Bad Super 16mm conversion

[Nigel Smith]

Hi

I took over caring for 3 H16 Bolexes in a university facility a couple of years ago. The cameras were converted to Super 16mm about 5 years ago, here in the UK.

After a couple of complaints from students i did some camera tests recently, and discovered that the framing is significantly out on the reflex viewfinder on all 3 cameras. They have a 'shift' of around 20% to the right, and one of them is also rotated about 20% clockwise ie crooked!

I found a new camera engineer recently, who used to work for ARRI [we have an SR2 as well as the Bolexes], and he is attempting to re-align the cameras. He says that a shift of a few % is not uncommon, but our cameras are spectacularly bad.

Has anybody out there experienced similar problems with conversions?

[Nick Mulder]

When they were converted to super16 is when the misalignment probably happened...

 

The holes in which the gate screws go through have reasonably large tolerances and there is also the screws that hold the whole prism mechanism down.. they sit in slots which can be moved both up and down... Basically, whenever any work is done with any of this there will most probably be a misalignment

 

Not to mention the convex-planar lens that sits atop the prism is removed for modification and is replaced with a simple mask at the new aspect, this is where the actual alignment is done once all the other fiddling mentioned above is complete...

 

Its pretty easy - it is held on by two screws so loosen them, now blast a light like an LED torch down the eye piece of the finder and then look at the prism from the front - you should now see the ground glass all lit up and showing your super16 mask ... - now set your camera to bulb mode and open the shutter (or simply run it if you have an EBM or EL) - now align the illuminated mask with the gate (takes a bit of fiddling and a light touch) - within reason the 'straighter' you are and the further you are away from the prism to remove problems with parallax the better, my results just from eye are fine as the mask is slightly smaller than the frame in any case (a small safety) - rotation is much worse than shift though - ouch!

 

Anyways... done ? cool !

 

so screw the two screws back down and double check to see the screwing down didn't move the mask again ...

 

easy ! (and free)

 

now - you might find that in your finder view the mask in its proper position is now off to the side and obscured by finder internals - easy fix again... open up the top of the finder and adjust the sprung adjustment screws on the 90deg prism at the front until it lines up somewhere the whole frame can be seen and is not obscured (they usually don't need much movement at all)

[Nigel Smith]

Wow!

Thanks a lot Nick.

what an excellent explanation. :D

[Nick Mulder]

To answer your original question - I'd say either a bad original super16 mod is to blame or the gate or mask screws (or both) got loose over time, which again is most likely due to them not being fastened correctly during the modification ...

 

Any idea who did it ?

[Nigel Smith]

To answer your original question - I'd say either a bad original super16 mod is to blame or the gate or mask screws (or both) got loose over time, which again is most likely due to them not being fastened correctly during the modification ...

 

Any idea who did it ?

Sorry it took me a while to find out :)

Martin Stent did the conversions in 2000.

The camera with the crooked mask has been straightened.

The parallax shift cannot be corrected though. :(

Apparently the main casting of the front turret above the prism is masking the view.

It should have been machined away? but it has 2 optics sitting on it which would then be unsupported...

The aperture of 12.mm is blocked by 1.4mm, so the film captures more image camera right than the viewfinder sees - by about 10%.

Apologies if this makes no sense.

 

To cut a long story short, Mr Stent is no longer on my christmas card list!

[Don Brown]

Sorry it took me a while to find out :)

Martin Stent did the conversions in 2000.

The camera with the crooked mask has been straightened.

The parallax shift cannot be corrected though. :(

Apparently the main casting of the front turret above the prism is masking the view.

It should have been machined away? but it has 2 optics sitting on it which would then be unsupported...

The aperture of 12.mm is blocked by 1.4mm, so the film captures more image camera right than the viewfinder sees - by about 10%.

Apologies if this makes no sense.

 

To cut a long story short, Mr Stent is no longer on my christmas card list!

Hi

Have you tried talking to Martin as far as I know he has done many conversion for David Warren who up until a couple of years ago before he retired was the top service engineer for Bolex in UK.

 

Regards

 

Don

[Jean-Louis Seguin]

Sorry it took me a while to find out :)

Martin Stent did the conversions in 2000.

The camera with the crooked mask has been straightened.

The parallax shift cannot be corrected though. :(

Apparently the main casting of the front turret above the prism is masking the view.

It should have been machined away? but it has 2 optics sitting on it which would then be unsupported...

The aperture of 12.mm is blocked by 1.4mm, so the film captures more image camera right than the viewfinder sees - by about 10%.

Apologies if this makes no sense.

 

To cut a long story short, Mr Stent is no longer on my christmas card list!

 

 

Hi Nigel,

 

I have converting Bolex cameras to super16 here in Canada since 1994.

You are right about the part of the casting that should have been machined. It should have.

This would enable the shifting of the rhomboid prism a little to give better distribution of the light.

The two condenser lenses are eliminated anyway as part of the conversion as they are redundant.

They provide too much magnification for the widened groundglass frame.

The end result is a viewfinder image that is a little smaller but at least you can see everything clearly.

 

Cheers,

Jean-Louis

[Nick Mulder]

right,

 

my description works for the newer H16's with the magnifying optic that is mounted directly above the prism (as in onto it) - yours is an RX4 (or five?) that has the older more slightly more destructive/problematic design for conversion ...

 

 

more info here:

 

http://www.sci.fi/~animato/s16/s16.html

 

Hopefully your turret has already been modified correctly and had a proper re-centre of sorts - have a read at that site and see the different options ... I'm scared your conversion may have just been widening the gate and bodging the finder !

 

BTW: a quick way to find out if the lens mount is centered is to put a vignetting lens on the front like a wide with heaps of filters on it ...

[Nigel Smith]

Hi

Have you tried talking to Martin as far as I know he has done many conversion for David Warren who up until a couple of years ago before he retired was the top service engineer for Bolex in UK.

 

Regards

 

Don

Hi Don

That's right - we went to Andrew Alden's repairer David Warren for the modification and he apparently passed it on to Mr Stent.

The cameras are currently with Simon Challenor, who is the "Officially accredited Service Engineer for Bolex here in the UK", and David's successor. He spoke to Mr Stent and found him at best "unhelpful" and denying all responsibility.

Thanks for the input

Nigel

[Nigel Smith]

Hi Nigel,

 

I have converting Bolex cameras to super16 here in Canada since 1994.

You are right about the part of the casting that should have been machined. It should have.

This would enable the shifting of the rhomboid prism a little to give better distribution of the light.

The two condenser lenses are eliminated anyway as part of the conversion as they are redundant.

They provide too much magnification for the widened groundglass frame.

The end result is a viewfinder image that is a little smaller but at least you can see everything clearly.

 

Cheers,

Jean-Louis

Thanks for the info Jean-Louis :)

Nigel

[Nigel Smith]

right,

 

my description works for the newer H16's with the magnifying optic that is mounted directly above the prism (as in onto it) - yours is an RX4 (or five?) that has the older more slightly more destructive/problematic design for conversion ...

 

 

more info here:

 

http://www.sci.fi/~animato/s16/s16.html

 

Hopefully your turret has already been modified correctly and had a proper re-centre of sorts - have a read at that site and see the different options ... I'm scared your conversion may have just been widening the gate and bodging the finder !

 

BTW: a quick way to find out if the lens mount is centered is to put a vignetting lens on the front like a wide with heaps of filters on it ...

Thanks a lot for the info and link Nick.

This forum certainly is an excellent resource :)

Unfortunately the cameras are not currently here for me to examine but I am starting to suspect that your fear may be proved right. :(

[Nigel Smith]

Thanks a lot for the info and link Nick.

This forum certainly is an excellent resource :)

Unfortunately the cameras are not currently here for me to examine but I am starting to suspect that your fear may be proved right. :(

The edit post function won't work for me on this forum :(

I forgot to mention - the cameras are RX4s.

[Don Brown]

Hi Don

That's right - we went to Andrew Alden's repairer David Warren for the modification and he apparently passed it on to Mr Stent.

The cameras are currently with Simon Challenor, who is the "Officially accredited Service Engineer for Bolex here in the UK", and David's successor. He spoke to Mr Stent and found him at best "unhelpful" and denying all responsibility.

Thanks for the input

Nigel

Hi Nigel

OK on that when I was thinking of having my RX5 done Andrew recommended David Warren who at the time was the UK service agent but sent all his S16 mods to Martin, so where to send now I will give Les Bosher a call and get a price from him but with the £ strong against the $ it might be cheaper in the States, glad you have found Simon I found his Website in my files is out of date and I can not access it.

 

Don

[Nigel Smith]

Hi Nigel

OK on that when I was thinking of having my RX5 done Andrew recommended David Warren who at the time was the UK service agent but sent all his S16 mods to Martin, so where to send now I will give Les Bosher a call and get a price from him but with the £ strong against the $ it might be cheaper in the States, glad you have found Simon I found his Website in my files is out of date and I can not access it.

 

Don

Cheers Don.

PM me if you want Simon's contact details - he is based in Uxbridge.

[Don Brown]

Cheers Don.

PM me if you want Simon's contact details - he is based in Uxbridge.

 

Hi Nigel

Thanks for that, found his number in my little book

 

 

Don

[Craig Mieritz]

Hi Nigel

Thanks for that, found his number in my little book

 

 

Don

 

 

I am quite surprised at the quality of some of the S16 conversions out there. I have a camera where the frame was off vertically by 1/4 frame and horizontally by nearly as much. The glue on the ground glass looks like it was applied by a grade schooler. If anyone is thinking about converting a Bolex, or purchasing a converted camera, send me a PM and I'd be happy to discuss my experience and what I've learned. I would definitely recommend having the camera looked at by a professional before purchasing it if it is already converted. And if you buy it on eBay, even if they swear that it's "ready to shoot", plan on spending $500 on servicing. The "official" Bolex repair person in the U.S. refers conversions to JK Cameras in the San Francisco Bay area. http://www.jkcamera.com/Super16.htm

[banba ban]

I had an RX5 converted to S16 in the States a few years ago from a well known and supposedly reputable company.

I was not happy with the results to say the least...

I then sent the camera to Bolex in Switzerland and their conversion was excellent.

I have had no problems with the camera or conversion since and wish I had opted for the factory conversion in the first place.

Just my 2 cents...

[Craig Mieritz]

I had an RX5 converted to S16 in the States a few years ago from a well known and supposedly reputable company.

I was not happy with the results to say the least...

I then sent the camera to Bolex in Switzerland and their conversion was excellent.

I have had no problems with the camera or conversion since and wish I had opted for the factory conversion in the first place.

Just my 2 cents...

 

 

From the stories I have been hearing about conversions gone bad, it seems like a factory conversion would be the safest route. I know the other vendors are substantially cheaper, but once you start paying to fix the original conversion, I don't know how much money you will have saved, and you don't have a camera to use while you are messing around with it. I guess it all goes back to "if it seems too good to be true, it is."

 

Dieter, a Bolex factory trained technician (http://www.bolex-usa.com/), made it very clear to me that he did not want to work on after-market S16 conversions to Bolex cameras. That is also something to consider. If something goes wrong with the conversion or the camera, you will need someone reputable to repair it.

 

And I would reiterate for the second time, if it's on eBay, think really hard about how much effort (and money) you are going to be willing to put into getting the camera into perfect running order before you bid.

[Nick Mulder]

I am quite surprised at the quality of some of the S16 conversions out there. I have a camera where the frame was off vertically by 1/4 frame and horizontally by nearly as much. The glue on the ground glass looks like it was applied by a grade schooler. [/url]

eh???

 

Glue ? There aint no glue that needs to be involved installing a super16 ground glass masking.

 

Anyone can check if the masking is correct by simply shooting a flashlight (LED is perfect) down the finder - it will light up the GG in reverse which will reveal the masking and by opening the shutter you can now at least eye the gate and maskings orientation with each other and screw it down once its ready... Due to the fact the gate aperture is usually larger than the mask this could be enough in lieu of a proper factory rigged alignment.

[Craig Mieritz]

eh???

 

Glue ? There aint no glue that needs to be involved installing a super16 ground glass masking.

 

Anyone can check if the masking is correct by simply shooting a flashlight (LED is perfect) down the finder - it will light up the GG in reverse which will reveal the masking and by opening the shutter you can now at least eye the gate and maskings orientation with each other and screw it down once its ready... Due to the fact the gate aperture is usually larger than the mask this could be enough in lieu of a proper factory rigged alignment.

 

 

Yes, Nick, glue. Given your history, you're probably going to tell me my eyesight (and Dieter's) is fluxy (even if you've never seen the camera in question).

 

If it's glued too far out of alignment, you can't just loosen the screws to compensate, the ground glass needs to be removed and replaced correctly. This conversion was done by a well-known company (at least in the S16 conversion world). There are conversions out there with no frame markings, or worse. Unfortunately, there is no standardized process being followed by the vendors out there. If they all used the same process as Bolex uses, their conversions would cost as much. Buyer beware.

[Nick Mulder]

Yes, Nick, glue. Given your history, you're probably going to tell me my eyesight (and Dieter's) is fluxy (even if you've never seen the camera in question).

 

If it's glued too far out of alignment, you can't just loosen the screws to compensate, the ground glass needs to be removed and replaced correctly. This conversion was done by a well-known company (at least in the S16 conversion world). There are conversions out there with no frame markings, or worse. Unfortunately, there is no standardized process being followed by the vendors out there. If they all used the same process as Bolex uses, their conversions would cost as much. Buyer beware.

 

 

Although I have been sent a PM by Craig asking me to 'don't reply to any more of my posts. Seriously' - I dont quite understand what I am meant to do here ... I've been discussing something in a thread and then he comes along mentioning something I dont understand and try to clarify/correct and then I'm kindly asked to refrain ?

 

You're not the first - I take it as a compliment - anyway...

 

There is no glue involved - in an original (reg16) RX4, RX5, SB, SBM, EBM, EL the finder mask is held on to the prism by two screws and the ground glass has been etched (or how ever they make GG in Switzerland) directly on top of the prism - in a conversion there is never a need for the ground glass "to be removed and replaced correctly" - that would be one and the same as removing the prism...

 

In both my conversions I did however have to move the prism slightly more to the 'left' (the film compartment side) which is achieved by loosening a further two (or three, cant remember) screws behind the adjustable shutter in a wind up or behind the light meter in an EL - the holes are slotted already and can be moved up and L-R so the adjustment is very easy - no 'removal and replacement' at all.

 

What is replaced is the little lens that sits atop the finder mask which actually is held on by glue to a regular16 mask which in turn is held onto the GG/prism by two screws it is here that it is loosened to be moved about - Now, if you are Bolex, which is to say, smart, you dont rip the lens off and file out the reg16mask to super16, you take it off and put it in your spare parts box and replace the mask with a new one - no glue! just two screws ... I am not Bolex, but I have access to a factory converted EL so I had a gander at it, figured out how they did it, designed my own and had it laser cut by a gobo manufacturer to similar spec. I made sure in my design that the screw holes were large enough for there to be a little slop for easy adjustment. I can now sandwich whatever markings I want between the hard mask and the GG - i.e. adjustable markings, mostly I just leave it open at the full super16 frame with no distractions, but a grid may come in handy one day. I may also make a behind the prism filter holder/mask combo so I can use heavy gel filters without them also coming through the finder, although I'm still not too sure if it will best optically...

 

The local bona-fide Bolex technician (trained in Switzerland) down the road (thanks for the bag of kiwifruit!) has seen both my conversions and has semi-seriously joked "do you want to buy a business?", on a more serious note he has mentioned that if an EL came in he might send it to me as his area of expertise is in the wind ups... My conversions have been used on prime-time nationally broadcast TV advertisements - I'm trying rather pompously to say that although I am a backyard operator, both of my conversions have come out smelling a lot finer that what we are discussing here.

 

as for standardization it would go something like this: make the gate super16 dimensions (look them up in your ASC manual or otherwise) - centre the lens for this new aperture, but also make some kind of re16/super16 lens centre changeover registration marks (which on the factory Bolex conversions there is only one mark, which can be 'pivoted' around, i.e. more often than not the lens centre is actually OFF) - make the finder represent the new shooting ratio and correct positioning for this ratio, perhaps some kind of marking showing the reg16 frame also - make sure the film transport no longer touches the new exposed area - the camera should operate the same as pre-conversion in all other aspects -

 

 

Nick

[Jean-Louis Seguin]

I had an RX5 converted to S16 in the States a few years ago from a well known and supposedly reputable company.

I was not happy with the results to say the least...

I then sent the camera to Bolex in Switzerland and their conversion was excellent.

I have had no problems with the camera or conversion since and wish I had opted for the factory conversion in the first place.

Just my 2 cents...

 

 

Hi banba ban,

 

You mention that you were not happy with the first conversion done at the "reputable" company.

I would be curious to find out what exactly were the problems with this particular conversion.

Or what did you find was done improperly or sloppily?

Did it prevent you from obtaining the results you were expecting?

Thanks.

 

Cheers,

Jean-Louis

[banba ban]

Hi banba ban,

 

You mention that you were not happy with the first conversion done at the "reputable" company.

I would be curious to find out what exactly were the problems with this particular conversion.

Or what did you find was done improperly or sloppily?

Did it prevent you from obtaining the results you were expecting?

Thanks.

 

Cheers,

Jean-Louis

 

 

The first thing I noticed was that cosmetically the camera didn't look very good anymore.

The original turret plate had been replaced and the new plate didn't look right on the camera - It was also a fixed turret ie no longer able to be rotated.

 

The first roll of film I shot had registration issues and some scratching - which I had previously never experienced with this camera. The markings in the viewfinder were poor quality. Bear in mind that this was an expensive conversion.

 

Apparently the pressure plate and gate had not been changed and they should have been. Also the S16 markings had been glued to the prism which meant that the prism had to be replaced. Some of the components on the film transport path were also supposed to be replaced and had not been.

 

Since the factory conversion I have had no problems. The viewfinder markings are accurate, the registration is good (for a non pin registered camera) and I get consistently good pictures from the camera.

 

The camera was also given a good general check up by the factory which gave me more confidence when using it.

 

Hope this helps.

[Jean-Louis Seguin]

The first thing I noticed was that cosmetically the camera didn't look very good anymore.

The original turret plate had been replaced and the new plate didn't look right on the camera - It was also a fixed turret ie no longer able to be rotated.

 

The first roll of film I shot had registration issues and some scratching - which I had previously never experienced with this camera. The markings in the viewfinder were poor quality. Bear in mind that this was an expensive conversion.

 

Apparently the pressure plate and gate had not been changed and they should have been. Also the S16 markings had been glued to the prism which meant that the prism had to be replaced. Some of the components on the film transport path were also supposed to be replaced and had not been.

 

Since the factory conversion I have had no problems. The viewfinder markings are accurate, the registration is good (for a non pin registered camera) and I get consistently good pictures from the camera.

 

The camera was also given a good general check up by the factory which gave me more confidence when using it.

 

Hope this helps.

 

 

 

 

Thank you very much banba ban for taking the time to go into such detail.

I think this is the kind of information forum members would appreciate.

 

Like I mentioned in a previous post on this subject, I am a motion picture equipment technician specializing in Bolex for close to 20 years now. I have done dozens of Super16 conversions over the years here in Montreal, Canada.

 

I think it's totally unnecessary to exchange a perfectly good turret when all that is required is a shift in the position of the turret axis. In addition, the turret must be able to rotate freely to provide quick access to the beamsplitter if it becomes necessary to clean it front and back.

 

The scratching could be caused by many things, but obviously care was not exercised in this area and it should have been thoroughly tested before it was delivered to you.

 

I personally do not put markings of any kind in the viewfinder. I find they just distract.

The vast majority of users will have their footage telecined to 16:9 ratio and that is what I provide; a 16:9 version of the original Bolex viewfinder frame. If a user wants full-frame super16 1.66 ratio, that can be done too. In my earliest conversions, it was sometimes desired to have the option to go back to regular 16, so I did put some markings similar to the ones Bolex uses, but nowadays nobody who converts to super16 ever goes back to the old format, so I have abandoned this practice.

 

I find it is not necessary to change the aperture plate but of course it must be milled properly.

I find it is also unnecessary to change the pressure plate, if is realigned correctly.

 

Jean-Louis Seguin

Montreal, Canada

[banba ban]

I find it is not necessary to change the aperture plate but of course it must be milled properly.

I find it is also unnecessary to change the pressure plate, if is realigned correctly.

 

Jean-Louis Seguin

Montreal, Canada

 

I think my aperture plate was damaged in the original conversion, which is why it needed to be replaced at the factory.

I am guessing that the pressure plate was worn and should have been replaced in the original conversion but wasn't.

 

Shipping to Switzerland is fairly involved and the conversion isn't cheap, but I've heard many horror stories, and experienced my own.

As I mentioned, I am totally happy with the camera now and it is producing really good quality images.