AF trouble with 3rd party lens on D300

[ted_springer]

Hi all,

 

I just bought a Tamron 17-50mm f/2.8 for my D300. It's a sweet lens but the auto focus is tiny bit off. I only noticed it at f/2.8. When I switched

to manual focus I was able to get it sharp. I was going to return the lens but then it occurred to me that there might be a way to fix the af. Does

anyone know how to fix the problem?

[eric_arnold]

i have this combo and it works perfect.

 

not sure eactly what the 'problem' is from your terse description.

you say AF is a tiny bit 'off' at f/2.8, what do you mean, exactly?

front-focus? back-focus? softness?

 

it would be helpful if you could post examples; also, to know what settings you have on the d300 for troubleshooting purposes.

 

and is this the micromotor version of the 17-50 or the older screw-drive version?

[ted_springer]

front focus.. and it is the newest version with the internal motor

[eric_arnold]

can you post some examples?

 

hard to say whether its a lens issue or OE without that. if you were shooting a low-contrast scene in low-light, that would be challenging for any lens/body combo. you say this only happens at f/2.8?

 

also, what metering setting were you using? (matrix/spot/cw) what C/S/M setting did you have? and what area-AF setting did you set?

[peter_k4]

can't you use the AF fine tuning feature?

[bruce_margolis]

Ted, I have the same combo and also found the 17-50 to be off a bit. In fact, I also found it to be off with the 90mm macro. You have a couple choices. You can try to adjust it with the AF in-camera or do what I did..... just send it back to Tamron. That was a nuisance but it worked fine after that. Other than that, a great lens.