# Need Source for Equivalent f-stops, pls

#### JumboShrimp

##### EOS RP
Does anyone out there know of a reliable source for equivalent f-stops for 1"-type sensors? Thanks in advance.

#### privatebydesign

##### EOS-1D X Mark III
CR Pro
JumboShrimp said:
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.

#### neuroanatomist

##### I post too Much on Here!!
CR Pro
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).

#### JumboShrimp

##### EOS RP
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

##### I post too Much on Here!!
CR Pro
JumboShrimp said:
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/

Thanks !

#### privatebydesign

##### EOS-1D X Mark III
CR Pro
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.

#### Mt Spokane Photography

##### I post too Much on Here!!
CR Pro
privatebydesign said:
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.

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.

#### stevelee

##### FT-QL
CR Pro
Plus in terms of exposure, f/2.8 is still f/2.8, not f/7, so you get the best of both. The trade offs obviously are elsewhere.

#### unfocused

##### EOS-1D X Mark III
stevelee said:
Plus in terms of exposure, f/2.8 is still f/2.8, not f/7, so you get the best of both. The trade offs obviously are elsewhere.

Yes! As many on this forum know, I have a pet peeve about the way people throw around the term "equivalent" for f-stops when using different sensor sizes. The exposure is not only identical, but the truth is, the depth of field is as well if you shoot from the same distance to subject using the same focal length. All you are doing is cropping a portion of the full frame image in-camera instead of when processing the image. I know I won't win this argument, too many people are too invested in their own concepts to accept the reality, but I still have to try.

But, to the OP, please!!! Understand that we are ONLY talking about apparent depth of field, nothing else.

#### privatebydesign

##### EOS-1D X Mark III
CR Pro
unfocused said:
stevelee said:
Plus in terms of exposure, f/2.8 is still f/2.8, not f/7, so you get the best of both. The trade offs obviously are elsewhere.

Yes! As many on this forum know, I have a pet peeve about the way people throw around the term "equivalent" for f-stops when using different sensor sizes. The exposure is not only identical, but the truth is, the depth of field is as well if you shoot from the same distance to subject using the same focal length. All you are doing is cropping a portion of the full frame image in-camera instead of when processing the image. I know I won't win this argument, too many people are too invested in their own concepts to accept the reality, but I still have to try.

But, to the OP, please!!! Understand that we are ONLY talking about apparent depth of field, nothing else.

That is only because you refuse to accept that noise is part of the equivalence equation.

#### unfocused

##### EOS-1D X Mark III
privatebydesign said:
...That is only because you refuse to accept that noise is part of the equivalence equation.

Huh...what???

When have I ever said that? And what does that have to do with the OP's question? He/She is asking about equivalent f-stops. How does changing f-stops affect noise if the exposure remains the same?

#### privatebydesign

##### EOS-1D X Mark III
CR Pro
unfocused said:
privatebydesign said:
...That is only because you refuse to accept that noise is part of the equivalence equation.

Huh...what???

When have I ever said that? And what does that have to do with the OP's question? He/She is asking about equivalent f-stops. How does changing f-stops affect noise if the exposure remains the same?

I rest my case!

If he/she changes aperture because they have changed sensor size they have also changed the noise characteristics, that is equivalence, and is directly relevant to your post.

#### neuroanatomist

##### I post too Much on Here!!
CR Pro
unfocused said:
The exposure is not only identical, but the truth is, the depth of field is as well if you shoot from the same distance to subject using the same focal length. All you are doing is cropping a portion of the full frame image in-camera instead of when processing the image. I know I won't win this argument, too many people are too invested in their own concepts to accept the reality, but I still have to try.

You won't win the argument...becuase you're wrong. It has nothing to do with people being invested in their own concepts, and everything to do with optical physics.

For clarity, and for the benefit of those who can understand and want to accept reality...if all else is equal and the only thing that differs is the sensor size, the DoF will be shallower with the smaller sensor. The exact same thing would be true if you crop the image in post, instead of using a smaller sensor. Note that 'all else being equal' assumes the other factors affecting DoF (output size, viewing distance, visual acuity) are also held constant. Granted, the magnitude of the difference is relatively small compared to the difference you'd see changing focal length or subject distance to match framing, and note that the difference is in the opposite direction from that latter situation (where smaller sensors are said to have deeper DoF). But there is a difference, and thus your statement that they are identical is wrong.

So please, stop trying...it would be unfortunate if you were to convince people of something that is not real.

#### unfocused

##### EOS-1D X Mark III
neuroanatomist said:
unfocused said:
The exposure is not only identical, but the truth is, the depth of field is as well if you shoot from the same distance to subject using the same focal length. All you are doing is cropping a portion of the full frame image in-camera instead of when processing the image. I know I won't win this argument, too many people are too invested in their own concepts to accept the reality, but I still have to try.

You won't win the argument...becuase you're wrong. It has nothing to do with people being invested in their own concepts, and everything to do with optical physics.

For clarity, and for the benefit of those who can understand and want to accept reality...if all else is equal and the only thing that differs is the sensor size, the DoF will be shallower with the smaller sensor. The exact same thing would be true if you crop the image in post, instead of using a smaller sensor. Note that 'all else being equal' assumes the other factors affecting DoF (output size, viewing distance, visual acuity) are also held constant. Granted, the magnitude of the difference is relatively small compared to the difference you'd see changing focal length or subject distance to match framing, and note that the difference is in the opposite direction from that latter situation (where smaller sensors are said to have deeper DoF). But there is a difference, and thus your statement that they are identical is wrong.

So please, stop trying...it would be unfortunate if you were to convince people of something that is not real.

Just to be clear. You are stating that if someone places a 5DS and a 7DII on tripods next to each other, places a 200 mm lens on both cameras, focuses on a target 50 feet away, shoots both images at f8 and then crops the 5DS image to exactly match the cropping of the 70D, that there will be a discernible difference in the depth of field?

I'm not afraid to be proven wrong, I'd just like to see the proof or a reliable source.

#### privatebydesign

##### EOS-1D X Mark III
CR Pro
unfocused said:
neuroanatomist said:
unfocused said:
The exposure is not only identical, but the truth is, the depth of field is as well if you shoot from the same distance to subject using the same focal length. All you are doing is cropping a portion of the full frame image in-camera instead of when processing the image. I know I won't win this argument, too many people are too invested in their own concepts to accept the reality, but I still have to try.

You won't win the argument...becuase you're wrong. It has nothing to do with people being invested in their own concepts, and everything to do with optical physics.

For clarity, and for the benefit of those who can understand and want to accept reality...if all else is equal and the only thing that differs is the sensor size, the DoF will be shallower with the smaller sensor. The exact same thing would be true if you crop the image in post, instead of using a smaller sensor. Note that 'all else being equal' assumes the other factors affecting DoF (output size, viewing distance, visual acuity) are also held constant. Granted, the magnitude of the difference is relatively small compared to the difference you'd see changing focal length or subject distance to match framing, and note that the difference is in the opposite direction from that latter situation (where smaller sensors are said to have deeper DoF). But there is a difference, and thus your statement that they are identical is wrong.

So please, stop trying...it would be unfortunate if you were to convince people of something that is not real.

Just to be clear. You are stating that if someone places a 5DS and a 7DII on tripods next to each other, places a 200 mm lens on both cameras, focuses on a target 50 feet away, shoots both images at f8 and then crops the 5DS image to exactly match the cropping of the 70D, that there will be a discernible difference in the depth of field?

I'm not afraid to be proven wrong, I'd just like to see the proof or a reliable source.

No he isn't, but then the comparison is not equivalent. Output size is part of the equivalence equation and as such throwing away over half one result isn't equal, is it?

#### Mikehit

##### EOS R6
unfocused said:
Just to be clear. You are stating that if someone places a 5DS and a 7DII on tripods next to each other, places a 200 mm lens on both cameras, focuses on a target 50 feet away, shoots both images at f8 and then crops the 5DS image to exactly match the cropping of the 70D, that there will be a discernible difference in the depth of field?

I'm not afraid to be proven wrong, I'd just like to see the proof or a reliable source.

But that is not what you do.
You would use the appropriate lens on both bodies to give the same framing from where you are standing. And you would use the appropriate aperture to give the DOF you want.

#### unfocused

##### EOS-1D X Mark III
privatebydesign said:
unfocused said:
neuroanatomist said:
...if all else is equal and the only thing that differs is the sensor size, the DoF will be shallower with the smaller sensor...

Just to be clear. You are stating that if someone places a 5DS and a 7DII on tripods next to each other, places a 200 mm lens on both cameras, focuses on a target 50 feet away, shoots both images at f8 and then crops the 5DS image to exactly match the cropping of the 70D, that there will be a discernible difference in the depth of field?

No he isn't...

How is that not what he is saying? Read his statement.

#### privatebydesign

##### EOS-1D X Mark III
CR Pro
unfocused said:
privatebydesign said:
unfocused said:
neuroanatomist said:
...if all else is equal and the only thing that differs is the sensor size, the DoF will be shallower with the smaller sensor...

Just to be clear. You are stating that if someone places a 5DS and a 7DII on tripods next to each other, places a 200 mm lens on both cameras, focuses on a target 50 feet away, shoots both images at f8 and then crops the 5DS image to exactly match the cropping of the 70D, that there will be a discernible difference in the depth of field?

No he isn't...

How is that not what he is saying? Read his statement.

Good god!

If you crop then all else isn't equal, you have thrown away half your image. Reproduction ratio is a key element of equivalence, you are reducing the ff camera to a crop camera and upping the reproduction ratio so there is no equivalence calculation, they are the same, but that is not the same as all else being equal.

#### unfocused

##### EOS-1D X Mark III
privatebydesign said:
unfocused said:
privatebydesign said:
unfocused said:
neuroanatomist said:
...if all else is equal and the only thing that differs is the sensor size, the DoF will be shallower with the smaller sensor...

Just to be clear. You are stating that if someone places a 5DS and a 7DII on tripods next to each other, places a 200 mm lens on both cameras, focuses on a target 50 feet away, shoots both images at f8 and then crops the 5DS image to exactly match the cropping of the 70D, that there will be a discernible difference in the depth of field?

No he isn't...

How is that not what he is saying? Read his statement.

Good god!

If you crop then all else isn't equal, you have thrown away half your image. Reproduction ratio is a key element of equivalence, you are reducing the ff camera to a crop camera and upping the reproduction ratio so there is no equivalence calculation, they are the same, but that is not the same as all else being equal.

Oh, I get it now.

...if all else is equal (except it really isn't equal, because we are either changing the position of the camera or the focal length of the lens) and the only thing that differs is the sensor size (except that it isn't the only thing that differs, because we are changing positions, lenses and or cropping), the DoF will be shallower with the smaller sensor...

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