I'm fine with using 1:1 as a general guide and it definitely helps to separate from zoom lenses that are described as having "macro" (but are usually 1:2 or 1:4) - and find my MP-E 65mm superb for macro (which does 1x - 5x)!
The shorter the FL, the more likely you'll be shutting out light with the shadow cast by camera and lens, so I tend to recommend the Tamron 90 or Sigma 105 as being the best 'bang for your buck' all rounder lenses
Used a Sigma 105 for years and found it excellent, progressed to the 150 but now use the Canon 100 IS (1:1 macro as well as great portraits) and Canon MP-E 65 (1-5:1 lens but only good for macro)
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