Autofocus problems

J

jessh

New member
Hi Guys

I'm brand new to photography so please bear with me!

I recently bought a D90 & bought the Nikon AF 50 mm f1.8 D to go with it. I'm having some problems using autofocus.

When I press the shutter down half way, it doesnt focus at all. The switch on the front of the camera is set to AF and the lens is locked to maximum aperture.

If I manually set the focus by twisting the lens and then press the shutter half way, it loses focus again & I'm really confused!

Any help much appreciated :)

Jess
 
Marcel

Marcel

Happily retired
Staff member
Super Mod
Your problem might come from your focusing settings. What are your focusing settings in the camera? How many focus points are there?

Try setting you focusing settings to only one point in the center and then you focus on your subject in the focusing target by pressing the shutter half way and then reframe your shot. Your focus setting has to be set at AF-S, NOT AF-C. AF-S means that you can focus and reframe and the camera won't be trying to change to focus.

It's all very well explained in the user's manual and I can't just find the right words to explain cause it's still too early for my brain to function properly... Haven't had my first coffee yet. :)

​Hope this helps a bit.
 
J

jessh

New member
Rexer John - thanks for that , ive had a look but it's a little confusing. Should I have bought the 50mm 1.8 g?

thanks Alan - whoops! thats what I meant haha.. aperture is set to minimum of f22 :)

Marcel - my autofocus settings are set to AF area - Single point, Center focus point - wide zone. Where abouts in the settings can I ensure it is AF-S?

I'm sitting on the sofa and for example if i point the camera at the tv stand or the window sill where there are 2 cats sitting and some ornaments nothing at all is in focus, which is the same if I go up close to something, unless I twist the lens to get it to focus myself. I am very confused and feeling a little out of my depth!

I think I might have had the same problem with the kit lens so I'm thinking it's something to do with the settings on the body rather than the lens...hmmm =/
 
J

jessh

New member
Oh hang on, it said AF-A so i've just changed it to AF-S. When I hold shutter down, it sounds like it tries to focus for a second...then just doesn't.
 
Marcel

Marcel

Happily retired
Staff member
Super Mod
jessh said:
Oh hang on, it said AF-A so i've just changed it to AF-S. When I hold shutter down, it sounds like it tries to focus for a second...then just doesn't.
Click to expand...

In the bottom left corner of the viewfinder, there are "focus confirmation" lights. Are they working? Can you take the picture? Is it in focus?

Could it be possible that you've mis-adjusted the dioptry adjustment on the actual viewfinder? But, you mentioned that when you focus manually you can get a clear image in the viewfinder?

Maybe there is a malfunction... It's really hard to diagnose from such a distance without having the camera in hand...
 
J

jessh

New member
Yeah when I manually focus it's fine. I'm not sure about the dioptry, I don't *think* I've messed with it although I bought the camera second hand so maybe the previous owner did.

There are 11 dots in the bottom left of the viewfinder. When I switch live view on, these go and on the live view screen there is 1 red square.

Just now, I took some photos of a few objects really close up and the photos great, crisp, sharp and focused but then if I point the camera towards the other side of the room, everything is a total blur unless I twist the lens to focus.

thanks, Jess
 
J

jessh

New member
Am I right in thinking perhaps it can't auto focus when I point it at the other side of the room because it can't find anything specifically to focus on?!
 
RockyNH_RIP

RockyNH_RIP

Senior Member
jessh said:
Am I right in thinking perhaps it can't auto focus when I point it at the other side of the room because it can't find anything specifically to focus on?!
Click to expand...

That would/could happen if there is not enough light/contrast for the camera to find a focus...

Does it autofocus outside in daylight?

Pat in NH
 
E

eurotrash

Senior Member
pedroj said:
Hi Jess and welcome...Maximum aperture...It needs to be set to minimum aperture F22
Click to expand...

What pedroj didnt mention is that this needs to be done on the lens itself as opposed to the camera body. Set lens to aperture 22, lock it with the little red button. Set camera to as-s and see if it focuses in broad daylight

Sent from my Nexus 7 using Tapatalk HD
 
N

nickt

Senior Member
Could the AE-L/AF-L button be set to AF-ON in the menu? This would prevent the shutter release from initiating focus and assign that role to the AE-L/AF-L button. Try pushing AE-L/AF-L button and see if it focuses. If it does then that's the problem. If not, I have no idea.
 
N

nickt

Senior Member
I don't know the d90 well, but I think it also has a 2 button reset. There should be 2 buttons on the body marked with a green dot. Hold them both for several seconds and most settings are reset.
 
N

nickt

Senior Member
Bill4282 said:
Correct. I forgot about that, so used to the menu
Click to expand...
Bill, it might be good to do both types of reset to get the d90 back to original. I just took a quick look at the d90 manual. If I am reading it right, the reset from menu just does the custom menu and the 2-button does other stuff. My d7000 is a little different with a menu item for shooting menu and another for the custom menu and I forget if the 2-button is the same or a little different.
 
B

Bill4282

Senior Member
Looked it up. The manual says using the reset from the menu resets the camera to factory settings and asks for confirmation that you intend to go back to factory settings.
 
J

jessh

New member
I played around a lot with it yesterday & it seems it autofocuses sometimes, usually when a subject is close up. I've got to grips with manually focusing it for now anyway and had a go with the kit lens which autofocus works fine with.... So i just dont think I am/was using the 50mm properly but I'll get there.

Thanks for all your help!
 
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