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Focal length confusion?

Discussion in 'Adapted Lenses' started by chalkie, May 19, 2013.

  1. chalkie

    chalkie New to Mu-43

    3
    Oct 11, 2011
    For my first post on the forum I'm having a blond moment, so forgive me.

    Having had some very good success with adapted lenses on my Fuji X-E1 I'm thinking about getting an adapter to try my Minolta MD lenses on my EPM1. Lets say I'm mounting my 50mm f1.8; am I effectively putting a 100mm lens on in 35mm terms, given MFT has an effect crop factor of 2?
     
  2. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Keith
    Correct. A 50mm lens on :43: gives a similar angle of view to a 100mm lens on a 35mm film (i.e. "full frame") camera.

    sent from my phone using the Mu-43 app
     
  3. speedandstyle

    speedandstyle Mu-43 Hall of Famer

    Yes, a 50mm would have a similar angle of view that a 100mm would on a 35mm film or full frame camera.
     
  4. chalkie

    chalkie New to Mu-43

    3
    Oct 11, 2011
    Cool, as I thought then, which means it could become quite an interesting proposition for (stealthy) telephoto shooting, especially given the built-in stabilisation.

    Sent from my iPad using Mu-43 App
     
  5. slothead

    slothead Mu-43 All-Pro

    Aug 14, 2012
    Frederick, MD
    But why do you care? Set an objective photographically and work, study and practice to achieve your objective. For the life of me, I can't understand why we continue to dwell on the 35mm film standards. It's history and it's not coming back! Granted that's my opinion, but if you don't agree, then just mark my words. If film continues it won't be that small format 35mm film size.
     
  6. RT_Panther

    RT_Panther Mu-43 Legend

    May 4, 2011
    Texas
    The 35mm standard never went anywhere since full frame DSLRs & full frame mirrorless (Sony RX1) are still around. :wink: :smile:
    Then there's the Leica M9 series....
     
  7. chalkie

    chalkie New to Mu-43

    3
    Oct 11, 2011
    From my point of view I find it easier to equate fields of view back to the 35mm negative, as years of experience shooting film have engrained themselves on my memory. I feel completely lost when I see a compact camera that's got a focal length range that's 4-32mm or 5x; it means nothing (which is why sites such as dpreview always quote the 35mm equivalent to give a sense of perspective) whereas 37-185mm is a known quantity in my mind.

    In terms of this post, my question was to ascertain what I would get when I bolted a lens to the EPM1 and what I could get from what lens. As my widest MD lens is 28mm I can expect a minimum field of view equivalent to 56mm in old-school terms, and my MC Rokkor 58mm 1.4 becomes a potentially interesting 116mm telephoto. So my EPM1 isn't going to be a street-shooter with adapted glass but it could be fun for portraits and beyond.

    Sent from my iPad using Mu-43 App
     
  8. carpandean

    carpandean Mu-43 Top Veteran

    827
    Oct 29, 2010
    Western NY
    If you really want to have some fun, take your final print sizes (if you actually print) into account. For example, say you want to make 8"x10" (or 11"x14") prints, then the 5:4 cropped image from the 50mm on your E-PM1 will have roughly the same AOV as a 92mm cropped 5:4 on FF.

    This is really fun when someone is convinced that the :43: sensor is so much smaller than the one in their Rebel. The effective crop factor for 8"x10" (or 11"x14") prints of :43: to Canon's APS-C is around 1.138x.
     
  9. kevinparis

    kevinparis Cantankerous Scotsman

    Feb 12, 2010
    Gent, Belgium
    odd definition of 'fun' :) ...but each to their own

    I have no idea what any of that means..and have no desire to find out....life is too short :)

    K
     
  10. Petrochemist

    Petrochemist Mu-43 Top Veteran

    651
    Mar 21, 2013
    N Essex, UK
    Mike
    Crop factor help considerably in judging the field of view for multiple bodies. I use a 1.5 crop DSLR, and a micro 4/3 body, and can use the same lenses on both.
    When I got my first dSLR the crop factor helped select lenses based on my old 35mm experience. Now it helps in choosing new lens for the Panny, as well as judging the right Legacy lens to try for a shot. - Yes I now know roughly what FOV view I'll get on the DSLR without using crop factors, but it helps with the newer system.

    The crop factor also helps with various rules of thumb, such as the astrophotography '600 rule' - use a Shutter speed faster than 600/(effective 35mm focal length) seconds to preserve pinpoint stars.

    If I ever play with my large format camera I'll use similar focal length equivalence to judge which lenses to get (the 'crop' factor here works out less than 0.2).

    It's in cases like the OP's trying to visualise a lens on a different system that they come into their own. I think the reason there is so much confusion over them is that some sellers use them to suggest their telephotos are super powerful claiming '500mm/750mm f8' or similar.
     
  11. Replytoken

    Replytoken Mu-43 Hall of Famer

    May 7, 2012
    Puget Sound
    Ken
    You lose a smaller percentage of the image when you crop an m43 file to 11x14 than when you crop an APS-C or full frame file to that size.

    --Ken
     
  12. carpandean

    carpandean Mu-43 Top Veteran

    827
    Oct 29, 2010
    Western NY
    Exactly. The native aspect ratio of :43: (other than the GH2, which maintains the same diagonal for all aspect ratios and, thus, has multiple "native" ratios), 4:3, is squarer than the native aspect ratio of most FF and APS-C DSLRs, 3:2. As such, much more of the difference in sensor size between :43: and most DSLRs' sensors is in the width, not the height. For example, compared to Canon's APS-C's sensor, a :43: sensor is 78% as wide, but 88% as tall. Therefore, any print size that is toward the squarer end of things (e.g., 8x10 is 5:4, which is actually squarer even than :43:) will yield an lower effective crop than a more rectangular format (e.g., 11x17) would.

    Really, it means little for taking pictures, but it is handy when you get sick of hearing things like "pitiful little sensor" or "just buy a Rebel and get a real sensor."
     
  13. slothead

    slothead Mu-43 All-Pro

    Aug 14, 2012
    Frederick, MD
    Most of you guys are missing my point. Why compare your captures to a 35mm film format (or "full frame" digital for that matter) when your real objective is producing a print (of whatever size) or an internet-based image. Why do you care how it compares to a 36mm by 24mm format?
     
  14. carpandean

    carpandean Mu-43 Top Veteran

    827
    Oct 29, 2010
    Western NY
    We (or, at least, I) understand the point, but most of us know what a wide angle lens will give us for FOV, what a short tele will give us, etc. This simply gives one scale for for all the sensor formats that we use. All we need to remember is the 35mm/FF scale and the crop factor for each format, instead of having to remember the scale for each an every format individually. Even if we want to talk about a lens in a different format, we can use those 35mm/FF crop factors to find the equivalence. For example, a 50mm on a Nikon APS-C is like a 50*(1.5/2) = 37.5mm on :43:.

    The choice of baseline scale is, in theory, irrelevant. However, given the popularity of the 35mm/FF format, it's not surprising that it became the standard. It's much like English becoming the universal language of business (and a lot of other things.) There is nothing inherently better about English and it certainly could have been one of several others. What matters is that there is a common standard, not which it is.
     
  15. Replytoken

    Replytoken Mu-43 Hall of Famer

    May 7, 2012
    Puget Sound
    Ken
    What is really needed is some standard that is not sensor dependent, like angle of view. Until that standard arrives, I need something that I can easily work with, and that is 35mm, as I shot it for over 30 years. I am sure that if I continue to shoot with m4/3rd's, then I will start to think equally in terms of both systems.

    --Ken
     
  16. edmsnap

    edmsnap Mu-43 Veteran

    430
    Dec 20, 2011
    Edmonton, Alberta
    Because when communicating about lenses (or anything in life really), speaking a common language is helpful.
     
  17. yekimrd

    yekimrd Mu-43 All-Pro

    Jun 14, 2012
    Cincinnati, OH
    Mikey
    The issue of using the US dollar as the worldwide standard of currency comes to mind here. People have questioned why we keep on using it when it really is as simple as having a standard for reference purposes. (I realize this may not be a good analogy but it's what this discussion made me think of. :tongue: )