Westminster fountain at sunset

by Jorge Córdoba

submit your photo


Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

Take the 2-minute tour ×
Photography Stack Exchange is a question and answer site for professional, enthusiast and amateur photographers. It's 100% free, no registration required.

I have a compact Pentax OptionM10 which I bought in 2006 and sometimes shutter-release button works only when pressing it on edge and under specific angle, but mostly as I apply little pressure which is required to achieve focus and then press fully to take a shot, it just refocuses and then takes a shot by itself so I don't even need to fully press shutter-release button. There is also situation as I hold it slightly pressed and as focus is achieved, it starts to refocus repeatedly until I release shutter button.

Please see this video

What can be done? Do you think shutter-release button worn out or got misplaced inside? Should I disassemble to see what is going on there or take it to electronics repairshop since warranty expired long time ago?

share|improve this question
    
Doing it yourself is the only way it will be worth it. Electronic shops will charge half the price of that camera to look at it and the other half to fix it. Unless it has sentimental value, you can get a brand new point and shoot for $120 or so without any trouble, a warranty and more capabilities. Of course, this is also the opportunity to consider and update to something more capable too :) –  Itai Jun 24 '12 at 17:30

2 Answers 2

When you'll try to disassemble camera - there will be large capacitor. The first thing you should do - discharge it. It have about 10000V inside and it bites hard.

also - i think, that you can try to find same broken camera somewhere on eBay and simply replace shutter release button. I don't think it will be very complicated.

Advice: get a camcoder and shoot all your disassembly work - it will be easier to assemble it back.

share|improve this answer
1  
Capacitor? This camera works on AA batteries. Why camcoder? I have HTC smartphone to do the job. –  John Vice Jun 24 '12 at 13:37
    
I've been electrocuted once or twice while taking apart cameras and it hurts - this is valuable advice! –  Matthew Dresser Jun 24 '12 at 21:21
1  
Capacitor and high voltage mentioned is from the flash. –  Russell McMahon Jun 25 '12 at 0:31
    
@RussellMcMahon Can capacitor be discharged to avoid electrocution? –  John Vice Jul 28 '12 at 13:12
    
@JohnVice - Capacitor will usually self discharge in minutes to tens of minutes. Maybe a few hours if very good quality. Shorting capacitor with a say 1k resistor will discharge it in a few seconds. Shorting with a wire will discharge it rapidly. Small danger of minor metal spatter into eyes if wire used. Ordinary glasses would protect OK. Can be a LARGE bang from high power flashes - 1 k resistor better. –  Russell McMahon Jul 28 '12 at 16:19

Shutter release button:

The fault sounds like it is mechanical BUT this sort of issue can be due to failure in an electronic sub-circuit.

For the reasons expanded on in the next paragraph, you MAY be able to easily access the switch in your camera BUT for certain, in some cameras it is an exceedingly demanding task. There is then the chance that the fault is electronic rather than mechanical and you may not easily be able to identify or obtain the required parts. Having a service manual would help greatly. I once dismantled part of the shutter mechanism of a DSLR to address a problem. Without a manual it took hours and hours and hours and many many attempts to reassemble. The manual explained the arcane tricks which made the task just very hard.

  • Accessibility of the switch depends very much on the specific camera. I had a very similar problem with a Minolta 5D "Alphasweet" [:-(] DSLR. The camera could be triggered using an external "shutter release cable" but could be focused but not released using the usual shutter button. I am reasonably experienced in dismantling and repairing mechanically complex and 'fiddly' equipment, but I found the camera to be too annoying to be worth doing myself. While the shutter button was just under the external surface of the camera you needed to progress around the whole camera modules and covers and wiring and connectors and more to finally get to the switch assembly. I entrusted the repair to the competent and value for money care of Steven at Camera Hospital in Singapore. I consider that that repair would not have been possible by other than a mechanically skilled and experienced repairer. I could have done it but it would have taken me far longer than an expert took.

Flash capacitor discharge: I would not be overly worried by the voltage which may be present due to the flash. A likely way of minimising voltage is to charge the flash, remove the battery and then fire the flash by taking a photo with the camera pointing into a large dark space which the flash cannot illuminate well. If it is not possible to tak a shot with no battery, do as above with battery in and then remove battery asasap after firing. Then lease the camera for a few hours but it will not be overly dangerous regardless. Very very very worst case a photflash shock MIGHT kill somebody by triggering eg a heart attack form the SURPRISE of the shock BUT in the very very large number of cases it will just bite you annoyingly and then be safe.

Capacitor will usually self discharge in minutes to tens of minutes. Maybe a few hours if very good quality. Shorting capacitor with a say 1k resistor will discharge it in a few seconds. Shorting with a wire will discharge it rapidly. Small danger of minor metal spatter into eyes if wire used. Ordinary glasses would protect OK. Can be a LARGE bang from high power flashes - 1 k resistor better.

Flash voltage: The "power" of the flash is only somewhat related to the flash voltage, and battery characteristics. A normal flash has a gas (usually Xenon. Krypton in some specialist applications) in a "discharge tube". The gas is ionised so that it conducts electricity and the discharge excites the gas to produce the flash that you see. The actual discharge voltage for even a very small flash is typically in the 200 - 300 Volt range. In addition there is a trigger coild that generates a MUCH higher voltage to initiate ionisation. This is typically in the 1000 - 5000 V range but may be 20 kV in some applications. That voltage is not stored and will not be a hazard in almost any case.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.