The Elpro close-up lens for the Leicaflex are two-element achromats especially designed for the prime lenses with which they are used. They are threaded into the front of the basic lens.
The Elpros retain the superb performance of the Leica lenses in the close-up area and also permit the automatic diaphragm of the lenses to function. And, since there is no bellows extension, Elpro-close-up photography requires no increase in exposure.
The Elpro VIIa was designed to be used with either the 90mm Elmarit-R F/2.8 or 90mm Summicron-R F/2.0 lenses.