Personally I don’t like to use TCs; although sometimes I get excited after testing them, over time I’ve never really liked images shot with TCs. The crispness of detail is lost, AF performance becomes more erratic, there is like a slight veil over the image. I am much happier not using them. For a while I shot deer with the D5, 300 PF and TC-14E III, and felt that sharpness was almost but not quite there, and in waning light the AF focused a bit here and there. Then I started to shoot more without TC and it was quite a ”Wow! Where did all this crisp fur detail come from?” experience. And I was using a D5 not even a high resolution body. With the 2X the 300 PF couldn’t focus at all in typical light I would have for these subjects (deer, moose), unless put on tripod and LV focused.
The 2x TC III came out right when the 300 f/2.8 VR II came out;
it was designed for f/2.8 lenses or wider (200mm f/2 VR II, 300 f/2.8 VR II, and 400 f/2.8 FL ED),
not for other lenses.
Therefore, using the 2x extender on the 300 f/4 PF is misuse of the 2x TC III. (Sure, you can try, but the lesser 300mm is
not the lens the 2x TC III was designed to complement.)
- "While this teleconverter works with any professional Nikon lens that can take teleconverters, it is specifically designed to work with fast prime lenses with an aperture of f/2.8 and larger."
~ Taken from Photography Life
That said, I have seen many,
many people post superb images with the 300 f/4 PF +
1.4 TC III(With the proper
1.4x TC III, the
300 f/4 PF becomes a ~420mm f/5.6 equivalent on FF ... or ~
630mm f/5.6 equivalent on DX).
On the other hand, the
2x TC III turns my D500 +
300 f/2.8 VR II into an equivalent
900mm f/5.6 ... that is easily as sharp or sharper @ 900mm with the 2x TC III as the 300 f/4 is @ 630mm with the 1.4 TC III
Regarding the subject of image quality, it is pretty much common knowledge that TCs produce
some image degradation.
However, the key thing to realize is you're hoping for "acceptable" sharpness, in exchange for the added reach, rather than "absolute" sharpness.
So, yes, if you want "absolute" sharpness, then don't use TCs.
However, if you want to dramatically-increase your lens reach, then 1) follow the instructions and use
the right TC for the right lens, and 2) don't expect "absolute" sharpness.
Instead,
be grateful you are able to get "acceptable" sharpness + far better reach that you could
not have gotten otherwise with your bare lens.
Here are some bird images I obtained with the 300mm f/2.8 VR II + 2x TC III at an equivalent 900mm on the D500.
They may not be the sharpest images in the world, but they are definitely "acceptably" sharp:
Black-Headed Grosbeak ♂ by
John A. Koerner II, on Flickr
Red-Whiskered Bulbul by
John A. Koerner II, on Flickr
Northern Mockingbird by
John A. Koerner II, on Flickr
Mourning Doves by
John A. Koerner II, on Flickr
Had I not had the 2x TC III, and tried to crop-in to the same compositions, they would not have turned out as well.
As a nature hiker, I would much rather have 300 VR II + 2x TC III, where I can keep the lens mounted on my gimbal head (and switch between TC, or no TC, to halve or double my reach) than I would to carry a bare 300mm lens, and a bare 600 mm lens, respectively, and try to alternate between these to halve or double my reach
The only better option for maximal range/minimal gear would be the recently-introduced 180-400mm f/4 FL ED + 1.4x TC (equivalent 270-840 on DX).
Jack
