Originally posted by Jewelltrail Stevebrot, early in this discussion, referring to your 2 posted pics, you state "You can tell which one was taken with the longer focal length by comparing the DOF, but that is another confusing discussion." Then, just a few posts later, you state this, "The link is about DOF, not perspective, and it is absolutely correct."
The link about DOF concludes that: "In fact, if the subject image size remains the same, then at any given aperture all lenses will give the same depth of field."
Can you explain your two above statements in light of the conclusion on focal length and DOF published at Luminous Landscape? Thanks.
As noted above and in one of my other posts, the original image size on the sensor for the two pictures was different. Both were cropped to the same composition and outputted to the same final size. The process was similar to if you were enlarging from film.
The cutting board pictures were originally posted on another thread where the equal size/equivalent DOF was also demonstrated. Here are the DOF pictures...the challenge was to tell which was taken at 50mm and which at 85mm.
BTW, if anyone is not convinced by the above or by the Luminous Landscape article, here is a link to a calculator page where you can prove it to yourself without even touching a camera or lens:
Julian's Lens Calculator
Steve