Just came back from a trip to Canada to photograph Puffins. This lens was just about perfect for this area. I used everything from the bare lens up to 600mm. The lens performed flawless. I had my 400mm also but I used this far more due to the versatility.
That said, the EF lineup has an outstanding 300mm f/2.8 option, the EF 300mm f/2.8L IS II USM Lens. This lens's image quality is stellar, and based on the MTF charts, the RF 100-300 was expected to match it. The image quality comparison shows this expectation met, even with a 2x mounted (the zoom has slightly more lateral CA). The prime lens has less peripheral shading and slightly less geometric distortion than the zoom lens at 300mm.
With the RF 1.4x behind the RF 100-300 L and a wide-open aperture selected, image sharpness is barely impacted. Let me make this clear — that is exceptional performance for any lens and outstanding performance for a zoom lens. The RF 1.4x adds a slight amount of barrel distortion, offsetting the slight pincushion distortion at 300mm, but it does not notably affect lateral CA.
The Canon EF 200-400mm f/4L IS USM Lens is currently Canon's other fixed-max-aperture, non-extending, big white zoom lens, and mounting a 1.4x extender behind the RF 100-300 creates a rather similar focal length range at the same aperture.
The 100-300 is slightly sharper in the center in the native range overlap, and impressively, about equivalent with a 1.4x in place (420mm vs. 400). At 600mm, the 100-300 is slightly sharper than the 200-400 at 560mm using the built-in 1.4x, but with more lateral CA. Here is the image quality comparison between these lenses.
Uarctos wrote:
Looks impressive, but I had the old 500mm f4 IS and that lens was so bad when tested in those charts and so good wide open in real life, so go figure.
I think it said that the 150 600 Tamron at 600mm beat my 180 Tamron. Then a lensrentals article apparently discussed if you should use the 150 600 at 500 and crop. So I'm skeptical.
AmbientMike wrote:
Wow Rob getting some great stuff! Is this mostly using 1.4 & 2X TC, and is the iq pretty close to no tc?
Thanks Mike, I have been very pleased. The image quality is excellent with both extenders. I am even more impressed with AF with the 2x in use. It does not miss a beat. I only used it with R3's so maybe that is the key for the best use. I seen a couple YouTube videos and they did not like the 2x, personally I am not seeing any issues myself. I really gave it a workout on this recent trip and was impressed.
