Autofocus unreliable (35mm Nikon prime)
Discussion
Hi,
I'm wondering if anyone can help me. I have a 35mm Nikon 1:1.8G (prime) lens and the autofocus isn't as it should be. If you turn the camera on and half-press the exposure button then the autofocus won't work - there is no noise, no buzzing, nothing. The focus indicators in the viewfinder light up to show you that it needs to be focussed but it won't focus for itself. After a period of time (5-15secs) however it all works as it should. I can't understand what makes it work; whether it's a gentle shake, removing and re-attaching the lens, changing some (any!) settings, manually twiddling the focus ring or just repeatedly tapping the exposure button have all done the trick. Once it's started working it will work fine, until the camera is left for a period of time (30 mins or so) whereupon we are back to square 1.
I am pretty sure that this is a lens problem. The body is a Nikon D7100 but other lenses on the body seem to work perfectly.
Has anyone come across this? Does anyone have any suggestions as to what could be wrong with it and how to fix it?
Given the value of the lens (perhaps £120) then I doubt it's worth spending much money having it assessed or repaired so I'd be tempted to have a go myself as I am fairly practical. There is a video here which shows how to take one apart to get to the motor.
https://www.youtube.com/watch?v=PzPq_jLhP2M
All comments welcomed - thanks.
I'm wondering if anyone can help me. I have a 35mm Nikon 1:1.8G (prime) lens and the autofocus isn't as it should be. If you turn the camera on and half-press the exposure button then the autofocus won't work - there is no noise, no buzzing, nothing. The focus indicators in the viewfinder light up to show you that it needs to be focussed but it won't focus for itself. After a period of time (5-15secs) however it all works as it should. I can't understand what makes it work; whether it's a gentle shake, removing and re-attaching the lens, changing some (any!) settings, manually twiddling the focus ring or just repeatedly tapping the exposure button have all done the trick. Once it's started working it will work fine, until the camera is left for a period of time (30 mins or so) whereupon we are back to square 1.
I am pretty sure that this is a lens problem. The body is a Nikon D7100 but other lenses on the body seem to work perfectly.
Has anyone come across this? Does anyone have any suggestions as to what could be wrong with it and how to fix it?
Given the value of the lens (perhaps £120) then I doubt it's worth spending much money having it assessed or repaired so I'd be tempted to have a go myself as I am fairly practical. There is a video here which shows how to take one apart to get to the motor.
https://www.youtube.com/watch?v=PzPq_jLhP2M
All comments welcomed - thanks.
Lens are usually built in special dust free environments, so I probably wouldn't risk taking it apart. If you hunt FB marketplace you can pick them up for £70-80. I got mine from there. No original box or soft case, but that didn't really matter. Bought it based ojn advice from this forum. Probably the best thing I have bought for my photograph.
New I think they are nearer £200.
New I think they are nearer £200.
Have the same lens and a a very similar camera (7200) and it sounds like I had the same issues.
It's my favourite lens but it's also rather dim-witted. Or it makes the camera dim-witted.
Took this pic of the OH at a party at the weekend using the 35mm. I had at least three shots prior to this of her finger tip in perfect focus and nothing else.
I need my camera in front of me to remind me exactly how I fixed it but in essence, you have to change the focus area when you put this lens on. I'll remind myself later and let you know.
It's my favourite lens but it's also rather dim-witted. Or it makes the camera dim-witted.
Took this pic of the OH at a party at the weekend using the 35mm. I had at least three shots prior to this of her finger tip in perfect focus and nothing else.
I need my camera in front of me to remind me exactly how I fixed it but in essence, you have to change the focus area when you put this lens on. I'll remind myself later and let you know.
StevieBee said:
Have the same lens and a a very similar camera (7200) and it sounds like I had the same issues.
It's my favourite lens but it's also rather dim-witted. Or it makes the camera dim-witted.
Took this pic of the OH at a party at the weekend using the 35mm. I had at least three shots prior to this of her finger tip in perfect focus and nothing else.
I need my camera in front of me to remind me exactly how I fixed it but in essence, you have to change the focus area when you put this lens on. I'll remind myself later and let you know.
I think the 7000 series have AF built into the body. How does the camera behave if you switch the AF off on the lens and leave it in manual. It's my favourite lens but it's also rather dim-witted. Or it makes the camera dim-witted.
Took this pic of the OH at a party at the weekend using the 35mm. I had at least three shots prior to this of her finger tip in perfect focus and nothing else.
I need my camera in front of me to remind me exactly how I fixed it but in essence, you have to change the focus area when you put this lens on. I'll remind myself later and let you know.
Also, out of interest what was the red dot pointing at when you took that photo? I presume it was the finger
Hi,
Thanks for your replies.
Bakerstreet: I think I will view taking it apart as a bit of a last-ditch option; if it improves things that is great but if I ruin it in the process then that's just too bad. However I've never thought about looking for one on FB Marketplace so thanks for the tip. (To be clear, I've never looked at FB marketplace! I'll have a try pronto!)
StevieBee: Indeed - it's a lovely lens, although I have always got on well with it and have never struggled with the the AF until now.
It sounds like your issue and mine are different though. You sound like you are struggling to set the focus area correctly, which can be a fiddle (ceding control entirely to the camera is usually OK but not always so, and doing it manually takes a second or so to set up). My issue is that the lens simply won't focus when the camera is first turned on; the screen lights up, I can select a focus box but the lens won't focus. However after a few seconds it comes to life and works exactly as it should. The problem is this delay.
Bakerstreet (2nd post): 7000 series have an AF motor in the body but that lens has an ultrasonic motor built in, which is where I think the problem lies.
Thanks for your input. I think my issue is whether to live with the lens as it is or whether to attempt to dismantle it.
Thanks for your replies.
Bakerstreet: I think I will view taking it apart as a bit of a last-ditch option; if it improves things that is great but if I ruin it in the process then that's just too bad. However I've never thought about looking for one on FB Marketplace so thanks for the tip. (To be clear, I've never looked at FB marketplace! I'll have a try pronto!)
StevieBee: Indeed - it's a lovely lens, although I have always got on well with it and have never struggled with the the AF until now.
It sounds like your issue and mine are different though. You sound like you are struggling to set the focus area correctly, which can be a fiddle (ceding control entirely to the camera is usually OK but not always so, and doing it manually takes a second or so to set up). My issue is that the lens simply won't focus when the camera is first turned on; the screen lights up, I can select a focus box but the lens won't focus. However after a few seconds it comes to life and works exactly as it should. The problem is this delay.
Bakerstreet (2nd post): 7000 series have an AF motor in the body but that lens has an ultrasonic motor built in, which is where I think the problem lies.
Thanks for your input. I think my issue is whether to live with the lens as it is or whether to attempt to dismantle it.
2Btoo said:
Hi,
Thanks for your replies.
Bakerstreet: I think I will view taking it apart as a bit of a last-ditch option; if it improves things that is great but if I ruin it in the process then that's just too bad. However I've never thought about looking for one on FB Marketplace so thanks for the tip. (To be clear, I've never looked at FB marketplace! I'll have a try pronto!)
StevieBee: Indeed - it's a lovely lens, although I have always got on well with it and have never struggled with the the AF until now.
It sounds like your issue and mine are different though. You sound like you are struggling to set the focus area correctly, which can be a fiddle (ceding control entirely to the camera is usually OK but not always so, and doing it manually takes a second or so to set up). My issue is that the lens simply won't focus when the camera is first turned on; the screen lights up, I can select a focus box but the lens won't focus. However after a few seconds it comes to life and works exactly as it should. The problem is this delay.
Bakerstreet (2nd post): 7000 series have an AF motor in the body but that lens has an ultrasonic motor built in, which is where I think the problem lies.
Thanks for your input. I think my issue is whether to live with the lens as it is or whether to attempt to dismantle it.
Have you tried cleaning the electrical contacts. The motors can fail but I’d start with the easy stuff first. If you don’t have contact cleaner, try an eraser first. Just make sure you hold the lens upward so the debris falls away from it. If the motor has failed I’d suggest the cheapest ‘fix’ is to sell it on eBay as is and buy a new one. You’d be surprised what people pay for broken stuff! Thanks for your replies.
Bakerstreet: I think I will view taking it apart as a bit of a last-ditch option; if it improves things that is great but if I ruin it in the process then that's just too bad. However I've never thought about looking for one on FB Marketplace so thanks for the tip. (To be clear, I've never looked at FB marketplace! I'll have a try pronto!)
StevieBee: Indeed - it's a lovely lens, although I have always got on well with it and have never struggled with the the AF until now.
It sounds like your issue and mine are different though. You sound like you are struggling to set the focus area correctly, which can be a fiddle (ceding control entirely to the camera is usually OK but not always so, and doing it manually takes a second or so to set up). My issue is that the lens simply won't focus when the camera is first turned on; the screen lights up, I can select a focus box but the lens won't focus. However after a few seconds it comes to life and works exactly as it should. The problem is this delay.
Bakerstreet (2nd post): 7000 series have an AF motor in the body but that lens has an ultrasonic motor built in, which is where I think the problem lies.
Thanks for your input. I think my issue is whether to live with the lens as it is or whether to attempt to dismantle it.
AF-S.
(AF-S Nikkor 35mm 1:1.8G)
Given the delay between turning it on and the lens AF coming to life I may almost wonder whether it is built-in in some way. It always seems to be the same duration of inactivity (around 2s), it always comes to life and it always works fine once it has done so.
Having said that I will now have jinxed it and it will probably refuse to work at all next time I turn it on!
(AF-S Nikkor 35mm 1:1.8G)
Given the delay between turning it on and the lens AF coming to life I may almost wonder whether it is built-in in some way. It always seems to be the same duration of inactivity (around 2s), it always comes to life and it always works fine once it has done so.
Having said that I will now have jinxed it and it will probably refuse to work at all next time I turn it on!
cherie171 said:
I did wonder if you'd picked up the AF-P, and it was incompatibility issues, but that shouldn't be a problem with the AF-S.
If you're on facebook, there's a couple of Nikon groups, and someone in one of those might know what the issue is.
There isn't a 35mm AF-P lens is there? If you're on facebook, there's a couple of Nikon groups, and someone in one of those might know what the issue is.
Can't think that there is any setting or anything else that should cause a consistent delay in response time but I guess if it does work after that, it might point towards it being repairable.
lowdrag said:
I don't have any experience of these bodies but it does seem that some fine tuning of the autofocus is needed. Are you using spot or matrix focusing? I'd suggest you need to use spot to get that photo right and focus on the finger tip. Or, of course, use manual focus!
But none of those things would effect the behaviour that the OP is seeing where they're having to wait a several seconds for the lens to focus at all. Spot and matrix are metering modes. Assuming you refer to single or multi area focus, again, they shouldn't matter in terms of this problem. It sounds knackered to me. Update on this (for anyone who cares): The focussing was getting ever so slightly slower but this made a big difference to the usability of the lens. I therefore bit the bullet and took the lens apart as per that video. (If you fancy doing the same then be warned - those screws are hellishly small and impossibly fiddly. And holding what is left of the lens to continue dismantling it definitely required a helper. It's nowhere near as easy as the video makes it look.) I didn't get as far as taking the motor out but did wiggle all the connections to make sure that they were well seated, and put a tiny amount of very light lubricant on the various gearwheels.
It's now back together and seems to work better than before; there is no delay on the autofocus after first turn-on and it definitely finds focus as it should - possibly even slightly quicker than when I first bought it (although this may be wishful thinking, I'll admit!) It's certainly quieter and smoother to use.
All in all, a success. Thanks for your input - it's appreciated.
It's now back together and seems to work better than before; there is no delay on the autofocus after first turn-on and it definitely finds focus as it should - possibly even slightly quicker than when I first bought it (although this may be wishful thinking, I'll admit!) It's certainly quieter and smoother to use.
All in all, a success. Thanks for your input - it's appreciated.
Edited by 2Btoo on Thursday 14th March 11:26
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