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PostPosted: Fri Jun 11, 2010 5:52 pm 
Guys

I am so new to lighting etc. Could you help me out with this?

I bought a Sekonic 308B light meter and if getting a reading say f/2.8 + 5/10ths how do I apply that to camera? Would it be say, 1/3rd stop higher f/3.2? How do you apply 10ths?

Cheers


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PostPosted: Fri Jun 11, 2010 11:30 pm 
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doesn't the 5/10ths (1/2?) refer to the required shutter speed?

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PostPosted: Sat Jun 12, 2010 8:51 am 
You need to know what ISO its using as well.


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PostPosted: Sat Jun 12, 2010 6:44 pm 
Yes the 1/2 does refer to the required shutter speed. I also had the ISO set the same in the camera. That is why I wondered if it was just a half stop of extra light needed?


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PostPosted: Sun Jun 13, 2010 11:50 am 
Is there not anyone here who can advise me how to apply 10ths to the stop value?


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PostPosted: Sun Jun 13, 2010 7:03 pm 
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We don't even know what camera you are using :wink:
But, the manual should probably be your first stop.

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PostPosted: Sun Jun 13, 2010 7:16 pm 
I would of thought the camera is of irrelevance? The question is about how you interpret 1/10th stops on a light meter..... I was just asking should I read 5/10ths as a third of a stop? My camera is a 5D MKII


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PostPosted: Sun Jun 13, 2010 7:36 pm 
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No, you asked how to set a 5/10ths stop ;)

5/10, also known as 1/2 or a "half a stop" is kind of uncommon, but I think you can set your camera to accept half a stop as a parameter.

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PostPosted: Sun Jun 13, 2010 8:21 pm 
Thanks for the answer so is 1/2 stop from f/2.8 - f/3.5?


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PostPosted: Sun Jun 13, 2010 9:48 pm 
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I think that's as close as you're going to get. Beware that the whole thing is logarithmic, so 0.5 stops from F/8 to F/11 is not F/9.5, but more like F/9.


Still, differences get kind of small here.

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PostPosted: Sun Jun 13, 2010 9:55 pm 
Exposure isnt an exact science. Sometimes the 'best' exposure is technically slightly over or under exposed, thats what exposure compensation is for. Digital cameras make this so easy for us. We can just take the shot, and if it isnt exposed correctly, we can look and change the settings slightly.


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PostPosted: Mon Jun 14, 2010 8:38 am 
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Then again, good film can give you more "breathing room", you can get back like 6 stops of highlights :shock:

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PostPosted: Thu Jun 17, 2010 7:35 pm 
I worked it out! I was looking at it too technically so if the result is f/1.4 + 5/10th that is near to f/2. Simple really when you take a step back.


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PostPosted: Fri Jun 18, 2010 12:24 pm 
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F/1.4 to F/2 is one full stop difference. ;)
But half a stop isn' t a horible deviation from the " perfect" exposure. :)

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PostPosted: Mon Jun 21, 2010 4:53 am 
Citruspers wrote:
I think that's as close as you're going to get. Beware that the whole thing is logarithmic, so 0.5 stops from F/8 to F/11 is not F/9.5, but more like F/9.


Yes, and its log base 2. Actually a simple solution to such problems as to do a little maths.

If any thing says: X + yStops (y can also be a fraction)
Then the required aperture is: X * 2^(y/2)

So in this example: 2.8 + 5/10
= 2.8 * 2^(5/20)
= 2.8 * 2^(1/4)
= 2.8 * 1.1892
= 3.3297
~ 3.33
But we do not have 3.33 so go to 3.5, thats the closest you can get. BTW 3.5 is actually 2/3stop down 2.8.

Similarly, For 1.4 + 5/10 gives 1.66 which is not not available so the closest will be 1.8. Again 1.8 is 2/3 stop down 1.4.

You see the problem here is that the aperture quantization is done in thirds not in halfs. But, if you really want your exposure to be spot on. Try nutral density filters. these filters can be combined for all kinds of fractional


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