The Junior was introduced in 1903 as a cheaper option to the Regular. At the time of introduction, it had a distinctive square lens panel, this was soon replaced by the normal Sanderson vertical oblong panel. From then the Junior tended to be a couple of years behind the Regular in adopting new features.

The body covering of the second example is seal-grain leather rather than Morocco used on the Regular, the body also has the finger recesses present on early versions of the Regular. The Junior is usually found with a cheaper lens, this example has a top-of-the-range Dagor in a Koilos shutter. This could be a replacement or the original fitted by Houghton, the lens matches the infinity stops and focusing scale. It is also a little longer than normally fitted.

For a list of Sanderson models, versions and an explanation of features see Sanderson Notes.