Entre les Série A ("Ordinaire") et les Série B ("Supérieur"), Dinesmann a intercalé un "modèle moyen" sur lequel le diaphragme est à l'intérieur de l'appareil, mais n'est pas pour autant à iris. Un levier sur la face avant  peut prendre plusieurs positions, chacune marquée par une tête de pointe qu'un évidement du levier peut recouvrir. Ce levier déplace une plaque interne percée de trous de diamètres différents, faisant fonction de diaphragme d'ouvertures variables. A chaque tête de pointe correspond le positionnement dans l'axe de l'objectif d'un des trous.

Ce type de diaphragme se retrouve sur plusieurs autres marques et modèles.

La gravure illustrant le catalogue ne porte pas d'inscription permettant de rapprocher cet appareil d'un quelconque fabricant, mais les principales caractéristiques sont celles des fabrications Natali, Collo et Cie.
 

Les modèles de cette série sont :
 

Natali, Collo & Company was the name of a subcontracting manufacturer, not a commercial brand of cameras. All the production was sold under more well-known brands like Manufrance, Plavic, etc. These were distributors or players in the photography market who aimed to add affordable cameras to their catalog.

The cameras manufactured by Natali and Collo were of the Box or Detective type, as the materials used were not suitable for other forms. The wood used was lightweight and not very durable. The covering was limited to decorative paper glued to the wood, which over time tended to wrinkle. Some unusual features for the time are worth noting, such as imitation reptile skin in blue color.

The manufacturing quality was low in order to produce budget cameras. This is the primary characteristic of Natali and Collo cameras. Certain technical characteristics were consistent across the manufacturer's cameras. The shape of the shutter speed selector (P/I) resembled a racket; this design was found on several models. The film advance key was simple, often a bar passing through the axis of the winding spool. The locking mechanism for the back door of detective cameras was circular with a circular notch that allowed it to lock onto a simple nail. On other models, a metal piece with a small hole was positioned over a nail head. The shutter release button was sometimes absent and was simply the end of a rod.

While these features were not universal, these unique characteristics serve as a good basis for identifying cameras from Natali, Collo & Co.