35mm lenses on HD10?

Alex Raskin · March 6th, 2004, 09:47 PM

David: >>are you considering making such a device?<<

Yes! But I'm not very proficient in Optics at all, so I'd like to have some proven, step-by-step instructions with the parts numbers etc. before I begin, if at all possible...

David Wislon · March 6th, 2004, 10:10 PM

Alex,

I'm not exactly an optical engineer either but I have been surprised how relatively easy it has been to create a contrivance that works, at least, acceptably well. We're feeling pretty confident that we will use some version of such an adapter on our upcoming project for at least some if not all of the shots. How the with and without shots would intercut remains to be seen.

If you were only a bit closer I ask you to drop by and show you what we've been able to cobble together thus far.

My name, for the record, is David Wilson (not Wislon) - a long standing miss-type I just recently discovered and am just now trying to correct.

Joe Russ · March 7th, 2004, 03:12 AM

...
i too am constructing a mini35 adapter for my hd10. its almost done, i just have to finish refining my GG after finals this week. i plan on shooting a short film with it after its constructed. i bought a +10 macro lens for it as the close up focus wasnt good enough on its own. so far tests have been promising....definately will need a lot of light. and right now im using a 50mm f2.8-16 lens. i should have some tests to show once i get all the scratches out of my GG and get everything cemented together.

Alex Raskin · March 8th, 2004, 07:29 AM

Original HD10 lens system, although controlled by servomotor, does Not accept remote controls a-la LANC. Also, manual rotation of the focus ring has the weirdest lag that makes it impossible to hit the same focus marks twice.

35mm adapter should fix this problem, as the quality lens is now attached externally. So manual follow focus should be no problem with the adapter (what are you guys using for FF?)

But let's go 1 step further. I noticed that practically *all* of the optics is AutoFocus lenses - which means, we can control the focusing servomotor inside electronically, and possibly have a completely electronic follow-focus system - with the advantage of *not* touching the camera/rig while focusing.

Is this feasible? Has it been implemented? Am I crazy and this can't be done?

Les Dit · March 8th, 2004, 01:22 PM

Auto focus 35mm lens's usually have a drive socket that the camera body turns. It would be possible to disable the electrical connection to the video cameras focus motor, and bring the connection outside the JVC to a connector. A small gear motor could be mounted to the 35mm lens and the JVC could then focus that. Most people would not be keen on hacking the camera like that, I think.
This would solve some of the problem of getting good focus with the short DOF lens.
-Les

Alex Raskin · March 8th, 2004, 02:19 PM

Les, that is not what I meant.

I proposed to use AutoFocus motor in 35mm lens as means of Follow Focus.

The question is, whether anyone knows what protocol AF servomotors use in 35mm lenses, so then I could make a totally independent (from the camera) electronic device that would be programmable to do Follow Focus electronically.

Just to clarify: I'm not talking autofocus at all.

Les Dit · March 8th, 2004, 05:32 PM

35mm AF lens's don't have a drive motor. The camera body has the motor in it. It's driven by a coupling to the lens.
See my above post.
-Les

Alex Raskin · March 8th, 2004, 07:30 PM

Thanks for clarification... I guess I got it backwards. So there's a Sensor, and not a servomotor in 35mm SLR lens? In this case, looks like the manual FollowFocus rig would be the best bet.

BTW, I'm working on the aldu35 adapter, but with a twist. I'm using old Nikon F body (same like F2) as SLR lens adapter and GG holder.

For GG, instead of the UV filter, I currently use D-type Nikon focusing screen (FS).

My current version has the FS removed from its position on top of the camera, and rather attached straight behind the lens, where the film is supposed to be. (Of course, the 45deg. mirror must be out of the way as well).

This way, HD10 is positioned straight behind the adapter, and not at right angle vertically to the Nikon - as others did.

Advantage: the whole rig can be mounted normally on tripod etc.

Current problem: the ground glass (brand new focusing screen) does not seem to be fine enough. HD10 can clearly see the grainy structure of it. Waiting for the fine aluminum oxide powder to try and improve the FS so the grain is no longer detectable.

Will report on progress (anyone else?)

Les Dit · March 8th, 2004, 07:59 PM

No sensor in the AF lens either. The focus is determined by the optics and sensors in the SLR body as well.

Back to what I thought was your intent: I like the idea of driving the focus of an external lens from the JVC's servo signal. It would not know that it is actually focusing an outside lens.

-Les

Alex Raskin · March 8th, 2004, 08:03 PM

Off-topic, but I just need to understand... you wrote:

>>No sensor in the AF lens either.

So no sensor and no servomotor in the SLR lenses? Then what the electric contacts on the AF SLR lens are for?

Les Dit · March 8th, 2004, 11:29 PM

F-stop info, and lens ID, perhaps focal length. Depends on manufacturer.
Do you have an AF SLR lens? Take it off, look on the back, and see the drive coupling, it may look like something a small screwdriver would turn.
Trust me, manufacturers are smart, they don't want to put a motor in each lens, when one in the body will cover any number of lenses. Same for focus electronics.
-Les

<<<-- Originally posted by Alex Raskin : Off-topic, but I just need to understand... you wrote:

>>No sensor in the AF lens either.

So no sensor and no servomotor in the SLR lenses? Then what the electric contacts on the AF SLR lens are for? -->>>

Alex Raskin · March 11th, 2004, 10:08 AM

OK, while waiting on the aluminum oxide powder to refine the ground glass, I decided to make yet another experiment.

I thought - why not use the 35mm photo film itself as ground glass?

It's already of the correct size and acceptable granularity.

So I shot uniformly white and grey out-of-focus surfaces of different intensities, and developed the film.

Result: failure. The film does not seem to "catch" and diffuse the light from the lens like Ground Glass does. Instead, I can see right through the film and into the lens, no matter how dark or light the film is. Bummer!

Seems like aluminum oxide and refined Ground Glass is about the only option now. I'll report on progress when the powder arrives.

Alex Raskin · April 1st, 2004, 09:43 AM

Seems like with HDV resolution, the GG grain issue becomes catastrophic.

After some experimentation with grounding of the UV filter glass, which proved still unacceptable even with the very fine grit (started with 9, finished with 25), I'm waiting on the Bosscreen material... but I don't hold my breath for it either.

So, is there positively no way to eliminate GG altogether? What if we use not 35mm SLR, but 16mm movie primes, thus making the "projected" image smaller and closer to the native size of the prosumer cams' CCD?

I'm willing to rip the JD10's original lens system out and replace it with the PL-mount and 16mm Zeiss Superspeed lenses. Why won't it work?

Les Dit · April 1st, 2004, 01:07 PM

If you removed the lens, the camera control electronics would error out and probably lock up the camera.
Why not just move the GG to get rid of the grain?
-L

Alex Raskin · April 1st, 2004, 02:08 PM

Les, moving GG means noise, possible vibration, definitely *much* larger size than static GG system, much lheavier weight of the adapter, and power concerns.

Will I go rotating GG route? Yes, if Bosscreen won't work. Supposedly, this should be clarified tomorrow, Friday.

March 8th, 2004, 07:29 AM	#19
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	Follow Focus on HD10 Original HD10 lens system, although controlled by servomotor, does Not accept remote controls a-la LANC. Also, manual rotation of the focus ring has the weirdest lag that makes it impossible to hit the same focus marks twice. 35mm adapter should fix this problem, as the quality lens is now attached externally. So manual follow focus should be no problem with the adapter (what are you guys using for FF?) But let's go 1 step further. I noticed that practically all of the optics is AutoFocus lenses - which means, we can control the focusing servomotor inside electronically, and possibly have a completely electronic follow-focus system - with the advantage of not touching the camera/rig while focusing. Is this feasible? Has it been implemented? Am I crazy and this can't be done?

March 8th, 2004, 01:22 PM	#20
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	yes Auto focus 35mm lens's usually have a drive socket that the camera body turns. It would be possible to disable the electrical connection to the video cameras focus motor, and bring the connection outside the JVC to a connector. A small gear motor could be mounted to the 35mm lens and the JVC could then focus that. Most people would not be keen on hacking the camera like that, I think. This would solve some of the problem of getting good focus with the short DOF lens. -Les

April 1st, 2004, 09:43 AM	#28
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	UPDATE Seems like with HDV resolution, the GG grain issue becomes catastrophic. After some experimentation with grounding of the UV filter glass, which proved still unacceptable even with the very fine grit (started with 9, finished with 25), I'm waiting on the Bosscreen material... but I don't hold my breath for it either. So, is there positively no way to eliminate GG altogether? What if we use not 35mm SLR, but 16mm movie primes, thus making the "projected" image smaller and closer to the native size of the prosumer cams' CCD? I'm willing to rip the JD10's original lens system out and replace it with the PL-mount and 16mm Zeiss Superspeed lenses. Why won't it work?

March 6th, 2004, 09:47 PM	#16
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	David: >>are you considering making such a device?<< Yes! But I'm not very proficient in Optics at all, so I'd like to have some proven, step-by-step instructions with the parts numbers etc. before I begin, if at all possible...

March 6th, 2004, 10:10 PM	#17
David Wislon New Boot Join Date: Jul 2003 Location: Los Angeles, CA Posts: 24	Alex, I'm not exactly an optical engineer either but I have been surprised how relatively easy it has been to create a contrivance that works, at least, acceptably well. We're feeling pretty confident that we will use some version of such an adapter on our upcoming project for at least some if not all of the shots. How the with and without shots would intercut remains to be seen. If you were only a bit closer I ask you to drop by and show you what we've been able to cobble together thus far. My name, for the record, is David Wilson (not Wislon) - a long standing miss-type I just recently discovered and am just now trying to correct.

March 7th, 2004, 03:12 AM	#18
Joe Russ Regular Crew Join Date: Jul 2003 Location: New York, NY Posts: 99	... i too am constructing a mini35 adapter for my hd10. its almost done, i just have to finish refining my GG after finals this week. i plan on shooting a short film with it after its constructed. i bought a +10 macro lens for it as the close up focus wasnt good enough on its own. so far tests have been promising....definately will need a lot of light. and right now im using a 50mm f2.8-16 lens. i should have some tests to show once i get all the scratches out of my GG and get everything cemented together.

March 8th, 2004, 02:19 PM	#21
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	Les, that is not what I meant. I proposed to use AutoFocus motor in 35mm lens as means of Follow Focus. The question is, whether anyone knows what protocol AF servomotors use in 35mm lenses, so then I could make a totally independent (from the camera) electronic device that would be programmable to do Follow Focus electronically. Just to clarify: I'm not talking autofocus at all.

March 8th, 2004, 05:32 PM	#22
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	35mm AF lens's don't have a drive motor. The camera body has the motor in it. It's driven by a coupling to the lens. See my above post. -Les

March 8th, 2004, 07:30 PM	#23
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	Thanks for clarification... I guess I got it backwards. So there's a Sensor, and not a servomotor in 35mm SLR lens? In this case, looks like the manual FollowFocus rig would be the best bet. BTW, I'm working on the aldu35 adapter, but with a twist. I'm using old Nikon F body (same like F2) as SLR lens adapter and GG holder. For GG, instead of the UV filter, I currently use D-type Nikon focusing screen (FS). My current version has the FS removed from its position on top of the camera, and rather attached straight behind the lens, where the film is supposed to be. (Of course, the 45deg. mirror must be out of the way as well). This way, HD10 is positioned straight behind the adapter, and not at right angle vertically to the Nikon - as others did. Advantage: the whole rig can be mounted normally on tripod etc. Current problem: the ground glass (brand new focusing screen) does not seem to be fine enough. HD10 can clearly see the grainy structure of it. Waiting for the fine aluminum oxide powder to try and improve the FS so the grain is no longer detectable. Will report on progress (anyone else?)

March 8th, 2004, 07:59 PM	#24
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	No sensor in the AF lens either. The focus is determined by the optics and sensors in the SLR body as well. Back to what I thought was your intent: I like the idea of driving the focus of an external lens from the JVC's servo signal. It would not know that it is actually focusing an outside lens. -Les

March 8th, 2004, 08:03 PM	#25
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	Off-topic, but I just need to understand... you wrote: >>No sensor in the AF lens either. So no sensor and no servomotor in the SLR lenses? Then what the electric contacts on the AF SLR lens are for?

March 8th, 2004, 11:29 PM	#26
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	F-stop info, and lens ID, perhaps focal length. Depends on manufacturer. Do you have an AF SLR lens? Take it off, look on the back, and see the drive coupling, it may look like something a small screwdriver would turn. Trust me, manufacturers are smart, they don't want to put a motor in each lens, when one in the body will cover any number of lenses. Same for focus electronics. -Les <<<-- Originally posted by Alex Raskin : Off-topic, but I just need to understand... you wrote: >>No sensor in the AF lens either. So no sensor and no servomotor in the SLR lenses? Then what the electric contacts on the AF SLR lens are for? -->>>

March 11th, 2004, 10:08 AM	#27
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	OK, while waiting on the aluminum oxide powder to refine the ground glass, I decided to make yet another experiment. I thought - why not use the 35mm photo film itself as ground glass? It's already of the correct size and acceptable granularity. So I shot uniformly white and grey out-of-focus surfaces of different intensities, and developed the film. Result: failure. The film does not seem to "catch" and diffuse the light from the lens like Ground Glass does. Instead, I can see right through the film and into the lens, no matter how dark or light the film is. Bummer! Seems like aluminum oxide and refined Ground Glass is about the only option now. I'll report on progress when the powder arrives.

April 1st, 2004, 01:07 PM	#29
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	If you removed the lens, the camera control electronics would error out and probably lock up the camera. Why not just move the GG to get rid of the grain? -L

April 1st, 2004, 02:08 PM	#30
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	Les, moving GG means noise, possible vibration, definitely much larger size than static GG system, much lheavier weight of the adapter, and power concerns. Will I go rotating GG route? Yes, if Bosscreen won't work. Supposedly, this should be clarified tomorrow, Friday.