ahsanford said:
Jim Saunders said:
So they show up five years later, $1400 more expensive and with underwhelming performance? Huh. All my work stuff is brand N and it's fine but I'm surprised they seem to have come up short on this one.
Jim
We don't have a great basis of comparison though. I trust LT at their word on the Nikon in-line TC, but they don't exactly make comparisons easy.
Few people quantify the hit for teleconverter use in general. TC sometimes tucks it under the resolution data for a longer lens (they published 1.4x use on the 400 DO, for instance) but they haven't tested the Canon 200-400 yet.
The best TC resource I've seen on teleconverters been the TDP IQ tool -- some folks don't even know TC use is baked in there. Just go to a lens that is (Canon) TC compatible and the FL pulldown will include 1.4x and 2.0x values in there.
- A
There are proper measurements on the effects of TCs posted in various places. From memory, Lenstip have looked at the 1.4xTC on other lenses such as the 70-200mm IS (which will no doubt interest you in particular) as well as the 400mm DO II. SLRgear has a section on TCs. Lensrentals have done it on the 300mm f/2.8 II and compared it with the 400mm DO II (and 400/5.6). https://www.lensrentals.com/blog/2015/01/more-canon-400m-do-ii-comparisons/
http://www.objektivtest.se/tester/canon-extender-ef-14x-iii-test/ has some good discussion and measurements.
In general, a 1.4xTC on a good lens lowers MTFs by about 10% or even less.
Again, I have to disagree with the TDP results. I use and have used 1.4xTCIIIs (2 copies) and 2xTCIII on a variety of telephoto lenses (300/2.8 II, 100-400mm II, 70-200mm II, 400mm DO II, Sigma 150-600mm C (Sigma 1.4xTC) on various bodies with often quite different experiences than TDP suggests. I'll give you an example. I have two excellent copies of the 100-400mm II (and have had a 3rd one). They all begin to approach my 400mm DO II at 400mm but not quite as good. Yet the TDP has the zoom sharper
https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=962&Camera=979&Sample=0&FLI=0&API=0&LensComp=972&CameraComp=979&SampleComp=0&FLIComp=4&APIComp=0
which not only goes against my experience under a variety of conditions but also proper analysis by lensrentals https://www.lensrentals.com/blog/2016/08/the-sort-of-great-400mm-shootout/ and also lenstip's measurements (see links below).
Put a 1.4xTCIII on the 400mm DO II, and TDP has it blurry, and far worse than the 100-400mm II https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=962&Camera=979&Sample=0&FLI=1&API=1&LensComp=972&CameraComp=979&SampleComp=0&FLIComp=5&APIComp=1
In contrast, my 400mm DO II is tack sharp with a 1.4xTC, and much better than my 100-400s with a 1.4xTC. This squares with lenstip's measurements: https://www.lenstip.com/509.4-Lens_review-Canon_EF_400_mm_f_4_DO_IS_II_USM_Image_resolution.html 400mm DO II at f/4 MTF = 45 lp/mm, 560mm = 41. The bare 100-400mm II only reaches 40 lp/mm!
So, don't take those TDP pull downs with anything other than a large pinch of salt - an otherwise great site but not good on charts.