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edwardkaraa wrote:
Lotusm50 wrote:
I further think that your method of method of discovering curvature of field is flawed. Simply, the distance to the object in the corner of of image in the place of focus, is not the same distance from the camera as an item in the center of the image and place of focus. So, if you focus on the item in the center of an image and then move it to the corner it will necessarily be out of focus becuase it is no longer in the plane of focus (it is closer).
Of course, you are absolutely right, but for a lens this wide, I don't think it would make a difference.
That depends on the object distance.
On the other hand, the field curvature effect can be very pronounced and much more obvious, and it can be experienced the way weekh did. I usually do differently, I focus manually at the frame center, then at the frame edge without moving the camera. Usually with my 16-35, when the center focus is at infinity, the extreme corner focus can be at just around 1-2 meters only. That's how pronounced it is.
That is how pronounced it can be for a poor lens. Such a level of field curvature is
irreconcilable with the stellar MTF of the Distagon 21/2.8, which excludes easily
noticeable effects of any aberration except distortion.
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