Nikon 50mm 1.8 AD lens focusing speed


andugo

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Dec 16, 2009
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#1
I found this lens auto focusing slower than nikon 18-105mm VR lens(comes with my D90 kit).. Is this common or my some problem with my lens?
 

ZerocoolAstra

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Mar 13, 2008
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#2
I found this lens auto focusing slower than nikon 18-105mm VR lens(comes with my D90 kit).. Is this common or my some problem with my lens?
haven't really done any direct comparison. Is it MUCH slower?

18-105 uses the SWM on the lens, which is claimed by Nikon to generally be faster at focusing. I think there are some cases (as claimed by users) that an AF-D lens focuses faster than the AF-S lens.
 

andugo

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Dec 16, 2009
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#3
I would say like 2-3sec slower..
 

ZerocoolAstra

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#4
2-3 seconds? That's like DSLR vs PnS speed.... sure? The 50/1.8D keeps on hunting for focus lock?
 

andugo

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Dec 16, 2009
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#5
sorry what is PnS speed?
 

ZerocoolAstra

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#6
sorry what is PnS speed?
y'know.... when you half-press ths shutter release button on a PnS (point-and-shoot compact camera), the darn thing makes some whirring noises and tries its darndest to achieve focus lock....

in comparison the DSLR usually seems instantaneous.
 

justarius

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#7
Is the lens hunting? Have you tried same focal length, same subject distance etc? How does the 50/1.8 focusing ring feel when you try manual focussing? silky smooth? or gear grinding? If gear grinding, your 50/1.8 may be a lemon.

Or is it just the sound of the 50/1.8 coming into focus compare to the near silence of an AFS lens which makes u think its focussing slower?

Generally AFS lens will focus faster than non-AFS; however depending on focusing throw of the lens, and motor of the camera body (DXXX up), some non-AFS lens can be just as fast.
 

andugo

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Dec 16, 2009
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#8
It is smooth when i switch to manual focus... i think is hunting focusing as I am tryin to shoot my hamster which is running nonstop.. thanks for the informations : )
 

ZerocoolAstra

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#9
It is smooth when i switch to manual focus... i think is hunting focusing as I am tryin to shoot my hamster which is running nonstop.. thanks for the informations : )
your comparison test has to be a bit more scientific.

1) mount 50/1.8 on camera
2) mount camera on tripod
3) frame your intended subject where the focus spot is
4) half-press the shutter release button
5) guess-timate how long it takes to achieve focus lock

6) un-mount 50/1.8
7) mount kit lens
8) turn to 50mm
9) repeat steps 3-5

The difference should be practically indistinguishable. If 50/1.8 is much slower, something is wrong with the lens, or your AF motor.

In fact, although the 50/1.8 is non-AFS, it has a larger aperture, which theoretically should aid quick-focusing. So it's really a toss-up (in my opinion) as to which lens is faster to achieve focus lock.
 

zac08

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Feb 21, 2005
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#10
The AF isn't particularly slow.. I use it as one of my primary lens and the only time I find it slow is when I am aiming it at a low contrast or dark scene. Tat's when it will try to hunt and acquire a lock.

Try a high contrasty scene and keep trying to lock. See if it's still tat slow.
 

aspenx

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Aug 10, 2008
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#11
I found this lens auto focusing slower than nikon 18-105mm VR lens(comes with my D90 kit).. Is this common or my some problem with my lens?
The 50mm f/1.8D was almost as fast as the 18-70 was on my D200. I don't see how the 18-105 can be any faster than the 18-70 so, maybe it's just your camera's AF motor being slow.
 

zac08

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#12
The 50mm f/1.8D was almost as fast as the 18-70 was on my D200. I don't see how the 18-105 can be any faster than the 18-70 so, maybe it's just your camera's AF motor being slow.
D200 focusing speed is definitely faster than the D90's.... :)
 

Foxshade

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#15
I guess the same thing happen to me too....:cry:

Yeah too bad, but I still like my equipments. It's just minor glitch I have to live with.
 

aspenx

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#16
the 50mm 1.8D has no internal AF motor. it depends on the body's AF motor, thats why some older model can only use this lens in MF.
TS is saying his/her 50mm f/1.8D's AF is slow... What has this got to do with MF or not?
 

#17
TS is saying his/her 50mm f/1.8D's AF is slow... What has this got to do with MF or not?
nothing to do with MF, i said MF in some older model, not his model...
18-105mm has internal motor whereas 50mm dont, so ofcoz its slower in comparison. do you run faster if you move your own legs or someone push you from behind?
 

ZerocoolAstra

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#18
nothing to do with MF, i said MF in some older model, not his model...
18-105mm has internal motor whereas 50mm dont, so ofcoz its slower in comparison. do you run faster if you move your own legs or someone push you from behind?
I wouldn't say OF COURSE so resoundingly.
There are cases of AF-D lenses focusing faster than AF-S lenses. Difficult to compare them because it's not apple vs apple. There are other considerations:

1) max aperture of the lens. large-aperture lenses allow more light to pass through, which theoretically aids auto-focusing
2) the focusing 'throw' (ie the amount of distance that the lens has to travel from MFD to infinity focus)
3) speed of the body's AF motor (eg. Dxxx series motor I think is faster than Dxx series motor)
and so on.

so it's not so clear cut.
My guesstimate is that the speed difference between AF-S 18-105DX and AF 50/1.8D should be hardly noticeable, so it puzzles me why TS said the 50/1.8 is 2-3 seconds slower.

anyway the point about some Nikon bodies not having internal motor is moot in this case. It's irrelevant to the TS' question.
 

aspenx

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#19
nothing to do with MF, i said MF in some older model, not his model...
18-105mm has internal motor whereas 50mm dont, so ofcoz its slower in comparison. do you run faster if you move your own legs or someone push you from behind?
I can't write any better than what ZerocoolAstra has done above this post.
 

ZerocoolAstra

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#20
just to add on, at 50mm, the 18-105 is probably at f/5 max aperture, which is about 3-stops slower (ie. it lets in 8 times less light than the 50/1.8)

That's like placing an ND8 filter in front of the lens. So.... still sure about the OF COURSE ??? :D
 

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