A Remarkable Long Lens

ProDude wrote:

The price of this bad boy sure did give me pause. But having the R5 I needed to add a competent longer lens than my RF70-200 f2.8L. So I managed to find one after months of looking. The build quality is stunningly solid all the way. There is NO play in this lens at all, and it's solid as a boulder. The IS on it is amazingly stable. I even use a RF1.4x on it from time to time with NO loss of sharpness or contrast which is rare. The focus on it is completely instant with NO hesitation. I've even shot with it in my dimly lit living room for fun and found it doesn't hesitate to lock focus across the room. The sharpness is absolutely unreal excellent. I've had many longer lenses from Nikon, Fuji and Sony and NONE have been sharp on this level. Once you've used it you realize just how valuable it is to have one on hand.

On the R6, the 1.4x provides higher IQ than cropping. With the R5, it's a wash, so it's not worth the loss of 100-420mm to use the 1.4x. The only advantage to the 1.4x on the R5 is for eye-AF since the subject is larger in the frame. So for wildlife/birds, the 1.4x can be an advantage for AF, but for landscape or other subjects on the R5, cropping from the bare lens at 500mm provides the same IQ as the 1.4x at 720mm. The other disadvantage to using the 1.4x versus cropping is the reduction in effectiveness of the stabilization shooting handheld. For landscape I found that distant detailed objects (pine trees in my case) are sharper at 500mm cropped since the stabilization isn't quite as effective with the TC attached.