May I be guided by you?

[Greg Beetham]

Ok ok, I see what you're getting at, the extension is quite a lot at 1:1, hmm I can measure the 100mm at full extension...ok carefully measured with a steel rule from the font of the lens to the mount surface (not including the flange) is 147mm, at full extension, the register is 38 (I think), so the 352 minus (147+38) = 167mm
Can't measure a 50mm, don't own one.
Greg

[Philip]

David, the clear distance from front rim of lens to subject at 1:1 on the Sony 100mm is 155mm.

Philip

[David Kilpatrick]

Thanks - the 50mm is presumably around 70mm because the lens itself is deeply recessed. The Tamron design is, I think, very close to the Nikon 85mm f/2.8 DX macro with internal focus and zero physical extension, and my guess is that the Nikon may allow 120mm or so clear between lens and subject.

This seems to be a new way to build macro lenses and if a 100mm was designed the same way, we could expect maybe 170mm clear working space.

David