ckw From UK - England, joined Aug 2010, 660 posts, RR: 17 Reply 1, posted (8 months 1 week 1 day 21 hours ago) and read 3635 times:
I would say that's pretty much what one would expect - the more powerful the convertor, the greater the image degradation. However, in specific terms I'm not sure how useful this review is. The test were carried out on a Nikon D800E - this camera is atypical in so much that it does not have an anti-aliasing filter.
While in theory the 800E can be sharper than a standard 800, lack of the antialiasing filter can have disadvantages - a greater potential for moire is well known (though perhaps surprisingly not evidenced much in real world tests by reviewers). Another is "early onset diffraction".
In brief where the 800E might show diffraction effects at f11, the "standard" 800 should be good to around f16-f22 which makes some of the comments in the article less applicable to most Nikon users.
Personally, I would not have thought the 800E a good choice for aviation photographers - while it offer advantages with natural subjects and wide - normal lenses (say landscape photography), the use of long lenses (forcing smaller apertures) on artificial subjects (which have edges and regular patterns) does not play to the 800E strengths. Having said that, the real world differences are likely to be small and only of concern to pixel peepers.
megatop412 From United States of America, joined Sep 2005, 294 posts, RR: 0 Reply 2, posted (8 months 1 week 1 day 13 hours ago) and read 3612 times:
One reason I decided against getting a 70-200mm f/2.8 was because I would need to add a 2X TC (or at least the 1.7x) to get to a reasonable focal length needed for aviation photography, which would degrade the IQ to or near the point at which a slower zoom with more useful focal range would actually be the more practical choice(to say nothing of the added cost). Since I rarely shoot in low light, 2.8 isn't needed. Plus I don't get hung up on extreme subject isolation- f/5.6 @ 300mm provides enough should I want that.