What's the difference?

[glf_sproull]

I was wondering if anyone could tell me what the difference is between Nikon and third party (Sigma and Tamron) lenses. I know that Nikon lenses have a built in AF system, so that speeds up the focusing process. But how much longer does it take the camera to focus with a third party than with a Nikon lens? Is that a real issue? I'm going to buy the D80 real soon and wasn't for sure if I should buy one of the "kit lenses" or buy a couple third party lenses. Any suggestions? Thanks for the input, it's appreciated!

[wh0128]

Um difference is that maybe most of the time Nikkor lenses are better than Sigma, Tamron, Quantaray, and any others you can think of. Though there are some Sigmas and Tamrons that may out run a Nikkor in the area of AF. Some of it is opinion on what lens to buy and some can be based up on specifications of the lens. You might need to research the lens.

IMO, I'd rather shoot a Nikkor way before I shot a 3rd party lens, becaue I know that if I buy a decent Nikkor lens that I will be getting acceptionable quality in my photographs. Generally, price is a big deal in this issue as well, because a Nikkor will be more expensive than a 3rd party lens.

[Forced Perfect]

I was wondering if anyone could tell me what the difference is between Nikon and third party (Sigma and Tamron) lenses. I know that Nikon lenses have a built in AF system, so that speeds up the focusing process. But how much longer does it take the camera to focus with a third party than with a Nikon lens? Is that a real issue? I'm going to buy the D80 real soon and wasn't for sure if I should buy one of the "kit lenses" or buy a couple third party lenses. Any suggestions? Thanks for the input, it's appreciated!

Not being a Nikon guy I can't be 100% (someone back me up on this?), but my understanding is many Nikon lenses aside from AF-s and AF-i (is the second one right?) do not have internal motors and rely on the slotted screw and internal motor of the camera itself to drive the focusing. AF-s lenses use SlientWave motors (USM if you speak Canon) and AF-i use regular motors to drive them. The D40 does not have an internal motor so cannot use a lens without a lens without an internal motor.

So regardless of if it is a 3rd party lens - such as Sigma - or a Nikon one it may or may not have a motor depending on the model. The focusing speed depends on the lens more than anything else. Generally a large lens will focus slower if it doesn't use an in-lens motor because unlike Canon which includes a motor in every lens, the camera motor isn't sized to match the lens. So a lens which uses the in-camera motor can vary greatly depending on it's size and focusing system.

So do I know my stuff at all Nikon guys? This is all coming from a guy who has never owned any Nikon product. :P

[K1W1]

But how much longer does it take the camera to focus with a third party than with a Nikon lens? Is that a real issue?

Lenses fall into two basic categories - Consumer and Pro. Anybodies Pro lens focuses faster than their equivalent Consumer lens.
In most cases a Pro lens will give better results than a Consumer lens so I would rather have a Sigma Pro lens than a Nikon Consumer lens. A Nikon Consumer lens is usually more expensive than a Sigma or Tamron consumer lens (but not necessarily better) and will always be cheaper than a Sigma Pro lens which will usually be cheaper than the equivalent Nikon Pro lens.
Lens selection is a very personal thing and can be very confusing as you can see.
My suggestion is to buy a body with a standard kit lens (18-55, 18-70 or 18-135), use the lens for a while and decide what sort of photography you like and what sort of lenses you really need. If you jump in on day one with a large chequebook the end result will probably be a smaller bank balance and a selection of lenses that are unused regardless of how good they are.

[Prospero]

Not being a Nikon guy I can't be 100% (someone back me up on this?), but my understanding is many Nikon lenses aside from AF-s and AF-i (is the second one right?) do not have internal motors and rely on the slotted screw and internal motor of the camera itself to drive the focusing. AF-s lenses use SlientWave motors (USM if you speak Canon) and AF-i use regular motors to drive them. The D40 does not have an internal motor so cannot use a lens without a lens without an internal motor.

You're almost right; af-s lenses indeed use a silent wave motor, but af-i lenses do not excist. You are probably confused with Nikkor AI lenses, which are manual focus lenses. The other types of lenses, af-g and af-d, both rely on the focus motor of the body. The only difference between the two is that the af-g lens has no apperture ring. The D40 only supports af-s lenses.

Third party lenses also come into a couple of categories in terms of autofocus. Sigma, for example, makes af-g lenses, like the Sigma 17-70, af-d lenses, for instance the 70-300 and HSM lenses (the Sigma equivalent of af-s). Sigma only includes HSM in their professional line (the EX line). Nikkor, on the other hand, includes af-s in almost all of their lenses (even in lenses like the 18-55).

AF-s lenses and HSM lenses focus a lot faster than lenses of the other types. So if fast focussing is the thing your looking for, than you should buy lenses of these types.

The suggestion made by K1W1 is also the one I would go for. Each of these lenses is also af-s, so they focus quickly. Personally I would choose the 18-70 from these lenses, because it has a better range and build quality than the 18-55, and it's optical quality is better than the 18-135.

[eduardofrances]

Well the difference lies in the standards of production, third party lens makers are known for producing one razor sharp lens and the next in the production can be dull as bottom of a bottle, if you are going to buy 3rd party lenses buy them from a brick and mortar store where you can try them, if one is soft ask the people there to hand you another copy until you find a good one, check for AF accuracy and border sharpness too. :)