In a word, yes. TLS will always service the optical unit as part of the rehousing process, and it is included within the price given. For a more in-depth discussion on this, read on.

At TLS, our number one guiding principle is ‘obsessed with quality’. This means that every step of the process, we’re always concentrating on the quality of the service and the product that we’re providing. Put simply, if one is going to go to the effort of a complete mechanical redesign of a lens, why would the optical unit not also get the attention to detail to match?

Why do we service the optical unit?

There are a few reasons why we service the optical unit as standard. The main reason is to make sure when the lens is received back by the customer, it is to the best standard. We take pride in our work and the technicians take great care in what they do. It would be wrong to send out a product with brand new mechanical components, looking like a new lens until you realise the optical unit has contamination within it.

There are also benefits to servicing the lens during the rehousing process. It allows the technicians to raise any concerns and deal with any imperfections. When servicing the optical unit, we are able to repair separation of doublets (please read our article here for more information on this process), re-edge black elements (more information on this process can be found here) and reduce the aging effect of yellowing elements (more details on this here). It also gives us the opportunity to remove years of contamination as well as any oil migration that has occurred.

What is involved when servicing the optical unit?

As part of the optical service, we also remove the iris blades and clean the whole assembly. The iris is reassembled and installed into the new housing (provided a new circular iris isn’t being incorporated in the rehousing). This is often overlooked, but an important task. When iris blades become contaminated with oil migration, it shows as a shiny surface on the blades. Initially, this isn’t too much of an issue. However, over time the blades start to stick and bind up due to the oil in between them. This can have catastrophic consequences. The iris blades are thin sheets of steel with pins intricately riveted to them. Any excess force will cause the blades to buckle or simply rip the pins out. Another adverse effect of irregular maintenance of the iris blades is that the oil, along with friction from use, will remove the matt black coating on the blades. This leaves the blades with a shiny finish which is irreversible.

Cleaning each optical component thoroughly gives the technician the opportunity to inspect each element too. They are then able to mark down any imperfections as well as checking for any signs of fungus or other ingress that may not be visible from the exterior of the fully assembled lens. It is always better for preventative maintenance in this regard, rather than reacting to it once it's too late.

During the optical service, the technician will also use their extensive knowledge to determine if anything is in the lens that shouldn’t be. As most of these lenses have been around for decades, generally this is not the first time they have been serviced or taken apart. You’d be surprised at what you might find inside the optical unit that shouldn’t be there! However, this is usually some form of shim in a place where it shouldn’t be. This tells us that there has been an issue with optical alignment in the past and the previous technician might not have enough experience to diagnose the issue so resorted to a trial-and-error method. It is best to restore the optical unit back to factory standard, so we have a sound starting point when aligning the lens once rehoused.

One final benefit of servicing the optical unit it that sometimes the lenses we receive for rehousing have been previously modified. Occasionally they’ve already been fully rehoused. This can mean that the original optical unit has been modified in some way. Therefore, we’re able to inspect and make corrections/manufacture bespoke components to rehouse the lens in our metalwork. During the servicing stage, these modifications can easily be seen and rectified. If this is the case, we would always feedback to the customer to let them know the situation and if any additional costs are involved.

It is always the aim of our technicians to provide the best quality service when rehousing any lens. Therefore, the service of the optical unit will always be a standard practice when it comes to TLS. If you have any further questions about this process, please get in touch with us at sales@truelens.co.uk or calling our office on +44 (0)1455 848411.