is autofocus compromised with a Hasselblad 1.7x ?

[Endeavour]

I usually rent an HC120mm when I do my fashion/portrait work. But I am having to reserve earlier and earlier to avoid missing it's availability.
 
as I have an 80mm kit lens aleady, I wonder if I could save a few pennies by buying myself a used 1.7x TC for when I need it.
I like the 120 but it isnt the fastest to autofocus

if I put a TC on the 80mm will that affect it's autofocus? (speed & accuracy) what about IQ?

The alternative is buying a 150mm but I know I'll also need an extension tube to get close autofocusing.

any thought please?

[landscapephoto]

if I put a TC on the 80mm will that affect it's autofocus? (speed & accuracy)

Not noticeably.

what about IQ?

The alternative is buying a 150mm

The 150 will be slightly better. Its AF is also quite fast. Used 150mm can be had for not much more than a x1.7 TC.

[hasselbladfan]

The 120mm version II will be sharper, but the 80 + 1,7x will have a faster AF, as the 120mm sometimes misses a beat and hunts.

[Dustbak]

The HC80 is already less contrasty than the 150 but with the converter it's contrast will be even more less. This is especially noticeable when shooting with backlight. The AF is somewhat slower but that if possible I would opt for a HC150. Faster AF and better contrast.

[shaun]

80mm & 1.7 slower but sharp.

Have used 1.7 with 210mm not sharp at edges, hasselblad looked at it and said it with good, nevertheless 210mm with tiltshift is pin sharp edge to edge.

Shaun