My D90 is Being Picky

[AdamBomb]

So I don't know exactly WHEN it does it, but sometimes, My D90 wont fire. Its normally in Low light, and I think its because of the AF. If I switch my Lens to M, then it will fire no problem, but if the AF can't focus, it just...wont let me take the picture. It's kind of frustrating, is this how it's supposed to be?

 

[Arch]

yup, if its not in focus it wont fire unless your in manual focus or hold focus lock. Think of it the other way... would you prefer the camera to fire all the time without being in proper focus?... you'd end up with a card full of blurry shots even when your trying to get sharp ones.

 

[AlexColeman]

Agreed, I think of it as a reminder to check focus and such, then it fires with no problem. It is just being helpful.

 

[inTempus]

I've never used a D90 but my 40D has a visual indicator that flashes if something is out of whack. If it doesn't fire, I can look and see exactly why in the view finder. I assume the D90 has a similar feature.

 

[CaptBill]

Yes, the D90 has a little green "In-focus" light in the lower left corner of the viewfinder. If it isn't lit, and you are not in Manual Focus mode, the shutter will not fire.

If it is having trouble focusing, you may have the focus-assist light turned off (a menu selection), and trying to autofocus in low light. The autofocus sensor needs to be able to see contrast in order to work. No contrast, or very low light: won't work.

 

[ShutterSpeed]

i learned this lesson when i started doing night photography...sometimes i couldn't get it to fire..and i was like ... WHAT THA!...then i realized, it couldn't find the focus subject

 

[djrichie28]

In most cases the camera won't fire if the auto focus is set to 'Single' until is can finish focusing. It should fire anytime if the auto focus is set to 'Continuous' or, of course, 'manual'

 

[DavidElliot]

In most cases the camera won't fire if the auto focus is set to 'Single' until is can finish focusing. It should fire anytime if the auto focus is set to 'Continuous' or, of course, 'manual'

really? because i have mine set to continuous and my camera still hunts before it fires and more often than not it has a terribly hard time focusing in low light situations. maybe i have it on the wrong settings...

 

[Domokun]

yeah, my XTi does that too. i'm pretty sure that it means that you're in low light or the subject is not in focus. now i just use manual focusing

 

[fwellers]

The autofocus section of the manual ( page 54 I believe ) describes this.
There are like 6 things that can prevent autofocus from focusing. Things like not enough contrast between subject and backround, too much contrast between them, geometric patterns etc...

I think one way to get around it is to use single point focus area as opposed to the 3d or dynamic area. You can hone in on the subject easier that way.

Also, AF-C mode ( continuous servo ) will allow the camera to take a shot even if it can't focus. Not sure why you would want to do that though.