The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Panasonic 10-25mm F1.7 ASPH and the Panasonic 8-18mm F2.8-4.0 ASPH 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. Panasonic 10-25mm F1.7 ASPH is the longer of the two lenses at 128mm. The Panasonic 8-18mm F2.8-4.0 ASPH with a length of 88mm, is 40mm shorter. Besides being longer, the Panasonic 10-25mm F1.7 ASPH also has a larger diameter of 88mm compared to the Panasonic 8-18mm F2.8-4.0 ASPH's 73mm diameter.
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Below you can find a scaled side-by-side image of Panasonic 10-25mm F1.7 ASPH and Panasonic 8-18mm F2.8-4.0 ASPH to get a better idea of how their sizes compare in real life.
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 8-18mm F2.8-4.0 ASPH weighs 315g, 54% (375g) lighter than the Panasonic 10-25mm F1.7 ASPH's weight of 690g.
Below you can find the dimension and weight table of the Wideangle Zoom Lenses in Micro Four Thirds Mount for size comparison purposes.
Ultra-Wideangle Lenses in Micro Four Thirds Mount for Size Comparison
Filter Threads
The Panasonic 10-25mm F1.7 ASPH has a filter size of 77mm whereas the Panasonic 8-18mm F2.8-4.0 ASPH has a 67mm 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 Panasonic 10-25mm F1.7 ASPH:
And these are the 67mm filters that we recommend for the Panasonic 8-18mm F2.8-4.0 ASPH:
Lens Mounts
Both the Panasonic 10-25mm F1.7 ASPH and the Panasonic 8-18mm F2.8-4.0 ASPH has the same Micro Four Thirds lens mount. Some of the latest released cameras that are compatible with the Micro Four Thirds lenses are OM System OM-1 II, Panasonic G9 II and OM System OM-5.
Focal Range
Panasonic 10-25mm F1.7 ASPH has a focal range of 10-25mm and
2.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
20-50mm when used on a FourThirds format camera.
On the other hand, the Panasonic 8-18mm F2.8-4.0 ASPH has a focal range of 8-18mm and 2.3X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 16-36mm when used on a FourThirds format camera.