Front lens cap for Mitutoyo objectives?
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Front lens cap for Mitutoyo objectives?
Just as the tittle says, is there a front lens cap available for Mitutoyo objectives? I quick Google search didn't bring up anything, but maybe someone came up with a 3D print?
Focus stacking has been on the back burner for the last couple of years, but most of the time I have an objective attached to my rig. It's under a dust cover and well protected, but I'd feel better, if I could put a cap over the front lens element for when I move things around.
Focus stacking has been on the back burner for the last couple of years, but most of the time I have an objective attached to my rig. It's under a dust cover and well protected, but I'd feel better, if I could put a cap over the front lens element for when I move things around.
Re: Front lens cap for Mitutoyo objectives?
The reason why there's no front cap:
The elements of the Mitty objectives are mostly friction fit, especially the ones in the front.
So if you accidentally push on them or their black plastic 'collar', it's possible to get them misaligned or damaged - just like when you drop them.
The elements of the Mitty objectives are mostly friction fit, especially the ones in the front.
So if you accidentally push on them or their black plastic 'collar', it's possible to get them misaligned or damaged - just like when you drop them.
Re: Front lens cap for Mitutoyo objectives?
Ah, makes sense.
Although - could this be circumvented by having a rigid cap that pushes against the knurled part of the objective (which then prevents it from moving further inward) and have the front of the cap being offset from the front element of the lens by a few millimeters?
Although - could this be circumvented by having a rigid cap that pushes against the knurled part of the objective (which then prevents it from moving further inward) and have the front of the cap being offset from the front element of the lens by a few millimeters?
Re: Front lens cap for Mitutoyo objectives?
Sure but it's pretty risky, every time you put the cap back on you risk bumping the front element.jnh wrote: ↑Fri Jan 17, 2025 7:02 pmAh, makes sense.
Although - could this be circumvented by having a rigid cap that pushes against the knurled part of the objective (which then prevents it from moving further inward) and have the front of the cap being offset from the front element of the lens by a few millimeters?
I made a hood for the 5x which only touches the knurled bits but it's still nerve-wrecking whenever I put it on... so...
Re: Front lens cap for Mitutoyo objectives?
That is hard to believe, really. What do they do when during adjustment it was pushed too deep to the inside? Normally an engineer makes an adjustable system in that way, that you can adjust it forth and back and lock once you are happy with the adjustment. Also for a microscope lens, which is prone to be slightly bumped, a friction fit of the front element (if not spring loaded from the backside) would be a very poor decision.
Re: Front lens cap for Mitutoyo objectives?
I would assume you disassemble and reassemble the lens? Most likely they have special tools that allow for a fast and precise positioning (like metal rods with precise lengths so the lenses are pushed into the correct position without much fuss.lothman wrote: ↑Sat Jan 18, 2025 3:46 amThat is hard to believe, really. What do they do when during adjustment it was pushed too deep to the inside? Normally an engineer makes an adjustable system in that way, that you can adjust it forth and back and lock once you are happy with the adjustment. Also for a microscope lens, which is prone to be slightly bumped, a friction fit of the front element (if not spring loaded from the backside) would be a very poor decision.
Re: Front lens cap for Mitutoyo objectives?
this would be a pure assembly and not an adjustment (in order to compensate tolerances). I still cannot believe the friction fit front element story.
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Re: Front lens cap for Mitutoyo objectives?
Given that ring lights are designed specifically to fit the front of these objectives I suspect this isn't likely to be a problem.
Re: Front lens cap for Mitutoyo objectives?
https://youtu.be/J16EeaibdNE?si=JjSc5_rciM0KV7F5&t=882
Looks like the individual elements aren't individually secured, they're just sandwiched so I can imagine a bump/drop/fall or pressing against the elements can create some serious problems.
It seems like the front element is sort of screwed in with a few rings but not really "directly" like with regular lenses and retaining rings. The inner elements are the really tricky part.
Re: Front lens cap for Mitutoyo objectives?
Yes but the front element is rigidly housed in a black metal ring which has a shoulder that is clamped axially against the base body with a union nut. So a dust cap never will never push it out of position as you mentioned.CrispyBee wrote: ↑Sat Jan 18, 2025 4:35 pmhttps://youtu.be/J16EeaibdNE?si=JjSc5_rciM0KV7F5&t=882
Looks like the individual elements aren't individually secured, they're just sandwiched so I can imagine a bump/drop/fall or pressing against the elements can create some serious problems.
It seems like the front element is sort of screwed in with a few rings but not really "directly" like with regular lenses and retaining rings. The inner elements are the really tricky part.
Screenshot around minute 15: On the other hand some of the Mitys seems to get out of alignment when dropped or seriously bumped. But I think this will not be the case when attaching a front lens cap. Such an attached cap might even reduce the risk of misalignment because it will dampen a drop at the front end of such a heavy lens when being dropped.
Re: Front lens cap for Mitutoyo objectives?
Granted, I haven't taken mine apart - but it looks like that front element itself isn't secured with a counter-ring but also just press-fit/sandwiched into its black metal ring. The ring does have a shoulder but the element itself is at best glued.
In any case I don't like the idea of pressing against of fiddling with those optics, with simpler and cheaper objectives/lenses I don't mind as much but the Mittys are notoriously delicate

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Re: Front lens cap for Mitutoyo objectives?
Blissfully unaware of possible weaknesses in the objective's construction I made it a lens cap some years ago, that has sit upon it since. Mind it is just a cap, not an armour nor a canister, and it serves to keep the dust away and protect the objective from hits by swinging wires and other pieces of equipment, including myself. The bottom (shown on top in the image below) is stopped by the M42 adapter on which the objective is mounted permanently. The sheath on the inside was cut from styrofoam.
It was made of the package of Swiss powder cheese (stinking variety). Originally this cheese came in lovely cardboard tapering cylinders, but it is more modern of course to use plastic.
It was made of the package of Swiss powder cheese (stinking variety). Originally this cheese came in lovely cardboard tapering cylinders, but it is more modern of course to use plastic.
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