"If you're photographing the Milky Way, for example, you can't use an exposure that's too long if you don't want motion blur," Radomir continues. "Having the option to go to f/2.8 means that you don't have to go so high with the ISO."
For those photos where you want to squeeze as much of the scenery into the frame as possible, reach for the Canon RF 14-35mm F4L IS USM – the widest native lens for the RF system. "The 1mm difference between 14mm and 15mm makes an incredible difference to the coverage of the subject," says Mike. "Moving from 300mm to 400mm in a telephoto lens might not be that noticeable, but every millimetre counts with a wide-angle lens."
As Radomir points out, the RF 14-35mm F4L IS USM also focuses a bit closer than the RF 15-35mm F2.8L IS USM (the former has a minimum focus distance of 0.2m, the latter 0.28m), so you can exploit the lens's wide angle of view while at the same time physically getting closer to foreground objects, thus making them fill more of the frame.
The filter thread size may also be an important consideration, Radomir adds. "The RF 14-35mm F4L IS USM has a 77mm filter thread and the RF 15-35mm F2.8L IS USM has an 82mm filter thread, which is something to think about if you want to easily share filters between your other Canon lenses."
One of the benefits of moving to the Canon EOS R System is that you can continue using your favourite Canon EF and EF-S lenses, such as the Canon EF 16-35mm f/4L IS USM or the EF 16-35mm f/2.8L III USM, via an EF-EOS R mount adapter.
There are three mount adapters available, including Drop-In Filter Mount Adapter EF-EOS R, which enables the use of drop-in filters. "You can use this to add a polariser to any EF or EF-S lens, including the Canon EF 11-24mm f/4L USM where it's not possible to fit a filter to the front of the lens," explains Mike. "A variable ND drop-in filter is also available, which is useful if you want to use a certain shutter speed and aperture combination, or if you want to shoot a long exposure landscape."