Fuji GFX 50s + Canon EF 300mm f 4 L IS

Manual focus

Remember that i used the lens in MANUAL FOCUS mode, not AF. I have not checked the AF out yet. But in terms of optical quality when adapted via the Fringer Pro adapter to the Fujifilm's GFX 50s II camera... i find the lens to perform excellent - both wide open (ever so slightly soft), as well stopped down (excellently sharp).

The lens performs ever so slightly behind the Pentax 67 SMX M* 300mm f 4 EF ID in terms of sharpness when used at wide open aperture ƒ4. Albeit it is easy to missfocus the bigger Pentax 67 lens so that the focus might be a sliver off... then you get overall the same performance wide open at ƒ4.

I would say there is isn't much difference between the two lenses at ƒ4 - they play in the same ballpark and perform admirably well, even at wide open aperture.

Very little corner shading

There is some slight corner darkness going on (no matter in which position you put the built-in lens hood - the extreme borders always have a little bit of shading... But boy - this is so easily corrected !

You can see this here below:

Worthy !

I consider this lens to be worthy to be used on a Fujifilm GFX 50s II camera. It is now on my list of "Fuji GFX" useful lenses - absolutely. I have no problem with the corner shading. I like the performance - but also the easy - given the relatively small size. The lens has always been a pleasure to use, no matter where or on which camera i used it. One of my favorites, especially on travel.

Images from Lisbon, Portugal
January 2007

They are all made with the Canon EF 300/4 L IS lens, often at wide open aperture - where it has some slight greenish fringing (easily corrected). It is such an amazing, easy, and above all - fun - lens, that i enjoyed it perhaps the most of all on travel, especially at those large plazas in Lisbon. It is a lens, despite being white - which is still small enough to melt in among people without they mind.

I absolutely LOVE this lens.

A total favorite on travel in cities. Well, Lisbon is one of a kind of city - with so much beauty and interesting people walking along. And you have plenty of light during daytime, which often makes images pop more compared to the often dull Scandinavian Winter... especially in cities.

Canon in 2023 with its sometimes rather weird lenses - either you have affordable ones but dreadfully slow in aperture (!) - or you have at times odd, premium lenses with a price tag beyond anything that is even remotely friendly.

Adapting older Canon EF lenses
on Canon R cameras - is really not a problem

So, you see - I really don't mind adapting 'older' Canon EF lenses on an EOS R types of cameras. What a wealth of fantastic lenses... It doesn't have to be all of the new RF mount type - which if you want the best, also breaks the bank these days.

There are many bright, sharp and affordable Canon EF lenses - and they work often better on Canon EOS R type of cameras, compared to Canon EOS EF mount cameras. The best example are the Canon EF 50/1.2 L and Canon EF 85/1.2 L II lenses, which give iffy, unreliable AF at best - but work very good on EOS R type of cameras !

In this example - the EF 300/4 L IS is a worthy lens, working very well, both on cameras with EF or RF mounts. Without breaking the bank account - and with very good optics and performance. The images speak for themselves.

.the poetic shapes of a woman, like a symphony