Difference between canon 1.4 extender ll and lll

[Dick Huberty]

I received my new canon 500mm f/4 ll this morning. Awesome! Took some test shots. Without extender. With canon 1.4 ll and canon 2.0 lll. The shots were excellent with little drop off in canon 2x lll, but with 1.4 ll the IQ dropped off quite a bit. Ia there really that much difference in the ll and lll extender?

Auto Focus work great on the 2x extender (f8) with the new firmware update on the Mark 5D lll.

[Juan Carlos Vindas]

The new 500f/4 USM II and 600f/4 USM II are intended to be used with 1.4X III and 2X III Tele converters due to new integrated chips that communicate with lens/camera and delivers better image quality, as far as I understand, you can use a 1.4X III and 2X III with older version lenses and it will be fine, but for the new lens you need new III TC's if you want to get the best image quality.

[John Chardine]

Hi Dick- All your gear is of the highest quality. Don't get too hung up about versions! Tests done by Doug Brown and Greg Basco show that there is effectively no difference in IQ between versions II and III 1.4x teleconverter used on the new crop of super-teles.

If you are having a real issue with the 1.4 teleconverter version II on the new 500 I would look at AF micro-adjustment as a starting point.

[Arthur Morris]

Hi Dick- All your gear is of the highest quality. Don't get too hung up about versions! Tests done by Doug Brown and Greg Basco show that there is effectively no difference in IQ between versions II and III 1.4x teleconverter used on the new crop of super-teles.

If you are having a real issue with the 1.4 teleconverter version II on the new 500 I would look at AF micro-adjustment as a starting point.

John is partially right but in his comment he is talking about sharpness. The 1.4X III TC is able to communicate with the Series II super-telephotos. The 1.4X II is not. Faster and more accurate AF is supposed to come with the upgrade but there is no way to prove that by me....