Focal reducers, could it replace large sensors?

Discussion in 'Adapted Lenses' started by swede, Feb 9, 2015.

  1. swede

    swede Mu-43 Veteran

    277
    Oct 25, 2014
    I've been seeing a lot from focal reducers and it seems to be a nice and creative tool with photography.
    But I'm a bit confused because in my imagination: Why hasn't it been done before? And why hasn't lens makers implemented the technology into lenses to replace the need for larger sensors?

    Im very limited in my knowledge in optic science, so... please enlighten me :)
     
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  2. nstelemark

    nstelemark Mu-43 Hall of Famer

    May 28, 2013
    Halifax, Nova Scotia Canada
    Larry
    Because FF sensors are the only way to achieve photographic nerdvana. FF being 35 mm film equivalent of course!
     
  3. Vivalo

    Vivalo Olympus Loser

    941
    Nov 16, 2010
    Finland
    This
    ...and because FF has larger pixels for the same resolution which helps to achieve better dynamic range. Also the focal reducer costs money and makes the lens bigger.
     
  4. nstelemark

    nstelemark Mu-43 Hall of Famer

    May 28, 2013
    Halifax, Nova Scotia Canada
    Larry
    I guess I didn't put in a big enough smiley!
     
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  5. Jonathan F/2

    Jonathan F/2 Mu-43 Hall of Famer

    Aug 10, 2011
    Los Angeles, CA
    I'm using FL reducers for both my M43 kit and Fuji X cameras and I think they're great to use especially if you want to use fast MF glass but keep within a budget. My take is that they deliver that wider FOV and shallower DOF while using a smaller sensor. Though it's also not a replacement for a larger-sized sensor which has it's own inherit advantages like fatter pixels allowing for high ISO sensitivity and/or more denser pixels over a large sensor plane.

    The nice thing about using FL reducer adapters with M43 or APS-C is that you can take advantage of the smaller native glass and then switch to FF MF glass when you want to achieve a different look all with the same camera.
     
  6. Talanis

    Talanis Mu-43 Top Veteran

    509
    Oct 15, 2012
    Sherbrooke, Canada
    Eric Cote
    To be able to use a focal reducer, you need lenses made for a sensor bigger than what you use. They are perfect for micro 4/3 and good for APS-C. To be able to use a focal reducer on a full frame, you would need to use medium format lenses that are usually priced higher than a full camera system with lenses (not unusual to have lenses at 8000$).

    Using one with micro 4/3 could replace large sensor (for me) but it negates two of the advantages of the micro 4/3 format: lightweight and small. Sure, I use my 35mm f/1.4 with a focal reducer but that lens is bigger than my Panasonic 100-300mm and it's heavier than one camera with 3 lenses. I like the combo and use it for specific things but I don't have it in my everyday carry along bag.
     
  7. Vivalo

    Vivalo Olympus Loser

    941
    Nov 16, 2010
    Finland
    :biggrin: I knew you were kidding! Sadly, what you said is something that many believe is the truth and nothing but the truth.
     
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  8. tkbslc

    tkbslc Mu-43 Hall of Famer

    Actually Olympus did use Focal reducers in their F2.0 zooms for their original 4/3 system. They were pretty basic lens designs and they used the focal reducer tech to get them to wider focal lengths and f2.0.

    One reason they aren't used more often is because it is expensive to make high quality reversing elements and often is is easier just to design a new lens.
     
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  9. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    Well, in general it makes the lens bigger if you're designing it from scratch (because you need the larger image circle). But if you've already got the FF lens, it's actually smaller in length with a focal reducer than with a standard adapter.

    A bit heavier thanks to the extra glass, of course...
     
  10. Vivalo

    Vivalo Olympus Loser

    941
    Nov 16, 2010
    Finland
    But the combination is still bigger than the bare FF lens
     
  11. brianc1959

    brianc1959 Mu-43 Regular

    38
    Sep 14, 2013
    Virginia
    Brian Caldwell
    Actually, no. A focal reducer actually shrinks the vertex length of the attached lens. This becomes clear when you observe that a focal reducing adapter is considerably thinner than a plain adapter.
     
  12. brianc1959

    brianc1959 Mu-43 Regular

    38
    Sep 14, 2013
    Virginia
    Brian Caldwell
    Actually, for a given focal length and aperture requirement, using a focal reducer that fully takes advantage of being able to get close to the sensor with mirrorless cameras is an excellent way to design a lens from scratch. In terms of giving you high speed and high image quality in a compact package it is hard to beat. Big lens companies have been slow to understand the concept for all the usual reasons that big companies can be out-innovated by small companies.
     
  13. brianc1959

    brianc1959 Mu-43 Regular

    38
    Sep 14, 2013
    Virginia
    Brian Caldwell
    This is an urban myth. The Olympus f/2 zooms are SLR lenses that have to clear a reflex mirror, just as any other SLR design. There is no portion of these lenses that could be removed and used as even a very poor focal reducer. The real breakthrough of general-purpose focal reducers only became possible with mirrorless cameras.
     
  14. OzRay

    OzRay Mu-43 Legend

    Jan 29, 2010
    South Gippsland, Australia
    Ray, not Oz
    Basic lens designs?
     
  15. tkbslc

    tkbslc Mu-43 Hall of Famer

    I can't find any sources that prove my claim, but it was a pretty widespread "fact" in the peak days of regular 4/3 reported to come from insiders. Of course it could be legend, too.

    I don't know if flange distance disproves it, though. It's not like they literally stole a Nikon lens and put a focal reducer on the back. They could design a more common lens type for a theoretical deep flange distance to leave room for the focal reducer.

    Consider that a 17-50mm f2.8 lens designed for APS-C circle with a one-stop focal reducer would be a 12-35mm f2.0. An APS-C 50-135mm f2.8 with a one-stop focal reducer would be 35-100mm f2.
     
  16. tkbslc

    tkbslc Mu-43 Hall of Famer

    f2.8 zooms for APS-C imaging circle are not uncommon. Maybe "basic" was the wrong the wording. A designed from scratch f2.0 zoom would definitely NOT be basic. An f2.8 zoom with a focal reducer is easier to fathom.

    Either way, they are definitely remarkable lenses. I don't care how Olympus did it.