Difference between T6-2X , Pentax 67 Rear converter 2X

Hello Folks,

is there a optical difference between the T6-2X , Pentax 67 Rear

converter 2X or are there more (origional) 2x convertors

as far as I could figure out T means tele 6 means 6 elements and 2x

multiplication

does the Pentax 67 also have 6 elements?

and how about the gray editon?

Kind regards

Gert Jan

The Rear Converter 2x (gray) is made of 6 elements in 4 groups,

and is a newer model than the T6-2x (black). I'm not sure which

converter would be sharper, if there is a difference.

The T6-2x is limited as to the lenses it will work with because the

front element of the converter will collide with the rear element of

some lenses. It will work with focal lengths of 135mm and up,

with at least one exception being the 165mm leaf shutter lens.

I don't believe the Rear Converter 2x has this limitation, and will

work with all P67 lenses.

According to Pentax, the newer Rear Converter 2x (gray) is indeed made of 6 elements in 4 groups, and is a general purpose

converter and will work with all lenses.

In researching this I found that the T6-2x is comprised of 6 elements in 6 groups, and the "T" designates that it is a

converter specifically designed for telephoto lenses. Additonally, Pentax states that the T6-2x is optimised for distance work

and that perfomance suffers at close range. I have the newer gray 2x, but will likely pick up a T6-2x and test it on a

M* 800/6.7.

There is also an older black model designated Rear Converter 2x, that is an outer bayonet only model, meaning it can only

be used on the 400,600,800 Takumars. I could not find it's optical formula.