Actually, I neglected to include some numbers. Where as before I used a bellows device (camera mount and lens mount separated by an expandable, light-tight bellows riding atop a rack-and-pinion track), this time I used a rigid #2 extension tube (the medium-sized of the trio of three tubes that comes with any kit). The #1 is only about 5mm long and the #3 is 30 mm long. Of course you can mix it up by combining more than one tube end-to-end providing seven permutations in all. By the time you make your mind up which tube, or combination of tubes to use the subject may have long gone. Ideally I should have Canon tubes with electrical connections for AF but they cost a few hundred bucks and the legacy tubes that I already have are Minolta, which is why I also insert the EF-MD adapter before selective a tube. The viewfinder darkens when you close down the lens iris making focusing challenging so bright sunlight is a prerequisite to using these old things. It's only fitting really ... an old guy using old things. Some day I may get a macro lens and do it properly.