What is the difference between the Canon 2x Extender II and III?
Results with the Extender 2x III are overall slightly sharper than the Extender 2x II with a difference being most noticeable in the mid-frame and corner areas. The 2x II added pincushion distortion to the lens it was used with whereas the 2x version III adds slight barrel distortion.
Is the Canon 2x Extender worth it?
The Canon Extender 2x II works great, but it only can do so much. It really does give a much longer focal length, but with two stops less speed, while remaining pretty sharp and with very good AF performance. AF is slower, especially if it has to rack a long way in or out.
What is the difference between an extender and a teleconverter?
Quick contrast. Teleconverters act as a magnifying glass vs. an extension tube pushes the lens element closer to the subject. Teleconverters can focus to infinity, an extension tube reduces the maximum focal distance.
What does a 2x extender do?
The 1.4x Extender causes a decrease of one stop in the maximum aperture of the lens, while the 2x Extender causes a loss of two stops. This means you gain extra focal length at the expense of losing some light.
Will a Canon Extender work with a Tamron lens?
Probably not. The Canon extenders have a protruding front element that may interfere with the rear element of the lens. Apart from that an 18-270 lens is not a good starting point for an extender. You’ll loose a lot of quality, probably autofocus as well.
What is the main disadvantage of a teleconverter?
The main downside of teleconverters is a loss of lens speed, which is directly related to the magnification factor of the teleconverter. A 1.4x teleconverter will reduce the maximum aperture of the lens by a full f-stop, while a 2x teleconverter cuts it by two full stops.
Will a Canon 1.4 extender work on a Tamron lens?
It will not work with the Canon 1.4x. A third-party extender (Tamron, Kenko) would mount and probably “work” depending on what you mean by work. Michael points out that the autofocus would be questionable at best.