Setting the focal length in the IBIS menu

Discussion in 'Olympus Cameras' started by pwol, Jul 15, 2015.

  1. pwol

    pwol Mu-43 Regular

    66
    Apr 21, 2015
    CT
    This might be a stupid question, but why do we have to do this?

    So the camera (I just bought an E-M5ii) can detect the focal length you are using and display it on the top right of the screen when you half press the shutter button. It also detects the focal length when it adjusts the minimum shutter speed in aperture priority for example. How difficult would it be to detect the FL and adjust it in the IBIS menu for you?

    I don't mind this with my primes, but it's pretty annoying with my zoom lens. I'm new to Olympus, is there something I'm missing or just unaware of?
     
  2. RamblinR

    RamblinR Mu-43 Top Veteran

    545
    Aug 16, 2012
    Sunshine Coast, Qld Australia
    Maria
    You only need to do this with adapted lenses as there is no information fed to the camera to advise the focal length. ibis adjusts it's strength by the focal length of the lens. If you don't want to do this and shutter speeds are fast enough to not need ibis then turn ibis off.

    If you are using m43 lenses then it is all automatic.
     
  3. alan1972

    alan1972 Mu-43 Top Veteran

    592
    Jun 23, 2012
    Malaga, Spain
    Alan Grant
    Yes, you are missing something. You only need to do this for lens that do not communicate electronically with the camera. Typically these are either legacy lenses used with adapters, or a small number of lenses from other manufacturers such as Samyang, or the two Olympus "body cap lenses". Of course these lenses are also unable to display the focal length on screen.

    For lenses that do communicate with the camera it works exactly as you describe - the camera detects the focal length and adjusts the IBIS accordingly, ignoring any focal length input in the menu.
     
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  4. Klorenzo

    Klorenzo Mu-43 All-Pro

    Mar 10, 2014
    Lorenzo
    You need to manually set the IBIS FL only for adapted or non electronic (like the BCL) lenses. For normal m43 lenses, from any producer, you do not need to.
     
  5. alan1972

    alan1972 Mu-43 Top Veteran

    592
    Jun 23, 2012
    Malaga, Spain
    Alan Grant
    I think we have tri-simultaneous replies!
     
  6. pwol

    pwol Mu-43 Regular

    66
    Apr 21, 2015
    CT
    Awesome thanks guys. I was like this cant be right lol
     
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  7. NWright

    NWright Mu-43 Regular

    193
    Jan 13, 2014
    Michigan
    Quick question on this topic.

    Say I mount a legacy 50mm f1.4. Should I tell the camera I have a 50mm or should I factor in the 2x crop factor, telling it 100mm?
     
  8. tkbslc

    tkbslc Mu-43 Hall of Famer

    ALWAYS use the actual focal length printed on the lens.
     
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  9. bassman

    bassman Mu-43 Top Veteran

    680
    Apr 22, 2013
    New Jersey
    Scott
    Repeat after me: focal length is focal length. "Equivalent" focal length is misleading and just confuses everything and everybody.
     
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  10. wjiang

    wjiang Mu-43 Hall of Famer

    There is only equivalent DoF and equivalent FoV. Focal length, aperture size (and therefore f/stop) are functions of an optic regardless of what it's used for or on.
     
  11. Klorenzo

    Klorenzo Mu-43 All-Pro

    Mar 10, 2014
    Lorenzo
    Yes, focal length is focal length (optical property of the lens, that you can measure with a ruler). But equivalent focal length is a very useful concept otherwise how can you make sense of any generic article on photography where you talk about focal length and perspective? For "classic" headshots should I use a 45, 85, 58 or a 6mm on compact camera? That would be very confusing too.
    What if I use different systems? I would go mad if the "step zoom" of the Pana LX-5 would show native focal lengths.

    In this specific case there is simply no reason for the IBIS system to ask for the focal length of another lens that on a different camera would give you the same FoV.
     
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  12. NWright

    NWright Mu-43 Regular

    193
    Jan 13, 2014
    Michigan
    Thanks. You are the best. I even gave you a gold star.
     
  13. RamblinR

    RamblinR Mu-43 Top Veteran

    545
    Aug 16, 2012
    Sunshine Coast, Qld Australia
    Maria
    Question in regard to same matter.
    What if your adapted lens is a zoom?
    What are people doing then?
    Turning IBIS off or is there some trick to this?
     
  14. bassman

    bassman Mu-43 Top Veteran

    680
    Apr 22, 2013
    New Jersey
    Scott
    If you're speaking generically - without regard to sensor size - you can use terms like "wide", "normal", etc. If that's not specific enough, then note that 25mm on a 43 sensor is about 48 degrees, as is 35mm on APC and 50mm on 36x24. If the conversion is 48 degrees, it's quite clear and each reader can easily adapt to their own format. Your "classic" headshot is 29 degrees. Although some people prefer narrower, perhaps 23 degrees (105mm on 36x24).

    The problem is that this discussion of "equivalence" often devolves into confusion. And furthermore, exactly which "equivalence" are we discussing? Field of view? Depth of field? Etc.

    As this is a micro 43 forum, I would expect most conversations to be relative to that sensor size and therefore can easily - and clearly - talk about (actual) focal lengths.
     
  15. Klorenzo

    Klorenzo Mu-43 All-Pro

    Mar 10, 2014
    Lorenzo
    I agree with you that FoV degrees could be a better standard than 35mm. But then you have the actual/real world situation where the 35mm was the standard for consumer photography up to a few years ago. There are a lot of books, articles, etc. still using that as a reference. And also no manufacturer clearly indicates the FoV of their lenses except in the full specs doc. Can you imagine telling a new user to buy a 23 degrees lens?

    So focal length equivalence can create confusion but also the alternatives do. What if I read in a book (old or new? Digital crop o full sensor?) that 24 is wide and I go to the shop and ask for a m43 24mm lens? The solution is only to understand a little how things actually works, not to sweep the problem under the rug. Then you can use normal or equivalent FoV according to the context.

    Aperture equivalence IMO is an ugly non-sense full of hidden assumption and not consistent with the exposure triangle. Good only to compare the blur of compact cameras.

    What focal length is better to use in this forum I leave up to any user depending on the situation.
     
  16. bassman

    bassman Mu-43 Top Veteran

    680
    Apr 22, 2013
    New Jersey
    Scott
    I agree that the naive consumer who goes into a store won't know what 48 degrees means. But they also won't really know what 25mm or 50mm means. They're dependent on a knowledgable and thoughtful salesperson to help them. We, on the other hand, are more knowledgable than the average naive consumer about cameras and photography. So we can have a more sophisticated conversation without subjecting ourselves to the confusion which comes along with this focal length "equivalence" (or aperture, or ...). We should strive always to use terminology which is unambiguous.

    So ... If we're talking about a 25mm lens, it's fine to talk about it like that. If we're talking about the angle of view that a 25mm lens would give on an m43 camera, it's fine to reference the focal length. If we're trying to talk about angel of view independent of a camera system, then saying "I used a mid-range zoom" or "you need a wide angle, maybe 20 degrees or better, to capture Mount Rushmore" seems ultimately more helpful. Once we all get used to it, of course .
     
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  17. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Probably best to turn it off unless you're only using a narrow range of the zoom.

    If shutter speed is at least 1/ 2*FL, you don't need IS.

    Barry
     
  18. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    I've had decent luck setting it to about 1/3 in the lens range, or at the very least the shortest focal length. Say you're adapting a 24-70mm zoom - if the camera is correcting shake for 24mm, it's going to still help with a shot taken at 70mm, but it'll undercompensate.

    Setting it to, say, 35mm in the context will do a small amount of overcorrection for the 24mm shot, but probably not noticeable, and will help a bit more at 70mm. I wouldn't recommend setting it much longer than 1/3 through the zoom range, though, since the overcompensation will do more harm than good.
     
  19. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    Personally, I might suggest that you'll get a much more interesting shot if you shoot Mount Rushmore with a short telephoto, say 45mm or 75mm, and then stitch the shots together in a panorama. But then that's opening a whole other kettle of fish about focal lengths - it's not just about angle of view, it's about what it does to the spacial relationships within that angle of view.

    ...I'll just let myself out. :whistling:
     
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  20. RAH

    RAH Mu-43 Veteran

    271
    Dec 1, 2013
    New Hampshire
    Rich
    Another trick(y) question - when I add the WCON-P01 to the 14-42 II R lens, should I (can I??) change the focal length for the IBIS? The specs say that it makes it into an 11mm lens; I'm sure the camera has no way of knowing it has been clamped onto the front of the lens. But then, if the detection is automatic with a native MFT lens, it might not even allow you to change it.