The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samsung 20-50mm F3.5-5.6 ED and the Samsung 18-55mm F3.5-5.6 OIS 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. Samsung 18-55mm F3.5-5.6 OIS is the longer of the two lenses at 65mm. The Samsung 20-50mm F3.5-5.6 ED with a length of 40mm, is 25mm shorter. On the other hand, the Samsung 20-50mm F3.5-5.6 ED has a larger diameter of 64mm compared to the Samsung 18-55mm F3.5-5.6 OIS's 63mm 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. Samsung 20-50mm F3.5-5.6 ED weighs 119g, which means it is 79g (39%) lighter than the Samsung 18-55mm F3.5-5.6 OIS which has a weight of 198g.
Below you can find the dimension and weight table of the Standard Zoom Lenses in Samsung NX Mount for size comparison purposes.
Standard Lenses in Samsung NX Mount for Size Comparison
Filter Threads
The Samsung 20-50mm F3.5-5.6 ED has a filter size of 41mm whereas the Samsung 18-55mm F3.5-5.6 OIS has a 58mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 41mm filters that we recommend you to consider for the Samsung 20-50mm F3.5-5.6 ED:
And these are the 58mm filters that we recommend for the Samsung 18-55mm F3.5-5.6 OIS:
Lens Mounts
Both the Samsung 20-50mm F3.5-5.6 ED and the Samsung 18-55mm F3.5-5.6 OIS has the same Samsung NX lens mount. Some of the latest released cameras that are compatible with the Samsung NX lenses are Samsung NX1, Samsung NX3000 and Samsung NX30.
Focal Range
Samsung 20-50mm F3.5-5.6 ED has a focal range of 20-50mm and
2.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
30-75mm when used on a APS-C / DX format camera.
On the other hand, the Samsung 18-55mm F3.5-5.6 OIS has a focal range of 18-55mm and 3.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-82.5mm when used on a APS-C / DX format camera.