Mechanical Relationship: What is the relationship between the lens and the shutter?

In the workshop, photographers are surprised when, when diagnosing the shutter, I ask: * “What lenses do you mainly use? Did you shoot with a light fifty-kopeck 50mm f/1.8G or a heavy professional 70-200mm f/2.8 VR zoom?”*.

It seems, what does the lens have to do with it? Let's show the kinematic connection from the inside.

3 Factors of influence of optics on the shutter drive unit

1. Aperture Lever operation:On all Nikon F-mount lenses (except series E with an electromagnetic diaphragm) the shutter and the diaphragm driver are cocked **by one single electric motor**! When Each frame, a lever in the bayonet shaft spring-loadedly pulls down the lens aperture. On tight old lenses the load on this motor increases by 40%.
2. Microdeformations of the magnesium chassis from heavy optics:If you constantly carry the D750 carcass with with a 2-kilogram 70-200mm f/2.8 telephoto camera attached to the belt by the body (and not by the tripod leg!), under the weight lens, microbending of the front frame of the bayonet occurs. This creates a misalignment of the shutter seat.
3. Electromagnetic diaphragm (E-type):Modern Nikkor E lenses (for example, 200-500mm f/5.6E) remove the mechanical load from the shutter lever by closing the aperture with its own stepper motor.

Drive load table depending on optics type

Lens type	Principle of aperture control	Shutter Drive Motor Load
Primes 50mm f/1.8G / 35mm f/1.8G	Mechanical leash (Light spring)	Standard (Minimal wear)
Heavy zooms 80-200mm f/2.8D / 70-200mm f/2.8G	Mechanical leash (Hard spring + Weight)	Increased load on the gearbox
Modern Nikkor E/Z-mount optics	Electromagnetic diaphragm	Minimum (Leash not engaged)