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tony
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 06, 2005 - 01:52 am: | 
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I picked up an Electro 35 with a rotted pad, which I have replaced. The shutter works OK now, except that it appears to over-expose in the middle of the speed range.
I took a test film and the pictures inside the handhend range came out OK, as did the exposures 3 or 4 stops slower than the handheld range. Only the ones 1 or two stops slower than the handheld range seem overexposed.
Does anyone have a guess what might be causing this please?
There is brief whirring squeaking noise when the lens closes on long exposures. Is that normal or is that perhaps connected to the problem? |
Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 07, 2005 - 11:13 am: |
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Hi Tony,
I am honestly a bit confused about your explanation therefore I will ask you a couple of questions.
1) Have you compared the light meter readings with another camera (or an external light meter)?
2) Have you tried shooting several frames at the same subject with different time / diaphragm combinations?
3) Have you checked if the diaphragm is closing properly?
My apologies if some of those questions seem a bit stupid... However from your short description of the problem, I have the impression that the diaphragm stays open: indoor too little light, camera probably tested with diaphragm completely open or so; outdoor, the fast speeds requires the diaphragm quite open whereas medium speed require it to be close.... ...Therefore if it doesn't close, you overexpose...
Does it make it make sense?
Paolo |
tony
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 07, 2005 - 10:20 pm: |
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Hi Paolo
Thanks for answering. I'm a bit miffed about the problem too 
The Electro 35 has an automatic stepless shutter, so it's not possible to easily check the meter or shutter speeds against another camera.
As far as I can see the diaphragm is fine.
I tried taking several scenes at different diaphragm settings. The pictures at 1.7, 2.8 are OK, as are ones with longer exposures at 8, 16. It's the ones in the middle that over-exposure.
Its quite clear that the shutter is shutting at a range of different speeds for about 1/500 to several seconds.
I'm wondering whether there are different electronic shutter speed control systems for different speed ranges, and maybe one is malfunctioning?
Alternatively. Perhaps the shutter is sticking slightly on exposures longer than say 1/30? (but not for the fastest speeds) Presumably, the overexposure would be less noticeable the longer the shutter-speed. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 08, 2005 - 12:08 am: |
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The shutter speed control system is identical for all aperture setting. The aperture ring has a slide contact which slides over a bank of resistors, telling the shutter circuitry which aperture is selected. These resistors build a timing circuit together with the meter cell. I.e., exposure time is determined by both aperture setting and (light dependent) resistance of the CdS cell.
There is also circutry for the indicator lamps but this works almost independent from the exposure time control, the lamps simply indicate shutter speeds longer than 1/30 or shorter than 1/500 respectively.
My best guess would be that the slide contacts under the aperture ring have some dirt. You can easily remove it by rubbing them gently with electronic contact cleaner (do NOT use WD40 or similar, use contact cleaner spray from the electronic components supplier). |
tony
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 08, 2005 - 05:18 am: |
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Thanks Winfried. That makes sense, I just checked my test film and 5.6, 8 and 11 were the only apertures that didn't expose properly.
By the way, when I replaced the pad I had to unattach then resolder a white wire that ran from the lens assembly to the body under the viewfinder. Knowing the standard of my soldering, could that be the culprit? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 08, 2005 - 06:02 am: |
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If I remember correctly there are only two wires connecting the aperture resistor board to the rest of the circuitry. If it was one of these wires you did not solder correctly it would affect ALL aperture settings.
BTW I don't think that the soldering skills of most of the people assembling the E35 were too high. |
tony mcnicol
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 15, 2005 - 06:12 am: |
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Took the lens out and had a go at cleaning the contacts. Took a test film, but not sure if the camera is working OK or not. Here is a link to an index of the film.
www.tonymcnicol.com/blog/archives/ntest.jpg
Does anyone have an idea what's going on here please? Looks to me like something happens between 4 and 5.6 |
tony
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 17, 2005 - 03:49 am: |
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Help! Have hit a dead end here and would be grateful for any suggestions from Electro 35 owners. |
WernerJB
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 17, 2005 - 09:02 am: |
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Hi, Tony, I have never encountered a problem like yours on any one of my cameras, and I cannot find a sensible explanation for the over-/underexposure problem in your pictures either, sorry. But maybe somebody else knows what has caused all the fuss. |
