The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 45mm F1.8 Di VC USD and the Irix 45mm F1.4 for their suitability to various photography scenarios:
Size and Weight Comparison
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Tamron 45mm F1.8 Di VC USD weighs 540g, which means it is 385g (41%) lighter than the Irix 45mm F1.4 which has a weight of 925g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Canon EF Mount for size comparison purposes.
Standard Lenses in Canon EF Mount for Size Comparison
Filter Threads
The Tamron 45mm F1.8 Di VC USD has a filter size of 67mm whereas the Irix 45mm F1.4 has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Tamron 45mm F1.8 Di VC USD:
And these are the 77mm filters that we recommend for the Irix 45mm F1.4:
Lens Mounts
Both the Tamron 45mm F1.8 Di VC USD and the Irix 45mm F1.4 has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Tamron 45mm F1.8 Di VC USD is also available in Nikon F (FX) and Sony Alpha mounts.
Irix 45mm F1.4 is also available in Nikon F (FX) and Pentax KAF2 mounts.
Focal Range
Both lenses have the same focal range of
45mm but while Tamron 45mm F1.8 Di VC USD has the fastest aperture of
F1.8, the Irix 45mm F1.4's widest aperture value is
F1.4.