2-touch mount?

Discussion in 'Photography Beginners' Forum' started by stevet1, Sep 27, 2019.

  1. stevet1

    stevet1 TPF Noob!

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    What is a 2-touch mount?
    I've seen references to a 2-touch mount both within and without this context...

    "SSC Breech Lock 2-touch FD mount lens."

    Does that mean it requires the push of two buttons to amount and and dismount the lens?

    Steve Thomas


     
  2. Dacaur

    Dacaur TPF Noob!

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    It's nothing to do with mounting. (In your example, it's a two touch lense with an FD mount)

    One touch = you have a rotating ring for focus, and to zoom to push/pull the lense in/out. I.e., you only have touch the lense once to both zoom and focus.

    Two touch = you have two separate rotating rings, one for focus and one for zoom. You touch the lense once to zoom, then have to let go and touch it a second time to focus.
     
    Last edited: Sep 27, 2019
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  3. stevet1

    stevet1 TPF Noob!

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    Dacaur,

    Ah.

    Okay. Thanks. I had just never run across that term before and didn't know what it meant.

    Steve Thomas
     
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  4. clarc

    clarc TPF Noob!

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  5. Original katomi

    Original katomi TPF Supporters Supporting Member

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    Whilst I have not heated the term there is quite a difference. I have two push pull zoom lens and the rest are twist.
    Catches me every time when I change between the two
     
  6. vintagesnaps

    vintagesnaps Been spending a lot of time on here!

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    The breech lock on some Canon FD lenses is a metal ring at the base of the lens. When you mount the lens on a Canon FD film camera you then need to turn the metal ring to tighten it (then loosen it to detach the lens).

    I think the purpose of the breech lock was to keep the lens secure so it couldn't accidently turn and start to detach from the camera. I have/had earlier screw mount lenses (other brands, not Canon) that can sometimes loosen and turn when you're focusing.

    Most brands developed their own bayonet mounts like the Canon FD. I don't think the breech lock was made for very long because it's not on many of their lenses.

    I don't remember offhand the breech lock being referred to as 'two touch', but apparently that was in a description wherever the OP read it.
     

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