The lens uses an early form of “IS” (Image stabilisation) which is well known for many of the 300mm f4 lenses to sound loud and rather clunky. This is quite common with multiple forums discussing this.
Canon EF 300mm f4 L USM AF Lens For EF Mount From JAPAN *Near Mint* #5354
Canon EF 300mm f4 L USM ULTRASONIC Telephoto Lens From JAPAN Exc+++
Canon EF 300mm f4 L IS USM Telephoto Lens [Very Good] Japan Fast Shipping
[MINT] Canon EF 300mm f4 L IS USM Telephoto Prime Lens AF From JAPAN
Faulty Canon EF 300mm f4 L IS USM Lens - Fungus
[Top MINT+++] Canon EF 300mm f4 L IS USM Telephoto Prime Lens From JAPAN
![Canon EF 300mm f4 L IS USM Telephoto Lens [Very Good] Japan Fast Shipping](https://images.buynet.work/thumb.php?i=397865736&s=240)
![[MINT] Canon EF 300mm f4 L IS USM Telephoto Prime Lens AF From JAPAN](https://images.buynet.work/thumb.php?i=397866106&s=240)
![[Top MINT+++] Canon EF 300mm f4 L IS USM Telephoto Prime Lens From JAPAN](https://images.buynet.work/thumb.php?i=401837501&s=240)