CLA-FW-Canon EOS Adapter

Discussion in 'STF Series CCD Cameras' started by Kenn Hopkins, Mar 30, 2020.

  1. Kenn Hopkins

    Kenn Hopkins Standard User

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    Purchased your CLA-FW-CANON EOS Adapter so I could attach my Canon Lens to the STF8300m I have. Great I received the product and placed my 75-300 lens in the adapter. Now I'm unable to detach the lens from the adapter. The little silver knob will not depress and I'm unable to move the lens either left or right to detach.

    Any suggestions?
    Kenn
     
  2. Peter Bresler

    Peter Bresler Standard User

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    I actually do not recall selling you an adapter through this forum. Maybe Cloudynights several months ago?? I might suggest some lubricant though; also if threads are jammed sometimes a heat gun will get them loose.

    Peter
     
  3. Kenn Hopkins

    Kenn Hopkins Standard User

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    Thanks for the response.

    I purchased the product through OPT. Does it really matter who I purchased the product from since it is a SBIG EOS Adapter?

    Kenn
     
  4. Colin Haig

    Colin Haig Staff Member

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    Kenn, I don't know why Peter is commenting. (Sorry Peter).
    Ignore his advice as it will likely damage the lens.
    He's another customer and does not speak for Diffraction Limited or OPT.

    Please confirm you've tried this:
    With the camera sitting with the lens pointing up...
    The Red Dot on the lens body is about a thumb width to the right of the unlock lever.
    Push the side lever down to retract the lock pin.
    Then remove the lens by turning it to the right (Counter clockwise from above, looking down on the front of the lens).
    Can you confirm the lever moves down? If it is not a lever, then I need to see a photo - there are a few variations in these parts over the years, but they are precisely made.

    Can you use the Upload a File button to the lower right to upload a picture of the adapter and lens, showing the labeling on the lens adapter.

    What lens is it exactly? Full Canon model number please.
    e.g. EF 75-300mm f/4.0-5.6 III
    or is it the USM version?

    Is it this adapter?
    https://diffractionlimited.com/product/cla-fw-canon-canon-lens-adapter-stf-stt-cameras-filter-wheel/

    When was it purchased, and was it purchased as a new item?
     
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  5. Kenn Hopkins

    Kenn Hopkins Standard User

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    Thank you for your response, the first response was a little disconcerting. It was purchased from OPT March 26, 2020 as a New Item. I'm unable to 'push' the silver button down but I'm able to move/rotate the lens maybe 1/32 of an inch both ways and that is it. Lens is CANON ZOOM LENS EF 75-300mm 1:4-5.6 III.
    Any assistance would be helpful. Again thanks for your response.
     

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  6. Colin Haig

    Colin Haig Staff Member

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    My colleague @Colin (the engineer) will chime in on this - we've just discussed.
     
  7. Colin

    Colin Guest

    Hi Kenn,

    I just confirmed that to unlatch the lens you must push down (towards the bottom of the lens) on the round silver button.
    Does the knob move side to side slightly? If not, it could be jammed. How much force are you using to push down on the button?
     
  8. Kenn Hopkins

    Kenn Hopkins Standard User

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    Duh...…………… I was pressing the 'round silver button' in towards the lens, similar to how the 20D Lens Release works. It took me a minute to understand the 'push down' but eureka I finally understood.

    I have now separated the lens from the adapter; perhaps include instructions when shipping the adapter on the difference between your adapter and the camera lens release.

    Thank you very much for your time and instructions.

    Kenn
     
  9. Kenn Hopkins

    Kenn Hopkins Standard User

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    One final question. I was unable to obtain focus using the 75-300 Canon Lens but I have two other lens for my Canon 20D the 50mm and another zoom 18-200. Is there a secret to obtaining focus like another spacer or some other additional piece of equipment I would need so focus can be reached or am I SOL?

    Again thanks for your time.
    Kenn
     
  10. Colin Haig

    Colin Haig Staff Member

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    The ideal distance for a Canon EF lens from the back of the len's mounting surface (flat part, not the bayonets) to the CCD sensors is 44mm.
    The backfocus on an STF-8300 + filter wheel is about 35.7mm, less about 1mm for 3mm filters, and then you add the distance of the adapter from the top of the filter wheel to the flat on the top of the adapter.
    So, this can be off just a bit.
    Usually I start by setting the lens to its widest aperture and widest angle eg 75mm not 300mm.
    Then point it at a target at a mid distance, say 30 feet or so, and see what you get.
    Some lenses are more tolerant of where the "infinity" setting is - either a hard physical stop, or a bit beyond infinity.
    The moon is also a good target.
    The adapter can be "raised" a bit by shimming if needed to reach infinity.
     
  11. Kenn Hopkins

    Kenn Hopkins Standard User

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    Again, Thanks for the insight.
    If I understand correctly: if I 'raised' the adapter--say 4 washers between the adapter and the STF8300 body where the screws are it might raise the adapter enough to allow for focus? Would not this also cause light to seep in? I guess Duct Tape around the base of the adapter could solve the light seeping in.

    Again I really appreciate your time and assistance in my understanding.
    Kenn
     
  12. Colin Haig

    Colin Haig Staff Member

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    Avoid Duct Tape. Black electrical tape works wonders as it is removable. Large O-rings and rubber gasket material are available at some hardware stores.
    You can do the tests in a dimly lit room, and not worry about the tape.
    If the lens has a distance scale on it, that's a good start - dial the manual focus to the position of your target.
     
  13. Kenn Hopkins

    Kenn Hopkins Standard User

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    KennPlease forgive my continued questions. I've tried to add some washers, had to cut off one side of the washer to make them fit, and almost reached focus. I then started looking at your products and in the CLA-FW-CANON EOS Adapter there was a link for the Filter Wheel Spacer SKU: CA-FWSPACER. Can this be the answer I'm looking for to attached it and the CLA-FW-CANON EOS Adapter to the STF8300 for my Canon Len? Or would the Adapter Plate, 2.156″ x 24 thread SKU: 40-12053-00 be a better addition?
     
  14. Colin Haig

    Colin Haig Staff Member

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    No worries, it's what we're here for.

    Shim washers are better than regular washers - they aren't as wide. For example:
    https://www.mcmaster.com/shim-washers/

    The other thing is a metal feeler gauge, you can take apart, drill some holes, and have a ton of precise spacers.

    If you don't have a filter wheel, then you need the Filter Wheel spacer. It takes up the distance that a filterwheel normally uses.

    This is desgined for the filter wheel to accept an STL-thread nosepiece (it's slightly bigger than 2" to allow more light to pass through).
    How much of a gap have you got to get to focus?
     

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