25 Vs 45

Pretty different lenses. Probably would depend on what one shoots. If you're asking, "if you could only have one lens… period" then this is my answer. They are both great lenses but, while I don't shoot with 25mm focal lengths very much (prefer wider or longer), I'd have to go with the 25mm based on it likely being a bit more versatile.

If you're asking, "keep the lenses you have, pick a new one to add," then I would say the 45 hands down. I have a 14, 20 and a 30 so the 25, despite being significantly faster than my 30, would be redundant for me.

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