Calculate crop factor from an APS-C lens onto a M4/3

[Michael Perfect]

Hey all

I'm not sure if this is a smart question or if it makes no sense. Sorry :-|

If you mount an APS-C lens on a M4/3 camera, how do you calculate the 35mm equivalent ? Does that even change anything ?

For example, a 9mm APS-C lens on a M4/3 camera, using an adapter (without any optical elements) will give... what ?

Thanks a lot !

 

[s_grins]

Hey all

I'm not sure if this is a smart question or if it makes no sense. Sorry :-|

If you mount an APS-C lens on a M4/3 camera, how do you calculate the 35mm equivalent ? Does that even change anything ?

For example, a 9mm APS-C lens on a M4/3 camera, using an adapter (without any optical elements) will give... what ?

Thanks a lot !

KISS

All lenses have been marked in their real (35 mm based) FL

If your APS lens has 9 mm FL than CROP for APS sensor will be 8*1.5= 12 and in M43 department this lens has 8"2=16 mm

Cheers

 

[Great Bustard]

Hey all

I'm not sure if this is a smart question or if it makes no sense. Sorry :-|

If you mount an APS-C lens on a M4/3 camera, how do you calculate the 35mm equivalent ? Does that even change anything ?

For example, a 9mm APS-C lens on a M4/3 camera, using an adapter (without any optical elements) will give... what ?

Thanks a lot !

Doesn't matter if the lens is an mFT lens, APS-C lens, or FF lens -- when a lens is mounted on an mFT camera, multiply the actual focal length and actual relative aperture by 2 to get the [diagonal] FF equivalent.

 

[Michael Perfect]

If your APS lens has 9 mm FL than CROP for APS sensor will be 8*1.5= 12 and in M43 department this lens has 8"2=16 mm

Thanks for your answer ! Just trying to understand where the 8 comes from. Did you mean 9 or am I missing something ? Thx !

 

[s_grins]

If your APS lens has 9 mm FL than CROP for APS sensor will be 8*1.5= 12 and in M43 department this lens has 8"2=16 mm

Thanks for your answer ! Just trying to understand where the 8 comes from. Did you mean 9 or am I missing something ? Thx !

My bad: it suppose to be 9*1.5=14 and 9*2=18

Sorry for making you puzzled.

 

[Michael Perfect]

Cool, thank you everyone especially Mister Grins & Great Bustard, your answers really helped.
Good day !

--
Michael
Current work : MIKRO, the Aliens from Earth (self produced)
https://www.youtube.com/channel/UCC71RypUFAfLnXEVIzw-llA

 

[Mark Ransom]

If you want to know what filed of view it has in terms of a 35mm camera, do what everybody else says - multiply by 2. The 9mm lens will have the field of view of 18mm on FF.

But if you want to know how it would compare to another lens on APS-C, multiply by 1.3. The 9mm lens on m43 will have the same field of view as a 12mm lens on APS-C, which will both have the same field of view as 18mm on FF.

 

[Great Bustard]

If you want to know what filed of view it has in terms of a 35mm camera, do what everybody else says - multiply by 2. The 9mm lens will have the field of view of 18mm on FF.

But if you want to know how it would compare to another lens on APS-C, multiply by 1.3. The 9mm lens on m43 will have the same field of view as a 12mm lens on APS-C, which will both have the same field of view as 18mm on FF.

The [diagonal] equivalence ratio (crop factor) for Canon APS-C (1.6) is 1.25 and for everyone else's APS-C (1.5x) is 1.33.

 

[Messier Object]

If you want to know what filed of view it has in terms of a 35mm camera, do what everybody else says - multiply by 2. The 9mm lens will have the field of view of 18mm on FF.

But if you want to know how it would compare to another lens on APS-C, multiply by 1.3. The 9mm lens on m43 will have the same field of view as a 12mm lens on APS-C, which will both have the same field of view as 18mm on FF.

I agree with this approach.

An APS-C user is really concerned with how different the view with their DX or EF-S lens will be on the MFT body. And most APS-C users don’t have a FF camera as a reference

So yes, x1.3 if it’s a Nikon DX or x1.25 if it’s an EF-S lens

Peter

 

[Mark Ransom]

If you want to know what filed of view it has in terms of a 35mm camera, do what everybody else says - multiply by 2. The 9mm lens will have the field of view of 18mm on FF.

But if you want to know how it would compare to another lens on APS-C, multiply by 1.3. The 9mm lens on m43 will have the same field of view as a 12mm lens on APS-C, which will both have the same field of view as 18mm on FF.

The [diagonal] equivalence ratio (crop factor) for Canon APS-C (1.6) is 1.25 and for everyone else's APS-C (1.5x) is 1.33.

Thanks for reminding me that Canon is different. I'm used to Pentax which is 1.53x, and the difference between m43 and Pentax is 1.30x. I did apply some rounding above.

 

[alcelc]

Hey all

I'm not sure if this is a smart question or if it makes no sense. Sorry :-|

If you mount an APS-C lens on a M4/3 camera, how do you calculate the 35mm equivalent ? Does that even change anything ?

For example, a 9mm APS-C lens on a M4/3 camera, using an adapter (without any optical elements) will give... what ?

Thanks a lot !

KISS

All lenses have been marked in their real (35 mm based) FL

If your APS lens has 9 mm FL than CROP for APS sensor will be 8*1.5= 12 and in M43 department this lens has 8"2=16 mm

Cheers

If the APS lens has a physical focal length of 9mm, the equivalent AoV of it on M43 camera should be 18mm. On an APS camera, it is equivalent to 12mm.

The AoV is the "Physical focal length x crop factor". Therefore it should be 9mm x crop factor of the format to be put on, nothing related to whether it is originally design for FF, APS, M43 nor 1" (provided the image circle can cover the sensor surface properly ).

 

[Wu Jiaqiu]

much easier

https://www.pointsinfocus.com/tools...,"av":"4","fl":200,"d":3048,"cm":"0"}],"m":0}

 

[Michael Perfect]

Nice link, thanks a lot !

 

[Michael Perfect]

Thanks again everyone from jumping in;

What do you guys think of this "lens" simulator from Nikon ? Do you find it accurate ?

https://imaging.nikon.com/lineup/lens/simulator/

 

[Mark Ransom]

Thanks again everyone from jumping in;

What do you guys think of this "lens" simulator from Nikon ? Do you find it accurate ?

https://imaging.nikon.com/lineup/lens/simulator/

I don't see any reason why it wouldn't be accurate. Unfortunately it's not quite useful for us since you can't select a m43 sensor, and the widest lens is 14mm.

 

[new_horizons]

Hey all

I'm not sure if this is a smart question or if it makes no sense. Sorry :-|

If you mount an APS-C lens on a M4/3 camera, how do you calculate the 35mm equivalent ? Does that even change anything ?

For example, a 9mm APS-C lens on a M4/3 camera, using an adapter (without any optical elements) will give... what ?

Thanks a lot !

You calculate equivalence the same as you would for any MFT lens. For example, a 9mm lens would be equivalent to an 18mm lens on a 35mm camera.