Nikon 300 F4 + TC 1.7 = no auto focus?

[Brian Kent]

Just wanted to get a "real world" answer to this question. On Nikon's site, in describing the Nikon 300m F4 lens, the specs indicate that while the 1.4 TC allows for Auto Focus, the 1.7 TC is, and I quote: "Usable, but autofocusing is not possible."

Is this Nikon just being "conservative"? I know I'll lose 1.5 stops of light, so I'll be shooting wide open somewhere between 5.6 and 8 (5.6?) - so obviously available light will be a factor in my ability to auto focus. But, given enought light, I should have no issues auto focusing with a 1.7 TC on this lens. Right (gulp)?

Brian

[PeterCollins]

It depends on which version of the 300 F4 the afs one works with the nikon 1.7 convertor i believe

I have the 300 f4 on order (should be here tomorrow) the non AF-S one and will be sticking it on a convertor :)

[Brian Kent]

Yep - it's the AFS model that I'm referring to on the Nikon web page. Definately works with the 1.7 TC, but it's ability to auto focus is what I'm wondering about.

[PeterCollins]

no the AF wont work

was just thinking about it

The convetor needs a min apeture of 5.6 on the 300mm f4 with a 1.7 on it you lose 1.5 stops putting it at 6.3, above the threshold for the af

so no af

[Tony Whitehead]

My 200-400f4 and 500f4 both work with 1.7x. AF is slower than with a f2.8 lens but works in good lighting. The f5.6 for AF is conservative.

[Phil Seu]

ditto: my 200-400 and 600 f/4 both autofocus with the 1.7 t.c.

[Gene C. Callison]

The 300 F4 AFS will work just fine with the 1.7. Focus will slow down and it could be a problem in low light but there are lots of peole using this combo. I am assuming you have a D300 or better.

Gene

[Brian Kent]

You are all confirming what further research reveals - that this combo on my D300s will work FINE in good light, slow focus/hunt in shade and I'll probably have to manual focus in poor light. This is all exactly as I had hoped for! Ordering this lens tonight - thanks folks!
Brian