You have good answers already. I am just summarizing and posting my cute images :).
Focal length does not care about your camera sensor at all.
The framing is where you need to take into account the sensor size. But I think you have the idea backward.
A. You have a framing using some lens, in this case, 85mm.
B. On a Crop factor sensor, you simply have a &...
No. You should set your zoom to 85mm to see what an 85mm lens looks like on your camera.
The focal length of a lens is a physical property that does not change no matter what size sensor you put behind it.
The distinction between a crop (DX) and full frame (FX) lens is how big an image circle it projects. A crop lens can only cover an APS-C sized sensor, ...
I wish the concept of “crop factor” would disappear, it’s the source of so much confusion. Further, it’s main value, it helps people that have worked with a given format camera for years switch to a different format. For novices and those who never worked a specific format, it has little value.
If you mount an 85mm lens on a full frame camera the angle of ...
No. You should set lens to 85mm. The focal length of the lens do not change magically when you put the lens on crop camera. The marks on the lens are about factory (FF) focal length.
You will have equivalent focal length of 127mm because of the crop factor which mean you will see what FF camera see with lens with such focal length.
The primary design intent of speed boosters is exactly what the name suggests. They make the lens "faster" (i.e. provide more light to the image plane).
They are primarily an alternative to increasing ISO and secondarily an alternative to spending lots of money expensiver faster lenses. Being an alternative to higher ISO's sets the ...
The 35mm f1.8 DX lens is sharp as a pin, distortion-free and cheap as chips. If you want a 'normal' lens (eg for candids or small-group portraits) you can't do better. As others have said, no speedbooster made for Nikon F-mount bodies.
My question would be... why do you want a 50mm lens FoV? My opinion is that about the worst thing you can do in photography is to create "normal" images. And for many things the 75mm EFL is arguably better.
The speed boosters function by inserting additional optics into the light path... in my experience that always has some ...