Ross 5X40 Mk V 6E/392 5X40 (View 1)
Manufacturer/Model: Ross 5X40 Mk V 6E/392 5X40
Field of View: Probably same as Mk. IV i.e. 10 deg = 175 yd/1,000 yd; 50 APFOV deg
Weight: 846 gr
Exit Pupil: 8 mm
Serial #/Year of Manufacture: 20485 = 1947/8 - early 1950's
Notes: The marking 6E/392 on the right prism plate is a Royal Air Force stores code for this type of instrument. The MK V is a fixed focus aircraft spotting and maritime reconnaissance binocular succeeding the 5X40 Mk. IV 6E/383 (See Ross X5 Bino.Prism Mk IV: www.flickr.com/photos/binocwpg/4372051428/in/set-72157623... ). Like the Mk IV it accepts a large one-piece rubber eye shield absent on this example. The Mk V has silver colored flat desiccator vent plugs with pin spanner holes (for dry air purging) while the Mk IV’s are red painted domed ones slotted for a bladed screwdriver.
The Mk V was introduced 1947/48, and used by the Royal Air Force at least into the 1990’s. Serial numbers indicate about 2,000 were built, the first 1,000 marked Mk V and the later ones Mk 5. William Reid has written that the binocular is a 5X military version of Ross’ civilian Tropical 7X40 and 10X50 models whereas Ross researcher, Terence Wayland, believes the Mk V was introduced before the Tropical series, and the Tropicals were, in fact, civilian versions of the Mk V. At any rate, its build is very much the same as the Tropicals (excepting the fixed focus oculars) and actually quite a bit different and superior to that of the Mk IV. Though the Mk IV and V have obvious similarities - both are 5X40 configuration, fixed focus, dry-air vented, and of Porro II construction - , the Mk V differs from the Mk IV by having: 1) rubber gaskets sealing almost all joints, 2) a wide-angle Erfle 3 lens eyepiece, 3) the eyepiece field lens cemented to the prism cluster to reduce light reflecting surfaces and increase light transmission, 4) almost all light reflecting surfaces coated, 5) prism plates secured with screwed down gasketed rings, 6) mechanical adjustment of fixed focus to suit individual eyesight is simpler and easier to perform, 8) less weight and being more compact i.e. 234 grams lighter and 2.5 cm shorter (See View 2: www.flickr.com/photos/binocwpg/8020965844/in/photostream).
When using this binocular one of the first things noticed is that it is exceptionally sharp to the edge of the field, at least 85%. This exceeds the edge performance of the Mk IV by a great deal which is sharp to about 65% at best. This particular Mk V’s view was noticeably dimmer than that of the Mk IV because the exterior surfaces of the eyelenses had numerous rub markings penetrating the glass as well as the anti-reflective coating. These markings were removed by polishing with jeweler's rouge (ferric oxide) and the view is now slightly brighter than that of the Mk IV (and if the anti-reflective coatings on the exterior of the eyelenses were intact, it would be brighter still). Overall, the optics of this binocular are outstandingly good.
This binocular is pictured and described in Seeger's grey book on page 214.
Revised December 28, 2012
Note: If you have a vintage binocular you either wish to sell or would just like some information about, I can be contacted at flagorio12@gmail.com .
Ross 5X40 Mk V 6E/392 5X40 (View 1)
Manufacturer/Model: Ross 5X40 Mk V 6E/392 5X40
Field of View: Probably same as Mk. IV i.e. 10 deg = 175 yd/1,000 yd; 50 APFOV deg
Weight: 846 gr
Exit Pupil: 8 mm
Serial #/Year of Manufacture: 20485 = 1947/8 - early 1950's
Notes: The marking 6E/392 on the right prism plate is a Royal Air Force stores code for this type of instrument. The MK V is a fixed focus aircraft spotting and maritime reconnaissance binocular succeeding the 5X40 Mk. IV 6E/383 (See Ross X5 Bino.Prism Mk IV: www.flickr.com/photos/binocwpg/4372051428/in/set-72157623... ). Like the Mk IV it accepts a large one-piece rubber eye shield absent on this example. The Mk V has silver colored flat desiccator vent plugs with pin spanner holes (for dry air purging) while the Mk IV’s are red painted domed ones slotted for a bladed screwdriver.
The Mk V was introduced 1947/48, and used by the Royal Air Force at least into the 1990’s. Serial numbers indicate about 2,000 were built, the first 1,000 marked Mk V and the later ones Mk 5. William Reid has written that the binocular is a 5X military version of Ross’ civilian Tropical 7X40 and 10X50 models whereas Ross researcher, Terence Wayland, believes the Mk V was introduced before the Tropical series, and the Tropicals were, in fact, civilian versions of the Mk V. At any rate, its build is very much the same as the Tropicals (excepting the fixed focus oculars) and actually quite a bit different and superior to that of the Mk IV. Though the Mk IV and V have obvious similarities - both are 5X40 configuration, fixed focus, dry-air vented, and of Porro II construction - , the Mk V differs from the Mk IV by having: 1) rubber gaskets sealing almost all joints, 2) a wide-angle Erfle 3 lens eyepiece, 3) the eyepiece field lens cemented to the prism cluster to reduce light reflecting surfaces and increase light transmission, 4) almost all light reflecting surfaces coated, 5) prism plates secured with screwed down gasketed rings, 6) mechanical adjustment of fixed focus to suit individual eyesight is simpler and easier to perform, 8) less weight and being more compact i.e. 234 grams lighter and 2.5 cm shorter (See View 2: www.flickr.com/photos/binocwpg/8020965844/in/photostream).
When using this binocular one of the first things noticed is that it is exceptionally sharp to the edge of the field, at least 85%. This exceeds the edge performance of the Mk IV by a great deal which is sharp to about 65% at best. This particular Mk V’s view was noticeably dimmer than that of the Mk IV because the exterior surfaces of the eyelenses had numerous rub markings penetrating the glass as well as the anti-reflective coating. These markings were removed by polishing with jeweler's rouge (ferric oxide) and the view is now slightly brighter than that of the Mk IV (and if the anti-reflective coatings on the exterior of the eyelenses were intact, it would be brighter still). Overall, the optics of this binocular are outstandingly good.
This binocular is pictured and described in Seeger's grey book on page 214.
Revised December 28, 2012
Note: If you have a vintage binocular you either wish to sell or would just like some information about, I can be contacted at flagorio12@gmail.com .