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800mm f11 / 600mm f11

Discussion in 'Canon Conflab' started by EightBitTony, Aug 4, 2020.

  1. Bazarchie

    Bazarchie Well-Known Member

    Although not a mirror lens, has anyone used a Canon EF 400 f4 DO IS USM?I have only ever seen one once and the owner singed its praises and the results on his camera screen were impressive.
     
    Last edited: Aug 6, 2020
  2. Benchista

    Benchista Which Tyler

    No. I did have the 70-300 DO, and it wasn't particularly good at all. The 400 looks a LOT better.
     
  3. Chester AP

    Chester AP Well-Known Member

    My query about apertures available on these lenses can now be answered because they are now on the Park Cameras website. The 800 mm has an aperture 'range' of F 11 to F16, but I still don't see why they bothered and instead just made it F 11 only. The absence of an adjustable aperture would simplify the design and possibly make it less expensive.

    Having ready the technical stuff about the camera bodies it's designed to be used with, a lens like this is the best reason I can think of for a serious wildlife photographer ditching their old stuff and getting a big bank loan. A lens like this would be far less practical with a DSLR when using the viewfinder. I once borrowed a Tamron 500 F8 mirror lens and recall the biggest problem was focusing it accurately because of the dim viewfinder image.

    https://www.parkcameras.com/p/12421...anon-rf-800mm-f11-is-stm-super-telephoto-lens
     
  4. EightBitTony

    EightBitTony Well-Known Member

    Yes the whole point of these lenses is they have been designed to exploit the benefits of mirrorless cameras, freed from the tyranny of mirrors, view finders and DSLR auto-focus ;)
     
  5. Learning

    Learning Ethelred the Ill-Named

    But how accurate is the phase detect at very small apertures. Do we know if Canon are using only phase detect or a two stage process where phase detect sends the focus roughly to the right place and then contrast finishes the job. One could imagine quite nice algorithms to use both systems together.
     
  6. Benchista

    Benchista Which Tyler

    We know that EOS R series cameras don't have contrast detect AF at all, only DPAF, so we can be pretty sure that phase detect does the lot. ;)
     
    EightBitTony likes this.

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