Using a screw on wide converter with a fast lens will result in a poor quality image. If you need to shoot wide angle images at large apertures like f/1.8 then your options are limited to something like the Sigma 20mm f/1.8 or Sigma 24 f/1.8 both of which are around £450.

Alternatively upgrading your camera to the original 5D would cost about the same, and act like a 0.625x wide converter that improves  image quality!

Using a screw on wide converter with a fast lens will result in a poor quality image. If you need to shoot wide angle images at large apertures like f/1.8 then your options are limited to something like the Canon 28mm f/1.8 Sigma 30 f/1.4 both of which are around £350.

Alternatively upgrading your camera to the original 5D would cost a little more (~£450) but would act like a 0.4x wide converter that improves  image quality!

Using a screw on wide converter with a fast lens will result in a poor quality image. If you need to shoot wide angle images at large apertures like f/1.8 then your options are limited to something like the Sigma 20mm f/1.8 or Sigma 24 f/1.8 both of which are around £450.

Alternatively upgrading to the original 5D would cost about the same, and act like a 0.625x wide converter that improves image quality!

Using a screw on wide converter with a fast lens will result in a poor quality image. If you need to shoot wide angle images at large apertures like f/1.8 then your options are limited to something like the Sigma 20mm f/1.8 or Sigma 24 f/1.8 both of which are around £450.

Alternatively upgrading your camera to the original 5D would cost about the same, and act like a 0.625x wide converter that improves  image quality!