RF 600mm f/4 L IS USM

[Busted Knuckles]

This looks like a job for the guys at lens rentals

[HDNitehawk]

My testing was with just one lens, the EF 600/4L IS II. I was going to write that I've offloaded all my EF lenses that take a TC so that is my only option, but upon reflection while that would be technically true since TS-E lenses aren't EF, I could actually repeat the test of EF vs RF extenders alone and combined with my TS-E 24L II, a wickedly sharp lens.

Could be that Bryan got a suboptimal copy of the 600 III.

Will be interesting to see what you learn!

The lens checks out with my limited ability.
I printed an 11x17 ISO 12233 chart.
Set up the camera in manual and set locked the settings in identical, wide open at 300 shutter speed and let Auto ISO adjust exposure.
Basically I was shooting for an equal comparison at equal settings.
I set them up at 20' and 24' for equal framing.
Shot three sets of pictures with both lenses native, 1.4x and 2x.

Here is what I found:

The bare lens 500mm was just slightly sharper in the center, but the 600 mm was sharper in the corners. From all the reviews I expected this.

With the 1.4x the 600mm was just slightly sharper all around. This was surprising.

At 2x the ISO's were getting high. The 500mm 2x shot was at an 8000 ISO and wasn't bad.
However the 600mm at a 6000 ISO was a mess. I brought in a lamp from the garage and reshot it at 1000 ISO, that shot was comparable but the 500mm was still sharper. Looking at Bryans charts I think the comparison I have is the same. I am debating on whether to return the 2x or not. Its use would be limited.



Overall I think I have a good copy. It needs to warm up outside so I can put it to use.

[Busted Knuckles]

Very interesting. I have been GAS defying a super tele f4. But I am getting weak....

The lens checks out with my limited ability.
I printed an 11x17 ISO 12233 chart.
Set up the camera in manual and set locked the settings in identical, wide open at 300 shutter speed and let Auto ISO adjust exposure.
Basically I was shooting for an equal comparison at equal settings.
I set them up at 20' and 24' for equal framing.
Shot three sets of pictures with both lenses native, 1.4x and 2x.

Here is what I found:

The bare lens 500mm was just slightly sharper in the center, but the 600 mm was sharper in the corners. From all the reviews I expected this.

With the 1.4x the 600mm was just slightly sharper all around. This was surprising.

At 2x the ISO's were getting high. The 500mm 2x shot was at an 8000 ISO and wasn't bad.
However the 600mm at a 6000 ISO was a mess. I brought in a lamp from the garage and reshot it at 1000 ISO, that shot was comparable but the 500mm was still sharper. Looking at Bryans charts I think the comparison I have is the same. I am debating on whether to return the 2x or not. Its use would be limited.



Overall I think I have a good copy. It needs to warm up outside so I can put it to use.