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After seeing some old forum posts talking about creating a DIY video tap for older 16mm cameras, I thought I’d give it a shot. There’s an old thread about exactly the camera I’m using, an Eclair ACL, but the photo of the rig that they posted is no longer on the internet. So I put a super rough $20 thing together (plus an iPhone 8+). You can see it here: https://imgur.com/gallery/aNxfqXV

Any suggestions? There are definitely some things that could be improved. It takes a while to set up since it doesn’t want to stay in place unless I use tape. It’d be nice to have a more rigid arm, but I’m not sure I could find one that’s the exact length and angle needed (that’s why I ended up with the “gooseneck”). And for actual shooting I’ll need to make sure that I’ve covered up all possible points where light can come in the viewfinder so it doesn’t cause light leaks.

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I think that's pretty good for a no money ad hoc solution. What about making a little clamp that grips on the lip of the ACL viewfinder,  the lip that holds the rubber eye cup, or anywhere on the outer part of the view finder. You could make a little foam seal, or just use tape. Black paper camera tape, like Scotch 235, really opaque, and comes off clean even if left for years.

PS: recomending that tape as they say it is the same as the original Scotch black paper camera tape...Good for mags etc, no gum residue, reusable..

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Hmm attaching it directly to the viewfinder is not a bad idea. Probably would make it easier to remove and put back on when need be.

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I’ve made a similar system with a small m12  $40 camera you can buy off amazon.

 

in this video I set it up with the beam splitter, but it can also be used with the eyepiece no problem 

 

 

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D John, looks great!

I also have an Eclair ACL and tried to put a similar (SD) small CCTV-camera up against the viewfinder -- ACL doesn't have the slot for a viewfinder -- but I wasn't able to align it well enough and thus the results were just bad.

The AZ Spectrum videotap for ACL is a box embedded between the viewfinder and the camera. I wonder what would it take to put together a box with a CCTV module such as in John's with a prism?

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Posted (edited)

Ha, for some reason I hadn't before this realized which ring to turn in order to remove the VF. Turned out to be very straightforward.

I think I'll begin with trying to implement the M12 camera without the viewfinder. If that turns out to work well, I'll try to look in to one mounted between the camera and the VF....

Edited by Heikki Repo

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Nice! 
yes I had an eclair NPR and I began this whole process with that camera.

i agree removing the eyepiece is best. Lessen the number of elements you’re working with.

 

Now that you see the ease of introducing another element between the viewfinder and body once you removed it, you’ll see the ease with which you could introduce a    50/50 beam splitter, which you can purchase  on eBay quite easily. 

you’ll need to have the proper threaded mounts on either side to secure it

thats why I purchased the 3d printer. My first one was about $150 and performs as well just slower. Very helpful for this type of prototyping. 

 


 

 

 

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I notice that you installed a standard definition camera and upscale the signal? Looking around for small enough HD cameras, it seems that for the Raspberry Pi there is one, v2.1. Perhaps using it would open a way to also achieve "flicker free" signal, since it supports frame rates 1-90 per second while the signal passed to LCD would still be the standard hdmi output from Pi:

https://www.raspberrypi.org/documentation/hardware/camera/

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Yea I agree this is the better option.

ive actually done a bunch of looking into Computer Vision and  OpenCV for using it. And implementing other functionality. Honestly I got a little out of my depth with the coding since it’s not an area I know much about. But it does seem like a reasonable thing to want to do. 
 

as far as a straight HDMI pass through system yea. Especially with the new HD camera they just announced

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I went ahead and bought Raspberry Pi and camera module (v2.1) for it. As I had previously bought some M12 lenses, camera with composite output and a car lcd screen with composite input, I decided to see what I could achieve with them.

My first results were ok'ish. By changing the default lens to a 6mm M12 lens, I was able to see the ground glass. Unfortunately 6mm was somewhat too short focal length, would need to replace that with a 8mm. Also: do not push the lens inside the camera, some part of the turning shutter likely will hit it (mine did, but it seems no harm was done - it just nudged the lens away).

The bigger issue is definitely the dynamic range. Let's just say that while someone might use this for director's monitor, for camera operator it just won't work.

This brought me to think about Last Light movie, which was shot on an Eclair ACL. If you look through their behind the scenes photos, you'll see this:

 

As I own a Pocket Camera, I decided to try if that could work. I don't have any magic arms nor did I know at that point what the exact pieces were. However, even with my crude setup of holding the Pocket with my hands, it became evident how big difference there is between the Pocket and the RPi camera module. It's like day and night. The image on the ground glass looked good. It was easy to see what was happening even when the camera was running 25 fps.

Having reached these results I then decided to contact the DoP of The Last Light, Victor Capiz, who very generously shared the details with me:

They had a BMPCC with a Bell & Howell Super Comat 25mm and some 1mm shims there. The BMPCC was then positioned with magic arms so that it wouldn't move from it place pointing towards the ground glass. Quite simple but very ingenious!

So, having ordered the missing pieces I have high hopes that this route might make it viable to use video assist as the only viewfinder for my ACL. We'll see!

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Very nice!

ive haven’t had an issue with the dynamic range on my camera, I’ve tested it in both extreme low light and daylight. As it’s a cctv security camera it needs to have pretty wide operating conditions. 

it needs to be set in automatic shutter, dwdr, and auto iris. It compensates very well.


as far as the bore hole, 

there are no moving parts that interfere with the bore hole, so I haven’t had any issues. Getting too close to the beam splitter yes, but otherwise no. 
 

I have a bmpcc, the reason I haven’t tested with it is due to the size, though if you are very interested I could set it up and see how it looks.

 

glad we’re testing out options on this!

 

i have a new camera board arriving Friday to test

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I think it is very important not only to experiment, but to also share results of those experiments 🙂 Explore all new options that weren't available in the past and keep the film based cinematography moving forward.

It's very fortunate that I had to buy a new (used) car a couple of years ago. Otherwise I might have bought the AZ Spectrum video tap. Not a bad choice, certainly, but compared to a potential HD color output with an option to record it as well it would now seem somewhat expensive and lacking, especially considering all the hassle and expense of camera shipping (Europe-USA-Europe)...

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Aha yes I agree! Good investment! 
 

my hope is once we finds good camera (raspberry pi or otherwise) I can design a nice 3d housing for it and release the .stl files for anyone to use. 
 

im going to try with my bmpcc and Aaton now. See how it works. 

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Wow these are some interesting options. I was just strapping an iPhone to my camera haha. Will need to try these out once I’ve got time and a little expendable cash.

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And here it is:

IMG-20200519-145128.jpg

Ahh, the sheer size of it. But it's okay, works well even handheld on the shoulder.

IMG-20200519-150653-600.jpg

Yay, focus assist works!

And then the final, missing piece... thanks to my son, who hasn't always been that nice to his toys...

IMG-20200519-152651.jpg

IMG-20200519-152755.jpg

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The nice thing about this setup is that BMPCC has many shutter angles. With the widest angles the ACL shutter becomes practically invisible, only darkening the screen a bit.

Surprisingly this video assist also seems to make it possible to pull focus while operating - I really haven't been able to do that with the optical viewfinder.

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Hey this is awesome! I love it. Very nice work. 
 

you didn’t even have to use macro step up rings, hit it right with that minimum focus. Great! Is it a 25mm lens?

yes there’s definitely a good Phase point between the shutter and the bmpcc. 
 

Just gotta get you a nice secure mount and it’s perfect!

I also love that you now have a recording tap for playback. 
 

 

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I have there a 5mm macro ring, the lens is 25mm. Still waiting for 1mm rings to get it in the sweet spot without having the lens partly out of the mount 😉

How to mount this securely is definitely a good question - it is currently usable but might occasionally need a bit wiggling to get the exact framing. The toy car tire helps to keep the lens quite close to the right position.

As the lens is only 25mm, I use the zoom setting on my monitor. I have ordered from China a 50mm lens just to see, if it would allow for a better resolution by not having to use the digital zoom feature.

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If the front of the taking lens is threaded, using step-up couplers you could connect it to the original eye piece mount via the thread. It would require a little research to figure the thread of the original eyepiece but I’m sure it can be done.

 

that would at least give it a 2nd point of stability. 
 

it could also have another arm going from the top cheese plate of the bmpcc to the 15mm rods, gripping them with a nano clamp.

or use a dog leg similar to when a zoom motor is mounted above the lens 

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it should be pretty easy to machine a suitable adapter tube to hold the lens in place if you have access to metal lathe. if it is just a correct sized tube with screws or similar to hold it in place it would be easier to do than a threaded one.

The bmpc could be supported by making a bracket which mounts to the top of the bmpc cage with two or three screws and the other end attaches to the handle of the ACL by some secure way (screws would probably be the best option)

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Yea I agree.

i use my 3D printer. It has a .4mm nozzle so it can handle printing fine threads. I’ve done m12 and C mount threads without issue.

once you find a design you like it can be emailed to a company with a CNC or lathe.

if I were rigging the camera on set in this way, I would use steel arms to mount it where the 15mm rods go, and then add a hole for the rods to mount on. 

basically a cheese plate in between the rods and the camera body, using that thread position. That would give it the least travel distance and wouldn’t interfere with the top handle.

 

any offset issue introduced for the follow focus in the 15mm rods would be solved by using a dog leg 

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Nice ideas, thanks!

There are threads on the viewfinder and in the lens, but the difference between them is enormous. The viewfinder threads are more like plumbing sizes whereas the lens threads are normal filter threads. I'll have to try to find out the viewfinder thread size, I'd guess that it adheres to some thread standard.

I myself don't have access to a metal lathe nor the expertise to run one. But hey, I know the Hydraulic Press Channel guy, perhaps he (or more likely his father, haha) would have time to do such machining for me. No idea about the cost though...

Aapo, are you suggesting a bracket around here?

IMG-20200519-21033-v2.jpg

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