[Agazir]

I currently shoot with a Canon 7D MII + Canon 100-400. At full extension with the sensor, that's an equivalent to 640 mm.

I've been toying with the idea of getting a Canon 1.4x extender. Advantage I'd be playing with nearly 900 mm equivalent. Disadvantage, slower autofocus which is a problem with birds in flight. And losing a few f-stops. At nearly US$500, my brain tells me it's not worth it. My heart tells me I might catch better closer up shots of birds.

I'd love to hear your thoughts. Pros? Cons? Have you used something like that setup? Suggestions for alternatives?

Thank you

[zwest]

In most cases with a zoom lens it’s probably not worth it, but maybe occasionally (for example getting an ID shot of a distant seabird) it could come in handy. I would look for a used one personally - $500 is a lot for something that will be impractical 99% of the time.

Unless you plan to buy a prime lens, of course, then the TC will be used lots...

[Agazir]

Thank you - that's good feedback!

[Robert]

You'll lose some focus points with the extender - only center point for cross focus. Otherwise it works pretty good as optics only degrade a bit and the stabilization of the lens is very good.