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Thread: photography question.

  1. #1
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    Default photography question.

    Can someone help me out with this calculation:

    Quite a journey for light to travel and as one would no doubt expects loss of light to the tune of 4 stops occurs.

    a) Which meant? full stop or half stops?
    b) if the aperture is at f5.6, after 4 stop loss of light? Which aperture is it?
    c) Do I have to recalculate the shutter speed as well to compensate the loss of light?



    Sorry for the inconvenience

    Thanks

  2. #2
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    a) if it's half-stop, then it'll be a lost of 2 stops isn't it?

    b) 5.6, 4, 2.8, 2, 1.4

    c) u either compensate by changing the shutter spd or the aperture. doing both means u compensate twice. Unless the aperture doesn't open enough, then u sld compensate through shutter spd.
    Last edited by foxtwo; 6th June 2005 at 09:11 AM.

  3. #3

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    Quote Originally Posted by Benign
    Can someone help me out with this calculation:

    Quite a journey for light to travel and as one would no doubt expects loss of light to the tune of 4 stops occurs.

    a) Which meant? full stop or half stops?
    b) if the aperture is at f5.6, after 4 stop loss of light? Which aperture is it?
    c) Do I have to recalculate the shutter speed as well to compensate the loss of light?



    Sorry for the inconvenience

    Thanks
    a) full stop.
    b) f1.4
    c) no.

    there are other ways of compensating for the reduced light;

    i) reduce shutter speed. by halving the shutter speed every time, you allow twice as much light to enter the camera, thus compensating 1 stop of light. e.g. if your original shutter speed is 1/250 s, a 4-stop compensation is 1/15 s.

    ii) increase ISO setting. by doubling the ISO every time, you enable the sensor/film to be twice as sensitive to the light entering the camera, thus compensating 1 stop of light. e.g. if your original ISO setting is 100, a 4-stop compensation is ISO 1600.

  4. #4
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    Thanks again to foxtwo and zaren

    Lucky I had the doubt cleared up by your two sifus, if not, I would have wasted quite alot of 4x5 sheet films, processing cost and time

    The equipment in question is a piece of nikon accessories: Speed Magny 45 which can be attached to Nikon F, F2 series.
    I just received it this afternoon.....so happy now(pity it came with only double sided ritek film holder).

    Now need to hunt for grafmatic film holder liao......

  5. #5
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    wow chio. how much did the 45 back cost ya?

    Can you post a picture of the F2 with 45 back? thx!

  6. #6
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    Can you post a picture of the F2 with 45 back? thx!
    I will do it when I figure out how to mout the F2 with the 45 back Anything mechanical is trivial to me. It took me ages to remove the double sided film back

    The price I paid? Less than $100 lor. Came with original box some more. Condition would be around 8+

  7. #7

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    Quote Originally Posted by Benign
    Can someone help me out with this calculation:

    b) if the aperture is at f5.6, after 4 stop loss of light? Which aperture is it?
    5.6 ->8 ->11 ->16 ->22

    result will be f22

  8. #8
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    5.6 ->8 ->11 ->16 ->22

    Err, which way is it?

  9. #9

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    Quote Originally Posted by Benign
    Err, which way is it?
    I had wanted to respond to this question. But withheld, expecting this confusion to arise.

    My reason for not writing earlier? Your question was not clear. I have absolutely no idea what you were asking, or what you were trying to achieve.

  10. #10

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    Quote Originally Posted by user111
    5.6 ->8 ->11 ->16 ->22

    result will be f22
    how do you count f stops. i thought it is a multiple of the previous f stop?

  11. #11

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    Quote Originally Posted by Fluorite
    how do you count f stops. i thought it is a multiple of the previous f stop?
    The number is double of the the number two stops before....hmm.... i think that doesn't really make sense. maybe writing it out helps..

    1.4 -> 2 -> 2.8 -> 4 -> 5.6 -> 8 -> 11 -> 16 -> 22

    cool eh?! (haha.. no i didn't discover this by myself). I think this is just the more common scale. I believe there are some cameras that doesn't follow this scale?

  12. #12

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    Quote Originally Posted by Fluorite
    how do you count f stops. i thought it is a multiple of the previous f stop?
    yes, it is the multiple of approximately 1.4 times the previous f-stop, and rounded to 1 decimal place.
    Last edited by zaren; 7th June 2005 at 01:10 PM.

  13. #13

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    Quote Originally Posted by Benign
    Can someone help me out with this calculation:

    Quite a journey for light to travel and as one would no doubt expects loss of light to the tune of 4 stops occurs.

    a) Which meant? full stop or half stops?
    b) if the aperture is at f5.6, after 4 stop loss of light? Which aperture is it?
    c) Do I have to recalculate the shutter speed as well to compensate the loss of light?



    Sorry for the inconvenience

    Thanks
    my understanding of the question is;

    from c), the issue is one of compensating the loss of light.
    from the 1st sentence and b), the lost amount of light to be compensated is 4 stops.

    so...

    to compensate for the loss of 4 stops of light, an aperture of f5.6 will need to be increased to f1.4 as stated in my previous post.
    Last edited by zaren; 7th June 2005 at 01:11 PM.

  14. #14

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    the multiplying factor is square-root-2. round off will be approx 1.4

    as student have pointed out..the question (b) is ambiguous
    but the full sequence as listed by mickey is correct

  15. #15
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    Quote Originally Posted by zaren
    yes, it is the multiple of approximately 1.4 times the previous f-stop, and rounded to 1 decimal place.
    To be precise, it's a multiplication of the previous f-stop by square root of 2 to get the next f-stop
    eat. drink. shoot

  16. #16

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    I think it will be easier if Benign clarifies his question and tell us what he was actually trying to do.

    Otherwise, a benign question may turn malignant!

  17. #17

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    from c) we can infer that benign first wants to recalculate the aperture setting to compensate the loss of light.

    of course it would be *much* clearer if he had originally written,

    "I want to recalculate the aperture setting in my camera to compensate the loss of 4 stops of light. if the aperture is originally at f5.6, what should the new aperture setting be to compensate for the 4-stop loss of light? Do I have to recalculate the shutter speed as well to compensate the loss of light?"

  18. #18
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    Otherwise, a benign question may turn malignant!
    Wah lau eh, my nick or question becoming a fiasco liao.....


    I know I am 'lauyah' at asking question.....but dun get bitchy mah


    Thank you Zaren for doing a 'pro' job on my malignant questions

    Now back to the point, can someone please give a correct answer boh?

  19. #19

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    Quote Originally Posted by Benign
    Wah lau eh, my nick or question becoming a fiasco liao.....


    I know I am 'lauyah' at asking question.....but dun get bitchy mah


    Thank you Zaren for doing a 'pro' job on my malignant questions

    Now back to the point, can someone please give a correct answer boh?
    the correct answer was already given in posts #2 and #3.
    Last edited by zaren; 7th June 2005 at 05:27 PM.

  20. #20
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    the correct answer was already given in posts #2 and #3.
    Sorri sorri......BIG brothas sistas

    I am too occupied with trying to remove the base of the F2 lor

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