Telephoto/Convertor query.

[eyedeebee]

I have currently (temporarily) got hold of a Nikon 80-400 f4.5-f5.6, which is great in terms of reach, and I really like it's sharpness. I do, however, find the auto-focus pretty slow, which can be frustrating.

My question is related to the relative performance of, say the Sigmas 70-200 f2.8, with a 2X convertor. I know that I'd lose a couple of aperture stops using the convertor, but is a teleconvertor likely to also have an adverse impact on autofocus as well?

 

[StewartR]

Yes.

How much of an impact, I don't know, but probably quite a lot. Also mounting a 2x TC on a zoom is going to have a big impact on the image quality.

I really don't like the Nikon 80-400VR myself, because the AF is so slow and noisy. But it is quite decent optically and it's very well built. I don't think there's a better way of getting to 400mm without spending huge amounts of money. (Except by buying a Canon, of course. )

 

[Dal]

I have currently (temporarily) got hold of a Nikon 80-400 f4.5-f5.6, which is great in terms of reach, and I really like it's sharpness. I do, however, find the auto-focus pretty slow, which can be frustrating.

My question is related to the relative performance of, say the Sigmas 70-200 f2.8, with a 2X convertor. I know that I'd lose a couple of aperture stops using the convertor, but is a teleconvertor likely to also have an adverse impact on autofocus as well?

I'll let you know in a couple of days when m sigma 70-200f2.8 turns up with the x2 tele convertor

 

[eyedeebee]

Yes.

How much of an impact, I don't know, but probably quite a lot. Also mounting a 2x TC on a zoom is going to have a big impact on the image quality.

I really don't like the Nikon 80-400VR myself, because the AF is so slow and noisy. But it is quite decent optically and it's very well built. I don't think there's a better way of getting to 400mm without spending huge amounts of money. (Except by buying a Canon, of course. )

Thanks Stewart - the copy of the lens I have at the moment, is of course hired from you!! - Brilliant service as usual.