Add a Focus Knob to Any Lens!

Early Leica rangefinders were so small that focusing their tiny lenses with the conventional thumb and forefinger method was cumbersome.  So Leica came up with a simple, elegant solution, as Leica often does; a focus knob.

 

KONICAIII_JohnnyMartyr_D20_3157
Note the milled chrome barrel on the bottom of the lens of this Konica III

Many classic rangefinder lenses have a focus knob to aid in speedy, accurate focusing.

The focus knob allows for rapid movement from infinity to minimal focus distance and back again.  The knobs are positioned on the lower part of the focus ring so as to discourage hands from moving in front of the viewfinder, blocking the scene from the eye of the photographer.

 

JohnnyMartyrJoePascoOlySP415610301_29fae6f0ed_b
Joey Pasco works the focus lever on my Olympus 35SP

But what does a shooter do when that otherwise perfect rangefinder lens does not have a focus knob (as many modern ones do not)?

Such is the case with the brilliant Cosina Voigtlander 50mm 1.5 Nokton.  This lens has a more modern style barrel sans knob.

Get yourself some cable ties aka zip ties from the electrics aisle of your local hardware store.  Pick up a pair of flush cutters from the tools section too.

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Cable tie with flush cutters

Maybe you see where I’m going?

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Leica M6 TTL with Voigtlander 50mm 1.5 Nokton mounted, featuring a DYI cable tie focus knob

Every lens is going to be a little different and you may want to try different size ties.  I’m fortunate enough to work in television where we buy Panduit brand, slip-resistant cable ties by the thousand.  (Thanks Discovery!)  But any brand will do.  I would recommend something with a larger “buckle,” but of course this is a personal preference.  If you’re curious, I’m using 14.5″ Panduit model PLT4S on the Nokton above.

Zip that cable tie around the focus ring of your favorite lens.  Keep it a little loose then take a moment to rotate it into a comfortable position.  Practice racking the focus back and forth with it.  Once it’s where you want it, pull that tie down as tight as you can crank it.  You likely won’t get it so tight that it can’t slip at all but you want it pretty tight so it’s not sliding around during use.  Once cranked down, get your flush cutters and clip off the excess cable tie such that it no longer extends past the buckle.  It should be smooth to the touch.

And voila!

There you have it!

A focus knob for your lens.

Give it a spin, see how you like it.  It can always be carefully cut off if you decide you don’t like it or just want a different size/color etc.

I’ll be curious what lens(es) you try.  Leave me a comment with a photo of your lens and have fun with this cool little hack!

 

 

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