Homemade telecine using 24p video cam

[Filmosity]

So, has anyone experimented with using a 24p camera (i.e., Panasonic's DVX100a) to do a homemade transfer?

I would imagine that if you were to use even a regular 8mm projector that runs at 24fps with footage shot at 24fps, you could use a camera such as the DVX100 to do the transfer to video. I would think that because everything is running at the same speed, the flicker issue would disappear.

Am I on to something here? or is there something I'm missing?

-Cavs

[mattias]

I would think that because everything is running at the same speed, the flicker issue would disappear.

the flicker issue disappears with any camera if everything is running at the correct speed. the problem is that projectors generally don't. you'd still need a crystal synced one or one with variable speed so you can dial it out.

/matt

[Filmosity]

I would think that because everything is running at the same speed, the flicker issue would disappear.

the flicker issue disappears with any camera if everything is running at the correct speed. the problem is that projectors generally don't. you'd still need a crystal synced one or one with variable speed so you can dial it out.

/matt

Right, but I mean if you only have a regular 24fps projector (not one specifically made for telecine), could the camera be used with good results?

It stands to reason that if both the camera and the projector are projecting/capturing at 24fps, there should be little to no flicker. Right?

[mattias]

if [the projector is projecting] at 24fps

if, sure, but it isn't unless it's crystal synced or has a manual speed dial that you can turn to an exact match. you'd also have to replace the shutter with a one or two blade one if you expect perfect results with no frame blending.

/matt

[Lunar07]

I would think that because everything is running at the same speed, the flicker issue would disappear.

the flicker issue disappears with any camera if everything is running at the correct speed. the problem is that projectors generally don't. you'd still need a crystal synced one or one with variable speed so you can dial it out.

/matt

I do not have the answer to the original question because I know nothing about 24p video cams. But I believe you needlessly complicated the issue here :-D
We know that with a 3-blade shutter on a projector running at 20FPS one can capture to a video cam running at 30 FPS (60 fields per second) with no flicker. The thing here is that the video cam synchs well with what it sees coming from projector.
How does the above compare or translates to a 24p video cam regarding the speed of the projector and number of blades.
Crystal Synching the projector is not the issue here.

[mattias]

We know that with a 3-blade shutter on a projector running at 20FPS one can capture to a video cam running at 30 FPS (60 fields per second) with no flicker.

*if* it's running at 20fps, which it isn't unless it crystal synced or you have a variable speed dial. i have a very hard time understanding what's at all "complicated" about that. wait until i tell you what two plus two is, then you'll see complicated...

Crystal Synching the projector is not the issue here

of course it is. you can use any camera and any number of shutter blades if you just have a way of controlling the projector speed, but if you don't, changing the number of blades or spending millions on cameras won't help you at all.

/matt

[Filmosity]

whoa, let's not get nasty here. I'm very new to this whole thing. I've never shot anything on film (aside from stills), so i'm trying to figure things out.

Bascially, I want to be able to shoot film, get it processed, and -on the cheap- telecine it myself so I can edit on my Final Cut Pro system and master back to tape. I may have access to a 24p camera, and I have a Kodak Brownie 300 Model 1 projector, so I was curious if it would work.
Hell, I don't even what speed the projector runs at.

no need to make fun of people.

[mattias]

whoa, let's not get nasty here. I'm very new to this whole thing.

that's what i thought, which is why i explained that even though a projector says it's 24fps it never is, so the perfect match you were hoping for doesn't exist. as for nastyness lunar said i was complicating the issue when it was in fact him who was, and i'm known for being a bit nasty in those situations so i'm sure he doesn't mind much. :-)

/matt

[Lunar07]

Ok! The projector we have is crystal synched. We know that this crystal synched 3-blade shutter projector running at 20fps will synch well with a video cam running at 30 fps.
How does this map to a 24p video cam? What is the speed of the crystal synched projector and how many blades it should have in order to synch it well to a 24p video cam.
This is the orignal question that was complicated needlessly by mattias answer :-D

We know that with a 3-blade shutter on a projector running at 20FPS one can capture to a video cam running at 30 FPS (60 fields per second) with no flicker.

*if* it's running at 20fps, which it isn't unless it crystal synced or you have a variable speed dial. i have a very hard time understanding what's at all "complicated" about that. wait until i tell you what two plus two is, then you'll see complicated...

Crystal Synching the projector is not the issue here

of course it is. you can use any camera and any number of shutter blades if you just have a way of controlling the projector speed, but if you don't, changing the number of blades or spending millions on cameras won't help you at all.

/matt

[Lunar07]

I would think that because everything is running at the same speed, the flicker issue would disappear.

the flicker issue disappears with any camera if everything is running at the correct speed. the problem is that projectors generally don't. you'd still need a crystal synced one or one with variable speed so you can dial it out.

/matt

Assumig that the projector is crystal synched, what is the correct combination of projector speed (that can be dialled on that crystal synched projector of yours :-D )and blades to transfer to with no flicker to the 24p video cam. We go back to the original question.

[mattias]

Ok! The projector we have is crystal synched.

yeah, i know what you're saying. i just didn't answer since you accused me of not answering the original question, which i think i was. :-)

the number of blades doesn't really matter in this case. it only does when the camera is faster than the speed of the projector, as is the case with ntsc transfers or 18 fps pal transfers (i'm assuming 24 fps pal transfers are always done at 25 fps). so yes, it will work just fine, if we're only considering flicker. i'd recommend using a one or two bladed shutter to avoid frame blending though. with a three bladed shutter two film frames can span one video frame, and when the camera adds its 3:2 pulldown on playback that won't look very good.

/matt

[paulcotto]

You can use a projector that has a synchronous motor. I.E. one that locks to the line frequency. In the USA the line frequency is 60hz. In most of Europe it's 50hz. If you use a toothed timing belt and cogged pulleys you can drive a projector locked to the line frequency. You don't need a fancy crystal sync to drive a projector at a constant rate. Most such motors turn at a multiple of 60. 1800 rpm is the most common. 1800 rpm divided by 60 = 30 turns per second. IF you want the projector main shaft to turn at 24 turns per second you would have to have a ratio that drops the 30 turns per second down to the 24 turns per second. This can be done by dividing 6 into each number. 24 divided by 6 = 4. 30 divided by 6 is 5. So now you know you need a 4:5 ratio. If you buy yourself a 40 cog and 50 cog pulley and a timing belt to run between the two of them. You can buy all this stuff at Sterling Instrument Stock Drive Products. Here is the URL>>>>

http://www.sdp-si.com/

Now stop the arguing and try to find solutions to your problems

Regards,
Paul Cotto
PS: Thanks to Clive Tobin for teaching me this stuff!

[mattias]

Now stop the arguing and try to find solutions to your problems :(

i thought we did?!? as an argument this has to be the least heated ones on this board ever... :-)

/matt

[Carlos 8mm]

With a two blade shutter is possible to trasferring film to video (PAL) at 24fps.

With a 24p video camera, It will be necesary a two-blade shutter variable speed projector if you wish to transfer the film at about 24fps.

Or, It is possible trasferring the film with a 3-blade shutter projector at about 16 fps. Some video frames will be an exact copy of the original film frames, others will looks like two "mixded" frames in both cases, using 2 or 3 blade shutter projectors.

I think the best solutuion is using a 2 blade shutter projector. The blade angles must to be very precise to avoid fickering.

Get some 16 mm projector with a two blade shutter (I recommend Siemens 2000) and do some tests.

Carlos.

[mattias]

With a two blade shutter is possible to trasferring film to video (PAL) at 24fps.

you mean 25 fps.

With a 24p video camera, It will be necesary a two-blade shutter variable speed projector if you wish to transfer the film at about 24fps.

not really. only if you want to completely avoid frame blending. there should be no flicker even with a 3 bladed shutter.

I think the best solutuion is using a 2 blade shutter projector. The blade angles must to be very precise to avoid fickering.

true. or a one blade shutter since the camera's progressive, and it wouldn't have to be as precise.

/matt