2 replies to this topic

[sidraphotography]

Hi! I shoot with a Nikon D750 combined with the Sigma 150-600 Contemporary.  I get tack-sharp results with my 150-600, however when I add my new TC-1401 2x teleconverter I'm having real issues with fuzziness in my images. I read such great reviews of this teleconverter and cannot figure out what I'm doing wrong to be getting unusable results.  See attached images of larger image and then zoomed in.  Took these just to display the issue.  Shot at 1/3200, f/9, so not a shutter speed issue. 

[Merco_61]

Have the reviewers used the TC with a slow consumer telezoom or with a f/2.8 pro lens?

How do you get f/9 with that combination? The TC steals 2 stops, so your f/9 in the lens is f/18, well into diffraction territory.

Another factor is that the AF gets erratic below a max aperture of f/8. With third-party TC-s that don't report the aperture correctly, the AF won't stop working but the focus plane will seldom be where you want it to be. From what waves are sharpish, it looks like a bit of front focus in this situation.

[mikew]

Normally with consumer lenses the max converter that works is a 1.4 the 2x needs an exceptionally sharp lens in the first place, i have been using the Sigma 100-400 with a Sigma 1.4 and getting decent results.

Most lens and converter combinations need a separate fine tune adjustment ime fairly sure your 750 would remember a with and with out setting my 500 did so i would make this your next step if you want to continue using the 2x.