I wandered upon this sight as I searched for advice on older lower powered stereo scopes. Seems I would best be served by an AO Cycloptic, but until then I need to address what I perceive to be an issue w/Swift sm80. Vintage mid seventies modest student scope seemed to have held up well enough over the years, However, adjusting the IPD whilst not mounted it appears the right side is canted a mite to the right. It isn't bent and no physical damage can be ascertained.
The movement is smooth enough though when I start closing in to the minimum IPD I notice the right side a tad CW in relation to the left. Or for arguments sake the left is a bit CCW when compared to the right. With the 1.5X lens removed and at 10X I see a clear pic w/o hint of collimation issues. However, extended viewing produces a headache from eyestrain.
I've no no clue of the mechanics that allow the left & right barrels move in unison, so I must ask those knowledgeable. Is it possible for someone to disassemble the unit for cleaning/lubrication and upon assembly inadvertently have the, for lack of appropriate word, timing off where the right side is roughly 3mm CW from optimum position?
Perhaps I'm merely believing what sounds to me as plausible. The IPD movement has no slack. Regardless of IPD position, if collimated, the view is true. Yet, if one side is out of sync, even by a small amount, it forces the eyes to split the difference looking at a slight angle instead of straight down the tubes. They're on a 45* which should also translate to the right side dipping down an extra 3mm making a clean shot all but impossible.
Anyhoo, the thought crossed me mind. Am I mad or is this possible? As far as I know, and that's very little, they could've all been produced that way. Thanks in advance
Swift SM 80 stereo/IPD out of sync
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Scarodactyl
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Re: Swift SM 80 stereo/IPD out of sync
I am really not sure what your acronyms mean there.
It's certainly possible for these scopes to wear out and lose collimation if they are used a lot. I haven't opened one of these old Swifts (probably made in Japan, a Kyowa or Carton maybe), but in Bausch and Lomb stereozooms there is a yoke made of fairly soft metal that keeps the IPD alignment and it can be easily bent or broken if mishandled.
It's certainly possible for these scopes to wear out and lose collimation if they are used a lot. I haven't opened one of these old Swifts (probably made in Japan, a Kyowa or Carton maybe), but in Bausch and Lomb stereozooms there is a yoke made of fairly soft metal that keeps the IPD alignment and it can be easily bent or broken if mishandled.
Re: Swift SM 80 stereo/IPD out of sync
Thanks for the prompt reply.
It is MIJ and from perusing the bay I've managed to determine that the auld Swifts were dated, in the last century at least for a while, by the first two digits of SN. This not so little or light jewel celebrated the bicentennial of the states being a 76 model.
Greenough design, reversible body, 1 & 2X slip lock turret for 10/20X equipped w/screw on 1.5X auxiliary lens boosting mag to 15/25X. The 5 stepped Cyclonic would be more convenient, yet I am impressed with the image from the 45 yr old low power scope.
This yoke that you reference in the B&L is solid w/o adjustment correct? I realize my Swift may or may not be of similar design.
Please bear w/me as I'm having some difficulty wrapping the noggin around what may not be an issue at all.
Let's say instead of a yoke there were two straight cut circular gears each mounted on one of the tubes. In attempt to explain my point these gears would mesh together. [doesn't matter that it really cannot operate this way] If in assembly the right tube gear was one tooth off CW the relationship of the two tubes would be out of phase.
When you adjust the IPD the EPs, in the tubes, do not slide in & out on a horizontal plane. They move on a slight arc as each person strives for their IPD. One could claim that even w/"1 tooth off" proposal that a IPD could still be obtained. If the scope had an IPD scale in MM, as bins, then a "1 tooth off CW" would result in a lower IPD reading because the move out of phase CW would increase the IPD regardless of reading on the scale.
But, even though, regardless of phase, say a 63MM IPD could be obtained the arc of movement for the right tube is out of phase and position in relation to the left tube. Is it perceivable that under those conditions one might at the least have to tilt their head to accommodate two differing planes of view?
I realize it appears as if I'm searching for an problem to fit my assumption. When I unboxed the scope I adjusted the height to check for slack, tension & ease of movement. Likewise I moved the tubes inside to out and back for slack, tension & ease of movement.
That is when I noticed the right prism housing/tube was not synchronized w/left. The right side is "twisted" CW.
The prism housings are flat on the inside rounded on the outside. Left side C shape right side reverse C shape. If I were to place say a 6" metal rule on the inside left prism housing and determine a point parallel w/head then the same point on the right side would be further CW by about 3mm.
The IPD relies on the arc for adjustment, but the IPD chosen should be on a level horizontal plane. Mine isn't and I thought perhaps that was contributing to eye fatigue. On your yoke as the IPD moves in an arc it is still maintaining the relationship betwixt the two tubes for a stereo view.
If you required a 63mm IPD and you had no yoke theoretically you would have to manually adjust each side independently.
What if anything would happen w/stereo view if you moved the left tube 30mm and the right side 33mm and this movement is still on the arc of the yoke?
So, w/o tearing the head open I'm trying to determine how that could happen.
It is MIJ and from perusing the bay I've managed to determine that the auld Swifts were dated, in the last century at least for a while, by the first two digits of SN. This not so little or light jewel celebrated the bicentennial of the states being a 76 model.
Greenough design, reversible body, 1 & 2X slip lock turret for 10/20X equipped w/screw on 1.5X auxiliary lens boosting mag to 15/25X. The 5 stepped Cyclonic would be more convenient, yet I am impressed with the image from the 45 yr old low power scope.
This yoke that you reference in the B&L is solid w/o adjustment correct? I realize my Swift may or may not be of similar design.
Please bear w/me as I'm having some difficulty wrapping the noggin around what may not be an issue at all.
Let's say instead of a yoke there were two straight cut circular gears each mounted on one of the tubes. In attempt to explain my point these gears would mesh together. [doesn't matter that it really cannot operate this way] If in assembly the right tube gear was one tooth off CW the relationship of the two tubes would be out of phase.
When you adjust the IPD the EPs, in the tubes, do not slide in & out on a horizontal plane. They move on a slight arc as each person strives for their IPD. One could claim that even w/"1 tooth off" proposal that a IPD could still be obtained. If the scope had an IPD scale in MM, as bins, then a "1 tooth off CW" would result in a lower IPD reading because the move out of phase CW would increase the IPD regardless of reading on the scale.
But, even though, regardless of phase, say a 63MM IPD could be obtained the arc of movement for the right tube is out of phase and position in relation to the left tube. Is it perceivable that under those conditions one might at the least have to tilt their head to accommodate two differing planes of view?
I realize it appears as if I'm searching for an problem to fit my assumption. When I unboxed the scope I adjusted the height to check for slack, tension & ease of movement. Likewise I moved the tubes inside to out and back for slack, tension & ease of movement.
That is when I noticed the right prism housing/tube was not synchronized w/left. The right side is "twisted" CW.
The prism housings are flat on the inside rounded on the outside. Left side C shape right side reverse C shape. If I were to place say a 6" metal rule on the inside left prism housing and determine a point parallel w/head then the same point on the right side would be further CW by about 3mm.
The IPD relies on the arc for adjustment, but the IPD chosen should be on a level horizontal plane. Mine isn't and I thought perhaps that was contributing to eye fatigue. On your yoke as the IPD moves in an arc it is still maintaining the relationship betwixt the two tubes for a stereo view.
If you required a 63mm IPD and you had no yoke theoretically you would have to manually adjust each side independently.
What if anything would happen w/stereo view if you moved the left tube 30mm and the right side 33mm and this movement is still on the arc of the yoke?
So, w/o tearing the head open I'm trying to determine how that could happen.
Last edited by nixnix on Mon Jul 12, 2021 12:22 pm, edited 1 time in total.
Re: Swift SM 80 stereo/IPD out of sync
"yet I am impressed with the image from the 45 yr old low power scope."
At 10X or very quick view 20X. Bumping to 20X doesn't show dbl image or feel as if eyeballs are being sucked out of sockets, but within a few seconds I start feeling the strain in me brain. Though I can view easy enough at 10X for a while In short time at 20X I have to stop.
I'm suggesting collimation issues due to the tubes being out of sync. Whether the prisms are a contributing factor at this point I cannot say.
ETA: sorry about just realizing how to edit. Could've saved posting to meself.
At 10X or very quick view 20X. Bumping to 20X doesn't show dbl image or feel as if eyeballs are being sucked out of sockets, but within a few seconds I start feeling the strain in me brain. Though I can view easy enough at 10X for a while In short time at 20X I have to stop.
I'm suggesting collimation issues due to the tubes being out of sync. Whether the prisms are a contributing factor at this point I cannot say.
ETA: sorry about just realizing how to edit. Could've saved posting to meself.
Re: Swift SM 80 stereo/IPD out of sync
This will probably not directly solve your problem … but it’s worth reading:
https://archive.org/details/APracticalG ... n/mode/2up
… also downloadable as PDF
MichaelG.
https://archive.org/details/APracticalG ... n/mode/2up
… also downloadable as PDF
MichaelG.
Too many 'projects'
Re: Swift SM 80 stereo/IPD out of sync
Thanks for the link I'll check it out.
I hope to restore this scope to acceptable condition so I might gift it to a brother. Or I'm a fool for punishment and cannot learn from mistakes as I purchased another.
Perhaps betwixt the twain one in working shall emerge.
Things are slow on the AO Cycloptic search. I see various branded AO scopes that at times do not go into much detail on magnification. It's hard to get excited about a scope that's 7/15/25X.
Why do I see so many heads for sale w/o a base/stand? Are they replacing units & keeping the stands?
I hope to restore this scope to acceptable condition so I might gift it to a brother. Or I'm a fool for punishment and cannot learn from mistakes as I purchased another.
Perhaps betwixt the twain one in working shall emerge.
Things are slow on the AO Cycloptic search. I see various branded AO scopes that at times do not go into much detail on magnification. It's hard to get excited about a scope that's 7/15/25X.
Why do I see so many heads for sale w/o a base/stand? Are they replacing units & keeping the stands?
Re: Swift SM 80 stereo/IPD out of sync
Sometimes it’s ‘Asset Stripping’
Grab the high-value items that don’t take-up too much room, and sell them.
Sad, but true.
MichaelG.
Too many 'projects'
Re: Swift SM 80 stereo/IPD out of sync
So, five finger salvage and/or a trip to bases are us to save postage? Are there universal bases that would fit the majority of more recent heads?
What I'm seeing of these 70's Swift SM80 for example are shipping prices in low to mid 20 spot for the whole kit and caboodle. Although for sake of lower starting price I see inflated shipping upwards of half a C note.
ETA: my stand is around 61mm circle. Are the odds nil and none that a differing newer low power scope would drop in?
This looks appealing: Nikon SMZ 1B 0.5 objective - 181mm working distance - 10X EP 4-17.5X real field 52.5-12mm
Though what I see currently available uses 1X objective though I suppose for a price 0.5 could be had.
Still a bit pricey for me. Considering the head seems to be from the last century, due service in 12/2000, no EPs or stand and thirty-two simoleons shipping to boot.. On wee budget little wonder I'm looking at vintage junk.
What I'm seeing of these 70's Swift SM80 for example are shipping prices in low to mid 20 spot for the whole kit and caboodle. Although for sake of lower starting price I see inflated shipping upwards of half a C note.
ETA: my stand is around 61mm circle. Are the odds nil and none that a differing newer low power scope would drop in?
This looks appealing: Nikon SMZ 1B 0.5 objective - 181mm working distance - 10X EP 4-17.5X real field 52.5-12mm
Though what I see currently available uses 1X objective though I suppose for a price 0.5 could be had.
Still a bit pricey for me. Considering the head seems to be from the last century, due service in 12/2000, no EPs or stand and thirty-two simoleons shipping to boot.. On wee budget little wonder I'm looking at vintage junk.