Focus indicator blinks erratically

[jeff_emtman]

I'm shooting on a d80. When I use my old manual focus 105mm f/2.5 I've noticed that the in-focus indicator tends to

blink erratically, the pictures look fine though.

 

Does anyone know what causes this, or what the blinks mean.

 

Thanks,

~Jeff

[sam_motskin]

I have it when I take hand held shots using a non-CPU lens on D300 when I am focusing on a subject that's not

parallel to the focal plane. I believe that's because the distance fluctuates slightly since it's hard to keep the

camera absolutely steady. Try it with a tripod and see if the problem goes away.

[alvin_lim5]

If you are manual focusing, it is fine. I never base my shots on the dot when I manual focus. Guess for me, what appears in the focusing screen matters more and my manual focus shots tend to appear fine. So I think it is normal for manual focusing.

[leicaglow]

I always base my MF lenses on the blinking, but it just means your camera is moving and the AF sensor (used to indicate if it's in focus) is finding different points to focus on as it hunts. Just use it to get the least amount of "off" indication and you'll be fine.

 

If you put the camera on a tripod you wouldn't see this problem. Great lens choice though. It's one of my favorites. Not sure what I'd do if I lost it.

[jeff_emtman]

Thanks for the help everyone, putting the cam on a tripod helped :)

[seismiccwave]

105 mm has a shallower depth of field compare to standard and wide angle lenses. You are probably rocking the camera

back and forth (slightly) so the focus indicator goes in and out of focus range.

[flaviosganzerla]

What hansen said!