The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 24mm f1.4 and the Panasonic Leica 25mm 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. Panasonic Leica 25mm F1.4 weighs 510g, 12% (70g) lighter than the Samyang 24mm f1.4's weight of 580g.
Filter Threads
The Samyang 24mm f1.4 has a filter size of 77mm whereas the Panasonic Leica 25mm F1.4 has a 46mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Samyang 24mm f1.4:
And these are the 46mm filters that we recommend for the Panasonic Leica 25mm F1.4:
Lens Mounts
Both the Samyang 24mm f1.4 and the Panasonic Leica 25mm F1.4 has the same Four Thirds lens mount. Some of the latest released cameras that are compatible with the Four Thirds lenses are Olympus E-5, Olympus E-600 and Olympus E-620.
Samyang 24mm f1.4 is also available in Canon EF , Nikon F (FX), Pentax KAF, Sony Alpha, Sony E and Samsung NX mounts.
Panasonic Leica 25mm F1.4 is also available in Micro Four Thirds mount.
Focal Range
Samyang 24mm f1.4 is a prime lens with fixed focal lenght of 24mm.
On the other hand, the Panasonic Leica 25mm F1.4 is a prime lens with fixed focal lenght of 25mm which has an effective (full-frame 35mm equivalent) focal range of 50mm when used on a FourThirds format camera.