February 26, 2017, 12:31:29 PM

Author Topic: Need Source for Equivalent f-stops, pls  (Read 1437 times)

JumboShrimp

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Need Source for Equivalent f-stops, pls
« on: January 19, 2017, 02:31:05 PM »
Does anyone out there know of a reliable source for equivalent f-stops for 1"-type sensors? Thanks in advance.

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Need Source for Equivalent f-stops, pls
« on: January 19, 2017, 02:31:05 PM »

privatebydesign

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Re: Need Source for Equivalent f-stops, pls
« Reply #1 on: January 19, 2017, 02:39:59 PM »
Does anyone out there know of a reliable source for equivalent f-stops for 1"-type sensors? Thanks in advance.

As not all 1" sensors are the same size, just like APS, you need the actual sensor dimensions. Once you have that the factor is a constant.

Tell us what size your 1" sensor actually is and we'll give you the factor.
Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, DR, MP's or AF, it is about the light.

neuroanatomist

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Re: Need Source for Equivalent f-stops, pls
« Reply #2 on: January 19, 2017, 02:42:27 PM »
As an approximation, the Sony RX100-type sensor has a crop factor of 2.72, so to get the equivalent f/number you just multiply by that (e.g. 50mm f/2 on an RX100 is equivalent to approximately 136mm f/5.4 on FF).   
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JumboShrimp

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Re: Need Source for Equivalent f-stops, pls
« Reply #3 on: January 19, 2017, 03:28:06 PM »
Thanks for the replies, gents. The camera in question is the Lumix FZ1000. It has a 1"-type sensor with dim's of 8.8 x 13.2 mm.

Mt Spokane Photography

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Re: Need Source for Equivalent f-stops, pls
« Reply #4 on: January 19, 2017, 07:00:12 PM »
Thanks for the replies, gents. The camera in question is the Lumix FZ1000. It has a 1"-type sensor with dim's of 8.8 x 13.2 mm.

Same as the Sony, 2.72 or some say 2.73.

http://www.digicamdb.com/compare/panasonic_lumix-dmc-fz1000-vs-sony_cybershot-dsc-rx100-iii/

JumboShrimp

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Re: Need Source for Equivalent f-stops, pls
« Reply #5 on: January 19, 2017, 08:41:37 PM »
Thanks !

privatebydesign

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Re: Need Source for Equivalent f-stops, pls
« Reply #6 on: January 19, 2017, 09:31:59 PM »
Hey Jumbo,

Obviously Mt Spokane is right.

If you want to know the way to do it for any sensor here is the formula.

Divide the diagonal of a FF sensor by the diagonal of the sensor you want a multiplication factor for.

So 'FF' sensor diagonal equals square root of 24mm sq plus 36mm sq. Or a 43mm diagonal. Now take your 1" sensor, 8.8mm x 13.2 mm at 15.9mm diagonal.  43/15.9 = 2.70 crop factor for focal length and aperture.

Any figure you want on a ff camera divide by 2.7 to get on your 1" sensor. A 200mm f2.8 on FF would be a 74mm f1.0 equivalent on the 1" sensor. To go the other way multiply your 1" sensor lens by 2.7 to get the FF equivalent, so an 8mm f2.8 on the small camera would be a 22mm f7.6 on FF.

This also works for sensors larger than the base sensor, so you can work out equivalence figures in the negative for say a medium format sensor in relation to a 'FF' sensor.

Hope this addendum helps.
Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, DR, MP's or AF, it is about the light.

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Re: Need Source for Equivalent f-stops, pls
« Reply #6 on: January 19, 2017, 09:31:59 PM »

Mt Spokane Photography

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Re: Need Source for Equivalent f-stops, pls
« Reply #7 on: January 19, 2017, 10:40:56 PM »
Hey Jumbo,

Obviously Mt Spokane is right.

If you want to know the way to do it for any sensor here is the formula.

Divide the diagonal of a FF sensor by the diagonal of the sensor you want a multiplication factor for.

So 'FF' sensor diagonal equals square root of 24mm sq plus 36mm sq. Or a 43mm diagonal. Now take your 1" sensor, 8.8mm x 13.2 mm at 15.9mm diagonal.  43/15.9 = 2.70 crop factor for focal length and aperture.

Any figure you want on a ff camera divide by 2.7 to get on your 1" sensor. A 200mm f2.8 on FF would be a 74mm f1.0 equivalent on the 1" sensor. To go the other way multiply your 1" sensor lens by 2.7 to get the FF equivalent, so an 8mm f2.8 on the small camera would be a 22mm f7.6 on FF.

This also works for sensors larger than the base sensor, so you can work out equivalence figures in the negative for say a medium format sensor in relation to a 'FF' sensor.

Hope this addendum helps.

The equivalent aperture is why small sensor bodies can have a huge depth of field, and why autofocus can be easily made faster.  Focusing to 1/3 of the depth of focus for a f/7 aperture means fast focusing is easy.

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Re: Need Source for Equivalent f-stops, pls
« Reply #7 on: January 19, 2017, 10:40:56 PM »