papageno wrote:
Whats the point of the 1.7 when using the 80-200? The 1.4 gives you a 112-280, and the 2x a160-320. Since they overlap so much, what does the 1.7 give that is actually useful?
Don't mean this as snotty; just puzzled.
That is a great question. Now if you only could have just one TC in your bag, which one would a person want, would be the question. IMHO I have always found the 2x tc to be just too soft with just about any lens, while someone else might be just find with it. I think that Nikon recognized that something else was needed in the TC lineup that might reach a happy medium between the 1.4 and 2.0. You pick up 1/2 stop in speed with the 1.7 over the 2.0 and gain some sharpness in the process.
Remember that TC's are actually designed for the larger primes and not zooms, however we photogs will try anything to save a buck or two. Let's say that you had a 300 prime, so with the 1.4 you would end up basically with a 400mm and with the 1.7 you would end up with a 500mm. If you were using the 300 f/2.8 prime then you would have f-stops of 4.0 and 4.8 respectively. Now if you take in to consideration the size, weight and cost of the 400 and 500 primes you get a great bargain. I refer you to this post. Again only my opinion here, which doesn't mean much. If a person was more interested in details then the 1.4 would probably be their pick, they would just have to get a little closer. Now if the nit picky details weren't your bag then the 1.7 surely performs much better than the 2.0 IMHO with some extra speed that can make a difference in certain situations.
With your 80-200 the results would actually be a little better than the ones shown here. If you look at the MTF tables on the 70-200 vs the 80-200 at the 200mm mark the 80-200 outperforms the 70-200 at 200mm. The advantage of the 70-200 is VR.
Let's say that you had a 300 prime, so with the 1.4 you would end up basically with a 400mm and with the 1.7 you would end up with a 500mm. If you were using the 300 f/2.8 prime then you would have f-stops of 4.0 and 4.8 respectively. Now if you take in to consideration the size, weight and cost of the 400 and 500 primes you get a great bargain. I refer you to