I use a D7100 body with some lightweight lenses (Nikkor 50mm and Nikkor 55-300mm) with the back button as AF-ON, with the trigger in first press in light measurement mode and the trigger in second press for capture. Nothing fancy.

Recently I bought a Sigma 60-600mm and I want to use it by freehand (with both hands on the lens) so I also bought a small external trigger that I attached to the arcaswiss/tripod attach system.

It's working perfectly, I can lift the lens and the camera body without any problem, and I can zoom in and zoom out very easily.

The only problem is that I can't make the light measurement without pressing a button on the camera body because my both hands are on the lens.

So I was wondering if an external trigger support the feature of AF-ON, light measurement and trigger of course. If not, is it possible to Do It Myself by using the GPS port where the actual external trigger is connected ?

  • \$\begingroup\$ I don't know how the Nikon camera works, but my Canon remote will do the half-press, and the one you are pointing to seems to do so too. Otherwise there are just three wires, contact between one wire and common is exposure/focus and contact between third wire and common is trigger. \$\endgroup\$
    – xenoid
    Commented Sep 16, 2019 at 14:54

1 Answer 1


AF-ON disables the half press focussing in some Nikon cameras - though some are switchable, for AF-ON/shutter release or both interchangeably - but I know of no way to remote the actual back button itself, only to restore the function to the shutter release & use a regular wired remote with half-press.

Presumably remoting to your phone etc would be even more ungainly.

What puzzles me slightly [though I don't know the D7100 specifically] is why it won't meter light without a button being held. My D5500 is always metering.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.