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10-06-2015, 10:38 PM   #1

Join Date: May 2010
Location: Sydney
Posts: 503
Comparing 1.4x converters (645 versus 67)

Hello all,

Like several of us here, I use a selection of 6x7 lenses with my 645Z and have been wondering whether anyone has any hard data or experience comparing the optical performance of the 645 and 67 1.4x teleconverters (latest versions in each case). Since the lenses I am talking about are 6x7, I could obviously use either converter. At present, I only have the 645 converter, which is pretty good - but would be nice to know if improvement is possible by using the 6x7 one.

N.B. I have already discounted the 2x converters, so not seeking information on those.

Many thanks!


10-07-2015, 01:35 AM   #2

Join Date: Dec 2010
Location: santa monica
Photos: Gallery
Posts: 418
I have put the 645 1.4 converter behind the P67 100mm Macro and the P67 200mm f4 with very good results ! The 67 1.4 converter I sometimes use behind the 400mm EDIF. The real issue is the overwhelming size and weight of the 67 converter……I generally end up leaving that one in camp, but think nothing of tossing the 645 one in the back pack for some hiking and shooting.

But, no I never did a direct test.
10-07-2015, 05:17 PM   #3

Join Date: May 2010
Location: Sydney
Posts: 503
Original Poster
Thanks 672 - sounds like you are pretty happy with them both. Is there a reason that you use the 67 converter behind the 400 EDIF rather than the 645 converter? Do you intuitively feel it's better somehow?
10-08-2015, 01:45 AM   #4

Join Date: Dec 2010
Location: santa monica
Photos: Gallery
Posts: 418
Again , the size, for those times that I drag the very large P67 400mm EDIF lens around, its really nothing to add the matching converter. Both converters are very nice and since the P67 one is next to worthless these days , there is no reason to sell it.

10-08-2015, 12:17 PM   #5

Join Date: Feb 2009
Location: Arizona
Posts: 911
The P67 1.4x does not degrade the image at all. In fact, for the lenses that have some CA, the 1.4x actually reduces it a bit because it intercepts the rays before they reach the film/sensor. Both 1.4 TCs have a 5 element design but their cross sections are quite different.
10-10-2015, 10:48 PM   #6
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Join Date: Nov 2011
Location: pontiac mi.
Posts: 353
when I use the pentax adapter I use both the 1.4 and the 2.0 645 tc's with my 6x7 135mm and 300mm.

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1.4x, 1.4x converters, 645, 645d, 645z, 67, 6x7, camera, converter, converters, lenses, medium format
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