180 mm on MF would be ???mm on APS-C ?

[DuckTape]

How to figure out how long should be the lens on croped camera if on medium format (6x6) it would be 180mm.

Thanks.

 

[xpatUSA]

The usual expression is like: equivalent focal length on target camera = lens focal length x target sensor diagonal / source sensor diagonal.

So, for MF to my Sigma (1.7 crop) it would be:

180 * (24.88) / (sqrt(6^2+6^2) *25.4) = 21mm

APS-C, approx

180 * (28) / (sqrt(6^2+6^2) *25.4) = 23mm

 

[Allan Olesen]

Since the aspect ratios of the two formats are different, the answer depends on whether you want the height or width or diagonal to have the same field of view.

Medium format 6x6: Height = 60 mm, Width = 60 mm, Diagonal = 84.9 mm

APS 1.5x crop: Height = 16 mm, Width = 24 mm, Diagonal =28.8 mm

The ratio between the two focal lengths has to be equal to the ratio between the two sensor sizes in the direction you want to compare.

So if you for example want the same field of view in the width of the photo, the answer will be 180 * 24 / 60 mm = 72 mm.

 

[Allan Olesen]

The usual expression is like: equivalent focal length on target camera = lens focal length x target sensor diagonal / source sensor diagonal.

So, for MF to my Sigma (1.7 crop) it would be:

180 * (24.88) / (sqrt(6^2+6^2) *25.4) = 21mm

APS-C, approx

180 * (28) / (sqrt(6^2+6^2) *25.4) = 23mm

 

[xpatUSA]

The usual expression is like: equivalent focal length on target camera = lens focal length x target sensor diagonal / source sensor diagonal.

So, for MF to my Sigma (1.7 crop) it would be:

180 * (24.88) / (sqrt(6^2+6^2) *25.4) = 21mm

APS-C, approx

180 * (28) / (sqrt(6^2+6^2) *25.4) = 23mm

 

[DuckTape]

Since the aspect ratios of the two formats are different, the answer depends on whether you want the height or width or diagonal to have the same field of view.

Medium format 6x6: Height = 60 mm, Width = 60 mm, Diagonal = 84.9 mm

APS 1.5x crop: Height = 16 mm, Width = 24 mm, Diagonal =28.8 mm

The ratio between the two focal lengths has to be equal to the ratio between the two sensor sizes in the direction you want to compare.

So if you for example want the same field of view in the width of the photo, the answer will be 180 * 24 / 60 mm = 72 mm.

Yes, I guess it sounds closer.

Thanks, Allan.

 

[JimKasson]

Medium format 6x6: Height = 60 mm, Width = 60 mm, Diagonal = 84.9 mm

Nominal 6x6 is actually about 56x56mm

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www.apug.org

Jim

 

[D Cox]

How to figure out how long should be the lens on cropped camera if on medium format (6x6) it would be 180mm.

Thanks.

The standard lens on a 6x6cm medium format camera is 80mm. So your tele lens is a bit more than double the standard length.

If the standard length for your APS-C camera is 35mm then a tele of about 80mm would give a similar angle of view.

No point in trying to be exact when one format is square and the other a rectangle.

 

[Allan Olesen]

Medium format 6x6: Height = 60 mm, Width = 60 mm, Diagonal = 84.9 mm

Nominal 6x6 is actually about 56x56mm

Loading…

www.apug.org

Jim

 

[xpatUSA]

Medium format 6x6: Height = 60 mm, Width = 60 mm, Diagonal = 84.9 mm

Nominal 6x6 is actually about 56x56mm

http://www.apug.org/forums/archive/index.php/t-75761.html

Jim

 

[Allan Olesen]

Medium format 6x6: Height = 60 mm, Width = 60 mm, Diagonal = 84.9 mm

Nominal 6x6 is actually about 56x56mm

http://www.apug.org/forums/archive/index.php/t-75761.html

Jim

--
http://blog.kasson.com

Heh, so my reply was only slightly better than Ted's. But we are getting closer an closer.

A sort of 'successive approximation', Allan?

I guess so.

 

[DuckTape]

How to figure out how long should be the lens on cropped camera if on medium format (6x6) it would be 180mm.

Thanks.

The standard lens on a 6x6cm medium format camera is 80mm. So your tele lens is a bit more than double the standard length.

If the standard length for your APS-C camera is 35mm then a tele of about 80mm would give a similar angle of view.

No point in trying to be exact when one format is square and the other a rectangle.

Yes, right. I think something like 80 mm is a proper thing.

Thanks to all. )))))

 

[bobn2]

How to figure out how long should be the lens on croped camera if on medium format (6x6) it would be 180mm.

Thanks.

How are you going to handle the format difference? Will you crop the crop (presumably APS-C) sqare or crop the 6x6 3:2, or crop them both to some other aspect ratio (8:10).

Assuming Crop is 15.6x28.4 mm and 56x56mm for 6x6, then

For square format, crop = 15.6x15.6, diagonal 22 mm, 6x6 = 56x56, diag 79, CF 3.6, FL = 50mm

For 3: 2, crop = 15.6x28.4, diag 28.4, 6x6 = 56x37.3, diag 67.3, CF 2.4, FL = 75mm

For 8x10, crop = 15.6x19.5, diag 25, 6x6 = 45x56, diag = 71.7, CF 2.9, FL = 63mm.

Hope that helps.

 

[xpatUSA]

How to figure out how long should be the lens on croped camera if on medium format (6x6) it would be 180mm.

Thanks.

How are you going to handle the format difference? Will you crop the crop (presumably APS-C) sqare or crop the 6x6 3:2, or crop them both to some other aspect ratio (8:10).

Assuming Crop is 15.6x28.4 mm and 56x56mm for 6x6, then

For square format, crop = 15.6x15.6, diagonal 22 mm, 6x6 = 56x56, diag 79, CF 3.6, FL = 50mm

For 3: 2, crop = 15.6x28.4, diag 28.4, 6x6 = 56x37.3, diag 67.3, CF 2.4, FL = 75mm

For 8x10, crop = 15.6x19.5, diag 25, 6x6 = 45x56, diag = 71.7, CF 2.9, FL = 63mm.

Hope that helps.

Not disagreeing with the figures in any way but they do prove what happens when we stop thinking of a 180mm lens as just that and no more.

Life gets immediately worse when we try to include close-up shots in all these FL equivalences :-|

For example, my full-frame 70mm macro lens on my 1.7 crop camera filling half of my 13.8mm sensor height with a 25mm tall subject . . . what you reckon? In my world: 70mm

--
radian measure is your friend; (me),
Ted

 

[bobn2]

How to figure out how long should be the lens on croped camera if on medium format (6x6) it would be 180mm.

Thanks.

How are you going to handle the format difference? Will you crop the crop (presumably APS-C) sqare or crop the 6x6 3:2, or crop them both to some other aspect ratio (8:10).

Assuming Crop is 15.6x28.4 mm and 56x56mm for 6x6, then

For square format, crop = 15.6x15.6, diagonal 22 mm, 6x6 = 56x56, diag 79, CF 3.6, FL = 50mm

For 3: 2, crop = 15.6x28.4, diag 28.4, 6x6 = 56x37.3, diag 67.3, CF 2.4, FL = 75mm

For 8x10, crop = 15.6x19.5, diag 25, 6x6 = 45x56, diag = 71.7, CF 2.9, FL = 63mm.

Hope that helps.

Not disagreeing with the figures in any way but they do prove what happens when we stop thinking of a 180mm lens as just that and no more.

Life gets immediately worse when we try to include close-up shots in all these FL equivalences :-|

For example, my full-frame 70mm macro lens on my 1.7 crop camera filling half of my 13.8mm sensor height with a 25mm tall subject . . . what you reckon? In my world: 70mm

Typically with macro you're controlling the subject distance to get the magnification that you want.

 

[xpatUSA]

How to figure out how long should be the lens on croped camera if on medium format (6x6) it would be 180mm.

Thanks.

How are you going to handle the format difference? Will you crop the crop (presumably APS-C) sqare or crop the 6x6 3:2, or crop them both to some other aspect ratio (8:10).

Assuming Crop is 15.6x28.4 mm and 56x56mm for 6x6, then

For square format, crop = 15.6x15.6, diagonal 22 mm, 6x6 = 56x56, diag 79, CF 3.6, FL = 50mm

For 3: 2, crop = 15.6x28.4, diag 28.4, 6x6 = 56x37.3, diag 67.3, CF 2.4, FL = 75mm

For 8x10, crop = 15.6x19.5, diag 25, 6x6 = 45x56, diag = 71.7, CF 2.9, FL = 63mm.

Hope that helps.

Not disagreeing with the figures in any way but they do prove what happens when we stop thinking of a 180mm lens as just that and no more.

Life gets immediately worse when we try to include close-up shots in all these FL equivalences :-|

For example, my full-frame 70mm macro lens on my 1.7 crop camera filling half of my 13.8mm sensor height with a 25mm tall subject . . . what you reckon? In my world: 70mm

Typically with macro you're controlling the subject distance to get the magnification that you want.

Thank you.