n00blet question about aperture and crops

[j-dogg]

If I have a 1.6x APS-C sensor and slap on a 50 1.8 made for a 35mm (full frame), does it shoot like an 80 1.8 or an 80 2.8?

also, if I have the APS-C and shoot a lens made for an APS-C (Tamron Di-II, Sigma DC, Canon EF-S) does my 18-270 3.5-6.3 become a 28-432 5.6-10?

Thanks in advance.

 

[rainking]

80 @ 1.8

No

Aperture doesn't change based on sensor size.

 

[chito beach]

80 @ 1.8

No

Aperture doesn't change based on sensor size.

you da man..........:thumbup:

 

[j-dogg]

Flawless victory, thanks. :thumbup:

 

[el_shorty]

If I have a 1.6x APS-C sensor and slap on a 50 1.8 made for a 35mm (full frame), does it shoot like an 80 1.8 or an 80 2.8?

also, if I have the APS-C and shoot a lens made for an APS-C (Tamron Di-II, Sigma DC, Canon EF-S) does my 18-270 3.5-6.3 become a 28-432 5.6-10?

Thanks in advance.

No, your lenses are still 50mm f/1.8 and 18-270mm 3.5-6.3, focal length doesn't change, only the field of view changes from what you would get from on a 35mm camera (full frame), so your 50mm f1.8 will give you the same field of view as a 80mm in a 35mm camera.
If you have not used 35mm cameras before this shouldn't be of any concern to you, since the cropped factor multiplier was for people who came from 35mm film cameras to digital, to explain how their existing lenses would perform on their new DSLR cameras.
Do a search in the forums, there are lots of threads explaining this.

 

[djacobox372]

80 @ 1.8

No

Aperture doesn't change based on sensor size.

True, but misleading.

Relating to DOF, it will be more like an 80 f2.8.

It's like an 80 f1.8 on 35mm only as it relates to shutter speed. A true 80 f1.8 on a full-frame would have a much narrower dof.

 

[djacobox372]

If I have a 1.6x APS-C sensor and slap on a 50 1.8 made for a 35mm (full frame), does it shoot like an 80 1.8 or an 80 2.8?

also, if I have the APS-C and shoot a lens made for an APS-C (Tamron Di-II, Sigma DC, Canon EF-S) does my 18-270 3.5-6.3 become a 28-432 5.6-10?

Thanks in advance.

No, your lenses are still 50mm f/1.8 and 18-270mm 3.5-6.3, focal length doesn't change, only the field of view changes from what you would get from on a 35mm camera (full frame), so your 50mm f1.8 will give you the same field of view as a 80mm in a 35mm camera.
If you have not used 35mm cameras before this shouldn't be of any concern to you, since the cropped factor multiplier was for people who came from 35mm film cameras to digital, to explain how their existing lenses would perform on their new DSLR cameras.
Do a search in the forums, there are lots of threads explaining this.

True, but most of those threads don't explain the effects of depth of field. A 50mm f1.8 on a aps size sensor doesn't have nearly as tight of DOF as a 80mm f1.8 on a full frame sensor.