Not all data sheets are created equal!
Schneider's MTF graphs contain polychromatic diffraction MTF data - not just geometric MTF data. Schneider's MTF graphs are realistic indicators of actual lens performance in the field. If you are considering a lens from another supplier, it is in your best interests to ask exactly what their data sheets contain.
 

	Relative Illumination, Distortion, Transmittance
		Modulation Transfer Function
			Mechanical Dimensions
				F-stop range	T/# (with spot filter)	Minimum object distance	Filter Thread	Max. Image Circle
Cinegon 1.8/4.8mm				1.8-22	2.1 - >2000	1mm	51mm push-on filter diameter	11mm
Cinegon 1.4/8mm				1.4-22	1.6 - >2000	5mm	M 49x0.75	11mm
Cinegon 1.4/12mm				1.4-22	1.6 - >2000	20mm	M 49x0.75	11mm
Xenoplan 1.4/17mm				1.4-22	1.6 - >2000	70mm	M 49x0.75	11mm
Xenoplan 1.4/23mm				1.4-22	1.6 - >2000	115mm	M 49x0.75	11mm
Xenoplan 1.9/35mm				1.9-22	2.1 - >2000	310mm	M 49x0.75	11mm
Tele-Xenar 2.2/70mm				2.2-22	2.3 - >2000	1250mm	M 49x0.75	11mm
	Click PDF icon above to view datasheet. Explanation of nomenclature in datasheets.