SpeedBooster makes lenses wider and faster?!?

Discussion in 'Micro 4/3 News and Rumors' started by kevwilfoto, Jan 13, 2013.

  1. kevwilfoto

    kevwilfoto Mu-43 Veteran

    Sep 23, 2011
  2. drewbot

    drewbot Mu-43 Top Veteran

    Oct 21, 2011
    Toronto, ON
  3. Promit

    Promit Mu-43 All-Pro

    Jun 6, 2011
    Baltimore, MD
    Real Name:
    Promit Roy
    Metabones aren't nobodies, and Philip Bloom certainly isn't a nobody. But this is firmly in the too good to be true category. I guess they'll be releasing it though, so we'll see...
  4. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Real Name:
    It's a focal reducer. Sort of the opposite of a teleconverter. It essentially reprojects the image onto a smaller circle, making the AoV narrower and the image brighter.

    IIRC Kodak patented something like this some years back. There's also some evidence that Olympus used this approach with their 14-35/2 and 35-100/2 by taking full-frame designs (28-70/2.8 and 70-200/2.8) and modifying them to incorporate a 2x focal reducer.

    The main question is optical quality, but I suppose for video it doesn't matter as much.
  5. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    This concept has been done before. For example, the very early Nikon E series DSLR, co-developed with Fuji, used a 4X focal reducer to get the full angle of view and light collecting power of full frame lenses condensed to a 2/3" sensor: Nikon E series - Wikipedia, the free encyclopedia

    Adapters serving this purpose are also used in astronomy, where they may be referred to as focal reducers or telecompressors.

    Kodak has a 1994 patent which describes a device similar to the one Metabones is introducing: United States Patent: 5499069
  6. pxpaulx

    pxpaulx Mu-43 All-Pro

    Jan 19, 2010
    Real Name:
    It sounds to me like they are saying they are increasing the amount of light hitting the sensor because they are increasing the physical image size, and therefore are creating an increase in aperture? I might have to call zombie BS on that one - glass is glass is glass. There is a reason nobody recommends buying cheap front element lens adapters, even the best made degrade IQ, not increase it.

    I think I've read philip bloom a few times...I noticed he passed the buck on this review to his 'right hand man' - who heartily recommends it - Phiilp pops back in to say he'll chime in later, and by the way check out his upcoming workshop. Way too much an advertising piece for my taste, rather than an unbiased review.

    Edit: Dhazeghi, it would really make the image brighter? I suppose if you're changing the optical formula it could (and if a teleconverter takes away stops, then a wide converter adds them...is that the basic logic to be applied?).
  7. usayit

    usayit Mu-43 Hall of Famer

    Speed is in the loosest sense a very common but fairly inaccurate way to describe aperture. Its really a ratio between area and focal length. Area = pi ( f/2 N) ^2 where f is focal length and N is aperture and in this case area is constant given the same lens. So its marketing really stretching the meaning of the math behind the numbers. Its like similar to saying that f/0.95 lenses actually magically intensify the light coming in the front element producing a brighter image out the rear element... and f/1 produce zero light loss. Pure B.S.

    Furthermore, like teleconverters there is an extra element in that "speed booster"... which is no way magically able to beat the laws of optics and physics. I can definitely see its uses though.... if a crop sensor camera is a backup to a full frame, it makes the lenses a bit more usable assuming there is no loss in IQ or light... which is highly unlikely.

    So in a practical sense... I'll pass on that idea.

    Also reading the US patent (I haven't finished) the intent was specifically for larger format to smaller format adaptation.... it doesn't look like their intention was to play fuzzy with aperture for the marketing department.
  8. dwig

    dwig Mu-43 Top Veteran

    Jun 26, 2010
    Key West FL
    Also, way back in the late 19th century and early 20th lenses were sold to increase (negative lenses) and decrease the FL of primary lenses and were used with bellows cameras that could adjust to accomidate the change in FL. A simple closeup lens will reduce the FL of any lens and if you can move the lens closer to the film/sensor you can restore infinity focus. If not, you get a closer focus. With adapted lenses its a simple matter of mounting the lens in a thinner than normal adapter. The principle is the same a teleextenders, where the extender's tube provided the needed extension, except instead of a negative lens and increased extension there is a positive lens and a reduced adapter length.

    Just like with teleextenders, you are changing the FL but not the absolute size of the aperture. Since f/stops are relative apertures (FL / aperture diamenter) an extender reduces the f/stop and a reducer increases it (new reduced FL / same old diameter).
  9. Vivalo

    Vivalo Olympus Loser

    Nov 16, 2010
    More like decreasing the physical image size. I think it works like magnifying glass when you try to set fire with it from the sunlight. It sort of intensifies the light on a smaller area, I think.... :confused:
  10. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    If it really is true that Olympus used a focal reducer in their 14-35mm/2 and 35-100mm/2, then how could there possibly be any question about optical quality? ;)
  11. Wayneb

    Wayneb Mu-43 Regular

    Jan 2, 2013
    But will I.S. and AF work on the m4/3 camera version like it does with the Sony cameras? I would gladly buy this if I can use my Canon lenses with aperture control and I.S..
  12. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Real Name:
    It's the same principle as a magnifying glass, just not as extreme. Reducing the area over which the light is spread amounts to making it brighter.

    Well presumably the focal reducing elements in those 2 lenses were designed specifically for those lenses. This thing from Metabones is supposed to work with basically any lens, which is a whole different ball of wax.
  13. napilopez

    napilopez Contributing Editor

    Feb 21, 2012
    NYC Area
    Real Name:
    Napier Lopez
    So I don't understand why people seem to doubt this so much; even though it does sound "magical", it's just clever physics.

    Very simply put, if you take a certain amount of light and compress it into a smaller area, you are going to have more light in that area. The light is "denser", and therefore brighter. The magnifying glass is one extreme example of this. Essentially the same "total" amount of light, you just aren't wasting light that is cropped off by the smaller sensor size.

    Metabones has a good reputation as far as I know. Looking at the product description, the glass is manufactured by "Caldwell Photographic", which a quick google search shows as dealing with large format glass and specialty products, and seems pretty reputable.

    Honestsly, I think the high price tag is good rather than bad. It means it's more likely to be a good product. For the video folk, where size, AF, and perfect optical quality are lesser concerns, this seems like a wonderful option.

    You also may wonder why no one has done this before(although as others have pointed out, the concept has been applied in different ways). Simple: this is only really possible on mirrorless cameras. You need to use the reduced space from the decreased flange distance in order to accommodate the reducing optic.

    I don't really see a reason to doubt it will work well with most glass. It will pretty much never be exactly as sharp or bright as the FF lens would be on an FF camera thanks to the extra element(unless it luckily works in a complementary manner with the other glass), but assuming a decent optic it will certainly be sharper than the same glass mounted on a smaller sensor camera without a focal length reducer. Or well, at least in the center. Lenses with really bad corners that might be cut off by a crop will show off this flaw once more. Same with vignetting.

    Regarding brightness/speed... Well, I've always thought T numbers were better than F numbers anyway, since they give you a more accurate assessment about how bright the image will be. If the aperture "speed" of this lens is increased by one stop using this FL reducer, it will probably lose a litttleee bit of light(T-value) relative to the aperture thanks to the extra glass/coatings, but I highly doubt it will be anything significant. It's just one element.

    In any case, look at the video samples. We don't know about stills yet, but I certainly see no loss of image quality based on the videos.
  14. elavon

    elavon Mu-43 All-Pro

    Sep 1, 2012
    Tel Aviv Israel
    Real Name:
    I just wonder when the Ebay cheap imitation will arrive.
    An all manual adapter like this can be very attractive on old manual lenses.
  15. xmsnx

    xmsnx Mu-43 Regular

    Mar 10, 2012
    Please correct me if I'm wrong:

    If for example I used a canon FD 50mm lens with this kind of device (I know it doesn't exist for µ4/3) on my epl3 I would get a focal length equal to a 25mm native µ4/3 lens?
    I understand the actual focal length would be the same regardless but the equivalent would be 25mm, because it now would be projecting the 50mm FF image without being cropped so would equal 25mm?

    Or have I completely lost it?
  16. gcogger

    gcogger Mu-43 Veteran

    May 25, 2010
    Real Name:
    I believe this is a 0.71x converter, so you'd end up at 35mm, but a stop faster.
  17. napilopez

    napilopez Contributing Editor

    Feb 21, 2012
    NYC Area
    Real Name:
    Napier Lopez
    As the above poster said, it's a 0.71x converter.

    If you wanted something close to 25mm, you'd have to look for a 35mm lens, which would be brought down to 24.5mm. It's a shame because it's easier to find fast 50s than 35s, but still quite cool nevertheless.
  18. elavon

    elavon Mu-43 All-Pro

    Sep 1, 2012
    Tel Aviv Israel
    Real Name:
    I have just finished reading the white paper. It looks very promising technology that will add significant advantage to the mirror less cameras. I suggest reading it especially the application and example parts.
  19. mister_roboto

    mister_roboto Mu-43 Top Veteran

    Jun 14, 2011
    Seattle, WA, USA
    Real Name:
    Interesting stuff.

    I'd be interested in this adapter, IF I had some nice L lenses, that cost point is a bit of a deterrent.
  20. meyerweb

    meyerweb Mu-43 Hall of Famer

    Sep 5, 2011
    Interesting, but I'd say it's a couple of years too late. Other than long teles (where you probably don't want the reduced the focal length, m43 now has a very good lineup of both primes and high quality zooms. I sooner buy a 25mm PL 1/4 than use a 35mm f 1.8 and this converter. While the converted lens might be faster, it will also be much larger and heavier and more expensive when combined with the converter.

    And it certainly won't AF, and we don't know if it will provide aperture control for lenses without aperture rings.

    For a photographer with a large collection of legacy glass who doesn't care about AF, this may be an effective tool. For most m43 users, I think it's an interesting novelty, and $600 is a lot to pay for "interesting."