(2) 16mm, Macro extension tube can be used alone or in superimposed. The extension tube does not affect image quality as there is no optics inside. When using the extension tubes alone (10mm or 16mm ) or combination (10mm+16mm=28mm),support AF(Auto-Focus), AF Motor Protection: while using 2 rings together, we suggest you to use manual focus or Increase the lens focal lengths for it's a little bit difficult to auto-focus with 2 rings together, and also protecting your lens motor.
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