What is the sony e 55 210mm f 4 5 6 3 oss good for?

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From Sony E 55-210mm f/4.5-6.3 OSS: Sony E 55-210mm f/4.5-6.3 OSS: A zoom lens by Sony for APS-C cameras, 55-210mm f/4.5-6.3. Specs - Maker: Sony - Focal length: 55-210mm (zoom) - Maximum aperture: f/4.5-6.3 (it gets darker as you zoom in) - Made for: APS-C sensors - Mounts: Sony E - Stabilised: yes - Autofocus: yes What it frames like - On APS-C (Sony E): like 82-315mm on full frame; f/4.5-6.3 gives about the depth of field of f/6.8-9.4 there. - ...

From Focal length converter: How it works: Multiply the focal length by the sensor's crop factor to get its full-frame equivalent. To go between two smaller formats, multiply by the first crop factor and divide by the second. Crop factors are measured on the sensor diagonal, so formats with a different shape (4:3 against 3:2) frame slightly differently across the width.

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