?'s about angle of view, focal length, and perspective

Discussion in 'Open Discussion' started by Djarum, Sep 30, 2010.

  1. Djarum

    Djarum Super Moderator Moderator Subscribing Member Charter Member

    Dec 15, 2009
    Huntsville, AL, USA
    Real Name:
    Jason
    So, on my trip to the smokey's, I had an "A HA" moment. Or sorta. When I was drivign and pulling off the Blue ridge parkway to take pictures, I noticed something. To get the widest possible view of the landscape of the mountains and valley's, I used 28mm. But the pictures didn't seem right. Of course at 50mm looked like what I wanted, but I didn't get all the landscape I wanted.

    To the point, my vision horizontally is 170 degees, but my perspective is at 50mm. How do I achieve both with a single lens and sensor?

    Dj
     
  2. Streetshooter

    Streetshooter Administrator Emeritus Subscribing Member Charter Member

    Dec 15, 2009
    Phila, Pa USA
    DJ, maybe try 16:9 aspect ratio...that might be close....
    shooter
     
  3. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    ... only on a GH1/GH2. It doesn't make any difference on any other MFT camera since it's ends up cropping the 4:3 image whereas on the GH1 it expands it horizontally to fill the width of the larger sensor.
     
  4. andrewteee

    andrewteee Mu-43 Regular Charter Member

    33
    Apr 14, 2009
    So, would that make the GH1/2 something of a panoramic camera, roughly speaking?
     
  5. Streetshooter

    Streetshooter Administrator Emeritus Subscribing Member Charter Member

    Dec 15, 2009
    Phila, Pa USA
    Dragos,
    Agreed in a way. For some reason, with the GF1 shooting raw only, with 16:9 ratio....
    That's what I get... Dunno... It's a raw 16:9 file...
    Weird huh?
     
  6. WT21

    WT21 Mu-43 Hall of Famer

    Feb 19, 2010
    Boston
    I have to say I don't fully understand what you are asking, but here's something that might or might not be on topic.

    As I understand it, our eyes are not cameras. They flit about, with the pupil widening and narrowing and building in our mind the impression of a completed picture with far more dynamic range than any camera (because the eye is moving about with the iris adjusting to let in more/less light).

    Perhaps anlge of view is the same thing. If you could somehow keep your eyes completely still, and looking only forward, then the full 170 degree vision is really only hazy at the edges. It's not really a clear 170 degrees. It's only from eye movements that our mind "builds" a clear mental picture of the scene in front of us. (this is what I am wondering. I'm not stating this, as I'm not really sure).

    I don't know about the perspective bit, for as far as I know our eyes don't have 2X zoom (unless it's digital zoom, lol).

    Any chance you could post two pics showing what you mean?
     
  7. antithetic

    antithetic Mu-43 Regular

    150
    Jun 7, 2010
    City of Angels
    I think what you are trying to say is at 50mm, the objects in the photography are roughly the same perspective/size as your eye vision but 28mm covers the area of your peripheral vision? Then I say try a stitched multi-shot panorama at 50mm and see if that's close to what your eyes see. =]
     
  8. Streetshooter

    Streetshooter Administrator Emeritus Subscribing Member Charter Member

    Dec 15, 2009
    Phila, Pa USA
    Whoa fellas....
    Let's keep something straight here....
    FOV changes with the lens. Perspective does not. Perspective changes as you/camera move.
    So, DJ looking for an angle that matches his FOV will come from...
    The lens
    Cropping
    Aspect ratio
    This is a confusing issue and we need to be certain that the "Perspective" issue is in the right place.
     
  9. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    Roughly speaking, yes. Because of the constant angle-of-view feature on the GHx cameras, you end up with a wider horizontal FOV in both 3:2 and 16:9 aspect ratios over 4:3. The 14mm lens in 3:2 ends up having the FOV of something closer to 13mm, and 12mm in 16:9 aspect ratio.
     
  10. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    That's because the RAW isn't corrected for lens curvature - that only happens in the JPEG. So in RAW you'll see some distortion, but it's not quite the same as the expanded horizontal FOV of the GHx cameras in the wider aspect ratio modes.
     
  11. Streetshooter

    Streetshooter Administrator Emeritus Subscribing Member Charter Member

    Dec 15, 2009
    Phila, Pa USA
    Dragos,
    So if I'm not confused... The GH cameras shoot aspect ratio in Raw?
     
  12. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    Yes. My 3:2 RAW files, for example, are 4144 x 2768, and the corresponding JPEGs are 4128 x 2752, so definitely wider than 4000 x 3000. In 16:9 the RAW files are 4368 x 2464, and the corresponding JPEGs are 4352 x 2448.
     
  13. Streetshooter

    Streetshooter Administrator Emeritus Subscribing Member Charter Member

    Dec 15, 2009
    Phila, Pa USA
    Dragos, I really didn't need to know about that... I never should have asked....
    Does the G2 do the same thing with raw....?
     
  14. Djarum

    Djarum Super Moderator Moderator Subscribing Member Charter Member

    Dec 15, 2009
    Huntsville, AL, USA
    Real Name:
    Jason
    I guess the problem I see is that if I use a wideangle lens and take a landscape picture, the perceived distance between objects close up and far away seem stretched. Obviously, changing focal length w/o moving my feet doesn't change perspective. So I back up, and increase focal length. Now I've matched perspective of where I was, not in my new location.

    Maybe I'll do some experiments. It maybe just the issue of that the pen doesn't do true 16x9.
     
  15. Djarum

    Djarum Super Moderator Moderator Subscribing Member Charter Member

    Dec 15, 2009
    Huntsville, AL, USA
    Real Name:
    Jason
    Some more thoughts...

    I was reading this:

    The Forgotten Lens

    Now, the writer says that the 50mm matches the perspective of what we see. Is he talking about FOV or how we percieved the distance between objects? When I see the pictures he's posted, I see that the perspective is natural. However, if I was standing there looking where the picture was taken, while the perspective was matched, my FOV is much greater in the context of landscapes.
     
  16. Streetshooter

    Streetshooter Administrator Emeritus Subscribing Member Charter Member

    Dec 15, 2009
    Phila, Pa USA
    DJ,
    Perspective and FOV are not the same thing. Your issues are with FOV not perspective. If the perspective were the issue then you would just move to change it. The FOV does not change when you move only the amount of subject matter and the PERSPECTIVE.

    This guy talking about a 50mm perspective is confusing the issue. If he said a 50mm FOV, then it would make more sense.
    Take any lenses you have and put them on the camera from exactly the same vantage point. You will see the FOV change but not the perspective.

    You seem to have a FOV/Aspect Ratio issue going. This can be a confusing thing but rather easy to solve....
    if you think I'm making sense, not everyone does, let me know and I'll tell you how to solve the issue.
     
  17. JoeFriday

    JoeFriday Mu-43 Regular

    88
    Jun 28, 2010
    Milwaukee, WI
    Basically, we're discussing the reasons 50mm and 35mm lenses were adopted as standards. The 50mm image being what looks natural to our eyes, with objects appearing with the correct proportion and depth in the frame. The 35mm (or slightly wider) image showing approximately the overall field of view our brain sees as we stare ahead, not taking into account the proportion and depth of objects.

    If there was a single lens that would accomplish both tasks at once, it would have long ago been adopted as the true standard. I personally gravitate toward a 40mm lens as a good compromise. But I don't think it works the same with a 20mm on a m4/3s camera.
     
  18. andrewteee

    andrewteee Mu-43 Regular Charter Member

    33
    Apr 14, 2009
    This reminds me of a forgotten recent blog posting and the author was comparing focal lengths for architecture photography. The 50mm focal length was the most accurate in terms of scale and proportion, but for marketing purposes it was not the most interesting.
     
  19. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    AFAIK all the MFT cameras match their RAW to the aspect ratio. I'm pretty sure my wife's G1 does that, so I'm guessing the G2 does as well. The difference is that you're not really gaining anything on those cameras by shooting in anything other than 4:3 because it's simply cropping the image, so you're just throwing away resolution. You might as well do that on your own in PP unless you don't feel like it. That's one of the features that makes the GHx series special. I normally shoot in 3:2 on my GH1 because I get a bit of extra wide FOV, and I like that aspect ratio.
     
  20. pictor

    pictor Mu-43 Top Veteran

    635
    Jul 17, 2010
    20mm on ยต4/3 offers exactly the same perspective as 40mm on full frame, since perspective does not depend on the focal length but on the angle of view.