Tele Converter or What for Canon EOS 77D

[georgeg2000]

I've just bought a Canon EOS 77D. It comes with an EF-S 18-55mm STM Lens and a 55-250mm STM Lens. From time to time, I may need a longer lens to reach out to shoot my favorite subject, airplanes. Long focal length lenses are expensive and take up a lot of room in my camera bag. I remember tele-converters from back in the day but they used to really degrade the image. Are they any better these days and if they are, can anyone recommend one that will work on the bigger of the two lenses I'll have without breaking the bank? Working with Canon autofocus is very desireable, of course. I realize it will be hard to hand hold what is effectively a long lens but its the only way I can go. Any help will be appreciated.

[TCav]

The Kenko 1.4X teleconverters are quite good, and they are sold under multiple names like Vivitar, Bower, and others.

The down side of teleconverters is that while they increase the focal length, they also decrease the maximum aperture. A 1.4X TC will change an f/4 lens to f/5.6, and a 2X TC will change it to f/8.

This has a significant effect because once the maximum aperture hits f/8, AF stops working. So your 55-250mm f/4-5.6 becomes a 77-350mm f/5.6-8.0, and AF won't work at the long end.

Now, you could get along without AF when shooting airplanes by setting the focus distance to infinity and relying on the depth of field to give you a sharp image. But if you really need AF, a TC won't help you.

[georgeg2000]

If I was crazy enough to buy a longer lens, say something that zooms to 500 or 600 mm focal length, what is out there that has decent performance and doesn't break the bank. If I ever won the lottery, I could buy the Canon lenses but we all know what the odds are on that.

[TCav]

Sigma and Tamron both have reasonably priced (all things being relative) 150-600mm stabilized lenses that you might want to look at, though they also have newer, more expensive versions.