 2013)

So I we just got a lens with an auto focus motor then the camera will have auto focus?

HS Ballard (0:08 AM, May 12, 2013)

Whats wrong when you put an older Nikon lens on a new D3100 and the camera says there is no lens attached? Whats missing or do you need a spacer between the lens and camera body?

John (9:38 PM, March 05, 2013)

Isn't it a bit misguiding to say that Canon bodies have built in AF motor, when to my knowledge there hasn't ever been a production Canon SLR with an in-body focus motor. The whole point of EF-mount was that the AF motor is in the lens.

AJ (9:46 PM, June 29, 2012)

I,m considering buying the d5100 and i have a tamron 28-200 mm af asperocal xr(if) lens.I'm not sure if it has an inbuilt autofocus motor.From the specs it says that it has an Internal Focusing System. Wondering if this is the same thing?If so it would mean that i can still use this lens on the new d5100. thanks aj

Marcwalsh67 (11:05 AM, March 03, 2012)

Basically, the only time you need to manually focus is when both body and lens do not have built in motor? Body has motor and lens has motor = autofocus available Body has motor and lens has no motor = autofocus available Body has no motor and lens has motor = autofocus available Body has no motor and lens has no motor = no autofocus, available

Arunkumar (2:21 PM, January 09, 2012)

Which Dslr camera is worth to buy? (With Auto focus motor from Canon or Without Auto focus motor from Nikon) How much price difference between with Auto focus motor lens and without Auto focus motor lens. Arun.

lenshero (3:12 AM, December 29, 2011)

Hi Carolina, I'm pretty sure the cameras will always use the lens's focus motor, unless it lacks one, then the body's motor will drive the lens to focus.  I don't think you can choose.

Pony (3:08 AM, December 29, 2011)

The Camera takes photos

Carolina (10:19 AM, December 28, 2011)

Does a camera with built in focus motor override the autofocus of the lens attached to it?  Which one takes precedence and can you choose which of the two you want to do the focussing?

Adam (10:47 PM, October 29, 2011)

Hey, would buying a camera without an autofocus motor built in be less cost effective in the long run as I buy more lenses to expand my camera having to be of the af-s variety?  My main attack is on whether I should buy the Canon 600D or Nikon 5100d as the only difference seems to be of it having an autofocus built in, (con of it being more expensive).

Snapsort (1:09 PM, September 14, 2011)

Hi Rg, I think the simple answer is that Nikon bodies such as the Nikon D5100 and D3100 can only autofocus with lenses that include a focus motor (AF-S lenses for example).   Other Nikon bodies such as the Nikon D7000 can autofocus with pretty much all autofocus lenses for Nikon cameras, not just the ones with focus motors.    For example, if you bought the Nikon 50mm f/1.8D lens, it would autofocus with the D7000 but not with the D5100 because this lens does not have a focus motor, whereas the Nikon 50mm AF-S f/1.8G lens does have a focus motor, so it will autofocus with both the D5100 and the D7000.

Rg Ballard (6:32 AM, September 14, 2011)

Hi, I was wondering, so a focus motor in the camera would focus a lens without a focus motor. However, some of these Nikon's that do not have a focus motor in the camera say they can do continuous focusing while in movie mode. This appeals to me as I would like to be able to capture movement I can't always predict. However, in order for this to work, would the lens then need to have a focus motor? If so, is there a camera like the Nikon D5100 but with a focus motor in the camera? I have only ever used a Canon T1i primarily for stills but would like to purchase my own DLSR and be able to use it for video also (and this Nikon is one of the first things I've looked at besides the Canon T2i).

Firmanshah (2:26 PM, June 14, 2011)

is there important to consider that DSLR with built-in focus motor? like canon eos 1100d......

Snapsort (1:06 AM, June 09, 2011)

Yes, you can definitely manually focus the lens.  The same thing is true if you put a manual focus lens (say an older Nikon lens) on any Nikon DSLR, you can manual focus using the ring on the lens.

Keeganl_92 (9:16 AM, June 02, 2011)

if you have a dslr without a focus motor in the body and attached is a lens without a focus motor can you just manually adjust the focus by turning and adjusting the lens?? (btw i dont have a dslr yet and im a complete amateur at photography).

Snapsort (3:00 PM, May 28, 2011)

Hi Ric, I'd summarize it as follows: - Almost all Nikon lenses can be used on any Nikon DSLR (old lenses on new cameras, and new lenses on old cameras) - Some Nikon DSLRs do not have a focus motor built in (see the list above), which means they can only autofocus with AF-S lenses, since AF-S lenses have their own focus motor.Does that answer your questions?

RicJAlonso (4:24 AM, May 28, 2011)

So if the camera has a built in focus motor, then can a lens without one still be used? In other words, could older Nikkor lenses be used in newer Nikon cameras? Also, is the reverse true? Can newer lenses be used in older cameras?