I own a Nikon in DX-format (Nikon name for APS-C sensor, crop factor ~1.5) and I'm considering buying a 50mm prime lens soon for it. (To be complete, my camera is a D5200, although I don't think the precise model matter so much.)
Of course, because of the crop factor, such a 50mm lens would give me a 75mm effective focal length (by which I mean when compared to a full frame body). I have two choices, as I see it:
- go for a 35mm lens instead to end up with a ~50mm effective focal length in the end,
- go for the 50mm together with a 0.6 or 0.7 speedbooster.
The second option has the advantage that I'll still have a 50mm lens if I decide to go for a FF body in the future. What are the drawbacks of a speedbooster really? From what I gather online, the only thing that could be bothering is that it shifts your aperture range towards low values (f4 becomes roughly f1.2 in my imaginary setup). And I would actually consider that a plus considering what I usually shoot.
I'm looking for the opinion of people who experienced one or both setups before. Would you recommend option 1 or option 2, and why?
Edit. By speedbooster, I mean something along the lines of what metabones has done since a few years for mirrorless cameras. Maybe focal reducer is more accurate.
This is new territory for me, and I surely don't understand everything optic-wise. Please do tell if this post is not making a lot of sense (for example if option 1 and 2 are widely different or not comparable in any way).