LightOmatic II repair (5 of 5)

On the third page

On the forth page


On this page

  • The inner workings of the lens

The inner workings of the lens


My camera has very clean aperture blades and a fully functional shutter. I cannot see anything amiss with these components. For this reason I have not attempted any further disassembly of the lens barrel beyond that described here. My interest in this area was simply: a) cleaning of the otherwise inaccessible rear lens-cluster face, to remove a tiny trace of fungal growth, and b) addressing a frozen focus adjustment.


A cylinder surrounding the rear lens element group (figure 29) should be removed by turning it anti-clockwise with a lens spanner or suitable alternative tool (I used an old 1 1/4" wood chisel). Note that there is a red coloured fibre washer beneath, which can be seen in figure 30. This first step allows the lens barrel to be separated from its mounting plate. 


The rear lens element cluster (shown in figure 33) can now be removed by unscrewing anti-clockwise (it should be finger tight). Note, it is possible to clean the inner element without disassembly, by removing the front lens element (figure 19 on page 3), setting the maximum aperture, holding the shutter open on "B", and going in from the front of the lens: if you trust yourself not to let the shutter accidently close. 


Figure 30 shows the lens mounting plate with the lens cluster removed, and figure 31 shows the flip-side (lens side) of the mounting plate. Note there is a very vulnerable hair-spring that returns the shutter actuating arm to its resting position, and this can be easily dislodged accidentally.


Figure 32 shows the rear of the lens barrel.  Note that there is a loose-fit metal spacer/washer beneath the threaded section where the lens cluster attached.


When refitting these two components together, the tricky part is adjusting the shutter actuation arm so that the tripping lever on the blind side correctly engages in the lens barrel cut-away designed to accommodate it. I have placed figures 31 and 32 side-by-side to better illustrate their relationship. Don't forget, when the two parts are mated, one of these images will be left-to-right reversed.


Figure 29 - separating the lens barrel from the lens mounting plate by unscrewing the retaining cylinder and then the lens cluster within.


Figure 30 - the separated lens mounting plate, with the red washer still in place. This component contains the focus helicoid.

fig32 (1).jpg

Figure 31 - the lens side of the lens mounting plate.

Figure 32 - the back side of the lens


Figure 33 - the rear lens cluster.

On my camera, the focus adjustment was solidly locked. Presumably an attempt to force the ring to move (by a previous owner), had almost detached the lens focus adjustment handle.

The lens mounting plate (figure 31), was soaked in methylated spirits, DW40, and followed by a detergent bath. After several hours the helicoid freed-up, but sadly the focus ring , which has been locked solid, was found to have detached from the helicoid. The only evidence of a physical connection between the two is the tiniest grub screw (maybe 0.5mm wide), set in the focusing ring. I guess this had been snapped in the past.

I concluded that the fault was unrepairable, although it would be feasible to swap the entire assembly to effect a repair. Sometimes this is just the way it goes. I may yet undertake a post-mortem on this component?


Circuit diagram

Here's a simple illustration of the wiring; excluding that within the lens barrel (figure 34).

Light seal replacement

The procedure is described in Jon Goodman's general light seal replacement instructions. These were written for SLRs, so I have edited-out the irrelevant sections.

Tools & supplies in the UK

I heartily recommend Polar Bear Camera for their promotion of products "Made in Britain", however, I would not personally shop there as the company does not comply with the UK Distance Selling Regulations by failing to disclose their bricks & mortar address. Jack the Hat Photographic have a slightly more extensive range of products, but only sell via eBay. Milly's Cameras are good for replacement leather.

Figure 34 - wiring diagram