Horoscope Fish
Senior Member
DX lenses carry the "DX" label on the lens itself and in the nomenclature (e.g. Nikon AF-S DX NIKKOR 18-105mm f/3.5-5.6G ED VR). If there is no label, it's an FX lens.Excuse my ignorance (stupidity) how do you know if your lens is FX? and would an FX lens make any difference on a DX body? I won't be looking to move from the D7100 for a long, long time if ever.
FX lenses transmit a larger circle of light, needed to cover the larger full-frame sensor of FX cameras, so when you use an FX lens with the smaller DX sensor you're using the center-most part of that circle of light. The center is considered the "sweet spot" because it's the sharpest and has the most contrast.
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