31-AUG-2007
TC-14E vs TC-17E at 280mm effective
While the TC-17E improves when stopped down to f/8 effective, the TC-14E is already rather good wide open, almost on par with the TC-17E at f/8.
That's two stops difference which I personally value much more than the relative higher reach attainable with the TC-17E.
The TC-17E at 340mm wide open performs better (see next comparison) but stopped down to f/8 it's not better than @280 mm
at the same aperture, so I still prefer the images from the TC-14E which can be interpolated later in Photoshop to the same 340mm
magnification if needed, with comparable results.
31-AUG-2007
TC-17E wide open at 280 mm vs 340 mm
Probably because of the complexity of the 70-200 design, the converters behave differently depending on the focal lenght.
This was the biggest difference I found and in my opinion the most important because it shows the performance wide open
at the longest focal lenght comparable with the TC-14E (280mm) and at the longest focal lenght for the TC-17E itself (340mm).
Wide open the TC-17E works better at 340mm than at 280mm.
Stopping down 1-2 stops evens this difference (at 280mm I see more of internal flare rather than loss of resolution, indeed
I can't recognize more details in the 340mm shot despite the better contrast and higher magnification due to the longer focal lenght).
31-AUG-2007
Which is the best 300 ?
Here are the two combos at their best settings, compared to THE reference (300/2.8 VR) at its worst aperture, which admittedly is almost equal to its best one ;-)
Ahem... as you see there's no substitute for REAL glass :-)
Anyway the TC-14E gives the 70-200 VR even more versatility with very nice image quality.
I never thought a TC worked so well on a zoom but now I won't worry when I'll have to use this combo.
