Focus twitching when camera and subject static

philthejuggler

philthejuggler

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Phil
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Hi all

I've just acquired two new 5DIV bodies and when micro-adjusting focus on a few lenses I noticed my 35mm 'twitches' if I repeatedly press the focus button with both subject and camera static. The other lenses seem not to do this.

Is this normal or does it indicate a problem with the lens?

Thanks


Phil
 
Never heard of any lens doing quite what you describe........Canon make a few 35mm variants so for those with a 35mm lens perhaps if you specified which version that will give other the opportunity for user insight ;)
 
Being a prime I take it doesn't have OIS? I found similar to what you are experiencing but it turned out to be the camera's IBIS so it's off for repairs. Without anything like that interfering it could be a loose element :/
 
It does have IS although that is switched off. It's odd, but my feeling is there is something not-quite-right with it. With the 50/1.2 it finds focus and then repeated half-pressing on the shutter doesn't involved any further movement.
 
philthejuggler said:
It does have IS although that is switched off. It's odd, but my feeling is there is something not-quite-right with it. With the 50/1.2 it finds focus and then repeated half-pressing on the shutter doesn't involved any further movement.
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It is this then?
http://www.fredmiranda.com/reviews/showproduct.php/product/438/sort/7/cat/2/page/1

It does get highly rated as linked above, so unless any other users at the above link or anyone here at TP can say if this is normal then perhaps it does need some attention?
 
Are you using a tripod for your testing?
 
The focus "twitches" every time you activate the autofocus... why would that be abnormal? There might be a difference in the gearing/rate for the AF, or it's just confirming/refining the AF each time. The 35 is a much newer lens and probably has a bit different programming for it.
Are you using a good test target?
 
Another thing to check is that I assume you have it on AF-S and not AF-C (or whatever Canon's equivalents are)?
 
snerkler said:
Another thing to check is that I assume you have it on AF-S and not AF-C (or whatever Canon's equivalents are)?
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AI Servo focus and AI focus, but it needs to be on standard AF... I think? I don't speak Nikonese but I think that might be what you're saying? ;)
 
Mr Badger said:
AI Servo focus and AI focus, but it needs to be on standard AF... I think? I don't speak Nikonese but I think that might be what you're saying? ;)
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Probably, basically focus once with half press of the shutter button, or continually focus whilst ever you're half pressing the shutter (y)
 
snerkler said:
Probably, basically focus once with half press of the shutter button, or continually focus whilst ever you're half pressing the shutter (y)
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That's the badger, but quite a few Canon DSLRs have two modes of predictive/tracking type focus, which I think are AI and AI Servo; plus the standard point, press, lock-on and shoot type AF. (y)
 
Mr Badger said:
That's the badger, but quite a few Canon DSLRs have two modes of predictive/tracking type focus, which I think are AI and AI Servo; plus the standard point, press, lock-on and shoot type AF. (y)
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Well yes Nikon have a host of different tracking modes in AF-C (continuous servo or whatever you said it was) but I was trying to keep it simple :p ;) The point I was making is that if it's continuously trying to achieve focus then this could cause it to 'twitch' (y)
 
snerkler said:
Well yes Nikon have a host of different tracking modes in AF-C (continuous servo or whatever you said it was) but I was trying to keep it simple :p ;) The point I was making is that if it's continuously trying to achieve focus then this could cause it to 'twitch' (y)
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Yes, I think he needs to make sure it's in 'one shot' AF mode. (y)
 
I'd like to think the op has checked that already after owning such high end gear. Otherwise it facepalm time.
 
Many thanks for all the comments - I tried it again in better light with more consistent results - I think that might be the issue!
 
twist said:
I'd like to think the op has checked that already after owning such high end gear. Otherwise it facepalm time.
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We all have “D’oh” moments ;) Besides I don’t know the OP or his background so could well have been a newbie splashing out on flash gear ;) :p
 
snerkler said:
We all have “D’oh” moments ;) Besides I don’t know the OP or his background so could well have been a newbie splashing out on flash gear ;) :p
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I'm a Professional wedding photographer - just seemed odd that this one lens was twitchy about focusing - I think poor light was to blame and it was possibly catching focus on something else in the foreground.
 
philthejuggler said:
I'm a Professional wedding photographer - just seemed odd that this one lens was twitchy about focusing - I think poor light was to blame and it was possibly catching focus on something else in the foreground.
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Sorry didn't mean to offend (y)
 
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