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Old September 28th, 2008, 03:09 PM   #1
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Ultimate build. Not.

Well,

Getting some really nice images with the Ultimate DOF I got (serial number 19). But only if I have the adapter mounted on legs and the shot is still. As soon as I pan, I get a whipping motion at the end of the shot and the cause is obvious. I cannot get a shot with any kind of movement, not even a simple pan, let alone any handheld or jib work.

Anyone else having this issue?

No matter how I have tried to secure and fit the Nikon mount and the backfocus ring, everything wobbles. I was expecting a near 'interference fit' but my sample doesn't offer anything like a secure mount. The back focus ring crashes forward, and none of my F mounts will fit without wobbling down or from side to side by as much as 1.5mm.

None of my 5, brand new Zeiss ZF lenses will sit properly on the end like they do on my Nikon D3, no matter how I 'finesse' the fit. On the Nikon, you'd be hard pressed to tell if the lens was even separate from the body when the lenses are mounted.

It nearly cost me my shoot today (for the main local Newspaper). It certainly cost me embarrassment that a US$5,000 adapter appeared to be so sloppily constructed.

I now have 2 weeks in which to be able to supply the 'film look' for my next job with them or I'm in danger of losing the work - and I could buy 6 Ultimates for the money I may lose.

Not. Funny. At. All.

Justin.
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Old September 28th, 2008, 03:46 PM   #2
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Justin.


I am not an ultimate user. So please ignore my comments unless they just happen to point you to a solution.

Have you contacted the vendors, Adapterplace or Letus direct?

A 1.5mm freeplay seems a bit excessive which makes me wonder if there is a spare sleeve, spacer or some cylindrical shaped part still in your kit somewhere.

If not here is another theory. There seems to be three screws on radial centres around the mount itself. Do you screw these in once the backfocus has been established.

My imagining, and it is just that and nothing more, is the backfocus ring may be an adjustable axial spacer system and not a sector helicoid movement like an ENG lens. Final security of the mount may still be the three radius screws around the front tube once correct backfocus has been found.

ADDED FOOTNOTE:

If your Nikons are a little loose in the actual Nikon mount itself, it may be like the early P+S Technik Nikon mount which sometimes had a similar habit which is why they replaced it with a PL-Style fixing.

If you study the lugs inside the mount closely, you may discover very fine slots cut into the metal and the slots to have been very slightly opened, which allow the back of the lugs to exert a spring pressure against the lugs on the lens. You can very carefully prise the split in the lugs just a whisker wider with a jewellers screwdriver to take up that clearance. A mere pinpoint of grease on the rubbing surface (rear surface) of each lug will help if you overdo it and get them a bit tight.

Last edited by Bob Hart; September 28th, 2008 at 04:14 PM. Reason: errors
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Old September 28th, 2008, 04:03 PM   #3
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Justin

Sounds almost certainly like you have steadyshot on. Take it off for starters!

The rest sounds like you have loose screws. Have you tightened everything?
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Old September 28th, 2008, 07:11 PM   #4
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...

Bob,

I have contacted the vendors and await a reply. I have also posted on their site. Please note that I have spent several weeks trying to master the configuration of this system and am still baffled.

I've checked my Letus box of tricks several times and can find no shim or sleeve. The only other item I have is, optimistically, a PL mount. I've tightened things to the point where I believe any more would be inadvisable and to within a whisker of that threshold. No joy. I'll examine the lugs and slots you mention in the morning when my mood has improved. Don't want to do any damage.

Have to wonder why I would be sent an older, superseded design of Nikon mount with their latest adapter though.

Phil,

That sounds like a plan. I'll toggle the steadyshot setting and check again. I'll gladly be proved a twit, offer up apologies and move on. However, regarding the mechanical slop, I simply cannot tighten anything further on my adapter without doing damage and am, unsurprisingly, reluctant to do so.

But Phil, I am not alone my assessment of these particular physical issues. I know I am not the first to have experienced this issue nor the first to have requested a replacement. Nor would I be the first, should I be offered one, to have been handed a replacement. The whole assembly forward of and including the backfocus control simply droops forward and rattles minutely, shifting the frame during movement. You can imagine how annoying that is.

Jus.
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Old September 28th, 2008, 09:51 PM   #5
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Quote:
Originally Posted by Justin Benn View Post
Bob,

But Phil, I am not alone my assessment of these particular physical issues. I know I am not the first to have experienced this issue nor the first to have requested a replacement. Nor would I be the first, should I be offered one, to have been handed a replacement. The whole assembly forward of and including the backfocus control simply droops forward and rattles minutely, shifting the frame during movement. You can imagine how annoying that is.

Jus.
I've not had a back focus issue but I have had a Nikon mount fail and go all loose this week. So where is the looseness coming from, can you pinpoint exactly. I have had the whole thing loose but the four screws just needed tightening.

My biggest problems have been dust getting into the prism somehow and giving me splotches.
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Old September 28th, 2008, 11:44 PM   #6
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Justin.


I have sowed a small seed of disinformation which I need to correct. This is a product of me doing a lot of guessing (I guess) and trying to extrapolate my knowing of the Extreme front-end to the Ultimate.

The Nikon mount used on the Letus Ultimate is their latest.

It is a very similar arrangement to that P+S Technik used for quite a few years and other third party Nikon mounts still use. All including the genuine Nikon used some sort of spring pressure to hold the lens firm against the flange face.

However genuine Nikon mounts have a thin circular stainless spring with three distinct bows pressed in it to achieve this pressure. Why the other third party mounts did not use this system I do not know. I assume it might be for registered design reasons.

P+S stepped up and changed their design last year and now use an entirely different principle, a PL style threaded clamping ring to pull the lens into firm flange contact. It is a complex beast with many finely machined parts and more expensive than most of the lenses which it holds.

On the jpg images I can find published on the sites, I observe what appears to be grub screws around the blue ring in radial centres.

They may be something else like pins or rivets. I can't tell from here.

They may be countersunk screws simply holding the blue ring onto an inner split collar or some other fitting.

However, if they are grubscrews, then there may be something to be done.


Some questions :-

Can you tell me how far deep down in the holes those grubscrews have gone. When you wobble the whole assembly, do any of those screws appear to also rock in their holes?

Between the rear of the blue ring and the front face of the disk enclosure body, is there a clearance. If there is, how wide is the gap?



Phil.


I am assuming from illustrations that there are three allen screws around the Nikon mount shoulder like the Extreme and that these firm up the mount after the backfocus has been set. The four screws you refer to I assume are in the blue collar.

I am furthur assuming two arrangements for the blue collar :-

That the collar actuates an internal thread and sleeve with a pin or threaded stud through a slot like a steeply pitched ENG lens backfocus/macro adjustment helicoid

or

the collar itself is fixed to the front tube, fits onto the front of the Ultimate over a threaded shoulder, is locked in place after adjustment by those screws and then the orientation of the Nikon lens and its witness marks is separately adjusted to the personal preference of the operator and then firmed down.

My imagining is that the thread would be a 1.25mm pitch or something fairly coarse and that without the grub screws in the blue ring being tightened, the whole assembly might move or rock if it is on a fairly narrow shoulder, say 7mm or so.

If there are four screws, then if for some reason, two do not bed down, the assembly might still rock on those two screw centres. If the whole assembly has had to come forward significantly to set backfocus, then some of those screws might be impinging on a front face corner of a shoulder instead of a cylindrical face or threaded section.

I am really only wildly guessing here but my sense is that if there is a structural problem, the blue ring might be where it is at.

Does the blue ring screw right off if the screws are loosened?


If my wild theory is correct, then there may exist, two actual steps or arrangements for backfocus.


These would be :-

initial adjustment by the axial prop screws in the rear face of the Nikon mount itself to set an approximate backfocus, then subsequent fine adjustments by means of the blue collar.

Am I in the ballpark with my wild guesses?

If so, then my solution for grubscrews misengaging on a front shoulder corner would be to bring the Nikon mount itself forward in the front tube by means of the rear axial prop screws and then reajdust the blue ring rearwards which would bring all the blue ring grubscrews back into engagement with a firm cylindrical surface.


Justin and other owners.

Please accept my comments in the form that they are, speculative guesses and not proven truths. If they send you down a dead-end, then please accept my apologies in advance.

Last edited by Bob Hart; September 28th, 2008 at 11:47 PM. Reason: errors
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Old September 29th, 2008, 04:08 PM   #7
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Following up

Quote:
Originally Posted by Phil Bloom View Post
I've not had a back focus issue but I have had a Nikon mount fail and go all loose this week. So where is the looseness coming from, can you pinpoint exactly. I have had the whole thing loose but the four screws just needed tightening.

My biggest problems have been dust getting into the prism somehow and giving me splotches.
I got a reply from Aaron about the Nikon mount and a suggested link on the Letus pages. This page illustrates what could generously be described as a tweak to help secure varying F mount lenses. I say generously, because the design seems destined to lessen the efficacy of the tweak every time one mounts a lens. Doing so will mechanically flex the 'leaves' of the F mount again and again til they supply ineffective pressure on the mounted lens to hold it securely. Is this what you experienced? Not sure I can post that link here but if you type in "My Nikon lenses are loose on the Nikon mount. What should I do?" on the Letus Direct helpdesk pages, you should be able to dig it out.

The back focus issues is less troublesome if i repeatedly tighten the grubscrews on the blue dial, but it still rocks.

However, the inner, black support ring that holds the Nikon mount to the backfocus assembly remains wobbly. Right now, this is not a precision system, as nice as the images are.

Jus.
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Old September 29th, 2008, 04:34 PM   #8
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Bob...

Quote:
Originally Posted by Bob Hart View Post
Justin.


I have sowed a small seed of disinformation which I need to correct. This is a product of me doing a lot of guessing (I guess) and trying to extrapolate my knowing of the Extreme front-end to the Ultimate.

The Nikon mount used on the Letus Ultimate is their latest.
Ho hum.

Quote:
Originally Posted by Bob Hart View Post
It is a very similar arrangement to that P+S Technik used for quite a few years and other third party Nikon mounts still use. All including the genuine Nikon used some sort of spring pressure to hold the lens firm against the flange face.

However genuine Nikon mounts have a thin circular stainless spring with three distinct bows pressed in it to achieve this pressure. Why the other third party mounts did not use this system I do not know. I assume it might be for registered design reasons.
And probably because it works, and they can. Can it be that expensive to license? I've paid US$5,000 already!


Quote:
Originally Posted by Bob Hart View Post
P+S stepped up and changed their design last year and now use an entirely different principle, a PL style threaded clamping ring to pull the lens into firm flange contact. It is a complex beast with many finely machined parts and more expensive than most of the lenses which it holds.
I am keeping an eye out for their EX3 pro/mini35 model which they are rumoured to be working on.


Quote:
Originally Posted by Bob Hart View Post
On the jpg images I can find published on the sites, I observe what appears to be grub screws around the blue ring in radial centres.

They may be something else like pins or rivets. I can't tell from here.
I have it in my hand and I can't tell either.


Quote:
Originally Posted by Bob Hart View Post
Some questions :-

Can you tell me how far deep down in the holes those grubscrews have gone. When you wobble the whole assembly, do any of those screws appear to also rock in their holes?
Grubscrews are in all the way. They do not rock in their holes.


Quote:
Originally Posted by Bob Hart View Post
Between the rear of the blue ring and the front face of the disk enclosure body, is there a clearance. If there is, how wide is the gap?
About 1.5mm. However - those silver screws are, unique, in the sens that they have some kind of delrin or teflon stub glued to the end, presumably to sacrificially mate to an inner, not ideal surface - like a thread? One of these stubs is shorter than the other.

Bob, my concern about all of this remains - making accurately repeatable changes seems chance at the moment. More feel than measurement. Just wasn't expecting that for these elevated prices. Could have bought a Canon 5D II and a couple of good lenses instead to get the "film look". And while there is a significant difference in size and concomitant production ability, Letus have not justified their high asking price to me just yet.

"I am not in love/but I'm open to persuasion..."


Jus.
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Old September 30th, 2008, 12:41 AM   #9
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Justin.


I managed to get a look at the Extreme version of the backfocus module on the Zacuto website. It is a little different to the Ultimate in that there is a section on back which replaces the entire front tube assembly.

The ring in the Extreme version has four holes around it on 90 degree centres for the "silver" screws which I interpret as being the arms or handles which stick out of the ring and appear to be screwed in to lock. These screws bind down onto the thread inside to lock off once the adjustment is done.

The only Ultimate version I have been able to look at seems to only have two holes for these "silver" screws on 180 degree radial centres which is directly opposite each other.

The smaller four rear screws appear to either be in themselves lock screws or retain two half collars. I can't get inside the photograph to look it so is yet one more guess.

However, there may be a bit of a workaround.

I am assuming your Nikon mount is tightening firm into the front ring with those three allen screws and the wobble is happening within the blue ring and frpont tube junction on the threads and that the blue ring itself it not moving on the front case.

If there are four holes for the "silver" screws (handles) in the blue ring, move one of those "silver" screws (handle) to a new position ninety degrees around from the other handle, not directly opposite.

If there are only two holes for the "silver" screws (handles), try leaving one of the "silver" screws undone and tighten firm on the other.

This should hopefully permit the thread inside the collar to pull into closer engagement with the thread in the tube on the opposite side and eliminate the other screw end as a pivot point. Movement may remain but hopefully should be less.

This problem would likely be completely eliminated with three screws on 120 degree radial centres. Movement due to looseness or face clearance on internal half collars would be another issue.

Last edited by Bob Hart; September 30th, 2008 at 12:47 AM. Reason: error
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Old September 30th, 2008, 04:27 PM   #10
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I got to hand it to you.

Bob,

Thanks for your attention and advice. Got to finish some edits this week so it won't be til the weekend til I get a chance to play again. I'll report back if I get any further with all of this.

It seems my expectations were just too high. Time to be a good workman again...

Jus.
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Old October 1st, 2008, 10:07 AM   #11
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Justin, Bob

Having gone through the same issue with the Extreme updated improved nikon mount, I have found that you need to place a small screwdriver in between the pressure points and expand the mount. looking at the opening at an angle you can see a small space in three palces around the opening to expand. Its touchy, too much and you need vice grips to put a lens on, too loose and well you get the point. They should have used the wavy washer method which not likely a patent issue as many tape machines used the same principal to apply spring like pressure.

I have not seen the nikon ultimate mount.


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Old October 1st, 2008, 11:56 AM   #12
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The spring washer method itself is probably not the issue but a registered design application of that spring washer method probably is.

The equipment required to make it is entirely different to equipment needed to make all the other components. The very thin stainless spring material itself has to be sourced.

It appears to be made with a stamping process. There is a lot of material wastage for each spring made. In relatively small volumes, the pricing would probably be horrendous. Both P+S and Letus likely adjusted the design so that it could be made with their existing resources rather than having to buy in from a third party.

I made my own P+S mount with a genuine Nikon mount and spring washer. This is not to rubbish the original P+S Nikon mount and the current Letus Nikon mount designs. I simply could not get hold of a P+S Nikon mount in time for a job.

Both designs are valid. Both are intended to mount the lens via the familiar method of offer-up and turn anticlockwise until the latch-pin engages.

Both manufacturers use a very fine cutting tool to mill out a thin slot in the metal of the lug then spread it just a little to make up excessive clearance and create a little spring compliance.

The old P+S Nikon mount had an additional transverse cut across one end of the split to leave an end which has been spread slightly free so that tension increased through the entire twist of the lens to the latching point.

Letus chose to leave both ends secure and to spread the centre to a profile more like the genuine Nikon spring.

On both, wear or crush by a particularly tight lens can reduce the height of the rear contact surface. Widening of the split a very tiny amount until clearance is taken up, is a valid method of eliminating movement with both.

The new P+S Nikon mount requires a method of offer-up and securing of the lens unfamiliar to Nikon users.

The front mount ring on the P+S mount must be checked to be in the open position.

The lens must be offered up so that a fixed pin locates into the groove in back of the lens monunt. The lens is no longer turned but the front mount ring is rotated until it pulls down tight.

Justin's problem seems to be not so much the Nikon mount itself, but with the assembly which comprises the backfocus ring, the threaded tube which appears to be supported within it and the method of securing the adjustment.

Until my fingers and eyes are all over one of these things close and personal, I am playing guessmeister from photographs and words. I think there will be a solution for Justin but maybe not within the time frame critical for him.

Last edited by Bob Hart; October 1st, 2008 at 12:11 PM. Reason: error
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Old October 2nd, 2008, 03:57 AM   #13
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the problem is the thread

Hi guys, ive recently openened a ultimate from a friend because he had kind of the same issues. and i found out that the thread used to adjust the backfocus is not tight enough. thats the thread inside the blue ring. i screwed it loose, by loosening the very small screw you can find behind the small holes, and put some very thin tape around it, so its tighter now. i think its the best way to do it like this. if it is hat you guys mean.

thanx, pim
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Old October 2nd, 2008, 08:13 AM   #14
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If excessive clearance on the threads is the problem, then tape as Pim suggests would fix it. Choose plumbers tape, which does not have sticky stuff on it. "White Denso tape" was the original almost industry standard for this stuff. It is like gladwrap, is not sticky and sinks into the threads when stretched around.

It is probably best to wrap it around in a clockwise direction as viewed from the front. Leave an edge hanging over all around the front so it is easier to start the blue ring back onto the thread. Pull tension on the tape as you wrap it around so there are no loose gathers or creases across the threads.

If you can't get plumbers tape, a strip cut from a thin stretchy grey-green shopping bag works nearly as well as plumbers tape. Otherwise budding tape from a garden centre or yellow bag tie may be a workable substitute.

Last edited by Bob Hart; October 2nd, 2008 at 08:17 AM. Reason: errors
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Old October 2nd, 2008, 02:54 PM   #15
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Sometimes it's called Teflon Tape and any hardware store or big box home center will have it. Exactly like Bob said, stretchy and will fit in and fill the grooves cleanly.
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