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exposure problems with my bauer royal c 10


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#1 andrew parrish

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Posted 23 August 2010 - 11:07 AM

Hi all,

I just got back test 4 carts of 100d, that I shot with a royal c10. I think that I am having a couple of problems that I've never had before. The first is that on the day of the shoot, I noticed that the the little oscillating lever in the view finder, that indicates when you are filling, was moving at an erratic speed. When I got the film back, the exposure was also erratic. It would go from normal exposure to being under exposed in a short rhythmic periods. It was only on one cart of 4. The camera runs smoothly at 18fps empty. Based upon what I have read, I thought that this might be a problem with the one cart.

The next problem might be more serious. The day of the shooting was too bright, so I stopped the camera down with a circular polarizer ( no NDs). Also, I made a mistake, and left the 85a filter on. I was shooting at 18fps, and using the instant slow motion (54fps) were appropriate. When I got the film back, I could see another problem with the exposure. The footage at 18fps looks under exposed, and the stuff at 54fps looks dead on. I have never used the instant 54fps button before, so I am not sure if the camera has been doing this the whole time. I had been writing off the underexposure to that " over expose 64t by 2/3rds of a stop" thing.

Any ideas?
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#2 Alessandro Machi

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Posted 23 August 2010 - 02:34 PM


Any ideas?


Ideas = guesses with this post.

Your first problem sounds like the camera was trying to run at the proper speed but either the cartridge, lack of lubrication, weak batteries or a combination of those three things might have caused the camera to run slower than normal, meaning your footage would look speeded up. Every now and then the filming speed would be ok, and the exposure would normalize for that brief moment.

The second problem. Again another guess here. When you kicked into slow motion, the exposure meter gained enough momentum to go to the right position, but when you release the slow motion button, the new exposure meter position, for some unknown reason, is not where it should be. It's possible there is a sticky spot on the meter wheel.

Assuming the meter should open up a little less than 2 f-stops when switching between 18 to 54 fps, watch the meter and push the button to see how much the meter actually shifts. The additional test to do is see if perhaps your camera just does not meter as accurately when you are over f-11, which is possible. I believe Super-8 cameras have a "sweet spot" for exposure range where you get the optimal results. My "guess" is the sweet spot is between f 2.8 - 4.0 on the open side, and F8 - F11 on the more closed side.

I'm surprised you could see through the viewfinder with both of those filters on the camera. It's been a long while since I used a polarizer so I've forgotten how feasible it is to use a polarize with an 85 filter as well on the front of the lens.
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#3 andrew parrish

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Posted 23 August 2010 - 07:32 PM

Thanks for the quick response. The view through the viewfinder was not bad, although the internal 85a filter was a mistake, and not an artistic choice. I was shooting skateboarding, over new white concrete, and even with the 85a in place it was reading over f22. It think the polarizer brought it down to to f16, if I remember correctly.

When I set the camera to 54fps, and point it at a gray card, the meter reads f8
at 24fps,"..........................."f11 and 1/3rd of the way to f16 (f12.6?)
at 18fps............................."f11 and 2/3rds of the way to f16 (f14.2?)

I think that the shutter angle is 150 degrees, therefor 18fps=1/40, 24 fps=1/60, and 54fps=1/130. By cranking these numbers into my dslr, it looks like fps 18 and 24 are about 1/3 of a stop over.

Can anybody else weigh in? does this sound like a camera lube issue ($150), or something that is going to take parts? ($150, then still junk)

Thanks,

AP
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#4 andrew parrish

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Posted 23 August 2010 - 07:38 PM

Thanks for the quick response. The view through the viewfinder was not bad, although the internal 85a filter was a mistake, and not an artistic choice. I was shooting skateboarding, over new white concrete, and even with the 85a in place it was reading over f22. It think the polarizer brought it down to to f16, if I remember correctly.

When I set the camera to 54fps, and point it at a gray card, the meter reads f8
at 24fps,"..........................."f11 and 1/3rd of the way to f16 (f12.6?)
at 18fps............................."f11 and 2/3rds of the way to f16 (f14.2?)

I think that the shutter angle is 150 degrees, therefor 18fps=1/40, 24 fps=1/60, and 54fps=1/130. By cranking these numbers into my dslr, it looks like fps 18 and 24 are about 1/3 of a stop under.

Can anybody else weigh in? does this sound like a camera lube issue ($150), or something that is going to take parts? ($150, then still junk)

Thanks,

AP
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#5 Alessandro Machi

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Posted 24 August 2010 - 03:07 PM

Nope, just me! (kidding)

Don't forget there is light transmission loss through the viewfinder,

Your readings as they relate to each other seem fine. I am going to go with the f-stop readings are just more accurate as you get closer to the middle of the f-stop range. AS much as I like Polarizers for adding a more saturated look, you may need to use an ND 6 or for your daytime shoots.

Another test to try is to see how much the exposure fluctuates between a wide shot and a telephoto shot. You may find the telephoto shots produce a more accurate overall exposure.

I'm also not so sure about the 150 degree setting, unless you set it to that setting, It might be closer to 160 to 190 degrees in the auto mode. Is the camera an "XL" camera? If it is, then the shutter setting could be as high as 220 degrees. If not, then probably around 160-180. If you can set the shutter yourself, why not go for a 90 degree shutter. You may get the best of all worlds. Less blurry images, better f-stop range for daytime shooting as well. You would probably only need an ND 3 if you have a 90 degree shutter to work with.

The bauer royal c 10 camera does time-exposure. If you decide you like shooting time-exposure you may want to use another camera for more daring shooting as time-exposure is considered rather rare on Super-8 camera.
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#6 andrew parrish

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Posted 26 August 2010 - 10:50 AM

Alessandro, thanks again for all your help. I appreciate your patient answers to my noob problems. I think I has just enough info to drive the topics on some pretty wild goose chases. Anyways, I was digging around the forums last night, and I came across something that might add a new layer to this story. Although I couldn't find specific info on my camera, allot of sights stated that bauer cameras do not use a filter notch, and the metering different types of light ( t or d ) is set manually with the filter switch. Because of this, and my erroneous use of the 85a filter, I am guessing that the under exposure at 18fps and 24fps were caused by the camera "thinking" it was eating up 160asa instead of 100asa. (2/3 of a stop under?). Is it possible that the exposure difference at 54fps was cause by this basic exposure mistake, made worst by three times as much speed?

(I'm working, so I haven't had time to experiment with the telephoto yet!)

Thanks again,

AP
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#7 Miguel Loredo

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Posted 26 August 2010 - 10:58 AM

Most Bauer cameras cannot read correctly a "100D" (ASA 100 with no filter enabled) cartridge. This was well explained to me by a French man who worked in the factory for years. He is now running this website and it's forum:

http://www.cine-supe...Accueil&ordpp=1
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#8 andrew parrish

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Posted 26 August 2010 - 05:52 PM

Sacredieu!! I hope the super8wiki has got it right, when it lists the royal 10c as one of the bauers that works. I think I'll fire off an e-mail. That web sight is cool, by the way. I wish I spoke better french, and didn't have to use the translator. It the translator always seems to add a certain Monty Phython spin to everything.

Cheers,

AP

Most Bauer cameras cannot read correctly a "100D" (ASA 100 with no filter enabled) cartridge. This was well explained to me by a French man who worked in the factory for years. He is now running this website and it's forum:

http://www.cine-supe...Accueil&ordpp=1


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