Soft images with long lens

You also need to keep in mind that f2.8 at 400mm will give you very shallow depth of field. That lens is great if you shoot night sports. For birds and wildlife during day time, for one thing 400mm is on the short side, and sometimes I prefer to shoot at f4 or f5.6 to have at least some depth of field.

 

To me, the main advantage for the 400mm/f2.8 is that it focuses closer than the 500mm/f4 and 600mm/f4. For subjects that I can get close, having the ability to focus to 8, 10 feet is more important. But if I used a 400mm/f2.8, I would most likely end up with a TC most of the time.

Shun, You nailed it. I chose a 400 2.8 as a multi tasker long lens for sports as well a wild life shooting behind my house. As a portrait guy, I like sports shots

tight on the face to capture the joy of victory and the agony of defeat. The 2.8 should get me "in the ball park" of 1/1000 with usable iso indoors as well. Outdoors in full sun should have plenty of shutter speed for sharp images. Another reason to be looking for at least 6 fps and good iso response. I think I would prefer to switch bodies from FF to crop instead of employ a tc that would loose that stop or two. Using this bad boy on a monopod will be a learning experience. As I mentioned earlier, my 7 foot octa was intimidating when I first got it and the 6' scrim outdoors alone, that was a challenge. But now, piece of cake- provided there is minimal wind. I have a shot of the 7' octa on a stand in my 10 ' fly fishing boat...as a sail. I pick up 10 lb plates at the gym with a couple of fingers. The length and diameter of a lens this size adds major leverage to the equation. I have been trying to handle it with the foot. Dieter, great explanation of what a tc does. I will test to see if 600 mm on a crop is enough reach or if a 1.4 will do the trick at 840. Thanks for all the help, this has been a crash course in long lens usage. Some of the best instruction I have seen on this site in a while.

About TCs, this is an important issue in bird photography. Even with a 500mm and a 1.4x TC-III, I find myself cropping. One thing is clear, you should the best TC available for your lens. With Canon, it's their Series III TCs. Not only were optics improved from prior generations, but the chips actually improve AF with Canon's Series II lenses. I think that the situation is similar. It makes no since to by a several thousand dollar lens and pair it with a cheap TC.

 

We're talking about some of the very best lenses ever made in this thread. I've got the Canon EF 500mm f/4L IS II and it has no "sweet spot." It's incredible from f/4, until around f/16, where diffraction starts to raise its ugly head. So I've got one of Canon's very best lenses and their very best TCs, yet, careful testing has shown me that, in tests, on a tripod, with mirror locked up and remote release, the bare lens' image, cropped to equal the image from the 1.4x and 2.0x TCs, is SUPERIOR to the TC-sourced images. Yet, I keep the 1.4x on my lens close to 90% of the time.

 

Why, you ask. Well, the differences that I saw were crystal clear, but at 200 and 400% viewing. Also, it was mainly chromatic aberration, on shiny details, like metal parts, not as readily seen on feathers and fur. Also, reality for me is that I'm often shooting on a full-frame at 700mm and still cropping the image further. My test images were at low ISO and f/4 and f/8. My real world shots are more likely at ISO 800 and f/8, or ISO 1600, or even ISO 3200. Hence, I chose to get more pixels on the subject, reducing the cropping to its minimum. Added cropping makes noise more visible.

 

So, why do I use a full-frame camera instead of a crop-sensor, with higher pixel-density? That's because the AF on my 5D MkIV is significantly better than on my 7D MkII, when it comes to speed of acquisition and tracking accuracy. If the 7D MkIII comes out and has AF as good or better than the 5D4, I'll be at the front of the line buying one. AF trumps pixel-density and image quality trumps focal length, BUT only to a degree. Shooting birds flying close, at 30-mph is a whole different matter from shooting a test pattern.

 

One more side thought, about minimum focus distance. My 500mm has a minimum focus distance around 12-ft, but that doesn't change as you add the TCs. I do that and add a 25mm Extension Tube, to get satisfying magnification. Still, my favorite macro, is the 100-400mm with the 1.4TC-III and the 25mm ET, so long as there's enough light. It's 3.2' minimum focus distance and zoom make it great for chasing bugs.

BTW, I hear raves about the D500, if it could possibly fit the budget. A new body every ten-years seems reasonable to me.

A trick not everyone likes equally, but that I have come to depend on: I have both my bodies (D5100 and D7100) set up to use back button focus. That way I can track moving subjects with continuous focus (while holding down the "auto-focus-on" button), or release the button to lock focus distance without having to balance my finger on the half-push of the shutter release. This also keeps the focus distance constant from shot to shot, unless or until I decide to re-focus. There are a bunch of tutorials touting both the pros and the cons. I like it.

BB AF is something that some find useful. I use shutter-button AF and see no disadvantage. AF is very important, so use the method that's most comfortable to you, but neither is "superior", per se.