Ok so I live in the woods and have no scientific equipment.
I strapped my 7D to a tripod with the 70-300 lens attached.
To take this shot I selected the center focal point. This rivet on top of the slab of wood was centered in the focal point box, the smaller box covered the shaft.
Camera distance to target - 86" to sensor plane
Image was cropped in Photoshop Elements with absolutely no PP and saved as a JPEG.
Uploaded to Photobucket and here it is .....
|IMAGE IS A REDIRECT OR MISSING!|
HTTP response: 404 | MIME changed to 'image/gif' | Byte size: ZERO
Tomorrow I will do a Macro shot of the same target using a Tamron SP 180mm Macro Lens