Minolta manufactured and marketed a line of 35mm film single lens reflex cameras (SLRs) and lenses with the Minolta SR-mount between 1958 and 1996; Minolta later introduced the Minolta A-mount system in 1985, a line of autofocus SLRs and lenses with the mechanically incompatible Minolta A-mount, which eventually supplanted the manual focus system.
The first Minolta SLRs were marketed with SR- model numbers starting from 1958 with the Minolta SR-2, which featured semi-automatic diaphragm operation with Auto-Rokkor lenses: winding the film advance lever opened the diaphragm and cocked the shutter; when the shutter was released, the iris would stop down to the selected aperture. These were succeeded by the SR-T models, which incorporated through-the-lens metering in the body, starting from 1966 with the SR-T 101. The SR-T models were succeeded by the X models, which include the X-1 flagship (1973), advanced XE (1974), and compact XD and lowered-cost XG (1977) lines; all of the X models have some form of autoexposure.
Starting from the 1960s, Seagull Camera has sold SLRs with Minolta SR-mount; the first cameras were labeled DF (after ), and were largely copied from the Minolta SR-2. Most of these were produced for the domestic market in China, but some were exported under multiple brands, including Seagull.
The modular XG line was developed into the X-700/570/370 line in the early 1980s. After Minolta introduced its autofocus A-mount system in 1985 under the trade names ñ (alpha, Japan), Maxxum (Americas), and Dynax (Europe), demand for the earlier manual-focus cameras dwindled. Minolta licensed the design of the X-370 to Seagull in 1987 and one more SR-mount SLR camera was released in 1990, the X-9 (aka X-300s in Europe); Minolta quietly outsourced production of the X-370 to Seagull in 1995, which continued to produce Minolta and Seagull-branded cameras based on the X-370 for a prolonged period.