I have surely asked for a great deal of advice lately...
I am trying to decide between four teleconverters that I may be able to get my hands on:
- Sigma 1.4x (older generation?)
- Sigma 1.4x APO
- Tamron 1.5x Pz-AF
- Kenko 1.5x Px-AF
My targeted lenses for use of the TC would be
- Sigma 170-500 f/5-6.3
- Sigma 100-300 f/4
- Sigma 400 f/5.6 telemacro
- Tokina 80-400 f/4-5.6
I know that a TC may cause severe IQ reduction in some of these lenses and my ultimate goal would be to only mate it with the 100-300 and 400 telemacro. But alas, I do not own those rare gems yet.
That being said, which TC would be the best for retaining IQ and AF?
I know the sigma lenses tend to work great with a sigma TC, but does the Tamron/Keno outshine?
Sigma 8-16 f/4.5-5.6 DC HSM
Pentax SMCP-DA 40 f/2.8 ED Limited Edition
Pentax D-FA 100 f/2.8 Macro WR
Sigma 170-500 5-6.3 Apo Asph F/px-af