willie35

Have had this camera several years.
Had a serious focus problem using Auto.
Just started experimenting with all the other settings.
ISO, Aperture and speed settings.
Any hints, tips, beware's out there.
I am a long time 35mm SLR user and familiar with all camera terms.
Thanks

Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

Just remember that this camera needs gelded lenses (G lenses) with a focus motor in them in order to be able to auto focus. Older, non gelded lenses ( original AF & "D" lenses) will meter, but not AF on this model. Even older manual focus lenses will mount & capture images, but you will not get any metering (or AF of course)... You would need either a hand held meter or to use the old "Sunny 16" rule & then fine tune using the LCD & Histogram if you go the manual lens route. Oh, and you would only be able to use the "manual" mode on the camera...Any other mode would give you an "error" message.

willie35

Mechanically has what is required.
Have tried AF and AS focus.
Strange, go to Live view, point at something, half press shutter..usually totally out of focus, just keep trying, if you are lucky it will eventually focus.
(Although not always perfect!)
This happens in all modes.

Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

Sounds like maybe the AF module needs to be replaced...

MtnMan Loc: ID

Be sure you have turned on the lens autofocus switch. Sometimes the switch can move.

Also check your menu settings regarding focus.

Finally check your shooting settings. I usually use single point focus so I'm sure it tries to focus on what I want it to. That is, autofocus set to AF-S AND select single point focus.

willie35

I am using AF-S and single point..
Single point I found was an absolute must!
I am about ready to give up experimenting, I think I have the best I am going to get.
My D3100 just has "soft" focus no matter what.
And I learned, take four of everything and pick the best!

skywolf

I've been pleased with my 3100. If you're not confident in the way the AF works, as I sometimes am not, I go to manual focus. I've come up with some great images.

SX2002 Loc: Adelaide, South Australia

Sounds like it needs a fix/check-up...
I don't have a 3100 but a D90 and a D7100 and their focus speed and accuracy is better than any camera I've ever tried regardless of which lens I'm using...
Take it to the shop and get it checked...

Bret Loc: Dayton Ohio

Hello willie and welcome to the UHH. Which lens are you using on your D3100?

willie35

Nikkor 18-55, Auto and VR....

CHG_CANON Loc: the Windy City

I've experienced the zoom break on the kit 18-55 which seems to be all plastic except the glass. Do you have another lens to test to maybe isolate the problem between the body and maybe the lens?

Revet Loc: Fairview Park, Ohio

I have had a 3100 for 3 years and it has been very good to me. I am upgrading to the 7100 soon but to be honest, the 3100 takes great pictures. I have never had a problem focusing with any lens I have used with it but all the lens have motors in them. I did switch to back button focus a half a year ago, you might try that (assign the AE/AF button to the 5th or last option in the button function in the menu). I do seem to over-exposure everything with the 3100 in any mode but manual. Someone on here said they had better luck with center weighted vs. matrix metering. That helped me also. Set your focus mode on single servo so that it will beep when it locks. Then try focusing on things near and far away to make sure your lens is trying to focus (you should be able to hear and see it). You could also do this in the continuous servo mode but it will not beep when it locks. I am not an expert but if your lens isn't doing this, I would think it is a lens problem. If your lens is searching but can't find a focus, I would think it would be the 3100. Also, if your ambient light is low, the 3100 does struggle to find the correct focus at times.

PhotoPhred Loc: Cheyney, Pa

I had a d3100 and I had no problems with it. You might try a different focus mode. Depending on your subject, you could try spot focus. Check the menu and try experimenting with different focus modes. If that doesn't work, you may need a repair. Let us know how you make out.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Scott, any AF-S lens will work with the D3100, it doesn't have to be a G lens. The G designation only means that is does not have the aperture ring and your only option for setting aperture is the camera body. I am not sure if G lenses can work with older film bodies.

Screamin Scott Loc: Marshfield Wi, Baltimore Md, now Dallas Ga

You are correct in that there are lenses other than gelded ones that are AFS.... The only manner in which the gelded lenses can work with older film bodies is at their minimum aperture & that is not even worth doing.