The history of the single-lens reflex camera predates the invention of photography in 1826/27 by one and a half centuries with the use of a reflex mirror in a camera obscura first described in 1676. Such SLR devices were popular as drawing aids throughout the 18th century, because an artist could trace over the ground glass image to produce a true-life realistic picture. A British patent was granted in 1861 for the first internal mirror SLR photographic camera, but the first production photographic SLR did not appear until 1884 in America. These primitive SLR cameras began to mature in the early 20th century, but their many disadvantages continued to make them unsatisfactory for general photographic use for decades. The SLR may be elegantly simple in concept, but it turned out to be fiendishly complex in practice. The SLR's shortcomings were solved one by one as optical and mechanical technology advanced and in the 1960s the SLR camera became the preferred design for many high-end camera formats.