Sony A7 III Sony to Sony to Sigma

[Ralph]

G'day there to you all I need some help again.
What I am after is with this combination going to work.
I have got the Sony A7iii and I want to get the Sony 1.4 teleconverter which will go on to the Sigma contemporary 100/400mm lens.

So here is the question and let me say sorry if it had been written about before.
Will this combination give me automatic focus or will it be manual focus.
I thought of this way as the big 600mm lens cost at the moment is just getting too far out of our budget.

So if this combination would work I would be happier with as it would bring me closer that the way it is now.
But if it made me go to make go to manual focus I would just have to do a lot more saving.
Thank you to those who help on this one which is tricky for me.

 

[Brownie]

You cannot use the 1.4 with the Sigma 100-400. In fact, you cannot use any TC's with third-party lenses. Most people believe that Sony limits third party manufacturers on purpose. Here's a list of lenses compatible with the 1.4 TC. It's the same list for the 2X TC. They are all Sony lenses.

Compatible Lenses
FE 70-200mm f/2.8 GM OSS
FE 70-200mm f/2.8 GM OSS II
FE 100-400mm f/4.5-5.6 GM OSS
FE 200-600mm f/5.6-6.3 G OSS
FE 400mm f/2.8 GM OSS
FE 600mm f/4 GM OSS

This isn't a matter of autofocus or any specific function, they literally won't fit because the rear glass needs to be set deeply into the lens barrel for clearance. Note how far the front lens extends beyond the mount:

 

[Gaz]

You might like to try clear image zoom for 1.5x and see if the results are inoffensive. One drawback is that it is always centre focus, which I work around by using DMF.

 

[Ralph]

You cannot use the 1.4 with the Sigma 100-400. In fact, you cannot use any TC's with third-party lenses. Most people believe that Sony limits third party manufacturers on purpose. Here's a list of lenses compatible with the 1.4 TC. It's the same list for the 2X TC. They are all Sony lenses.

Compatible Lenses
FE 70-200mm f/2.8 GM OSS
FE 70-200mm f/2.8 GM OSS II
FE 100-400mm f/4.5-5.6 GM OSS
FE 200-600mm f/5.6-6.3 G OSS
FE 400mm f/2.8 GM OSS
FE 600mm f/4 GM OSS

This isn't a matter of autofocus or any specific function, they literally won't fit because the rear glass needs to be set deeply into the lens barrel for clearance. Note how far the front lens extends beyond the mount:

View attachment 36567

I had know that it would work with the Sony Lens and if this is an on purpose job then I think it is a lot of smart thinking getting us to buy their lens. But means save no matter what way I go. Thanks for the reply.

You might like to try clear image zoom for 1.5x and see if the results are inoffensive. One drawback is that it is always centre focus, which I work around by using DMF.

I do the clear image zoom and I like it and with stick with that until I can get any sort of 600mm lens. And many time I don't think things are a drawback we just have to get use to the way of using it over anything else. Thanks for the help.