Conclusion

The 100-500mm F5-7.1 O.I.S. is the longest Lumix S series zoom lens released to date, filling a rather large void in Panasonic's full-frame range.

Joining the S PRO 70-200mm F2.8 O.I.S., S PRO 70-200mm F4 O.I.S. and the much cheaper S 70-300mm F4.5-5.6 MACRO O.I.S., Panasonic have certainly pushed the boat out by opting to release a 500mm reach lens squeezed into a typical 100-400mm form factor.

This has some notable benefits, the most obvious one being the 5x range rather than 4x - if you've ever used a 100-400mm zoom and always wanted a bit extra reach, this is the lens for you.

The fact that this lens isn't that much bigger or heavier than your typical 100-400mm zoom is also very attractive, especially as you can extend the reach even further up to a whopping 1000mm focal length thanks to full teleconverter compatibility.

The main downside of going for 100-500mm rather than 100-400mm are the rather slow maximum apertures on offer. Most comparable lenses of this ilk start at F4.5 and reach F6.3 at 400mm - the 100-500mm F5-7.1 O.I.S starts at F5.1 and reaches F6.8 at 400mm, which may or may not be a deal-breaker for some users.

This lens also extends a long way - 8.5cms to be precise - when zooming from 100mm out to 500mm, so while it's relatively compact at 100mm, at 500mm it's much more conspicuous and less well-balanced.

This new Panasonic offering is notably lighter, smaller and cheaper than the comparable Canon RF 100-500mm F4.5-7.1L IS USM lens from 2020, which is currently the only other 100-500mm zoom on the market.

It also takes some obvious design inspiration from the Canon lens, with the new tight-smooth ring, configurable focus/control ring, built-in image stabilisation and rotatable lens collar all paying homage to the RF 100-500mm.

The impressive 7 stops of image stabilisation (best ever for a Lumix S lens) is markedly better than Canon's 5 stops, though, helping to make the longer end of the zoom range very usable indeed even without the use of a tripod.

Ultimately comparing the 100-500mm F5-7.1 O.I.S. to the RF 100-500mm F4.5-7.1L IS USM is a rather fruitless endeavour, however interesting an exercise, as you obviously can't use either lens on the other rival system.

What's far more important is that Panasonic have finally released a serious super-telephoto zoom with most of the bells, whistles and image quality that the majority of people will need at a price that isn't too bad at all in this day and age...

Ratings (out of 5)
Design	4
Features	4.5
Ease-of-use	4
Image quality	4.5
Value for money	4.5