question on manual focus lenses

Discussion in 'Native Lenses' started by travelbug, Oct 11, 2015.

  1. travelbug

    travelbug Mu-43 Regular

    143
    Oct 20, 2014
    im interested in getting the rokinon 12mm f/2 which is a manual focus lens (never used one before and im relatively new to photography).
    ive read and watched reviews so i know mf lenses dont provide exif data. however i remember one or two videos mentioning that that mf lenses dont communicate with the camera body. is this true? ie will the lens feed the aperture value to the body or not?
     
  2. siftu

    siftu Mu-43 Top Veteran

    641
    Mar 26, 2015
    Bay Area, CA
    siftu
    No it wont but it's not much of an issue. Shoot in A or M mode and all will be ok.
     
  3. travelbug

    travelbug Mu-43 Regular

    143
    Oct 20, 2014
    could you expound on this for a newb like me? so if i shoot on A mode and its not feeding aperture data to the body, what use would that mode be?
     
  4. siftu

    siftu Mu-43 Top Veteran

    641
    Mar 26, 2015
    Bay Area, CA
    siftu
    Well you set the aperture on the lens itself. In A (aperture) mode the camera will adjust the shutter speed to get correct exposure.
     
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  5. travelbug

    travelbug Mu-43 Regular

    143
    Oct 20, 2014
    so the lens does give the correct aperture setting to the body still?
     
  6. siftu

    siftu Mu-43 Top Veteran

    641
    Mar 26, 2015
    Bay Area, CA
    siftu
    No. But the camera will adjust the exposure to compensate for your manual aperture setting. It can't change the aperture on the lens that is up to you
     
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  7. Carbonman

    Carbonman Mu-43 All-Pro

    Jul 10, 2014
    Vancouver BC
    Graham
    When you turn the aperture ring, the lens stops down to the working aperture; the camera doesn't briefly close it down automatically as happens with fully automatic lenses. What the metering system sees is the amount of light coming through the lens at the aperture you've set; it then adjusts the shutter speed accordingly. In the 1960s it was referred to as "stop down metering". Open aperture metering was developed with complicated mechanical linkages on a brand-by-brand basis. Now it's normally done electronically. Your 12mm f2.0 will only work in stopped down mode.
     
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  8. travelbug

    travelbug Mu-43 Regular

    143
    Oct 20, 2014
    ok so if you manually change the lens aperture to 2.8, the body will be able to read it as 2.8 and adjust shutter and exposure accordingly, correct?
     
  9. travelbug

    travelbug Mu-43 Regular

    143
    Oct 20, 2014
    thanks for the explanation. do i understand correctly that stop down metering is as accurate as electronic metering? so both systems would report the correct aperture all the time?
     
  10. siftu

    siftu Mu-43 Top Veteran

    641
    Mar 26, 2015
    Bay Area, CA
    siftu
    The camera adjusts what it can to get correct exposure. I.e shutter speed and optionally ISO since it has no knowledge or control over what the aperture is set on the lens. The exposure is still accurate according to the light meter
     
  11. MarkRyan

    MarkRyan Instagram: @MRSallee

    772
    May 3, 2013
    California
    Kind of yes, but really no.

    When you stop down a manual-aperture lens, there is no electronic message sent to the camera to let the camera know what your aperture is. HOWEVER, there is another much better signal...

    And that's the amount of light that comes through the lens. When you stop down the lens, less light comes through it. And the camera detects that there's less light, and adjusts the shutter speed + ISO accordingly. It doesn't need to know the aperture value because it can directly read the amount of light that passes through the lens.

    Hope that helps!
     
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  12. travelbug

    travelbug Mu-43 Regular

    143
    Oct 20, 2014
    thanks! i was just gonna ask you this on your yt tube channel actually. im just using an epm1 which at this point, is still quite ok for my needs. so if iwere to use a manual lens such as the rokinon 12mm f/2, i dont need to make any adjustments to the settings of the camera (i dont see any stop down setting in the menus), correct?
     
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  13. Gerard

    Gerard Mu-43 All-Pro

    May 12, 2015
    Vleuten, Utrecht
    Stopping down in this context only means changing the aperture, which in this you do youself, by turning the aperture setting on your MF lens.
    I have myself been reading blogs and reviews and sites on photography for over a year now and I still find the concept of 'stopping down' hard to understand, at least very confusing.
    In fact there is no need to understand this concept, when using a MF lens. Just turn the aperture ring and the metering system in the body will compensate, just as explained before.
    So there is no stop down setting in the menu. Life is complicaties enough as it is.

    Happy shooting :2thumbs:
     
  14. HarryS

    HarryS Mu-43 Top Veteran

    921
    Jun 23, 2012
    Midwest, USA
    You will likely want to learn how to manually focus that Rokinon, although at 12mm most of the scene will be in focus if you set it at 10 feet and use f2.8. Many users use magnify mode to zero in on focus, but the EPM1 has no dedicated magnify button. On my EPM1, I reprogrammed the REC button for magnify.

    You will also need to set the IS focal length to 12mm. It can only be set when an MF lens is attached and whatever value is set will be used. This value is ignored when an AF lens is attached.

    I also turn on the Super Control Panel, SCP. This allows me quicker access to change ISO and access the IS menu.

    Of course, you will set the mode to A. When using any manual lens, watch the shutter speed to make sure it's appropriate if needed to capture action and to be aware of camera shake issues.

    Whoever said that the EPM1 and other PEN's are glorified point and shoots never shot them with manual lenses. They can be quite serious cameras with good lenses.
     
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  15. travelbug

    travelbug Mu-43 Regular

    143
    Oct 20, 2014
    thanks for the tips HarryS. i havent shot with a manual focus lens yet but ive shot manual focus with my oly lenses and i do indeed use the record for magnify and for me it works as good if not better than focus peaking (in my friends em5). i also get sharper pics when i manually focus because i can choose which parts of the pics to focus on. scp is a must for this camera, and with scp on it operates in an identical fashion to the more high end omd's.

    thanks for making me aware of the is focal length setting as ive never tinkered with it. ive set it to 12mm now (im using my 25mm on the camera though) in preparation for the lenses arrival.

    i really find the epm1 a quite capable camera. i know the omds and newer pens can produce a better image especially at low light, but imo the epm-1 with a good lens can still give them a run for their money.

    one last question, do you use the anti-shock setting?
     
  16. ijm5012

    ijm5012 Mu-43 Hall of Famer

    Oct 2, 2013
    Pittsburgh, PA
    Ian
    your best bet is to shoot in M with auto ISO, and adjust your shutter speed as needed to achieve the desired exposure. It's actual quite simple, more so in practice than trying to communicate it via text.
     
  17. RnR

    RnR Mu-43 All-Pro

    Sep 25, 2011
    Brisbane, Australia
    Hasse
    On tripods and in lowish light I did. In better light I would try to make sure that the shutter speed was up there. Since you are rocking with the PM1, you need to get a custom grip from Richard Franiec - http://www.kleptography.com/rf/ Then you can look snazzy like mine...

    full.

    :D
     
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