"Does a teleconverter affect depth of field?
No, it does not. A teleconverter does not change the physical size of aperture of the primary lens – it only magnifies the projected image. A 300mm f/2.8 lens with a 2x teleconverter will have the same depth of field as a 600mm f/5.6 lens, at the same focusing distance".
When you use a teleconverter,
you keep your lens's shortest focus distance. -- NO impact on minimum focusing distance. As measured from the sensor plane.
Try using z-mount extension tubes/rings -- with electronic pass through -- extension rings do reduce minimum focus distance AND I have tried and successfully used them on many Z-mount lenses.
Remember extension tubes/rings increase the magnification of a lens as follows:
New magnification = Native lens magnification + (extension amount/focal length)
Using extension tubes/rings reduces the minimum focussing distance AND also reduce light transmission - effectively aperture.
Extension tubes also can severely impact the furthest focussing distance -- some find this can be too short. The come in various lengths/depths and this it is important to work out what works best with each lens AND each subject.
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