Nikon F lens to Nikon Z DX 'Speedbooster' Adapter Idea

Discussion in 'Nikon' started by mike_halliwell, Mar 1, 2021.

  1. I mentioned this idea in another thread but only in passing.

    Having come across a nice book on camera and telescope optics and found the bit detailing Afocal Teleconverters/Barlow lenses, I had a thought. These are largely used for making the image bigger but without messing with the focus. However, I then noticed the opposite exists and seems to be called a focal reducer. Some of them seem to be deliberately made to reduce 35mm to DX.

    Now the issue I can foresee is that telescopes focus in a very different way to cameras and any slight differences in flange requirements can be very easily adjusted, unlike DSLRs.

    The reason I'm thinking about this is very un-DX like. There's always the talk of more 'reach' with an FX lens on a DX sensor.

    What I want is more light! So my 300mm 2.8 becomes a 212mm f2 on DX. It then occurred to me that a Speedbooaster FTZ would be quite fun on a Z50 or even more extreme on the CX J5 with FT1.

    I then the lightbulb moment....:eek: Could I not just turn around a conventional TC1.4 for the same effect?

    Any ideas?
  2. Last edited: Mar 1, 2021
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  3. I see where I went wrong. I was looking for Nikon F > Nikon ZDX.

    I should have tried Nikon G >...


    But, Blimey nearly 600 Euros for ..

    • This adapter is manual aperture control. It does NOT support electronic aperture control, AF and image stabilization.
    Last edited: Mar 1, 2021
  4. Have a look to see if one of the Chinese manufacturers does one for about 1/4 the price?

    I have a Zohngyii Lens Turbo 2, in EOS to Fuji X mount, bought used for around half the new price.

    Not that I have any EOS manual lenses (or any EOS at all), but EOS is a good intermediary mount for stuff like m42, or Nikon F.

    It works as advertised, but performance varies with the lens used. In short, I would say that it works well with short tele lenses, but badly with anything that puts the rear element close to the converter glass. So my 85mm f2 keeps the same field of view and depth of field as it had on 35mm film when used on an APS sensor, but gathers light like a lens one stop faster.

    It's not big, but it is heavy, as it is mostly glass inside...
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  5. It is more complex than a TC-e20III, which is arround the same price...
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  6. Indeed!

    Any reason why it has to be a pretty 'dumb' adapter?

    Simple pass through electronics would be OK.

    OK, EXIF might be messed up, but AF should work. You almost wonder whether you could put the optics from this into the 'hollow' FTZ?
  7. Viltrox offer electronic focal reducers, with protocol translation, EOS to Fuji, m4/3, EF-M, Sony and Nikon Z:
    Viltrox EF-Z2 Speed Booster Allows Canon EF lenses Used on Nikon Z-mount Mirrorless Cameras Support Eye AF Lens Stabilization

    So that's closer to what you're thinking of.

    I think Kipon have some similar options?

    I don't have the Viltrox adaptor, but I do have a Viltrox 33mm f1.4 autofocus lens in Fuji mount and I'm very pleased with it. They strike me as a company that is trying hard, provide lots of firmware updates and are honest about what does/doesn't work.

    (and the 33/1.4 is a beautiful lens, it leans more toward character than clinical sharpness, but strikes a good balance, think 'classic fast fifty' and you're along the right lines)
  8. I for one would still like to know if Mike's idea of reversing the optics in a 1.4x TC would result in a workable speedbooster. Perhaps the TC optics could be removed and stuffed into an FTZ adapter, backwards.
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  9. mm sounds like a more expensive opton than an existing speedbooster, 1 perfectly good TC plus an FTZ adapter, and then still the electronics would be totally off because they where not designed for a "converted" FTZ ....

    But hey, if yuo have enough money to spend and like to do the "metal" work, and know how to calculate the correct adjustment, i'd say : Have fun with this!
  10. No, it wouldn't.
    A teleconverter is basically one big negative lens, which increases the focal length of whatever it's attached to. Turning it round doesn't stop it being a negative lens.

    A speed-booster is basically one big positive lens.
  11. I was thinking they worked like this, but I see these are put infront of the lens!

  12. Missed edit time..Doh!

    But I guess a dedicated x0.7 focal reducer shoe-horned into an FTZ might work?
  13. Obvious in hindsight.
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  14. I've sourced a 'cheap' focal reducer for FX to DX (but not Nikon) that has elements that might fit.....;)
  15. The optics are all pretty much the same, only the mounts change. Some of them have adjustment, allowing you to rack the optics backwards or forwards to tune infinity focus for a particular lens.

    As to adapting the FTZ to enable the use of electronic lenses, I'm not sure it'll work. When I looked into the Viltrox electronic adaptors, I discovered that they're not just a simple protocol translation, they inform the camera of the lenses 'new', modified characteristics, focal length and aperture. I imagine that not doing so may lead to problems with autofocus and metering, as the lens won't behave in the way the camera's autofocus algorithm expects. Contrast detection should work, but I could see phase detect being more problematic.

    Can't offer more advice than that I'm afraid, as my focal reducer is manual only. I looked at the electronic options, but after checking with Viltrox, they informed me that mounting a manual lens with no contacts would result in the camera reporting 'lens error' and not working, nor does their adaptor work with the 'fake' EOS chipped adaptors, it needs a real autofocus lens, which wasn't my intended use.
  16. However, all I want is 'space' and passthrough connections. I've found you can get inexpensive full-auto extension tubes for Z mount....:cool:

    They don't have aperture linkages, so E lenses only....:(

    I'll stick with thoughts for a Z50 for now, although I know they have a Phase Detect feature, I believe it's mainly by Contrast.

    So, I need to put the optics from a focal reducer, with the electronic connections from a set of auto tubes into a completely dumb Nikon F > Nikon Z adapter.......:eek::D:cool:

    Might be a bit of butchery, as I may need shimming etc., but the connections could go externally! Novoflex do it that way for a fully auto lens reverse-fitting adapter
    Last edited: Mar 11, 2021
  17. Focal reducers are physically shorter than the equivalent non-optical adapters, so just inserting the elements probably won't allow focusing to infinity...
  18. So, I just need a shorter adapter?
  19. Some time ago I bought a cheap set of extension tubes that offer both mechanical aperture coupling and passthrough electrical contacts. F-mount though, not Z.

    Now I'm confused. I thought the original idea was to use F-mount lenses?

    Via speedbooster modified F-mount extension tube and the whole lot attached to an FTZ?

    So where do the Z-mount extension tubes come into it?
  20. Indeed it is! The title is..

    Nikon F lens to Nikon Z DX 'Speedbooster' Adapter Idea

    The problem is how to get electronic connection between the F Mount (G) lens to the Z DX Body.

    If I could fit the elements from a suitable Focal Reducer into the FTZ, all good.

    However, there seems to be some doubt it will fit. So the only way I can see is the Frankendaptor!

    So no FTZ. Who needs it? :p

    Unless there's some comms protocol I need..?

    "I need to put the optics from a focal reducer, with the electronic connections from a set of auto tubes into a completely dumb Nikon F > Nikon Z adapter"

    No FTZ! (Not sure I can afford to trash one either...;))
    Last edited: Mar 11, 2021

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