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Stephen Gordon

Canon 518 Auto Zoom: Flashing frames problem

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I bought a Canon 814 Auto Zoom in excellent condition, with all functions apparently working, on ebay in April 2019. In May I shot a test cartridge of Kodak Vision 3 200T at the Lickey Hills near Birmingham. The results were very disappointing, with what seems like random, frequent flashes of extreme overexposure throughout, except for a couple of short sequences shot at 36fps which have consistent exposure. The film was processed by Andec and scanned by Gauge Film. I've had no previous problems with any work done by either company, so I think the problem must be with the camera. I am hoping that those with much greater experience of this system and these cameras might be able to take a moment to look at the uploaded footage and offer me any suggestions they may have as to the likely cause of the problem.

You can find the footage here:  https://www.youtube.com/watch?v=M0xmeKgPj9Y&feature=youtu.be

Thanks in advance to the incredibly knowledgeable contributors here!

Stephen 

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It's very difficult to isolate the problem frames on you tube- could you post some frame grabs, including the frames before, during and after the flash?

Until you do it's hard to tell whether the problem is a defective film advance or a sticky shutter. Either could cause overexposure, but my money is on defective advance. I think the problem is masked at 36fps just because the film is moving faster so there are more frames in between faults.

Also, your 18fps looks overcranked so the transfer must have been done at 24 or 25. Either that or the camera is running slow.

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Thanks very much for taking a look Mark!

You are right about the footage being scanned at 25 fps.

I have taken some snapshots in VLC before, after and during the flash as you suggested, but it seems I can only upload 0.29Mb of files and each screen grab is 4.5Mb!

Or am I missing something..?

 

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By the way: I checked the sections shot at 36fps frame-by-frame in VLC and there are no visible flashes that I can see...

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6 minutes ago, Stephen Gordon said:

By the way: I checked the sections shot at 36fps frame-by-frame in VLC and there are no visible flashes that I can see...

There are flashes in the high-speed at 0:57 and 1:02, but it does seem to be running better at 36.

Try uploading to a third-part site such as Photobucket and posting the links here.

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There's a clear double image in some frames usually followed by the overexposure, so my guess is the film is not advancing properly. It's  still moving when it should be stationary when the shutter is open. The shutter could be staying open for too long as well.

I'll let someone more knowledgeable chip in, but my guess is you're going to have to say goodbye to that camera. If it was a business seller you should be able to get a refund.

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Your analysis of the potential problem is much appreciated. I was puzzled because I hadn't come across this problem before, or read about anyone else having it during the seven years I've been following this forum. Your theory would certainly account for the occasional double image, and the shutter staying open too long would certainly account for the overexposure. I think it is the intermittent and random nature of the problem which most perplexed me in identifying a cause.

Thanks again for taking time to look and respond!

Would any other members care to chip in, as Mark suggests?

(I'm not sure I can really go back to the seller given the several months which have now elapsed since the sale)

 

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There are temporal jumps when the flashes occur, which tells you that the film is getting stuck and double exposed. 

Could be that the transport mechanism isn't working properly (damaged claw, gummed gears, intermittent motor, take-up slipping too easily), or the gate is sticky/catching, or the cartridge could be  jamming a bit. It's curious that the 36 fps footage is better - which suggests that the mechanism works at higher speeds, which would point away from the cartridge being the issue, and more towards the camera. 

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Thanks very much Dom - It's clear you are in broad agreement with Mark, and your comments are equally helpful in my understanding of what is causing the intermittent overexposure - the possibility that the film was intermittently jamming  and so double or triple exposing occasional frames had not occurred to me. 

I had already shot another cartridge before I got this one back and saw the problem, so if I get the same result I think I can be pretty sure you are both right and it is the camera. If all is well, I would have to suspect an occasionally jamming cartridge (although, as I've said, I don't remember reading here about anyone having had that problem before).

I'm very grateful for the huge experience and highly analytical minds of the members of this forum!

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1 hour ago, Stephen Gordon said:

Thanks very much Dom - It's clear you are in broad agreement with Mark, and your comments are equally helpful in my understanding of what is causing the intermittent overexposure - the possibility that the film was intermittently jamming  and so double or triple exposing occasional frames had not occurred to me. 

I had already shot another cartridge before I got this one back and saw the problem, so if I get the same result I think I can be pretty sure you are both right and it is the camera. If all is well, I would have to suspect an occasionally jamming cartridge (although, as I've said, I don't remember reading here about anyone having had that problem before).

I'm very grateful for the huge experience and highly analytical minds of the members of this forum!

If you haven't despatched the other roll yet, I would seriously consider ditching it and saving your money. You may be able to replace the camera with the saving.

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Thanks Mark - sound advice for sure, but unfortunately the charges are already paid. Half the roll was used to test another camera, however, so 50% chance of getting something usable back!

Looking again on ebay, it seems the Canon 518 Auto Zooms are going for more than I paid for mine even when they are sold 'spares or repair'! The one I had previously worked fine except the auto zoom buttons died, as did the 36fps. Hence my selling it in order to replace with one sold as supposedly fully functioning. To be fair to the seller, I asked every question except whether if it had been tested with film - caveat emptor indeed!

Still, I'm hopeful of selling mine as spares or repairs in order to partially cover the cost of an 814 Auto Zoom - which seem pretty sturdy according to folks on this forum...

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