The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Olympus 25mm f2.8 Pancake and the Sigma 30mm F1.4 EX DC HSM for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Sigma 30mm F1.4 EX DC HSM is the longer of the two lenses at 59mm. The Olympus 25mm f2.8 Pancake with a length of 24mm, is 35mm shorter. Besides being longer, the Sigma 30mm F1.4 EX DC HSM also has a larger diameter of 77mm compared to the Olympus 25mm f2.8 Pancake's 64mm diameter.
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. Olympus 25mm f2.8 Pancake weighs 95g, which means it is 335g (77%) lighter than the Sigma 30mm F1.4 EX DC HSM which has a weight of 430g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Four Thirds Mount for size comparison purposes.
Standard Lenses in Four Thirds Mount for Size Comparison
Filter Threads
The Olympus 25mm f2.8 Pancake has a filter size of 43mm whereas the Sigma 30mm F1.4 EX DC HSM has a 62mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 43mm filters that we recommend you to consider for the Olympus 25mm f2.8 Pancake:
And these are the 62mm filters that we recommend for the Sigma 30mm F1.4 EX DC HSM:
Lens Mounts
Both the Olympus 25mm f2.8 Pancake and the Sigma 30mm F1.4 EX DC HSM 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.
Sigma 30mm F1.4 EX DC HSM is also available in Canon EF-S , Nikon F (DX), Pentax KAF, Sony Alpha and Sigma SA mounts.
Focal Range
Olympus 25mm f2.8 Pancake 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.
On the other hand, the Sigma 30mm F1.4 EX DC HSM is a prime lens with fixed focal lenght of 30mm which has an effective (full-frame 35mm equivalent) focal range of 45mm when used on a APS-C / DX format camera.