For optical systems requiring more extensive measurement of image quality than is provided by a simple resolution test, MTF testing provides a reliable and objective means of evaluating lens image quality. In addition to providing much more detailed information about the image, it also provides a very precise means of locating the image plane. This permits very detailed and accurate mapping of field curvature, chromatic and spherical aberration, astigmatism, and geometric distortion.
We measure MTF directly at approximately one hundred different spatial frequencies, using a slit object and a sinusoidal target grating. Testing can be done at wavelengths between 400 and 800 nm, and at finite or infinite conjugates. Data is provided on printed MTF plots, and in Excel spreadsheet form.