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16mm grinding sound


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#1 Michael Collier

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Posted 15 December 2006 - 09:52 PM

So while I wait on my telecine, I have ample time to worry about the results. While I was organizing all the set audio, I found a few clips where there is an inconsistent grinding sound. I searched the web with 'CP-16 grinding' and found a site that tied the problem to the bowtie shutter. It sounded like a problem of timing, where the film moves before the shutter shuts off the light. Sounds like the same effect that can be gotten with more modern cameras (I have even seen a box to control that on the fly)

Now I am sort of worried, some shots theres that grinding sound during certian points. Its not consistent, sounds like something is rolling. Does anyone know what sort of footage I should expect if the shutter did have an error (is it slight, or completley rubbish?) if anyone has a pic of this error presenting on a CP-16 it might ease my mind.

If its slight and looks like it does in some music videos, I might be alright. In fact, if it looks the way I think it might, it might make the movie really great (its that sort of story where it would make sense). It only happens at times that I would have wanted the effect, if it were planned. Some scenes it can be cut around, some it can be cut between it happening and not for emphasis.

I can correct the audio and pull out the sound....im just worried about the film...I assume I will get smeared highlights if its the problem I am thinking of, I am just not sure how far off the timing could be. if its by a lot, then I would assume highlights would smear sooner (at lower levels) and have a stronger effect, if its by a little then maybe only the specular highlights and practicle lights would smear. at least it didn't happen in any of the EFX shots. This is weird because the camera teched out fine. any help would be appriciated
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#2 ryan_bennett

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Posted 15 December 2006 - 11:42 PM

Ya uh, I don't know how to say this but usually if the camera makes a different sound than normal, there's a problem. It probably is the shutter or the film lost its loop, it happened to me and ya I got the light streaks which was okay for two shots, the rest of the roll will just be left and maybe someday, It'll have a use. Good luck though, I hope it goes well.
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#3 K Borowski

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Posted 15 December 2006 - 11:53 PM

I"m confused: why didn't you hear this sound during the actual filming but heard it now?
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#4 Michael Collier

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Posted 17 December 2006 - 04:09 AM

Karl: Its actually quite soft grinding. I didn't notice on set I suppose because I paid too close attention to the performances. I only noticed when I went to see what could be done about the camera noise (even normal camera noise) and started boosting certain aspects of the noise so I could get an idea of where the camera fell. It was during that boosting that I noticed the sound.

In the end its in so few shots that I can cut around it if I like it, I just am mad I didn't hear it on set.

It wasn't from loosing a loop, we lost the loop only once during the shoot, and it was very apparent when that happened. this is very suttle sound. Maybe grinding puts too much emphasis on the sound.

At this point though I am trying to find a way to bring in the glitch as a story element, by augmenting it at certain points and using editing to bring it forward when the story warrents it, and out when it should be more straight forward. Maybe time away from seeing the film is giving me time to drive myself mad by imagining problems.

Ryan, is there any way you could post a single frame shot of the smearing, just to give me an idea?
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#5 Mike Panczenko

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Posted 17 December 2006 - 11:15 AM

If you didn't hear it on set, I'm wouldn't be as worried as you are. Without hearing it, I can only guess as to what it may be, but it could just be a mag "rubbing." This is where the film is slightly dished and rubs against the side of the mag- usually a smack or two can settle it back into place, but this is not usually a problem unless the rubbing is very severe. It's hard to diagnose what it is without hearing it, but all I can say is get it processed and you'll know- hate to say it, but that's really the only way to know. Congrats on your feature, by the way!
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#6 Hal Smith

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Posted 17 December 2006 - 11:40 AM

.........Its actually quite soft grinding.

One guess is that it's a bearing just starting to go bad. Bearings will often develop an intermittant "moan" when they're just starting to go south. If that's what it is, a good lube might solve the problem for good.
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#7 K Borowski

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Posted 17 December 2006 - 01:13 PM

Mike, you're worrying too much. Take a few days off and think of other things. There is nothing you can do now, so don't' waste your time worrying. I have the same propensity for worry that you do, and most of the time the worries turn out to be unfounded. I shot a wedding where the camera had a set of little red flags that masked off the area that was in frame, as you could rotate the film back to give it either vertical or horizontal composition. In horizontal mode they weren't extending, so I shot the wedding ceremony with the possibility that I had cut off the tops of people's heads because I hadn't caught on to the masks not going into place. I spent two needless weeks of worrying before developing and printing the film to find out that everything was fine. . .
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#8 ryan_bennett

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Posted 20 December 2006 - 01:14 AM

Smearing:
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