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 p.1 #14 · Oly 24/2.8 vs. Canon 24L TS-E II | |
RustyBug wrote:
Lens change only, no camera/tripod reposition (didn't anticpate the variance).
The TSE is much longer than the Oly, so while the film plane/camera position remained constant, the front element is certainly closer (i.e. greater magnification/different perspective). I thought about reshooting before posting these, but felt it still illustrates the difference between the two lenses (@ unchanged shooting position).
No, no, no. This is a categorically incorrect interpretation of focal length. A lens's physical dimensions does not directly imply a change in focal length. You should know this already just by looking at how certain zoom lenses like the EF 24-70/2.8L are designed--their shortest focal length corresponds to the longest barrel length.
The framing of these two lenses are different not because the TS-E is a bigger lens than the Olympus. It's because you're shooting both of them near MFD, where the nominal focal length matches actual focal length only when the lenses are focused at infinity. You've forgotten that focal length of an internal-focus lens may change as a function of its focusing distance (focus breathing). Thus, you cannot assume that both lenses are actually shooting at 24mm when you've got them positioned so close to your subject that the resultant change in focus affects the subject magnification, much like a macro lens behaves.
Furthermore, you also have to consider that when the manufacturer states a lens is "24 mm", that doesn't necessarily mean it is exactly 24mm. It could actually be a bit wider or a bit longer, say 24.39mm or 23.94mm, if we were to go by the patent filing for the optical formula. At long focal lengths, this difference is negligible; at shorter focal lengths, a fraction of a millimeter may actually be visible. But this "rounding error" is unlikely to be a significant contributor to the field of view discrepancy you are seeing here.
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