2 replies to this topic

[DavidV81]

I'm new to dslr, owning only fixed lens cameras prior to my d7500.  My understanding is a fx lens on a crop-sensor camera doesn't account for the crop factor, so my 50mm fx lens is actually around 75mm.  That said, if I bought a dx lens that said 50mm, would it actually have a  focal length of 50mm, or would it also be around 75mm?  I'm looking at macro lenses and if there's no advantage to buying a dx lens, I'd assume get the fx lens in case I upgrade bodies down the road to a full frame.

[Nikon Shooter]

I'm new to dslr, owning only fixed lens cameras prior to my d7500.  My understanding is a fx lens on a crop-sensor camera doesn't account for the crop factor, so my 50mm fx lens is actually around 75mm.  That said, if I bought a dx lens that said 50mm, would it actually have a  focal length of 50mm, or would it also be around 75mm?  I'm looking at macro lenses and if there's no advantage to buying a dx lens, I'd assume get the fx lens in case I upgrade bodies down the road to a full frame.

Welcome David!

Considerations about FX vs DX are sources of great misconceptions and
misunderstandings. There is NO change in focal length when using a FX
lens on a DX body… only a change in AoV — angle of view.

The advantages or using FX are multiple: greater choice, higher quality built,
brighter aperture, more blades just to name a few. Plus, if you get a FX body
down the line, everything will work together perfectly.

Have a good time!

[Merco_61]

Focal length is a physical property of a lens or lens system and doesn't change with how you crop the capture from the lens. 

 

The so called crop factor is only a convenient way of comparing the angle of view between systems.

 

The only advantage of buying a DX-optimised lens is that it is physically smaller and usually cheaper as it doesn't have to cover the larger image circle.