Q. regarding 70-200 2.8 IS II infinity performance @ 200mm

[jhanson25]

I am having the same issue with my 70-200 2.8 IS II on my 7D mark II. At 200 @2.8 it is quite soft until I stop it down to f/4 and beyond. Used to be super sharp on my 6D.

 

[Alex_M]

this moon shot is seriously soft ... something isn't right. AFMA at infinity?

here is what can be achieved with humble sigma 120 300 2.8 Sport + tc1.4 teleconverter @420mm. even sharper without 1.4tc

 

[liangming16]

If I do the test, I will pick a good light day to shoot the nearby object like rock or tree, or a tripod. That way you avoid all the different factors that may affect your result. Shooting moon is not good test of your lens, IMHO.

Lots of people use the 70-200 mm to take portrait too. That is another way to test your lens.

 

[Mt Spokane Photography]

The measured performance of the lens at 200mm shows it to be extremely sharp. It is not as sharp as it is at wide angles, but still extremely sharp. Some of the issue with the test results is just distance. Even 100 ft can reduce apparent sharpness. Getting sharp moon photos is a art. People staying up until 2 or 3 in the morning in very cold and clear weather over several nights with extreme care to eliminate vibration. Even a good tripod transmits vibration, so hang weights and sandbag legs on solid ground, no porch or deck will do. Get away from city lights, a long ways away.

 

[Larsskv]

Have you experienced any difference between IS on and IS off?

My experience is that IS in some lenses, occasionally will blur the picture.

This doesn't seem like a good explanation on why it is softer at 200, and not shorter focal lengths, but it should be easy to test and rule out.