Where can I buy an autocollimator?

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Grim Tuesday

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I want to buy an autocollimator to calibrate infinity focus on some of my cameras. I would like more precision than is offered by the "line up two cameras" method, mostly because I don't know if any of my cameras are correctly calibrated to begin with. Does anyone know where I can get an autocollimator, have one for sale, or know of someone who has one for sale?
 

Steve906

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Hi,
Main thing will be cost $$$$$$$$$
Where I work we use two in house manufactured collimators and a Chrosziel for setting infinity on cine lenses.
Way more than required to set up a stills camera.
An autocollimator is used to measure angular displacement of a mirrored target. but could with a little modification be used to set infinity on a stills lens. Also $$$$$$ though.
Simply all you need is a long focal length (500mm +) lens with large aperture set at it's focal length from an illuminated target. Simply place your unknown lens in the collimated (parallel ) beam produced with some means of viewing its image and adjust lens mount / focus ring to read infinity.
I do this daily so if you need any more in depth info please ask.
Steve.
 

reddesert

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Edmund Optics will sell you a house-brand autocollimator for US$1600. For you, today, $1599. If you step up to the Nikon autocollimator it's $9595.

One way to autocollimate a camera is to use the lens itself to self-collimate. You need a focus screen, like a piece of glass with Scotch tape on it, a groundglass, or something that can take a mark, placed on the film rails, with an off-center mark on it like a pencil X. You then place the camera lens face down on a flat mirrror - any mirror will do, doesn't have to be first surface. Illuminate the X by shining a flashlight down on it. The reflection, traveling through the lens twice, will form an image at the focus screen. Adjust the lens until this image is in focus. Now the lens is focused at infinity.

There is another way to self-collimate, by omitting the groundglass. You place a transparent target (like a reticle) at the film rails, mirror in front of the lens, and then move your head side-to-side to judge the parallax between the target and the aerial image of the target. When you reduce the parallax to zero, the lens is focused at infinity. This is, however, hard to demonstrate in words only.
 

Steve906

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An autocollimator is not what you need, a collimator produces a parallel image of a target meaning it would be seen at infinity by an imaging system.
Placing two cameras opposing is actually quite a good way to check a stills camera. The collimating camera should be fitted with the longest focal length lens available with a target of gound glass or a negative as flat as possible against the film plane. Illuminate this with the back open and the lens set to infinity (& possibly beyond:smile: ) The lens / camera combination under test can then be placed opposing to judge its setting. At the end of the day if you can go outside and focus on a power line or something fine at a distance of 500m wide open that's all you're going to need.
Steve.
 
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John Koehrer

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Hi,
Main thing will be cost $$$$$$$$$
Where I work we use two in house manufactured collimators and a Chrosziel for setting infinity on cine lenses.
Way more than required to set up a stills camera.
An autocollimator is used to measure angular displacement of a mirrored target. but could with a little modification be used to set infinity on a stills lens. Also $$$$$$ though.
Simply all you need is a long focal length (500mm +) lens with large aperture set at it's focal length from an illuminated target. Simply place your unknown lens in the collimated (parallel ) beam produced with some means of viewing its image and adjust lens mount / focus ring to read infinity.
I do this daily so if you need any more in depth info please ask.
Steve.

Years ago we used one made from a photo copier lens, PVC pipe and kodak focusing target. Worked pretty well and
allowed us to stay dry on those rainy days.
 

Maris

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An autocollimator is just a gadget that generates an visible target at optical infinity. This is an essential tool if you are working in an enclosed space and nothing is very far away. But if you can look out of a window and see something (say) a mile away or further there's your visible target at optical infinity all free of charge. Just focus that far object on a ground glass placed on the film register rails of your camera and your lens is focussed at infinity ... exact.
 
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Grim Tuesday

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Hi,
Main thing will be cost $$$$$$$$$
Where I work we use two in house manufactured collimators and a Chrosziel for setting infinity on cine lenses.
Way more than required to set up a stills camera.
An autocollimator is used to measure angular displacement of a mirrored target. but could with a little modification be used to set infinity on a stills lens. Also $$$$$$ though.
Simply all you need is a long focal length (500mm +) lens with large aperture set at it's focal length from an illuminated target. Simply place your unknown lens in the collimated (parallel ) beam produced with some means of viewing its image and adjust lens mount / focus ring to read infinity.
I do this daily so if you need any more in depth info please ask.
Steve.

Thank you Steve, this is very helpful! I was using the terminology I found here: https://learncamerarepair.com/downloads/pdf/NatCam-Auto-Collimators.pdf Are these really collimators and not autocollimators?

One question on this technique. How essential is the distance between focusing target and lens? I know marked focal lengths are mostly estimates - would I have to determine true focal length myself? If so, what's the best way to do that? Also, what would you suggest as the best way to avoid stray light and internal reflections? A 500mm long black PVC pipe?

One way to autocollimate a camera is to use the lens itself to self-collimate. You need a focus screen, like a piece of glass with Scotch tape on it, a groundglass, or something that can take a mark, placed on the film rails, with an off-center mark on it like a pencil X. You then place the camera lens face down on a flat mirrror - any mirror will do, doesn't have to be first surface. Illuminate the X by shining a flashlight down on it. The reflection, traveling through the lens twice, will form an image at the focus screen. Adjust the lens until this image is in focus. Now the lens is focused at infinity.

There is another way to self-collimate, by omitting the groundglass. You place a transparent target (like a reticle) at the film rails, mirror in front of the lens, and then move your head side-to-side to judge the parallax between the target and the aerial image of the target. When you reduce the parallax to zero, the lens is focused at infinity. This is, however, hard to demonstrate in words only.

Both of these are cool ideas and I just tested the first out with my TLR. I have to admit I have a bit of trouble seeing the return image but it is definitely there and I can see how you would use it and the optical principle behind it makes sense. Do you have any suggestions for making it both easy to illuminate and also not washed out by the illumination? For the second method, I am having some trouble seeing the aerial image. Do you have any tips?
 
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reddesert

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Both of these are cool ideas and I just tested the first out with my TLR. I have to admit I have a bit of trouble seeing the return image but it is definitely there and I can see how you would use it and the optical principle behind it makes sense. Do you have any suggestions for making it both easy to illuminate and also not washed out by the illumination? For the second method, I am having some trouble seeing the aerial image. Do you have any tips?

First let's say that in many ways, if you can put a ground glass on the film rails of your camera, as Maris said you can just focus on a real target at infinity, with a loupe, and know that it's taken care of. Autocollimators are a useful item on an optical bench and have some other uses like measuring alignment/angles that aren't necessary for our purposes. But it's also interesting to see what's going on. The basic idea with both of the self collimation methods is that the target at the film plane should be turned into a parallel bundle of rays exiting the lens, bounced off the mirror, and refocused on the film plane (with a 180 deg reflection). If the lens isn't focused at infinity, the ray bundle won't be parallel and the new image will be displaced forward/back of the correct plane.

For the first method, yes lighting is tricky and maybe the way to do it is to take advantage of the 180 deg reflection: put the X off-center to one side, shine the light on that side, and keep it off the other side, perhaps using a cardboard divider to shade the other side.

For the aerial image method, here is a picture:

IMG_8316.jpg


The test camera is face down on a mirror and I locked the shutter open on B with a locking cable release. I stuck a piece of Post-It note on the film rails as a target. I didn't take care to get it exactly even with the rails because this is just a demo; obviously you need to do that in real use.

The upper yellow triangle is the 180 deg reflected aerial image of the back of the post-it note, here imaged by my phone-camera lens. If the test camera lens is not focused at infinity, then the aerial image will be ahead of or behind the physical post-it note, and you can see the parallax - they move relative to each other as you shift your head side-to-side.

Some caveats are that it's hard to see tiny displacements, so you probably need a magnifier, and a measuring scale like a reticle would make this easier. When I learned to do this with a large optic a long time ago, it was with a longer focal length lens, and my eyes were better so I could focus really close. It's kind of an interesting test to do though, just to understand what is going on, and doesn't require any special equipment.
 
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Grim Tuesday

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Super interesting, thank you! I'll keep playing with those techniques, they are very cool. For some reason in my house right now, I only have my bathroom mirror (which I did your previous suggestion with) but I've put in an order for a small piece of mirror I can play with.

As to why I don't use a "real" infinity target:

  1. I do not have a suitable infinity target visible near my house and I don't want to bring everything outside :smile:
  2. I would like to perform the adjustments on a piece of film in the film gate with the back closed (using the film as the reflector) because I think in a lot of folding cameras especially, the film is not exactly at where I might place a ground glass.
 

Steve906

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Thank you Steve, this is very helpful! I was using the terminology I found here: https://learncamerarepair.com/downloads/pdf/NatCam-Auto-Collimators.pdf Are these really collimators and not autocollimators?

One question on this technique. How essential is the distance between focusing target and lens? I know marked focal lengths are mostly estimates - would I have to determine true focal length myself? If so, what's the best way to do that? Also, what would you suggest as the best way to avoid stray light and internal reflections? A 500mm long black PVC pipe?



Both of these are cool ideas and I just tested the first out with my TLR. I have to admit I have a bit of trouble seeing the return image but it is definitely there and I can see how you would use it and the optical principle behind it makes sense. Do you have any suggestions for making it both easy to illuminate and also not washed out by the illumination? For the second method, I am having some trouble seeing the aerial image. Do you have any tips?
---------------------------
Yes the text you mention does refer too using an autocollimator, which can be used and has some other uses as described in the text. But that is not what is 'required' to set or test the infinity setting of your camera/lens and cost is a factor as mentioned. If you note in the main body of the text when referring to the device they do call it a collimator.
The collimators we use at work have no covering or tube they are just open and obviously work very well. Illumination of the target graticule is with an ordinary frosted domestic led lamp. The focal length of ours are 720mm and 1124mm (I'm not at work at the moment so cant check but that is very close.) Imagine trying to buy an autocollimator of that size in a tube and a clear aperture of some 100mm.
Yes the lens does have to be accurately at its focal length from the target. As a guide I'm working on a project to use one collimator (the 700mm one) to mark all lens distances on new lens barrels. It's ongoing but as a guide 100m is with the collimating lens approx 5mm closer to the target than at infinity. This is partly why a long lens is used this position is less critical the longer the focal length of the collimating lens. I would suggest +-0.5mm would be a good start. Unfortunately if the focal length is unknown that does make matters tricky without other equipment. Focusing the sun with a suitably extreme ND filter of some kind and measuring the position of the focal plane is something I've done in the past with of course all the safety measures in place (Don't look through it - Obviously!) Just clouds can be used on bright day if inside a relatively dark room - basically your inside a camera focusing on something far away!
Hope some of this helps.
Steve.
 

Mamiya_Repair

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I use an autocollimator every day in my camera repair business and I agree that it might be a bit of overkill just to check infinity focus but I can understand your desire to check focus on the film itself because this is, in fact, the best way to check focus. When you check focus with the image on film, you are checking the complete system of lens, camera body and pressure plate. And actually, most lenses go very slightly through infinity to make up for pressure plate/film curvature variance. As an example, the manufacturer might have a typical focus tolerance of (+.003mm) and (-0.000mm).for a 50mm lens on 35mm film. With some autocollimators you can measure the error in back focus and calculate shim thickness needed. And of course, lens image quality can be evaluated to determine optimal aperture. Many other tests can be made on lenses with the autocollimator and also filters can be easily tested for plane parallelism.

So yes, I understand your desire to have an autocollimator in lens/camera testing. I have sold some recently and no longer have any available for sale. I'd recommend the Pearl 6810 vertical autocollimator for camera/lens testing.
 
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Grim Tuesday

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---------------------------
Yes the text you mention does refer too using an autocollimator, which can be used and has some other uses as described in the text. But that is not what is 'required' to set or test the infinity setting of your camera/lens and cost is a factor as mentioned. If you note in the main body of the text when referring to the device they do call it a collimator.
The collimators we use at work have no covering or tube they are just open and obviously work very well. Illumination of the target graticule is with an ordinary frosted domestic led lamp. The focal length of ours are 720mm and 1124mm (I'm not at work at the moment so cant check but that is very close.) Imagine trying to buy an autocollimator of that size in a tube and a clear aperture of some 100mm.
Yes the lens does have to be accurately at its focal length from the target. As a guide I'm working on a project to use one collimator (the 700mm one) to mark all lens distances on new lens barrels. It's ongoing but as a guide 100m is with the collimating lens approx 5mm closer to the target than at infinity. This is partly why a long lens is used this position is less critical the longer the focal length of the collimating lens. I would suggest +-0.5mm would be a good start. Unfortunately if the focal length is unknown that does make matters tricky without other equipment. Focusing the sun with a suitably extreme ND filter of some kind and measuring the position of the focal plane is something I've done in the past with of course all the safety measures in place (Don't look through it - Obviously!) Just clouds can be used on bright day if inside a relatively dark room - basically your inside a camera focusing on something far away!
Hope some of this helps.
Steve.

It definitely helps! It has gotten me to want to make my own for sure. There is only one thing I am stuck on, which is I don't just want an infinity target, I want the reflection of an infinity target off the film plane of my camera (and back through my camera's lens focused at infinity, doubling any infinity error!) The normal collimator would be great for looking at just a lens, but I think want to check on the whole optical system.

Based on these descriptions, it seems reasonably easy to replicate the operation of the Pearl/gokosha collimator, roughly following these instructions and this diagram I just found:

http://www.conradhoffman.com/ac01.htm
http://www.conradhoffman.com/AC.pdf

If I use my Hasselblad 250mm as the objective, and buy a half surface mirror cube and some kind of reticle from surplus shed I will have almost all the parts I need. There are two things missing: The eyepiece and how to calibrate the system. Does anyone have any suggestions?
 
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Grim Tuesday

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Alright, I think I found a method that gives me most of what I want and avoids me having to buy a device that is no longer available for a reasonable price. My previous complaint with most of the methods on the web for setting infinity that uses two cameras is that it limits the maximum possible precision of the method to the calibration of another possibly-miscalibrated old film camera + lens combination with whatever loupe you have available. Also, most methods suggest using a ground glass that does not necessarily represent how film sits as it goes through the camera. I am not the complete originator of this method, and I've seen hints of it mentioned in a few old forum posts and archived geo-cities websites so I'm going to repeat it and add to it a bit here for completeness in case someone else runs across this thread. It requires a DSLR and the longest lens you have with a physical infinity stop.

You may want to prepare some special negatives for this method, but if you have any developed test rolls you don't care about lying around, they should be good as well. These instructions are for 120 cameras and folders in particular which are the most likely to need an infinity adjustment.

  1. Put the long lens on the DSLR, and take it outside. Open it to its widest aperture, set to infinity, take it outside, point it at something very far away and take a picture. On the DSLR, zoom in on the screen and verify that the object is perfectly in focus. If it is then you can be confident you will be setting your candidate camera to a good infinity.
  2. Closely examine the candidate camera for where film sits (in a channel usually) and where the pressure plate pushes on. There is often a lip for it, so that the film is sandwiched in, but not pushed on by the backing plate so that it will not scratch. Put an already developed negative in the candidate camera film gate. Ideally, it would be an uncut roll of 120 film, spooled into both sides and under the tension the camera would usually put it under. If you are persnickety, put a second piece of clear negative (make one of these by forgetting to take off your lens cap!) or similar acetate behind the negative to simulate the backing paper thickness, but I don't think this is necessary. Clear tape on the edges of the glass could work as well. On top of the negatives, put a piece of glass cut to the correct size of the backing plate so it sits on the same lip the pressure plate (Home Depot sells glass and glass cutters for cheap cheap, or a 6x6 ground glasses will work with most cameras).
  3. Put the two cameras on tripods and point them at each other. Illuminate the back of the candidate camera. Set the reference camera's lens to infinity. Open the shutter to "bulb" for your candidate camera, and turn your DSLR to live view mode. Zoom in as far as you can on the DSLR live view display, and then adjust the candidate camera's focus until the negative's grain is in sharp focus. Viola! You're all set! The longer the lens on the reference camera and the more accurate its infinity stop is, and the high resolution your DSLR is the better you can get!
I am pretty confident this "computer assisted" zoom can equal an optical autocollimator, and using a real negative is better than a ground glass. The only downside to the technique is you are limited to the sensor size on your DSLR -- you cannot examine focus at the edges of the frame, so if the lens has field curvature, you will have a very sharp center but less sharp edges (compared to some tutorials I've seen that call for setting the focus half way between the middle and edge of the frame so you get a relatively large ring of good focus, but less well focused edge and center). But that's nit picking.
 

Steve906

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Alright, I think I found a method that gives me most of what I want and avoids me having to buy a device that is no longer available for a reasonable price. My previous complaint with most of the methods on the web for setting infinity that uses two cameras is that it limits the maximum possible precision of the method to the calibration of another possibly-miscalibrated old film camera + lens combination with whatever loupe you have available. Also, most methods suggest using a ground glass that does not necessarily represent how film sits as it goes through the camera. I am not the complete originator of this method, and I've seen hints of it mentioned in a few old forum posts and archived geo-cities websites so I'm going to repeat it and add to it a bit here for completeness in case someone else runs across this thread. It requires a DSLR and the longest lens you have with a physical infinity stop.

You may want to prepare some special negatives for this method, but if you have any developed test rolls you don't care about lying around, they should be good as well. These instructions are for 120 cameras and folders in particular which are the most likely to need an infinity adjustment.

  1. Put the long lens on the DSLR, and take it outside. Open it to its widest aperture, set to infinity, take it outside, point it at something very far away and take a picture. On the DSLR, zoom in on the screen and verify that the object is perfectly in focus. If it is then you can be confident you will be setting your candidate camera to a good infinity.
  2. Closely examine the candidate camera for where film sits (in a channel usually) and where the pressure plate pushes on. There is often a lip for it, so that the film is sandwiched in, but not pushed on by the backing plate so that it will not scratch. Put an already developed negative in the candidate camera film gate. Ideally, it would be an uncut roll of 120 film, spooled into both sides and under the tension the camera would usually put it under. If you are persnickety, put a second piece of clear negative (make one of these by forgetting to take off your lens cap!) or similar acetate behind the negative to simulate the backing paper thickness, but I don't think this is necessary. Clear tape on the edges of the glass could work as well. On top of the negatives, put a piece of glass cut to the correct size of the backing plate so it sits on the same lip the pressure plate (Home Depot sells glass and glass cutters for cheap cheap, or a 6x6 ground glasses will work with most cameras).
  3. Put the two cameras on tripods and point them at each other. Illuminate the back of the candidate camera. Set the reference camera's lens to infinity. Open the shutter to "bulb" for your candidate camera, and turn your DSLR to live view mode. Zoom in as far as you can on the DSLR live view display, and then adjust the candidate camera's focus until the negative's grain is in sharp focus. Viola! You're all set! The longer the lens on the reference camera and the more accurate its infinity stop is, and the high resolution your DSLR is the better you can get!
I am pretty confident this "computer assisted" zoom can equal an optical autocollimator, and using a real negative is better than a ground glass. The only downside to the technique is you are limited to the sensor size on your DSLR -- you cannot examine focus at the edges of the frame, so if the lens has field curvature, you will have a very sharp center but less sharp edges (compared to some tutorials I've seen that call for setting the focus half way between the middle and edge of the frame so you get a relatively large ring of good focus, but less well focused edge and center). But that's nit picking.
I think a prime lens should be used on the DSLR to get anywhere near consistent results using this method. I assume by zoom you meant the screen display only. Most - if not all, still camera zoom lenses are nowhere near par-focal. This also means the cameras are going to have to be a long way apart as the close focus on a reasonably long lens with no digital intervention will not be great?
Still not sure how much an advantage it is to have infinity set perfect if all the other lens markings are just guides with no definite line markings and only mass produced original positioning to a standard design rather than actual position for an individual lens.
Edit. Sorry to sound a bit negative (excuse the pun) but trying hard to help. If all else fails take some photo's:smile:
 
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Grim Tuesday

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I think a prime lens should be used on the DSLR to get anywhere near consistent results using this method. I assume by zoom you meant the screen display only. Most - if not all, still camera zoom lenses are nowhere near par-focal. This also means the cameras are going to have to be a long way apart as the close focus on a reasonably long lens with no digital intervention will not be great?
Still not sure how much an advantage it is to have infinity set perfect if all the other lens markings are just guides with no definite line markings and only mass produced original positioning to a standard design rather than actual position for an individual lens.

Sorry, yes, I should have been clear about that. I meant a long prime lens with a hard infinity stop that you know to be good (reason for testing it outside). And digitally zoom into the image taken by the DSLR. I agree on zoom lenses, I am not very trusting of them keeping their infinity throughout their range without it being just out of the factory.

I am not sure what you exactly mean about close focus. The lens on the DSLR is set at infinity, not a close focus, and since it is looking through the lens of the other camera to that film plane, it shouldn't be on a close focus

Setting the infinity point is important to me for two reasons:

1. On scale-focusing cameras, the scale is all I have to work with, so it had better be right. At the very least I want it to be correct at infinity! I tested my Perkeo II today with this method and found it is totally wrong. Which explains why the images I've been getting out of it a year or two ago were so bad! Eventually I'd like to service its shutter, which will require taking off the front cell which is on a helicoid. And then I'll have to put it back on and make the front cell focus correctly. A sub-usage of this case is that any lens repair that requires a helicoid removal should be checked for proper infinity focus at the end.
2. On SLR or TLR cameras, the focusing screen has to be in sync with the image projected on the film. As far as I know, the only way to do this is by making them line up at infinity. I guess you could do it at another focal length, but infinity is easy because you can use a collimator to do it and there's a hard stop for it.

Oh and no worries for sounding negative! Thank you for all your help!
 
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Steve906

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Sorry, yes, I should have been clear about that. I meant a long prime lens with a hard infinity stop that you know to be good (reason for testing it outside). And digitally zoom into the image taken by the DSLR. I agree on zoom lenses, I am not very trusting of them keeping their infinity throughout their range without it being just out of the factory.

I am not sure what you exactly mean about close focus. The lens on the DSLR is set at infinity, not a close focus, and since it is looking through the lens of the other camera to that film plane, it shouldn't be on a close focus

Setting the infinity point is important to me for two reasons:

1. On scale-focusing cameras, the scale is all I have to work with, so it had better be right. At the very least I want it to be correct at infinity! I tested my Perkeo II today with this method and found it is totally wrong. Which explains why the images I've been getting out of it a year or two ago were so bad! Eventually I'd like to service its shutter, which will require taking off the front cell which is on a helicoid. And then I'll have to put it back on and make the front cell focus correctly. A sub-usage of this case is that any lens repair that requires a helicoid removal should be checked for proper infinity focus at the end.
2. On SLR or TLR cameras, the focusing screen has to be in sync with the image projected on the film. As far as I know, the only way to do this is by making them line up at infinity. I guess you could do it at another focal length, but infinity is easy because you can use a collimator to do it and there's a hard stop for it.

Yeah sorry close focus bit was a slip - late here - drinking whisky:unsure:.
Maybe my point of view is perhaps a bit different.
Where I work we re-house vintage Cine lenses such as Cooke speed panchro's, Kowa, Bausch & Lomb, Leica etc. into new metalwork.
They are set on the collimator by using shims to the P.L. mount nominal 52mm. Within 0 to .00025" through infinity (or more depending on the customers requirements.) Each lens is then mounted on a projector (wide open) at calibrated distances from a perpendicular wall and each footage position is individually marked and engraved onto a new focus barrel.
Many high end cameras have adjustable 'Back focus' distances to allow for sensor cover, film plane, filter distances etc. and will be adjusted to the lens. So the lens is the standard. Some adjust the lens to their camera? but I'll not go into that:blink:.
The lenses have definitive lines and are within a tolerance for each focal length. This is important to focus pullers who may only be working to a focus script and not be able to see the image. This sort of accuracy costs a lot of money! were talking 6-7-8k£ lenses.
All my still camera lenses have no lines to indicate exact distances. Using guesswork, range finder, tape measure - whatever lengths you wish to go to, most of the time it's just an estimate of the film to subject distance and then an estimate of what distance the lens is set to. With long focal length lenses this is more critical but stopping down a little or with shorter focal lengths the depth of acceptable focus usually gives good results. I have never had to set any of my lenses even after dismantling in any way other than by eye then shoot a film and see if it all seems Ok. even though I have access to all the possible equipment required to do so.
Never had a TLR. But SLR Bronica check with small led next to film plane at 30ft from bedroom mirror looked about right on viewer at 60ft and magic tape on film plane - good to go.:smile:
Again don't want sound too negative and I want an autocollimator of my own now:surprised: just to play with!.
Cheers.
Steve.

Edit:- Wow it's 4am here now :cry:.
 

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Location
Escondido, C
Format
35mm RF
Here is an autocollimator that I built:
[URL]https://fixfilmcamera.com/Collimator/collimator.htm[/URL]
I got the website fixfilmcamera.com running about 30 minutes ago, and you are the first to see it. :smile:
This autocollimator has been invaluable for calibrating focus of lenses. It also allows you to gauge the quality of a lens by noting fall-off in sharpness as you open the aperture.
Mark Overton
 

Hewa

Member
Joined
Sep 26, 2020
Messages
2
Location
Netherlands
Format
Hybrid
I want to buy an autocollimator to calibrate infinity focus on some of my cameras. I would like more precision than is offered by the "line up two cameras" method, mostly because I don't know if any of my cameras are correctly calibrated to begin with. Does anyone know where I can get an autocollimator, have one for sale, or know of someone who has one for sale?
I only did find this message today Sept. 26. I do own a National Camera autocollimator, made by Pearl Optical, In the Netherlands, it is set to 220 Volts AC, but it can easily be rewired for 110 volts. I used to work for Polaroid, and as such I acquired this autocollimator. I will offer it for a reasonable price, but shipping costs could be important, as this unit is rather large and weighs close to 15 kgs. I can send you some pictures if you still are searching such unit.
 
OP
OP

Grim Tuesday

Member
Joined
Oct 1, 2018
Messages
739
Location
Philadelphia
Format
Medium Format
I only did find this message today Sept. 26. I do own a National Camera autocollimator, made by Pearl Optical, In the Netherlands, it is set to 220 Volts AC, but it can easily be rewired for 110 volts. I used to work for Polaroid, and as such I acquired this autocollimator. I will offer it for a reasonable price, but shipping costs could be important, as this unit is rather large and weighs close to 15 kgs. I can send you some pictures if you still are searching such unit.

Yes, I am still looking and am interested in yours. I sent you a private message and hope to hear back!
 
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