2020 is wonderful!

Started 1 month ago | Discussions thread
Tomasg71 Regular Member • Posts: 299
Re: 2020 is wonderful!

fferreres wrote:

Lightshow wrote:

fferreres wrote:

OFF TOPIC: BTW: I just lubed a 2.8 85mm Rollei. I will never feel bad for saying how annoying to serve they are...[blah blah blah].

The secret to a headache free servicing of a lens is to use witness marks, these aid in providing you with away of avoiding any guesswork during reassembley, for example, as I'm about to separate the helicoid I look for features that align or that can be used to align the start point, the focus distance mark as an example, I'll sneak up on the point the helicoid separates, then right away I rejoin the helicoid (5mm/0.25 inch of overlap) find my alignment points or make one in a hidden area that won't be seen when the lens is fully reassembled, taking pictures or shooting a video during disassembly can also help when it comes to putting it back together right the first time.

I often add a witness mark before taking the helicoid apart with the lens at infinity so I know when I do put it together that I got it right.

Yes. I do them with every lens where I will service the helicoids. But quick question, did you service or lubricated the helicoids of any Zeiss QBM lens? Even with the marks, 20 things can go wrong anyway. I can't explain it more than say that in many steps, 7 things must be aligned to get to a correct next step. Because if this, in dissasembly, one needs to be extremely careful, as not noticing the 7 things BEFORE marking all points, leads to having changes some (even if 3mm) and things will not work well while re-assembling.

Any Rollei QBM work done from the front is safe. When you work from the back (ie. when lubing), I find myself invariable in "lens service" purgatory.

The last one I serviced is an 85/2.8, the second copy...only lubed the helicods. It took me 3 hours. This past Sun I serviced 2 Topcor 58/1.8. I cleaned all 12 surfaces, to pristine levels. It took me 1 hour. The 3 hours for the QBM lens was GOOD....the last one I did (a 25mm) took me 3 days.

I ll add one tip: try to think how they assembled the lens in the factory, take the helicoids for example, they usually come without any marks as a reference (the kind of we make whwn dissasembling the lens), and yet a worker at the factory had to do it tens of times a day (if not hundred or more). Same for the final assembly, if you have to allign 7 points to do it and it takes a lot of time than probably there is a faster way of doing it. After all a lens can be put back in various ways, take the "keys" (or key), for example, that translates the rotation of the helicoids into longitudinal movement, they can be fixed and you allign the helicoids accordingly, or you can first put the helicoids in place and then insert the keys and tighten them in place.

I hope that my english is good enough for this to make any sense

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