Angenieux 9.5 - 57 Non Parfocal?

[Tyler Fukuda]

Hey forum!

Recently purchased an Eclair ACL 2.0. It came with two lenses—One of which is an Angenieux 9.5 - 57 in Cameflex mount.

It’s currently not par-focal from what I can tell..

My instincts would say that the back-focus is off. Anyone have experience working with these?

[Dom Jaeger]

If it gets progressively softer as you zoom out, then yes it's either the zoom back-focus or the camera flange depth. If you're judging purely off the camera viewfinder then that is actually the ground glass (which should be locked to the gate depth but could also be out). If the other zoom seems ok, then it's likely the zoom just needs collimating. Or if using an adapter, that could be the issue. 

It should be parfocal, being a cine zoom, but age and wear can also cause focus drops. That tends to be more focus coming in and out, rather than getting progressivlely softer. 

The best thing to do with new camera and lens purchases is have a tech with a collimator and lens projector check it all. Doesn't take too long, and can save you lots of headaches, money and guesswork. 

Edited August 15 by Dom Jaeger

[Tyler Fukuda]

On 8/13/2026 at 11:25 PM, Dom Jaeger said:

If it gets progressively softer as you zoom out, then yes it's either the zoom back-focus or the camera flange depth. If you're judging purely off the camera viewfinder then that is actually the ground glass (which should be locked to the gate depth but could also be out). If the other zoom seems ok, then it's likely the zoom just needs collimating. Or if using an adapter, that could be the issue. 

It should be parfocal, being a cine zoom, but age and wear can also cause focus drops. That tends to be more focus coming in and out, rather than getting progressivlely softer. 

The best thing to do with new camera and lens purchases is have a tech with a collimator and lens projector check it all. Doesn't take too long, and can save you lots of headaches, money and guesswork. 

I checked it using a difference lens and it’s the same issue so i’m narrowing it down to the TS -> Cameflex adapter. Likely the mount just needs some shimming.

Edited August 15 by Tyler Fukuda

[Tyler Purcell]

20 minutes ago, Tyler Fukuda said:

I checked it using a difference lens and it’s the same issue so i’m narrowing it down to the TS -> Cameflex adapter. Likely the mount just needs some shimming.

Yea, they always need work, I have one coming to me that we're going to machine down slightly and then shim up if need be. 

[Tyler Fukuda]

8 minutes ago, Tyler Purcell said:

Yea, they always need work, I have one coming to me that we're going to machine down slightly and then shim up if need be. 

I can unscrew the mount slightly to essentially bring it further away and make it sharp on the wide end.. so would that mean I’m adding shims? How does this in-turn affect my long end. It’s likely a balancing act of getting both to be acceptably sharp?

[Gregg MacPherson]

3 hours ago, Tyler Fukuda said:

I checked it using a difference lens and it’s the same issue so i’m narrowing it down to the TS -> Cameflex adapter. Likely the mount just needs some shimming.

I don't understand that logic, or why TP is agreeing with you. If both lenses have the same symptom, the likely explanation is that the FFD is off, so could be the FFD of the TS flange (C mount) or the FFD with the TS/CA-1 mount adapter fitted. The correct FFD of the TS flange is primary, because all the other mount adapters you get will require it.

Did Tyler Percell (TP) get an autocollimator and a projector when he bought the camera service business? If so, who is the tech doing the collimations?

TF,  I believe that continuity with the camera service/repair tech will save money and effort, but for the first CLA of your kit I would find the best tech you can, even if you have to go far, like Paul Scaglione at VP. And there must be some super experienced ACL techs in LA. Who used to do the ACLs for Alan Gordon or AM camera?  The hourly at VP is I thought about USD145, and TP notes his rate at USD165. At the same time, Andrzej, the genius at AZ Spectrum, charges only USD85...!  

Any good tech can check the FFD on the ACL and check the GG position with an autocollimator, but adjusting the TS mount FFD may need some ACL familiarity,  same with adjusting the GG.  So there will be several good techs in LA with access to a projector and autocollimator who can answer the question.

[Gregg MacPherson]

TP, I recommend finding a TS/Arri-B mount adapter and swapping your Ang zooms out for a Zeiss 10-100 T3.1. They are very sharp, and can be quite cheap. The adapter you showed a pic of in a recent post somewhere (FB ?) is a type where the lens rotates to lock by friction. I think...There is a type where there is a definitive locking, and a release button on the side. Also, I am fairly sure that type will also take an Arri-S lens. There was a little locking tab that came into the grove on the Arri-s lens mount. OK for primes anyway. I'll see if I can find a picture. OK, it doesn't show the release button, but this is the type i was describing.

Edited August 15 by Gregg MacPherson

[Tyler Fukuda]

5 minutes ago, Gregg MacPherson said:

TP, I recommend finding a TS/Arri-B mount adapter and swapping your Ang zooms out for a Zeiss 10-100 T3.1. They are very sharp, and can be quite cheap. The adapter you showed a pic of in a recent post somewhere (FB ?) is a type where the lens rotates to lock by friction. I think...There is a type where there is a definitive locking, and a release button on the side. Also, I am fairly sure that type will also take an Arri-S lens. There was a little locking tab that came into the grove on the Arri-s lens mount. OK for primes anyway. I'll see if I can find a picture.

There are good techs in Los Angeles, but there are very-very limited techs that will want to touch one of these. This is not an SR3 or an 416, sadly it seems like a waste of time for most of the technicians, so i’m forced to essentially ship the camera out (other than Tyler Purcell) to get work done on that camera. That requires tons of money and time spent going back and forth between techs. Anyway I digress.

In the mean-time I’ve added shims between the TS mount and the adapter and viola, it worked. Lens feels good at both the wide and long ends. Not scientific by any means but will do for my purposes until I can get it on a collimator.

As far as a TS to Arri B-Mount goes, I will likely just need to be patient till one surfaces. They seem far and few between from what I can tell. 

[Gregg MacPherson]

To be clear on the logic. You have bought the CA-1 FFD closer to spec. The problem could be either the FFD of the TS mount or the distance increment from the adapter. If the problem is the TS flange, then you'll have to do this for any new mount adapters, and any C mount lenses will be off. The tools techs use for checking the lens port FFD are very simple. A dial indicator with a shoulder to sit on the port flange is set to zero with a gauge block, say 52mm for PL or Arri-B, then the indicator can show deviations of the film plane. But it does require the right tools and some skill.

Adjusting or shimming the FFD for the TS mount on ACL may need expertise with ACL. I had one ACL, a VP S16 conversion, and there was shim stock under each screw point for the camera mechanism plate. I don't know why he had not put it under the TS flange, There must be a good reason. If the TS flange needed negative shimming, I don't know what they do, For the VP S16 cameras, they have already been whittling away at the body casting, so what difference does a few more microns matter.

 

 

[Tyler Fukuda]

25 minutes ago, Gregg MacPherson said:

To be clear on the logic. You have bought the CA-1 FFD closer to spec. The problem could be either the FFD of the TS mount or the distance increment from the adapter. If the problem is the TS flange, then you'll have to do this for any new mount adapters, and any C mount lenses will be off. The tools techs use for checking the lens port FFD are very simple. A dial indicator with a shoulder to sit on the port flange is set to zero with a gauge block, say 52mm for PL or Arri-B, then the indicator can show deviations of the film plane. But it does require the right tools and some skill.

Adjusting or shimming the FFD for the TS mount on ACL may need expertise with ACL. I had one ACL, a VP S16 conversion, and there was shim stock under each screw point for the camera mechanism plate. I don't know why he had not put it under the TS flange, There must be a good reason. If the TS flange needed negative shimming, I don't know what they do, For the VP S16 cameras, they have already been whittling away at the body casting, so what difference does a few more microns matter.

 

 

Correct— It could be either or and I would need a collimator handy to determine it. Luckily, I have access to a good collimator and can check the TS mount with a known good C-Mount lens. 
 

It would be difficult to check whether the mount itself is off and I cannot check any of the Cameflex mount lenses on the collimator without finding a custom mount first.

Essentially once I determine that the TS mount is good I can move onto the Cameflex mount.
 

What I find somewhat interesting is that the magnification of the eyepiece on the Eclair is difficult to tell at wide angles 15mm and below if it’s close to critical focus. But to my eye, after adding the show shims It feels better when at wide.

For the dial indicator (micrometer) I would need some sort of race or flat block/bore that would essentially be the side depth as the cameflex mount, 48mm? The i’d Zero out the gauge and mount it to the front of the camera and see if there are deviations at the gate and determine how much i’d need to shim. Obviously is a very crude way of doing it but it could in theory show me how much it’s off.

[Ross Yeandle]

Hi Folks, I haven't read this whole thread but I have one of these lenses and it's very sharp wide open and is definitely par focal.

Best.

[Gregg MacPherson]

This "crude" method was what was always used AFAIK. Actually, I think they normally had basic dial indicators with 0.001" increments (0.0254 mm..25 microns) and they normally could judge quite well within an increment. If I have a go I'm going to get an indicator with 0.001mm increment (1 micron).

You can see the FFD kit that PS Technic sell online. Maybe one can make do with standard industrial indicators which won't give a nice circular platform to sit on the mount flange, but as long as you can move around enough to check depth over the whole frame area...

The gauge block is just a heavy cylinder that has been ground accurately to a specific length. A good machinist could make one in a lathe and finish it by lapping, that's my hope anyway. You will see that a good tech will have gauge blocks for the common FFDs...

[Gregg MacPherson]

Just now, Ross Yeandle said:

Hi Folks, I haven't read this whole thread but I have one of these lenses and it's very sharp wide open and is definitely par focal.

Best.

Everyone says that about the 9.5-57 Ang. I used the 12-120 a lot but not the 9.5-57. Maybe he doesn't need the Zeiss 10-100 T3.1 if 57 is long enough. I'll have to adjust my advice. The 9.5-57 should be more nimble for hand held than the Zeiss. Could be a big plus.

[Tyler Fukuda]

1 hour ago, Gregg MacPherson said:

Everyone says that about the 9.5-57 Ang. I used the 12-120 a lot but not the 9.5-57. Maybe he doesn't need the Zeiss 10-100 T3.1 if 57 is long enough. I'll have to adjust my advice. The 9.5-57 should be more nimble for hand held than the Zeiss. Could be a big plus.

I am fairly certain that it’s the mount. I actually own a Richter autocollimator. Though it’s not in the most pristine condition I can use it to check.. 
 

I will check with an actual collimator later and determine the precise shim i’d need, but temporarily I cut a piece of tin foil and placed just behind the mount. I imagine that’s between ~0.010 - 0.016mm. Once again I don’t have super precise calipers that can measure in thousands.

Seems to have helped

[Tyler Purcell]

8 hours ago, Tyler Fukuda said:

I can unscrew the mount slightly to essentially bring it further away and make it sharp on the wide end.. so would that mean I’m adding shims? How does this in-turn affect my long end. It’s likely a balancing act of getting both to be acceptably sharp?

Yea, we can figure that out, it's not that bad. I have tried using my FFD tools on those mounts, every one has been off. 

[Gregg MacPherson]

5 hours ago, Tyler Fukuda said:

Correct— It could be either or and I would need a collimator handy to determine it. Luckily, I have access to a good collimator and can check the TS mount with a known good C-Mount lens. 
 

It would be difficult to check whether the mount itself is off and I cannot check any of the Cameflex mount lenses on the collimator without finding a custom mount first.

Essentially once I determine that the TS mount is good I can move onto the Cameflex mount......

With the dial indicator the TS flange (the C mount) FFD is checked and corrections made, With that flange accurate, one can fit the TS/CA-1 lens port adapter and check that with the dial indicator. So the tech would use the C mount gauge block then the CA-1 mount gauge blocks. Anyway, that's how I assume he would do it.  This fix sequence seems simple enough.  

[Gregg MacPherson]

Sorry for my sloppy language. What I called a dial indicator is normally called a 'dial depth gauge". Dial indicators are the ones with the little lever arm on the end.

[Dom Jaeger]

On 8/16/2026 at 4:24 AM, Tyler Fukuda said:

I can unscrew the mount slightly to essentially bring it further away and make it sharp on the wide end.. so would that mean I’m adding shims? How does this in-turn affect my long end. It’s likely a balancing act of getting both to be acceptably sharp?

If you change the lens back-focus, yes it affects the long end too. You need to re-focus at the long end and check the zoom curve again out to the wide end, maybe make a further small back-focus adjustment. Once parfocal, the focus scale should line up (unless the lens has been messed with). 

23 hours ago, Tyler Purcell said:

Yea, we can figure that out, it's not that bad. I have tried using my FFD tools on those mounts, every one has been off. 

Eclair TS mount adapters were extremely accurate, so much so that Chrosziel used the same system for their collimators and projectors. If every TS adapter you check is out, it's statistically far more likely that your measuring tools or methodology are at fault. 

[Tyler Fukuda]

2 hours ago, Dom Jaeger said:

If you change the lens back-focus, yes it affects the long end too. You need to re-focus at the long end and check the zoom curve again out to the wide end, maybe make a further small back-focus adjustment. Once parfocal, the focus scale should line up (unless the lens has been messed with). 

Eclair TS mount adapters were extremely accurate, so much so that Chrosziel used the same system for their collimators and projectors. If every TS adapter you check is out, it's statistically far more likely that your measuring tools or methodology are at fault. 

I didn’t touch the lens at all and was unsure where to start, where I really got into was the actual TS -> CA mount adapter and essentially inserted a small cut piece of tin foil, sandwiched between the rear flange of the CA adapter and the face of the TS mount.

[Dom Jaeger]

1 hour ago, Tyler Fukuda said:

I didn’t touch the lens at all and was unsure where to start, where I really got into was the actual TS -> CA mount adapter and essentially inserted a small cut piece of tin foil, sandwiched between the rear flange of the CA adapter and the face of the TS mount.

Yes sure,  I was just answering your question about whether shimming affects the long end, and describing the basic procedure for collimating a zoom. You could shim the mount, the adapter or the lens and get the same result. Long term it would be good to know where the error actually is though, especially if you plan to use other adapters or lenses.

If your estimate of a 0.01mm to 0.016mm shim needed is correct, that's actually a very small error and would be next to impossible to see through the viewfinder. The tolerance for flange depth is about that much. If it's actually 0.10 to 0.16mm (more likely if you're using tin foil) then that is quite a large error. 

[Gregg MacPherson]

On 8/16/2026 at 10:21 AM, Gregg MacPherson said:

TP, I recommend finding a TS/Arri-B mount adapter and swapping your Ang zooms out for a Zeiss 10-100 T3.1. .......

I'm loosing it, getting my TPs and TFs mixed up...need another acronym...WTF...

[Tyler Fukuda]

6 hours ago, Dom Jaeger said:

Yes sure,  I was just answering your question about whether shimming affects the long end, and describing the basic procedure for collimating a zoom. You could shim the mount, the adapter or the lens and get the same result. Long term it would be good to know where the error actually is though, especially if you plan to use other adapters or lenses.

If your estimate of a 0.01mm to 0.016mm shim needed is correct, that's actually a very small error and would be next to impossible to see through the viewfinder. The tolerance for flange depth is about that much. If it's actually 0.10 to 0.16mm (more likely if you're using tin foil) then that is quite a large error. 

Without a very high end micrometer I sadly cannot truly determine what the actual thickness is of the foil—It is an approximation based on average thickness of household tin foil (lighter version, not heavy duty). I could be off by a few thousands but it seemed to have helped.

The VF magnification of the Eclair isn’t really that strong so at wider angles it’s acceptably sharp(15mm to 9.5mm), but I can’t discern.

For my autocollimator, my infinity seems good at the long end and as I zoom out the image oddly begins to dim until there is essentially nothing there and is OOF. I don’t know if this is inherent to zooms? But that doesn’t seem correct to me.

[Dom Jaeger]

10 hours ago, Tyler Fukuda said:

Without a very high end micrometer I sadly cannot truly determine what the actual thickness is of the foil—It is an approximation based on average thickness of household tin foil (lighter version, not heavy duty). I could be off by a few thousands but it seemed to have helped.

The VF magnification of the Eclair isn’t really that strong so at wider angles it’s acceptably sharp(15mm to 9.5mm), but I can’t discern.

For my autocollimator, my infinity seems good at the long end and as I zoom out the image oddly begins to dim until there is essentially nothing there and is OOF. I don’t know if this is inherent to zooms? But that doesn’t seem correct to me.

You can buy a low-end Mitutoyo micrometer that will measure 0.01mm for about $50, Chinese brands can be as cheap as $15. If you're interested in lens/camera service or calibration, a micrometer and Vernier calipers are essential. 

0.01mm (1/100th of a mm) is as fine as most shims go, usually made of steel that is so thin and papery it's like gold leaf. Household aluminium foil is much thicker, likely to be 0.15mm thick at a minimum. Lenses (and camera flange depths) need to be shimmed to within around 0.01mm for accuracy, especially wide focal lengths and 16mm zooms. 

On a collimator, the image will always be brighter and clearer at longer focal lengths and get dimmer as you go wide, that's normal. Under 10mm can be quite hard to see unless you have a good collimator and the right optical head. 

 

[Tyler Fukuda]

1 hour ago, Dom Jaeger said:

You can buy a low-end Mitutoyo micrometer that will measure 0.01mm for about $50, Chinese brands can be as cheap as $15. If you're interested in lens/camera service or calibration, a micrometer and Vernier calipers are essential. 

0.01mm (1/100th of a mm) is as fine as most shims go, usually made of steel that is so thin and papery it's like gold leaf. Household aluminium foil is much thicker, likely to be 0.15mm thick at a minimum. Lenses (and camera flange depths) need to be shimmed to within around 0.01mm for accuracy, especially wide focal lengths and 16mm zooms. 

On a collimator, the image will always be brighter and clearer at longer focal lengths and get dimmer as you go wide, that's normal. Under 10mm can be quite hard to see unless you have a good collimator and the right optical head. 

 

I’ll get a pair today!

Thanks for the info and will keep you updated as I get in front of a collimator! Cheers