# Nikon d3100 W/KitLens Wont Focus



## PewPewPhoto (Oct 21, 2012)

Last night at my i was shooting at my first wedding likely it was my aunts my auto focus just stops working/ :/ so i had to go manual the whole time what could i do to fix it or what happend to my camera or lens. please help :/


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## Light Guru (Oct 21, 2012)

Was the lens set to manual in the first place? 

Does autofocus work with other lenses on that body?
Does that lens auto focus on another body?


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## PewPewPhoto (Oct 21, 2012)

noo noo it was on auto focus but then i realized it wasn't working so i switched to manual.
and i haven't tried it on any other body or lens.


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## PewPewPhoto (Oct 21, 2012)

also there was times it would focus but wouldn't shoot. and at times it would shot but only if i was zoomed into the subject like if i was doing macro photography other than that it wouldnt shot. unless on manual.


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## Light Guru (Oct 21, 2012)

Test another lens on that camera body. And test that lens on on a different body.


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## PewPewPhoto (Oct 21, 2012)

i wont have that option .


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## Light Guru (Oct 21, 2012)

PewPewPhoto said:


> i wont have that option .



Are you saying that you shot a wedding with out any backup equipment?  What if the lens to body broke completely.  

I certainly hope you did not charge to shoot this wedding, if you did you really should have worked the small cost of renting some backup equipment into the price.


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## AaronLLockhart (Oct 21, 2012)

PewPewPhoto said:
			
		

> Last night at my i was shooting at my first wedding likely it was my aunts my auto focus just stops working/ :/ so i had to go manual the whole time what could i do to fix it or what happend to my camera or lens. please help :/





			
				PewPewPhoto said:
			
		

> also there was times it would focus but wouldn't shoot. and at times it would shot but only if i was zoomed into the subject like if i was doing macro photography other than that it wouldnt shot. unless on manual.



So, you're implying that the focus would cycle, it just wouldn't lock on, and there were times that, it would seem to lock, but wouldn't snap the photo? 

If this is the case, your biggest issue is the way it's focusing. Make sure you're shooting in manual mode, and set the focus setting to single point. And make sure it's set to AF-S. if it is set to AF-A or AF-C, it will tack with moving objects, and will not stop tacking focus until you or the subject stops moving. Also, make sure you're holding the AF Lock button down after it does the initial focus lock so that it doesn't attempt to retract once something in the frame changes position.

Last but not least, invest in a new lens. That 18-55 lens blows and I would even recommend switching it to its predecessor, the 18-70mm AF-S. the 18-55 is extremely slow to focus. You also need to invest in both 50mm and 85mm primes, and a good zoom lens. These are "must haves" when shooting weddings.

***edit***
Btw, the VR on that kit lens is completely irrelevant. You won't need VR until focal lengths of about 200mm and longer


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## SCraig (Oct 21, 2012)

AaronLLockhart said:


> ... If this is the case, your biggest issue is the way it's focusing. Make sure you're shooting in manual mode, and set the focus setting to single point. *And make sure it's set to AF-S. if it is set to AF-A or AF-C, it will tack with moving objects, and will not stop tacking focus until you or the subject stops moving.* Also, make sure you're holding the AF Lock button down after it does the initial focus lock so that it doesn't attempt to retract once something in the frame changes position...



Sorry, I have to disagree.  I *WANT* my camera to refocus as necessary to keep the subject in focus, which is why I very seldom use AF-S on anything except perfectly static objects.  I certainly don't want my subject to walk through the in-focus DOF at a wedding and the shot not be in focus.

Sounds to me like there was just not enough light or not enough contrast for the AF module to lock on.  The camera can be set so that the shutter release is disabled until focus lock is achieved.  Did the green in-focus light come on in the viewfinder?  Did you have the AF Assist light enabled?  Was the area dimly lighted?  There are a number of circumstances in which auto-focus just will not work.  I'd recommend reading that section of your owner's manual before shooting another wedding.


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## AaronLLockhart (Oct 21, 2012)

SCraig said:
			
		

> Sorry, I have to disagree.  I *WANT* my camera to refocus as necessary to keep the subject in focus, which is why I very seldom use AF-S on anything except perfectly static objects.  I certainly don't want my subject to walk through the in-focus DOF at a wedding and the shot not be in focus.



Scott, you run more at risk of that happening in AF-A or AF-C than AF-S. If your AF module locks on the bride and groom in afa or afc, when someone walks across the frame, it will readjust the focus t your new subject, unless you're holding the AF lock down. On AF-S, one it's locked on the bride and groom, the focus will not retract to anything new in the frame unless the initial shutter actuation is disengaged, and focus is administered again. It even does that for focus and recompose situations as well. In AF-A or AF-C, once you recompose, the AF module will re track focus on the new object that it is moved to. In AF-S, it will stay focused on the area you had designated prior to recomposition.

Not to mention that light probably had nothing to do with why her module won't catch focus, considering is uses phase detection instead of contrast detection for focus. In phase detect focus systems, the light would have to be in a night time environment with no surrounding light at all on the subject to have problems focusing. Your statement would have been a plausible answer on a camera with contrast detect focusing. 

I apologize for any grammatical errors or words out of context, as I am on an iPad and did not go back to re read and fix any mistakes made by auto correct.


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## SCraig (Oct 21, 2012)

AaronLLockhart said:


> Scott, you run more at risk of that happening in AF-A or AF-C than AF-S. If your AF module locks on the bride and groom in afa or afc, when someone walks across the frame, it will readjust the focus t your new subject, unless you're holding the AF lock down. On AF-S, one it's locked on the bride and groom, the focus will not retract to anything new in the frame unless the initial shutter actuation is disengaged, and focus is administered again. It even does that for focus and recompose situations as well. In AF-A or AF-C, once you recompose, the AF module will re track focus on the new object that it is moved to. In AF-S, it will stay focused on the area you had designated prior to recomposition.


Again, I disagree.  As I said, I use AF-C almost exclusively so I'm well aware of it's limitations and capabilities.  First, in a wedding there is a low likelihood of anyone walking between the wedding party and the camera.  Second, if someone does do that stay on the subject and it will come right back into focus as soon as they are out of the vicinity of the focus point (pretty much a moot point since one couldn't take the shot while they were there anyway).  Again, I would never recommend the use of AF-S if the subjects are not perfectly motionless, especially when I'm shooting at a wide aperture at an important event and there is the slightest chance of the subject moving out of my depth of field.  Primarily because there is no reason to do so.  My camera is perfectly capable of watching the focus point while I concentrate on other things.  Shoot a bird on a branch when a breeze is blowing sometime.  You can hear the AF constantly making minute adjustments to the focus the you won't be able to see.



> Not to mention that light probably had nothing to do with why her module won't catch focus, considering is uses phase detection instead of contrast detection for focus. In phase detect focus systems, the light would have to be in a night time environment with no surrounding light at all on the subject to have problems focusing. Your statement would have been a plausible answer on a camera with contrast detect focusing.



Take a look at the D3100 manual, Page 56.  Especially the line that reads, "There is little or no contrast between the subject and the background."


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## AaronLLockhart (Oct 21, 2012)

SCraig said:
			
		

> Take a look at the D3100 manual, Page 56.  Especially the line that reads, "There is little or no contrast between the subject and the background."



Which validates exactly what I said. I'm familiar with both phase and contrast detection, as I own both types. Contrast detection would have trouble focusing in an ambient lit church with indirect light, which would have certainly been the lighting conditions of a wedding. Phase detection would have trouble focusing if the wedding were shot at 7pm with all of the lights in the church turned off. When, "there is little or no contrast between the subject and the background."

In other words, phase detection equipped devices only have trouble focusing pretty much when strobes or flashes are needed, and contrast detection equipped devices have trouble focusing on subjects located in something as simple as shaded areas.


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## SCraig (Oct 21, 2012)

OK, you do things your way and I'll do things my way.  I won't argue the point.


AaronLLockhart said:


> Which validates exactly what I said. I'm familiar with both phase and contrast detection, as I own both types. Contrast detection would have trouble focusing in an ambient lit church with indirect light, which would have certainly been the lighting conditions of a wedding. Phase detection would have trouble focusing if the wedding were shot at 7pm with all of the lights in the church turned off. When, "there is little or no contrast between the subject and the background."
> 
> In other words, phase detection equipped devices only have trouble focusing pretty much when strobes or flashes are needed, and contrast detection equipped devices have trouble focusing on subjects located in something as simple as shaded areas.


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## KmH (Oct 21, 2012)

PewPewPhoto said:


> also there was times it would focus but wouldn't shoot. and at times it would shot but only if i was zoomed into the subject like if i was doing macro photography other than that it wouldnt shot. unless on manual.


Auto focus needs a minimum of light to work. In some AF modes the camera is in focus priority and will not release the shutter if focus has not been achieved.
There is a focus indicator in the viewfinder. If it is blinking focus has not been achieved.

See pages 55-63 of the D3100 user's manual (it's a PDF file on the software disc). Note on page 56 those AF situations when AF likely won't work very well.


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## PewPewPhoto (Oct 21, 2012)

it was my aunt wedding it was doing it for free. i have no back up gear im just starting out that was my first wedding i know how to shot . there was enough light everthing was fine but my lens or body was not working.

im thinking of taking it back to the store.
i been waiting to get a 50mm also.


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## AaronLLockhart (Oct 21, 2012)

PewPewPhoto said:
			
		

> it was my aunt wedding it was doing it for free. i have no back up gear im just starting out that was my first wedding i know how to shot . there was enough light everthing was fine but my lens or body was not working.
> 
> im thinking of taking it back to the store.
> i been waiting to get a 50mm also.



You're being very vague with your response. It would be your lens not "working" as the 3100 is a DX camera and has no internal focus motor. 

Does it cycle through the focus range without locking on, or when you press the shutter down, it doesn't do anything?

The reason you need to be detailed is that if its cycling, that means that the equipment is perfectly fine and then this becomes an end user malfunction.

You wouldn't call your auto mechanic and tell them something this vague when your car won't start.

Mechanic: What's the issue?
You: it won't start.
Mechanic: Well whats it doing?
You: I put the key in and turned it, but it won't work.
Mechanic: that's too vague, I need to know what the car does when you turn the key. Does it click, does it sputter, does the engine keep rolling over, does it not do anything at all?

Do you see why this is important? Everything could be working just fine and you might have a simple issue such as a dirty or smudged lens. I have ran into that issue a thousand times... Where the back glass has an oily fingerprint smudge and it won't hit  focus.


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## Light Guru (Oct 21, 2012)

PewPewPhoto said:


> it was my aunt wedding it was doing it for free. i have no back up gear im just starting out that was my first wedding



The wedding being a family members is an even bigger reason to make sure you have backup gear. Every family get together might be vary awkward had the wedding photos been botched. Like i said it is cheep to rent gear and I think it is perfectly appropriate to ask for enough money to cover the expense. 

Now if your shooting for free in addition to a paid professional photographer then fine you may not need to worry about backup gear. 



AaronLLockhart said:


> You're being very vague with your response. It would be your lens not "working" as the 3100 is a DX camera and has no internal focus motor. /QUOTE]
> 
> Yes the lens does the physical focusing but its the camera body that tells the lens how to focus so it could still be the body. That is why I said to test that lens on a different body and to test a different lens on that body.


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## PewPewPhoto (Oct 22, 2012)

okay well heres the thing it does cycle at times but then it dosnt. it also takes pictures while focusing but only close objects once i point somewhere else it wont even focus or take the picture.
it also locks but it will locks unfocused and sometimes focused but it wont take the shot.
you can hear it focusing but it wont focus right theres not smuge on the lens it self . on the inside i dont think so either i only took it out once and for just a few seconds and that was a while ago.
if it is dirty on the inside how can i clean it ? i really dont want to mess up my camera even more.


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## orb9220 (Oct 22, 2012)

Don't worry about the camera sensor or cleaning as that is not the issue. More likely sounds like the lens has gone wonky. I have a 18-55 is the exact same way tries to focus. Many efforts of it trying back..forth...back and forth and 50% of the time not acquiring focus at all. Have relegated to a manual focus when actually using it. 

As not enough light but also consider not enough contrast in a scene for the detection module to define and lock on to subject. Easy to determine find good light and subject and check for consistent AF of camera. If in good light focuses fine then it is the light levels and low contrast scene indoors that is the culprit. As the entry cameras are less capable in lower light of acquiring focus and lock.
.


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## PewPewPhoto (Oct 22, 2012)

welll i was wondering if i could send it back to nikon. ?


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## kingsgraphic (Oct 22, 2012)

PewPewPhoto said:


> also there was times it would focus but wouldn't shoot. and at times it would shot but only if i was zoomed into the subject like if i was doing macro photography other than that it wouldnt shot. unless on manual.



Hi, the camera has been set to shoot when AF is locked. So, no focus/no shoot....Have you got the AF assist light on? It's possible that lighting conditions were that the AF system couldn't see properly to get focus. This is more likely to happen if the subject matter has low contrast and in a low contrast background. Also you need to set a focus mode other than Auto-Area focus, such as single-point AF. Otherwise you may get a focus-point that is not your intended subject.


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## Light Guru (Oct 22, 2012)

PewPewPhoto said:


> welll i was wondering if i could send it back to nikon. ?



Well your going to have to contact Nikon about that.

I would take it down to the camera store and try the body with a different lens and test the lens on a different body.


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## PewPewPhoto (Oct 22, 2012)

Alright ill find a camera store and find out. thanks everyone for helping me out.


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