newbie question on f-stop

Discussion in 'Native Lenses' started by alan1206, Dec 26, 2011.

  1. alan1206

    alan1206 New to Mu-43

    3
    Oct 26, 2011
    I know m43 lenses is 2x is same as 35MM FF focus. but what about aperture ?
    let say
    m43 : 17mm f2.8
    equal to
    35mm ff : 34mm f5.6 ?

    thanks in advance
     
  2. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    Lens speed remains the same, DOF is broader than Full Frame.
     
  3. kytra

    kytra Mu-43 Regular

    126
    Feb 28, 2011
    From what I learned, the relation for the FOV/magnification applies fot the DOF either. So for a given FL AND aperture (later edit), the DOF in m4/3 is twice deeper compared with the DOF on 35mm
     
  4. stillshunter

    stillshunter Mu-43 Regular

    124
    Sep 27, 2011
    Well photozone.de backs you up on their specs of the 17mm here...
     
  5. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    Lens speed is the same, and that's normally what we're measuring when we list the "maximum aperture". What a weird spec to have an "equivalent aperture", lol. I think if you need such a thing, you don't really understand DOF at all (no offense to anyone here)...
     
  6. GaryAyala

    GaryAyala Mu-43 Legend

    Jan 2, 2011
    SoCal
    Yeah ... what the hell does that mean?
     
  7. zerotiu

    zerotiu Mu-43 Veteran

    222
    Sep 13, 2011
    Indonesia-Singapore
    Aperture isn't multiplied. Only the focal length.
    f1.8 is not the same with f3.6. f1.8 is f1.8.

    Maybe you can understand more about DOF from one of my post (HERE). Someone in canonrumors helped me out with this article.

    Any people who don't use m43 camera always tell me that it is harder for 4/3 sensor to produce 'bokeh' . But I find it's easier than my canon aps-c. One of the reason is because m43 lens minimal distance is shorter than aps-c (just don't compare m43 with fullframe :) ).

    My canon 85mm minimal focus distance is 0.85m while Oly 45mm is 0.5m. Oly win bokeh result.
     
  8. veereshai

    veereshai Mu-43 Top Veteran

    777
    May 12, 2011
    Arlington, VA
    The FOV also makes a big difference in perceived DOF. 2x crop factor helps there.

    EDIT: More stuff to get you confused: http://toothwalker.org/optics/dof.html
     
  9. Promit

    Promit Mu-43 All-Pro

    Jun 6, 2011
    Baltimore, MD
    Promit Roy
    Don't compute "equivalent depth of field", because it'll be misleading. Depth of field comes from the physical focal length and aperture of the lens. So the depth of field of the 45mm f/1.8 is exactly equivalent to a 45mm f/1.8 on a 35mm/full frame camera. Easy.
     
  10. zerotiu

    zerotiu Mu-43 Veteran

    222
    Sep 13, 2011
    Indonesia-Singapore
    it's basically the same I think but with a lot of terms I don't recognize :blush:
     
  11. veereshai

    veereshai Mu-43 Top Veteran

    777
    May 12, 2011
    Arlington, VA
    Umm, I don't buy that DOF is different here:
    FF vs. APS-C: DOF | Flickr - Photo Sharing!

    Yes, the blur is different, but I still feel that DOF is almost identical.

    A slightly more easier link to understand:
    Understanding Depth of Field in Photography

     
  12. alan1206

    alan1206 New to Mu-43

    3
    Oct 26, 2011
    I am concern about the speed. not really DOF.
     
  13. I question the usefulness of depth-of-field equivalence, not least of which because it causes confusion with the exposure values. Exposure on it's own is simple: f/1.8 is f/1.8 is f/1.8 regardless of format.

    I've found it useful to know what 28, 35, 50, 85mm, etc means in 35mm film (full-frame) terms because the terminology is still used so widely. I don't really worry too much about what f-stop I need to replicate a full-frame camera because there is nothing definitive to equate what the effects of depth-of-field looks like between formats. It gets further complicated when you start to consider the out-of-focus (bokeh) characteristics of one lens compared to another. I just work with what I have.
     
  14. veereshai

    veereshai Mu-43 Top Veteran

    777
    May 12, 2011
    Arlington, VA
    I agree to a very large extent. Most of us don't even spend time looking at DOF calculator on field. And the good part about EVF is that you get what you see, so you know the kind of DOF you will get. And the funny part is that (almost) everyone wants to pick on micro four thirds, because of the 2x crop factor when the same holds good for APS-C too. May be it's easier to multiply with 2 than with 1.5 or 1.6 :tongue:.