These things being known, I think I'll skip the idea of finding a 1.4X.
The Sigma 2X teleconverter that I bought almost 40 years ago has been a
very good performer, and the Vivitar macro teleconverters work very well also.
>> I've been interested in the Olympus/Zuiko 1.4X teleconverter, but
>>they tend to be horribly expensive. I looked into the Tamron 140F
>>(there is an affordable one on evilBay), but that one is intended to
>>work only with primary (fixed) lenses.
>While I don't know about other 1.4x teleconverters, the Zuiko
>protrudes quite extensively into the attached lens. Olympus was wise
>to put the guards in place on unmatched lenses to prevent optical
>impact. The only thing I can think of is that the Zuiko 1.4x
>teleconverter is overly happy.
>As to performance, it does magnify any flaws in the primary lens. With
>the 300/4.5, it performs pretty well on the A7 II, but is quite
>difficult on the Four-Thirds cameras. I believe the optical stack in
>front of the sensor is contributing to the problem. The thickness and
>makeup of the sensor stack in the Sony (as well as the Canon 6D)
>appear to be better matched for this lens combination.
When the going gets weird, the weird turn pro
- Hunter S. Thompson
Themed Olympus Photo Exhibition: http://www.tope.nl/