Super-16 Lens Adapter for Consumer Camcorders?
- Thread starter IRecordThings
- Start date
in theory yes. The problem will be the size of the project image on the ground glass. A lens for a super 16 camera will have a smaller circle of confusion (the projected image) than one that is meant to cover a 35mm piece of film. That being said. if you moved the ground glass closer to the front lens that may help. Then you will just have to adjust the distance to the back lens as well. That could be as simple as just zooming in the rear lens a little bit.
IRecordThings
Active member
Do you mean I should try attaching the 16mm lens onto the end of a 35mm adapter? And that I would have to grind it down? Is that really the easiest way? I was wondering if perhaps it could be done with its own set of adapter rings.
TiE_Shepherd
Well-known member
Why exactly do you want to do this? I understand you have the lens, but I really don't see the point. If you're after that 35mm adapter look, you're much better off picking up a used adapter and some used 35mm lenses. Plenty of lenses can be picked up petty cheaply.
IRecordThings
Active member
I ordered a D16 via Kickstarter but they won’t be available for a few months. Since they use 16mm lenses I wanted to try them out on my existing camera to practice while I wait as I don’t have any experience using non-fixed lenses yet. Is there a particular reason why this wouldn’t work too well?
David W. Jones
Veteran
If the Digital Bolex ever does materialize, they claim you could get either C-mount standard, or Optional PL, EF, or B4 mounts.
No don't grind anything.
If you look at the inside of how a 35mm adapter works it is merely projecting the image seen by the front lens onto a focusing screen similar to the way you look through the view finder of an SLR. You are then recording what the lens built into your camcorder sees what is project on the screen in front of it.
Now think about how a 16mm film camera or even a 35mm film camera works. They project an image of a certain size one the film plane. The key details of that process are the fixed distances( i.e. the distance from the rear element of the lens to the plane of the film) This makes it possible to both ensure that the image will correctly cover the entire image taking material (before the film now the ground glass focusing screen in your DOF adapter) and ensures that the lens can properly focus as infinity. If your lens is too close to the image taker then you will lose the ability to focus at short distances and if its too far you will lose infinity.
The advantage you have however is that your rear camera doesn't care all that much how far the screen its filming (the ground glass focusing screen), you can merely zoom in.
SO you can get a mount that goes from whatever your DOF adapter natively takes (mostlikely FD or nikon or EF) to a C-mount but you may end up with an image that is merely a circle in the middle of the frame. You could then go to the rear taking lens and zoom in so that the circle fills the frame. This however is not going to give you as good of a picture as mounting a proper lens
The last thing to try would to be open up your DOF adapter and figure out exactly how far from the lens the film distance was on the c-mount cameras your lenses work for and then move the focusing screen up to match that. Then you will get the largest image circle projected on your ground glass and the sharpest image. Again go back to your taking lens and zoom in until that image fills the frame.
Does it start to make sense now?
There are a few other draw backs you may not have realized to these DOF adapters however. Firstly think about how the image is projected by a lens, upside down and backwards (you can see an explanation here )
The next thing you need to take into account is that the image is being projected on a screen on one side while the camera is on the other. The image itself has another semi-opaque element to pass through. This effectively loses you light.
Just things to think about
If you look at the inside of how a 35mm adapter works it is merely projecting the image seen by the front lens onto a focusing screen similar to the way you look through the view finder of an SLR. You are then recording what the lens built into your camcorder sees what is project on the screen in front of it.
Now think about how a 16mm film camera or even a 35mm film camera works. They project an image of a certain size one the film plane. The key details of that process are the fixed distances( i.e. the distance from the rear element of the lens to the plane of the film) This makes it possible to both ensure that the image will correctly cover the entire image taking material (before the film now the ground glass focusing screen in your DOF adapter) and ensures that the lens can properly focus as infinity. If your lens is too close to the image taker then you will lose the ability to focus at short distances and if its too far you will lose infinity.
The advantage you have however is that your rear camera doesn't care all that much how far the screen its filming (the ground glass focusing screen), you can merely zoom in.
SO you can get a mount that goes from whatever your DOF adapter natively takes (mostlikely FD or nikon or EF) to a C-mount but you may end up with an image that is merely a circle in the middle of the frame. You could then go to the rear taking lens and zoom in so that the circle fills the frame. This however is not going to give you as good of a picture as mounting a proper lens
The last thing to try would to be open up your DOF adapter and figure out exactly how far from the lens the film distance was on the c-mount cameras your lenses work for and then move the focusing screen up to match that. Then you will get the largest image circle projected on your ground glass and the sharpest image. Again go back to your taking lens and zoom in until that image fills the frame.
Does it start to make sense now?
There are a few other draw backs you may not have realized to these DOF adapters however. Firstly think about how the image is projected by a lens, upside down and backwards (you can see an explanation here )
The next thing you need to take into account is that the image is being projected on a screen on one side while the camera is on the other. The image itself has another semi-opaque element to pass through. This effectively loses you light.
Just things to think about
TiE_Shepherd
Well-known member
In order to get anything close to something usable you'd have to change the distance between the lens mount and the GG, especially if you're adapting a c mount lens to an SLR mount. C mount flange focal distance is 17.52mm and the Canon FD is 42mm, so you're talking less than half the distance. Without getting the GG screen much closer to the lens, you'll never get anything close to accurate focus and without being within maybe at most a mm of 17.52mm you'll never be able to focus to infinity.
If you just want to play around with something, I would just pick up a used 35mm adapter and a couple SLR lenses for whatever mount you get. It won't be exactly the same as using a 16mm lens on the D16, but will give you the general idea. To adapt a 16mm lens to your camera, you'd pretty much be having to fab something together yourself and to get decent results, you have to be able to work to pretty tight tolerances. Like the GG screen having to be within about a mm for the lens to be able to focus to infinity.
skibovision
Active member
You can do this but it really won't be exact. What I would suggest is making the following
take this piece:
http://fotodioxpro.com/index.php/c-mount-lens-to-micro-4-3-mft-system-camera-lens-mount-adapter.html
figure out about how big it is in mm and buy slightly smaller spacer ring like this.
http://www.bhphotovideo.com/c/product/387531-REG/Cokin_CR6262_62mm_Extension_Ring_for.html
you will eventually epoxy that onto the m4/3 to cmount adapter but not yet.
you will need to purchase screw in macro filters like this in a size matching your spacer ring size (you will probably need 2 macro filters of at least +10 rating):
http://www.bhphotovideo.com/c/product/11207-REG/B_W_65076807_52mm_Macro_Close_up_10.html
if you stack 2 of them together you will probably need at least 1 spacer ring between them to space them out enough so that their glass elements do not touch.
it will mount as follows
camera / step up ring to match macro filter / macro filter 1 / spacer ring / macro filter 2
then comes the ground glass. This is what the lens will project onto. To start I would try taking a simply UV filter and then lightly sanding it with 220 grit sandpaper and see how that works. Your best choice would be to get a nikon f3 type D focusing screen. I think that is the one without a prism in the middle. They are hard to find but like I said start with sanding the UV filter until you can project an image onto it.
so now you have your back end and your front end. the flange distance for c mount (distance between focus screen and rear of lens) is 17.52 mm. You will not hit this exactly but you can try to get close. my recommendation is to set your lens to infinity and see how many spacer rings you need (use the minimum amount) until you can get your lens to focus to infinity when you hold it up to your assembly. Lets call the number of spacer rings you find that you need to be "S". Remember you will already have one spacer ring that will be glued to your m4/3 to c mount adapter.
your final assembly will be:
camera / step up to macro filter / macro +10 / spacer ring / macro +10 / sanded UV filter / spacer ring x S / spacer ring to attach to m4/3 adapter / m 4/3 to c mount adapter
now screw everything in to your camera nice and tight up to the final spacer ring. Then screw your lens onto your m4/3 adapter. Line up the adapter so that the witness marks of the lens are either facing the top or side, whichever you prefer and mark them so you can line them up again later.
unscrew your lens from the adapter, and unscrew your adapter assembly from the camera. Now line up the marks you made in the last step and epoxy the adapter onto the final step ring.
once it is dry you should be able to screw in your lens to your adapter and your adapter into your camera and there you have it. This set up will absolutely need rod support so if you need help building a custom support down the line I can give you some pointers on that as well
if you have any questions email peter@skibovision.com
take this piece:
http://fotodioxpro.com/index.php/c-mount-lens-to-micro-4-3-mft-system-camera-lens-mount-adapter.html
figure out about how big it is in mm and buy slightly smaller spacer ring like this.
http://www.bhphotovideo.com/c/product/387531-REG/Cokin_CR6262_62mm_Extension_Ring_for.html
you will eventually epoxy that onto the m4/3 to cmount adapter but not yet.
you will need to purchase screw in macro filters like this in a size matching your spacer ring size (you will probably need 2 macro filters of at least +10 rating):
http://www.bhphotovideo.com/c/product/11207-REG/B_W_65076807_52mm_Macro_Close_up_10.html
if you stack 2 of them together you will probably need at least 1 spacer ring between them to space them out enough so that their glass elements do not touch.
it will mount as follows
camera / step up ring to match macro filter / macro filter 1 / spacer ring / macro filter 2
then comes the ground glass. This is what the lens will project onto. To start I would try taking a simply UV filter and then lightly sanding it with 220 grit sandpaper and see how that works. Your best choice would be to get a nikon f3 type D focusing screen. I think that is the one without a prism in the middle. They are hard to find but like I said start with sanding the UV filter until you can project an image onto it.
so now you have your back end and your front end. the flange distance for c mount (distance between focus screen and rear of lens) is 17.52 mm. You will not hit this exactly but you can try to get close. my recommendation is to set your lens to infinity and see how many spacer rings you need (use the minimum amount) until you can get your lens to focus to infinity when you hold it up to your assembly. Lets call the number of spacer rings you find that you need to be "S". Remember you will already have one spacer ring that will be glued to your m4/3 to c mount adapter.
your final assembly will be:
camera / step up to macro filter / macro +10 / spacer ring / macro +10 / sanded UV filter / spacer ring x S / spacer ring to attach to m4/3 adapter / m 4/3 to c mount adapter
now screw everything in to your camera nice and tight up to the final spacer ring. Then screw your lens onto your m4/3 adapter. Line up the adapter so that the witness marks of the lens are either facing the top or side, whichever you prefer and mark them so you can line them up again later.
unscrew your lens from the adapter, and unscrew your adapter assembly from the camera. Now line up the marks you made in the last step and epoxy the adapter onto the final step ring.
once it is dry you should be able to screw in your lens to your adapter and your adapter into your camera and there you have it. This set up will absolutely need rod support so if you need help building a custom support down the line I can give you some pointers on that as well
if you have any questions email peter@skibovision.com
skibovision
Active member
oh and by the way you have to use the fotodiox adapter i included in the link. No other adapter will allow you to get infinity focus.