In the post on reviews today we got the old " a 50mm becomes a 75mm on DX" along with a f1 lens is 1.4 on DX.
Not wanting interrupt the high level discussion on sensor dyes etc I just want to say I dont get it.
A 50mm lens is a 50 mm lens just putting its image on a sensor of whatever size and this f1 going to 1.4 seems the ultimate stupidity. Its just passing light through to a sensor.
Perhaps the brains of this outfit can explain without telling me that a 75 on FX has the same angle of view as a 50 on DX
Comments
https://www.sansmirror.com/articles/equivalence-in-a-nutshell.html#:~:text=Equivalence in this context means,the same angle of view.
Field of view - this seems pretty straightforward to me - a 50 mm lens on DX will give approximatly the same field of view as a 75mm lens on FX.
Noise performance - this is directly related to the total amount of light gathered - so since a DX sensor is about half the size of an FX sensor you need to be one stop faster on DX to get the same amount of light.
DoF - kind of a hybrid between the field of view and the noise performance. Basically, continuing with the 50mm example on DX you get the field of view of a 75mm lens but keeping the DOF of a 50mm lens.
It kills me to recommend them because of all their other BS but the Northrups did have a good video on this, if you care to look:
Shooting 50mm f/1 on DX is equivalent to shooting 75mm f/1.4 on FX when comparing the two final pictures for both noise level, field of view, and DOF.