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p.1 #1 · p.1 #1 · Newbie question on relationship between MM and MFD | |
Hello everybody,
I am not looking at macro lenses specifically figured this may be the best spot for this question as I know these topics are very relevant in selecting a macro lens.
What I am confused about is the relationship between maximum magnification (MM) and minimum focal distance. I believe I understand the concept of each, that is that maximum magnification is how large an image is on the sensor, typically measured at the MFD and the longest focal length (if a zoom lens). I understand that MFD is how close the sensor can be to the object in question.
The real-life example that I don't understand is the Canon 24-70mm 2.8L I vs II.
Per Canon and many review sites, the original 24-70 2.8L has a MFD of 15" (38cm) and a MM of 0.29x. So presumably, this MM is observed by setting the lens to 70mm, and then moving as close to the object as possible (in theory 1.25' or 0.38m from the sensor item).
However, also per Canon and similar review sites, the revised version II of this lens has an EQUAL MFD of 15" (38cm) but only has a MM of 0.21x. How is it possible that you take a different lens at the same focal length, positioned at the same MFD, and yet the image appears as a different size on the sensor? (I would think the SIZE of the image on the sensor, i.e. the MM, is only affected by those two variables - focal length and distance to the subject)
Thank you for helping me understand! I am looking for a versatile multi-purpose lens but enjoy food photography and while a true macro lens is not needed, having a higher MM would be useful and is why I am trying to understand this.
Regards,
Mark
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