Reply to thread

Message

<blockquote data-quote="hark" data-source="post: 746038" data-attributes="member: 13196">What is the variable aperture on your 100-400mm lens? Does it go to f/5.6 or f/6.3 when it is zoomed out long? And what types of teleconverters does Sigma make that are compatible with that lens? You will need to use a Sigma TC, not a Nikon TC.The D850 has f/8 support which means you should be able to use a lens that is wide open up to f/8. So you'd have to determine what your lens' aperture is when zoomed out to 400mm then factor in how much light loss there is from the TC.My D500 has a 300mm f/4 lens (constant aperture, not a variable one) with a 1.7x TC. That means I lose 1.7 stops of light making my aperture f/6.7 wide open. Depending upon the contrast of my subject, sometimes it will hunt. But if your aperture will be f/8 wide open with a TC, I'm sure there will be some hunting going on. Please give us the details of your current lens' aperture and what length TC you are considering. That's where you need to start first.</blockquote>

[QUOTE="hark, post: 746038, member: 13196"] What is the variable aperture on your 100-400mm lens? Does it go to f/5.6 or f/6.3 when it is zoomed out long? And what types of teleconverters does Sigma make that are compatible with that lens? You will need to use a Sigma TC, not a Nikon TC. The D850 has f/8 support which means you should be able to use a lens that is wide open up to f/8. So you'd have to determine what your lens' aperture is when zoomed out to 400mm then factor in how much light loss there is from the TC. My D500 has a 300mm f/4 lens (constant aperture, not a variable one) with a 1.7x TC. That means I lose 1.7 stops of light making my aperture f/6.7 wide open. Depending upon the contrast of my subject, sometimes it will hunt. But if your aperture will be f/8 wide open with a TC, I'm sure there will be some hunting going on. Please give us the details of your current lens' aperture and what length TC you are considering. That's where you need to start first. [/QUOTE]

Verification