Feedback Desired: The next lens I'm considering ...

[neuroanatomist]

That is a common misunderstanding. The f3.5-6.3 zooms I've used focused fine along their entire range. I'm not sure why though--maybe they are chipped to tell the camera f/5.6?

Thanks for correcting me! It would make sense that the lens is chipped to give 'false' or no information on maximum aperture to the body (similar to the 'tape-the-pins' trick that can allow AF on too-slow Canon combinations like a teleconverter with a lens that's already f/5.6). That also makes Bryan's warning about current 3rd party lenses possibly not working with future Canon bodies very relevant, I would think.

[neuroanatomist]

Hi Denise,


As others have pointed out, you have great quality in the telephoto range already, with the 100mm f/2.8L Macro and the 300mm f/4L.


If you're looking for better image quality in the lower end of your shooting range, you might consider another prime lens such as the EF 50mm f/1.4 USM ($350 on Amazon), the very inexpensive but still sharp 'nifty-fifty' (EF 50mm f/1.8 II, $100 on Amazon), or for a more 'normal' perspective the EF 35mm f/2 ($320 on Amazon). Any of those will have better image quality than the kit lens covering that range, better build quality (except for the 50mm f/1.8 which is similar in quality to the kit lens), and also much wider apertures allowing ambient light pictures indoors or in low light. Compared to the kit lens at 50mm, which is at f/5.6, the 50mm f/1.4 is 4 stops faster, meaning 16 times more light. Yes, the kit lens has 4 stops of IS - the difference is that 4 stops of aperture means the ability to use a shutter speed fast enough to freeze the motion of those running grandkids.


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[Daniel Browning]

Should I sell the two Canon kit lenses and replace them with the Sigma?

If you want the convenience of an 11X superzoom, go for it!


But you should be aware that the quality will be much lower than your 18-55 and 55-250. Also be aware that some users have issues with autofocus on that Sigma superzoom.