Unlike one review posted, i find the build is very solid, top quality.

Unlike one review posted, i find the build is very solid, top quality.  Read Less

Great quality and you can count hairs on a bees knees.

Great quality and you can count hairs on a bees knees.  Read Less

It does not sacrifice auto focus performance and only degrade a little bit of image quality.

It does not sacrifice auto focus performance and only degrade a little bit of image quality.  Read Less

The lenses marked "mf can only be used for manual focus.

The lenses marked "mf can only be used for manual focus.  Read Less

I highly recommend this product as it has been very cost effective.

I highly recommend this product as it has been very cost effective.  Read Less

A great price for a fast focusing and optically stabilized 448 mm of equivalent focal length and f/4 aperture.

A great price for a fast focusing and optically stabilized 448 mm of equivalent focal length and f/4 aperture.  Read Less

Re sale of this item is nearly impossible.

Re sale of this item is nearly impossible.  Read Less

6 of course i will have to take the time to add or remove the tele converters but that's a small price to pay.

6 of course i will have to take the time to add or remove the tele converters but that's a small price to pay.  Read Less

I ordered and replacement and it was here in 2 days, no problem.

I ordered and replacement and it was here in 2 days, no problem.  Read Less

Sigma quickly repaired and sent it back to me.

Sigma quickly repaired and sent it back to me.  Read Less

The package came on time an it was in great condition.

The package came on time an it was in great condition.  Read Less

I took it out of the box and is a lot smaller than i thought it would be, based on the size of a canon teleconverter that i have.

I took it out of the box and is a lot smaller than i thought it would be, based on the size of a canon teleconverter that i have.  Read Less

4x is a great affordable alternative for sigma telephoto lens' user, especially for those who need extra reach.

4x is a great affordable alternative for sigma telephoto lens' user, especially for those who need extra reach.  Read Less

I already got a replacement and it's no better than the first.

I already got a replacement and it's no better than the first.  Read Less

Sigma has more lens that you can use compare to canon.

Sigma has more lens that you can use compare to canon.  Read Less

You have to look at the sigma chart to see what pentax or other third party lenses it will match fit.

You have to look at the sigma chart to see what pentax or other third party lenses it will match fit.  Read Less