picsman Loc: Scotland

I use zoom lenses, 80-400, 70-200, 24-120, 16-35 for different purposes and different sports. I know there is overlap but each lens serves a purpose depending on how close I want to get or how far away the participant is. Eg 80-400 for canoe and skiing, others for MTB.

I want to try a prime lens, probably 85mm or 105mm for the MTB events. Can anyone tell me about speed of autofocus and/or recommend a prime at or under 200mm? I use a D750 body.

CO

If you're going to be handholding the camera a lot you might take a look at Tamron's new SP series prime lenses. The reason is they all have stabilization. They also have a metal lens barrel and are fully weather sealed including a weather seal at the lens mount. I purchased the 45mm f/1.8 for my Nikons. The new lenses are the 35mm f/1.8, 45mm f/1.8, 85mm f/1.8, and 90mm f/2.8 macro.

JohnSwanda Loc: San Francisco

I can't see any advantage to using stabilized lenses for shooting sports. Stabilization only helps with camera motion, and with sports you are going to have to use a high enough shutter speed to stop subject motion.

picsman Loc: Scotland

Yes I usually switch off stabilisation for most sports images.

cmc65

This is a perfect case for renting the two lenses that you are considering first.

picsman Loc: Scotland

Cmc65 you make a good point.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

What is it that you are hoping an 85mm or 105mm lens will do that your 70-200 isn't doing for you? The 70-200 is one of the go-to lenses for action sports - outstanding sharpness, extremely fast AF, great handing. The others are 300 F2.8, Sigma 120-300 F2.8, 400mm F2.8, and every now and then I see a 200-400 F4.

picsman Loc: Scotland

All my lenses are f/4 or higher so a faster lens with enough distance to get the action, but that also means fast autofocus. I sometimes think that when zooming in/out that I loose focus and need to refocus. Perhaps a prime will hold focus better.

asiafish Loc: Bakersfield, CA

I've always enjoyed 85mm and 135mm lenses for events (including sports). These lenses are typically faster than their zoom counterparts, have wider apertures for both shallow depth of field and low light, and are smaller and lighter.

The 85mm f/1.8 G is excellent and very light. I'm not crazy about Nikon's 135mm f/2 and like Canon's much better. If you can deal with manual focus, Nikon made some outstanding 135mm f/2.8 lenses that are very compact, optically excellent and quite inexpensive on the used market. They will work just fine in A mode on your D750.

juicesqueezer Loc: Okeechobee, Florida

As others have stated, the 70-200 f2.8 is my go to lens for sports. However, when I need more reach, you just can't beat the 300 f2.8, 400 f2.8, 500 f4 as well as the big boys. Having owned the 300, I loved it, it just wasn't long enough. Saving for the 400 with a 1.4 tele. The IQ on this lens is outstanding.
Personally, I would rent one and see how you like it. They are heavy and you will need a monopod for support, but nothing better for sports, in my opinion!

FiddleMaker Loc: Merrimac, MA

Take the advice of Gene51. He knows what he is talking about.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

Your 70-200 should be ideal for sports on the D750. Look, if you want to stop action use the following. First, use GROUP AUTO FOCUS and pick the screens center point, then Nikon will put 4 points around that one for a total of 5, keep your subject in contact with one of the 5 central points and your in focus, second, use continuous auto focus, third, shoot at least one to two stops down from wide open (use aperture priority), third, shoot at least 1/2000 second, forth, use center weighted metering, and forth, use exposure compensation to fine turn your exposures. If hand held, on lens turn on VR and switch to Active.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

All of these are go to lenses for sports because of their outstanding AF performance. And the D750 has the best AF system Nikon has to offer. I have about 2 weeks experience with a D750 and found all the accolades to be true. One article compares the performance with an 85 F1.8 indoors, and found it to be " . . . so good indoors, that [he] never bothered changing my lens to the 70-200mm f/2.8G VR II, which has been more reliable for indoor shots. . ." To me this says two things - the D750 has great AF, and the AF with the 70-200 is excellent.

I don't have experience with that lens on that body, but I would gather that there is not a whole lot of advantage in getting a faster lens as far as AF performance is concerned.

https://photographylife.com/reviews/nikon-d750/3/

And this is an interesting article (same reviewer) with the 105mm F1.4. It has some comments on it's performance compared to the 85mm 1.4

https://photographylife.com/reviews/nikon-105mm-f1-4e/

Are you using Group Area AF? That was a game changer for me. I shoot lots of birds, some quite small, and the cameras I have tried that offer Group Area AF (D500, D750, D810) all acquire focus much better than the previous products without it.

I agree with the suggestion to rent what you are thinking about before buying it.

Dziadzi Loc: Wilkes-Barre, PA

Pardon my ignorance, what is "MTB"?

CO

The Nikon D5 and D500 have the best Nikon autofocus system. They are the first two Nikon cameras to have separate processor dedicated to just the autofocus system. They are rated to work dowm to -4EV.