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Thread: Software error in Canon A40?

  1. #1
    turbo_link
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    Default Software error in Canon A40?

    Upgraded from A20 to A40, due to it's ability to take Manual exposure.

    However, observed some weird display of the LCD when in M mode. Wonder is there something wrong with the software of A40.

    When in Manual mode, select 'No flash', set aperture to the smallest, and set any shutter speed. The LCD will turn very dark, and at night time, LCD goes nearly totally black, except the lights in the scene that are barely visible. Half depress the shutter, LCD lights up for a brief moment when camera is focusing, and then darken again when focus achieved. Picture taken is OK.

    It only happened in the above scenario. I have tried other different combination, but everything is OK. I'm wondering whether is it due to bug in the new A40 software.

    Can someone with A40 just try the above settings and help to confirm whether is it affecting all A40, or is it just me suay suay got a faulty one.

    Thanks.

  2. #2
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    Default Re: Software error in Canon A40?

    Originally posted by turbo_link
    Upgraded from A20 to A40, due to it's ability to take Manual exposure.

    However, observed some weird display of the LCD when in M mode. Wonder is there something wrong with the software of A40.

    When in Manual mode, select 'No flash', set aperture to the smallest, and set any shutter speed. The LCD will turn very dark, and at night time, LCD goes nearly totally black, except the lights in the scene that are barely visible. Half depress the shutter, LCD lights up for a brief moment when camera is focusing, and then darken again when focus achieved. Picture taken is OK.

    It only happened in the above scenario. I have tried other different combination, but everything is OK. I'm wondering whether is it due to bug in the new A40 software.

    Can someone with A40 just try the above settings and help to confirm whether is it affecting all A40, or is it just me suay suay got a faulty one.

    Thanks.
    i too have this "problem"....when u set to a large f number (small apperture) and no flash at night, the cam will simulate how your output(pic) will look like when it is taken lor....given such low light situation, u will get a black pic (under-exposed)....that explain for the dark screen we get...

  3. #3

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    I experience the same thing. anyone know why?

  4. #4
    turbo_link
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    Default Re: Re: Software error in Canon A40?

    Originally posted by ray_stinger
    i too have this "problem"....when u set to a large f number (small apperture) and no flash at night, the cam will simulate how your output(pic) will look like when it is taken lor....given such low light situation, u will get a black pic (under-exposed)....that explain for the dark screen we get...
    I first thought so also.
    But then it is not so.

    For my case:
    No flash, small aperature.
    1/500 - dark LCD
    1/60 - dark LCD
    10" - dark LCD
    So dunno what is the correct exposure, took photo with 10" and everything burnt out.


    If according to 'correct' logic, ie, LCD changes with shutter speed, then you should get something like below:
    No flash, small aperature.
    1/500 - darkest LCD
    1/60 - dark LCD
    1" - bright LCD (correct exposure)
    10" - burnt out LCD
    You can know the correct exposure by seeing the LCD.
    But in actual fact, the A40 is not behaving so.

    It also don't have a display of the metering, whether over/under exposure. So what is the use of using M option if you cannot know the metering, and the LCD darken in every stop? 'Agar agar' on an initial exposure and then do bracketing like crazy? That can be an option that I've thought of.

    Am I asking too much from a cheap digicam? Is Nikon digicam with manual option behaving like this?


    ray_stinger, maybe you can help me do a quick check and see whether does your camera behave the same as mine in the above scenario. Thanks.

  5. #5

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    I just did a check on my A40, the LCD react like the 2nd example you gave. I try it in my room with daylight from window and no light is turn on.

    1/500 - darkest LCD, darkest picture
    1/60 - dark LCD, dark picture
    1" - bright LCD (correct exposure) , bright picture
    10" - burnt out LCD, over exposure(all white)

    when using fast shutter, the only time that I can see picture on LCD is when I press the shutter release half way and it only last for like a second.

  6. #6
    turbo_link
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    Originally posted by PsychoBoy
    I just did a check on my A40, the LCD react like the 2nd example you gave. I try it in my room with daylight from window and no light is turn on.

    1/500 - darkest LCD, darkest picture
    1/60 - dark LCD, dark picture
    1" - bright LCD (correct exposure) , bright picture
    10" - burnt out LCD, over exposure(all white)

    when using fast shutter, the only time that I can see picture on LCD is when I press the shutter release half way and it only last for like a second.

    Ok, I did a more thorough testing yesterday nite.
    My experience on the original post was shooting outside the windows at night on the opposite flats.
    So yesterday, did it again, and upon close inspection on the LCD, there is indeed some changes in the lighting level upon changing shutter speed. But still very dark.

    Tried shooting inside the room. Fun begun.
    From 15" to 1/8, the LCD screen is the same brightness. (But still darker than the correct exposure, as when you half depress the shutter, the LCD lights up)
    From 1/13 - 1/xx, (forgotten the stop), the LCD brightness changes with each stop.(But still verk dark)
    From 1/xx - 1/500, LCD is the same darkness. (Can say is virtually black)

    So the correct exposure is somewhere between 15" to 1/8 !!
    End up the correct exposure is 1", after a few bracketing.

    I still believe that it is some software error, or the software engineer did not consider this situation. Since when you half depress the shutter the LCD will light up to the correct exposure, the camera knows the correct setting to use. AND IT SHOULD LET YOU KNOW THROUGH THE LCD BY CHANGING THE BRIGHTNESS.

  7. #7

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    that is pretty normal for a LCD, since the LCD is practically showing a series of still images (as how videos are constructed), the high refresh rate makes it rather impossible to show you the actual brightness of a 10s exposure in video. Usually the brightness of a video is bumped up by increasing the gain, but that will make the video very grainy and noisy, so there's a limit too.

    Anyway, very few metering systems are accurate for nightshots. Usually you have to set your own exposure settings through experience, or bracket. That's worse for a film camera cos you can't review the image, so since you are using a digicam, be thankful! So as long as the A40 shows you the correct effect in dayshots, I don't think it is anything wrong with the camera.

  8. #8
    turbo_link
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    Originally posted by Tweek
    that is pretty normal for a LCD, since the LCD is practically showing a series of still images (as how videos are constructed), the high refresh rate makes it rather impossible to show you the actual brightness of a 10s exposure in video. Usually the brightness of a video is bumped up by increasing the gain, but that will make the video very grainy and noisy, so there's a limit too.

    Anyway, very few metering systems are accurate for nightshots. Usually you have to set your own exposure settings through experience, or bracket. That's worse for a film camera cos you can't review the image, so since you are using a digicam, be thankful! So as long as the A40 shows you the correct effect in dayshots, I don't think it is anything wrong with the camera.
    Ok, Ok, maybe I'm asking too much from a digicam.
    Bo bian, used to the functions provided by SLR, so think likewise.

    Just one more question, is G1/G2 like this? Or did they provide the exposure meter?

  9. #9

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    Originally posted by turbo_link


    Ok, Ok, maybe I'm asking too much from a digicam.
    Bo bian, used to the functions provided by SLR, so think likewise.

    Just one more question, is G1/G2 like this? Or did they provide the exposure meter?
    don't know about that, but most cameras which let you go manual do. My EOS300 and c700uz both do....

    any G1/G2 users can help here?

  10. #10
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    My D5 don't have exposure meter in M mode, I notice that some newer cams don't give an expsoure indicator when in M mode. (well its M, you are the man... Don't want the camera to keep saying I'm under or over... hey I'm the Man right...er.. off topic liao). Use a seperate hand held light meter like what you do for MF, LF and SLR... If you want the built in light meter to help, you should be using the aperture Piority or Shuttle Piority along with the expsoure compensation to achieve the exposure you desire, But these are not available on the A40. So, just read the exposure during auto mode, then go to manual, dial in those values and adjust accordingly, or just use the Exposure compensation.

    But then why is it always dark screen? What's your aperture? Smallest... that'll be F4.8? I guess ISO would be at 50? And you are shooting out at the HDB opposite? You won't be able to capture the HDB except the lights at 10 seconds... Its too dark.

    From your description, I guess its limitation of A40's imaging... Anyway, the lighting up of lcd during half press is not the correct exposure. Its the digital camera's focusing system increasing the gain of the CCD to achieve a level where there's sufficient contrast to focus.

    But then, it could be intended by the engineers. It's known to design products that lacks some functionality so that they can cap the price of the product at a low level. Sometimes functions are not included even though they can be implemented cheaply. This is to justifies the cost of the company's higher end products. Just look at the aperture available... they could have easily allow you to use all those in between, but instead they limit you to the two extreme.
    Last edited by Flare; 23rd April 2002 at 09:38 PM.

  11. #11
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    Default

    Hmmm... the aperture range is 2.8 to 4.8... nothing much in between... hee hee...

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