AF Trouble... I think.

[MJinCP]

Nikon D70 with Tamron 18-270 lens. I've had both for several years. Having trouble with moving subjects - i.e. a wedding setting where a couple are walking towards me (I'm in an aisle seat), and the focus won't lock, so no matter how hard I try, the shutter won't trip. Moment is then gone, and I'm tearing my hair out. Tried bot AF-S and AF-C. Any help, please?

 

[orb9220]

Being a slower variable f-stop jack of all trades zoom lens. And indoor weddings famous for difficult low light shooting. Surprised you would get many decent keepers.

There is a reason wedding photographers use expensive fast glass like f1.8 or f2.8 zoom lenses. To get the shot where other's like with your setup would fail.
.

 

[SCraig]

Autofocus is not infallible. In fact there are a number of circumstances where autofocus just won't lock on. That's why you have manual focus, and it's the best solution to those times when autofocus won't lock. Take a look at page 73 of your owner's manual. If you don't have one you can download it Here. Also make sure that the AF illuminator is on under dim conditions (page 72).

 

[Overread]

The problem is that a subject moving toward you requires constant adjustment of the AF (ie the focus) to keep it in focus. For the auto focus this is tricky even in good light, in dim lighting its even harder as there is far less for the lens to get to the sensors in the camera. As a result getting a single lock is hard, let alone getting consecutive locks one after the other to keep the AF focused on the subject moving closer and closer.

Manual focusing is the only reliable option, yes its tricky and not easy to get a shot, but you can at least see more than the camera AF sensors can. That said manual focusing with DSLR is a bit more tricky than with the old film cameras as a typical DSLR has a smaller and somewhat darker viewfinder image and no focusing aids (although the red dot for AF confirm normally still blinks on and off when the shutter is held down (ie when you normally would engage AF).

 

[TheLost]

The Tamron 18-270 is a VERY slow focusing lens.. Here is a quote from one review:

AF performance was relatively slow and sometimes extremely indecisive

The D70 is a almost 9 years old.. It's not a speed daemon. (it still is a great little camera though).

Put the two together and you are going to have to work for your shots.