After an exercise to compare the sharpness of my 105mm macro lens with and without a cheapie 2x teleconverter, I took some photos of random stuff.

As for the sharpness comparison, it's apples and oranges because I had to move and refocus between the two takes, and the exposure also came out substantially different. All in all, though the picture of the cucumber with the teleconverter is clearly the better one.

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"Blonde" Cucumber Stem (105mm)
(M)(L)
"Blonde" Cucumber Stem (105mm + 2x TC)
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"Black Cherry" Tomato
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"Black Cherry" Tomato leaf
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Manufactured circuit board