The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 65mm F2 DG DN and the Sigma 56mm F1.4 DC DN C for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sigma 65mm F2 DG DN is the longer of the two lenses at 75mm. The Sigma 56mm F1.4 DC DN C with a length of 60mm is 15mm shorter. Besides being longer, the Sigma 65mm F2 DG DN also has a larger diameter of 72mm compared to Sigma 56mm F1.4 DC DN C's 67mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Sigma 56mm F1.4 DC DN C weighs 280g, 30% (125g) lighter than the Sigma 65mm F2 DG DN's weight of 405g.
Below you can find the dimension and weight table of the 'Standard Prime Lenses in Sony E Mount for size comparison purposes.
Standard Prime Lenses in Sony E Mount for Size Comparison
Both Sigma 65mm F2 DG DN and Sigma 56mm F1.4 DC DN C has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A7R V, Sony FX30 and Sony A7 IV.
Sigma 65mm F2 DG DN is also available in Leica L mount.
Sigma 56mm F1.4 DC DN C is also available in Micro Four Thirds and Leica L mounts.
Sigma 65mm F2 DG DN is a prime lens with fixed focal lenght of 65mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 97.5mm.
Sigma 56mm F1.4 DC DN C is a prime lens with fixed focal lenght of 56mm which has a 35mm equivalent focal range of 97.5mm when used on a APS-C / DX format camera.