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Effect of Lens Focal Length on Portraits
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  • Thanks for posting.

    I strongly suspected that I need 24mm for portraits :-)

  • Maybe Tim Burton would want 19mm for portraits.

  • By the way Olympus 45mm 1.8 might give portrait shot somewhere between the 135mm one and the 200mm one.

  • @stonebat How do you figure 45mm on GH2 translates to 135mm full frame? I'd think it'd be close to the 100mm photo, which to me looks best on this particular model's face.

  • well, as far as perspective is concerned, isn't 45mm a 45mm no matter what crop size? AFAIK perspective doesn't change (how would it?); what changes is FOV. So, Oly 45mm is 45mm in terms of perspective, but has a much narrower field of view, compared to 90mm of 35mm FF. If I'm right it's very misleading to say that "Olympus 45mm 1.8 might give portrait shot somewhere between the 135mm one and the 200mm one" or 100mm as LPowell said because perspective stays the same (therefore facial characteristics would be similar to that of 50mm above, not 100mm), what changes is FOV. Please correct me if I'm wrong.

  • @brudney: The FoV does actually affect pictures a lot more than you think. The thing that gives character is distortion, either tele-distortion (which "compresses" the picture, making everything look closer and so on) and most famous is wide-angle distortion (which keeps objects in the center of frame the same size, but "stretches" out the frame towards the edges), both of these types of "distortion" also increases the farther (in tele case) or closer (in the wide-angle case) the subject is from the lens. This is what makes a 45 look like an 85 (GH2 has a 1.86 crop, times 45 is rounded up an 84) are both the cropping and distance. First, most distortion you would see happens in the edges of the frame. But on cropped sensors, this part is cut, removing a large bit of distortion. Notice how her nose stays more or less the same between all the pictures. But as I also said, distance. The farther away something is from the lens, the less wide-angle distortion it would see (instead looking more "compressed") and on a crop sensor, to keep the same frame, you would need to back away the corresponding distance of your crop. This would remove even more of the distortion, which we of course do. So one could without a doubt say that the Oly 45 corresponds to an 85 on a GH2, as it would give the same FoV and more or less the same characteristics.

  • ok, thanks a lot Gabel. I've never had a FF camera so the topic of how m4/3 lenses compare to FF ones has always been a bit esoteric to me... (BTW GH2 has a crop of 1.86 but only in 16:9 right?) Anyway, I'd love someone who has both GH2 and say 5dmkii to make a couple of photos comparing lenses of similiar FOV to see how much they differ in terms of perspective.

  • I'd love someone who has both GH2 and say 5dmkii to make a couple of photos comparing lenses of similiar FOV to see how much they differ in terms of perspective.

    As I remember we have similar comparison.

  • 100-135 is perfect.

  • damn, can't find it. if someone manages to find the comparison VK mentioned above, pls post it here:)

  • @brudney: Yeah, it's 1.86 in 16x9 (as it's a native 16x9 sensor and a full-frame is cropped from 1.5:1) or a 1.24 crop compared to Super 35 (which is what you'd in cinematography think about).

  • @LPowell

    I did't mean FOV. I meant in terms of lens distortion. 45mm 1.8 has so little lens distortion that the distortion on the front subject might be somewhere between 135 and 200 shown above. Or I could be utterly wrong.

  • Perspective is strictly a function of distance. Focal length determines image size. Crop determines FOV.

  • Let's not forget in-body distortion correction :)

  • Let's not forget in-body distortion correction :)

    In body distortion correction is present exactly to correct lens distortion :-) So, again. All this look is defined by perspective, and perspective defined by subject and camera positions.

  • Samyang 14mm 2.8 shows more distortion than Lumix 14mm 2.5, right?

  • Never mind. Samyang 85mm 1.4 has very little distortion, too. In that case I agree that the perspective is defined by subject and camera position. Thanks guys.

  • Portrait Lenses - 85mm vs. 105mm vs. 135mm vs. 200mm