Sigma 17-70 focus issue

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jrad

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Hi there,

I have just bought myself a Sigma 17-70 HSM lens for Nikon however I am finding it is having major problems auto focusing.

It only seems to be at the 70mm end of the range. last night I was out taking some shots and the focus just cannot lock at all sometimes.

The lens motor will track in and out continuously (a few mm in and out) but doesn't seem to lock.

Has anyone else had this problem or is it normal? Sorry I am a newbie :)

cheers
James
 
Sounds like a AF problem on the body to me - my 17-70 hunts a little bit in the dark on my 450D, but not very often!
 
It is on a brand new d90. 2 days old...

Auto focus works perfectly on my other lens (50mm 1.8d) which made me think it wasn't the body.

It does focus when not zoomed in just seems to have a lot of problems when zoomed up close.
 
jrad said:
It only seems to be at the 70mm end of the range. last night I was out taking some shots and the focus just cannot lock at all sometimes.

The lens motor will track in and out continuously (a few mm in and out) but doesn't seem to lock.

Has anyone else had this problem or is it normal? Sorry I am a newbie :)
Click to expand...

When a lens is doing that it is referred to as 'hunting' (i.e. it's hunting for focus). A few questions...how dark was it? What mode where you using on your camera? How far away were you from the subject that you were trying to focus on?
 
If it were me I would take it in to my local jessops and ask to try it on another body.

Also try and AF on something 10ft away and then change the focal length and try say a dozen shots
 
jrad said:
It is on a brand new d90. 2 days old...

Auto focus works perfectly on my other lens (50mm 1.8d) which made me think it wasn't the body.

It does focus when not zoomed in just seems to have a lot of problems when zoomed up close.
Click to expand...

I'm pretty confident it won't be the body.

As per my previous question....how close were you to the subject? Was it within the MFD (Minimum Focusing Distance) of the lens?

The Sigma lens at 70mm has a maximum aperture of f/4 whereas the Nikon 50mm lens has a maximum aperture of f/1.8 - a big difference in ability to take pictures in low light conditions.
 
The siggy 17-70mm has a pretty crazy MFD so I don't think he would be too close.. I don't think I've ever managed to get within the MFD to be honest and I've managed to bump into my subject while shooting it lol

EDIT: although website say 7.9" I've managed to get focus at the wide end at distances of about 1cm
 
sdb123 said:
When a lens is doing that it is referred to as 'hunting' (i.e. it's hunting for focus). A few questions...how dark was it? What mode where you using on your camera? How far away were you from the subject that you were trying to focus on?
Click to expand...

I was in a reasonably lit room (630pm with no lights on but plenty of windows...) when i first noticed it. I was about 4 or 5 metres away from the item I was shooing and zoomed right it. Then when I went out later It was even worse. granted it was a bit darker but I wouldn't expect it to be this bad.

just tried a friends 18-70 nikon lens in the same conditions and it focuses very quickly...
 
jrad said:
just tried a friends 18-70 nikon lens in the same conditions and it focuses very quickly...
Click to expand...

It will focus more quickly as the Nikon lens has AF-S (silent wave motor) whereas the Sigma lens doesn't have Sigma's equivalent HSM (hyper sonic motor) built in.
 
jrad said:
I was in a reasonably lit room (630pm with no lights on but plenty of windows...) when i first noticed it. I was about 4 or 5 metres away from the item I was shooing and zoomed right it. Then when I went out later It was even worse. granted it was a bit darker but I wouldn't expect it to be this bad.
Click to expand...

What mode were you using?
 
sdb123 said:
It will focus more quickly as the Nikon lens has AF-S (silent wave motor) whereas the Sigma lens doesn't have Sigma's equivalent HSM (hyper sonic motor) built in.
Click to expand...

It is the HSM version! I was using AV mode but even in manual and auto modes it was not working. Anyway I have returned it to Microglobe for a full refund :).

In the mean time I have bought a Nikon 18-200 lens which focuses very quickly and has better range. As a newbie I think that and the 50mm 1.8 will be a good starting point. :D

Thanks for your help guys!
 
sdb123 said:
Glad you're happy and sorted things out.

I looked on Sigma's website and the lens doesn't have HSM built-in (unless there has been a brand new version released that I'm unaware of).
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Hi,

there is an HSM version out for Nikon users but not for Canon users unfortunately. it's only been out for a couple of months or so. That link you provided states "17-70mm f/2.8-4.5 DC Macro / HSM" :D:p

W.E. have it HERE

Mike.
 
mikeyb said:
Hi,

there is an HSM version out for Nikon users but not for Canon users unfortunately. it's only been out for a couple of months or so. That link you provided states "17-70mm f/2.8-4.5 DC Macro / HSM" :D:p
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:bonk:

I didn't even read the title! I always look at the description of the lens which Sigma list the 'features' listed on the lens. On the other HSM lenses I've looked at the HSM symbol is listed in the description.

:nuts:
 
sdb123 said:
:bonk:

I didn't even read the title! I always look at the description of the lens which Sigma list the 'features' listed on the lens. On the other HSM lenses I've looked at the HSM symbol is listed in the description.

:nuts:
Click to expand...

Hi,

:D easy done, I only noticed it as I knew there was one available and was 'looking' for it on the Sigma page, it should really be better highlighted as the Nikon version is much more desirable being HSM, it was the lack of HSM on the Canon version that swayed me towards selling mine as I kept gripping it on the focus ring and it would twist the camera in my hand, it was capable of great images though and IF there was a Canon HSM version then I would probably own one (y)

Mike.
 
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