Have you tried http://www.quickmtf.com/ ?

The idea of measuring MTF by shooting charts is somehow flawed at its root. A proper MTF test should be performed on an optical bench.

http://toothwalker.org/optics/lenstest.html

I've read somewhere that MTF tests are heavily influenced by the quality of lights, so that proper results are obtained by a properly equipped laboratory, and results are not even constant between laboratories for light quality problems.

You don't need to send the lenses to Zeiss, any laboratory equipped for this kind of tests will do, they should be a bit everywhere, this is 1940 technology after all. I have no idea of how much this would cost.