Reply To: Tele extender

#75563
Sudhir Shivaram
Keymaster

Hello Surendar Singh,

Thank you so much and best wishes to you as well.

Since the Canon 90D is a APS-C sensor any lens you mount will have a effective focal length of 1.6x. So yes, the 100-400 top end zoom will be 640mm at f5.6.
But the image quality of a full frame cannot be compared with APS-C as full frame sensor are way better. You did not mention if the 100-400 is IS1 or IS2. If it’s IS2, then my preference would be the 1st setup in good lighting.

Rgds,
Sudhir