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Message: <blockquote data-quote="aroy" data-source="post: 476306" data-attributes="member: 16090">I see no optical disadvantages in using a lens with an image circle much larger than the sensor. Here are some facts. Unless the lens is designed for copy work and is absolutely linear, is is sharper in the centre and vignettes less. Check the MTF curves for most lenses.. The so called magnification factor of a smaller with respect to a FF sensor, is there because the smaller sensors have higher pixel density. If a CX, DX and FX sensors are all 24MP, then there will be more pixels per square mm of the sensor in a CX than a DX sensor. Similarly a DX sensor will have more pixels than a FX sensor. To get the pixel density of a 24MP DX sensor, an FX sensor needs to be around 56MP.. If all the sensors had the same pixel density and you took images with CX, DX and FX sensors, then when you superimpose the images of CX on DX and DX on FX, you will find no difference, just that the CX image will be smaller than DX which it self will be smaller than FX.. The major disadvantage of using a lens with a larger image circle (that is lens designed for a bigger sensor) is the size, and the resultant cost. There for a Native lens design for the Nikon J series will be appreciably smaller (and may be cheaper) than that designed for FX sensor. We can see that happening in DX world. The 35mm F1.8DX lens is smaller and much cheape than its FX version.Another example of lenses designed for larger image circle are Meduim Format lenses. These were designed for 60mm square negative, they are massive. Just compare the 80mm F2.8 (standard MF lens) with 85mm F1.4, both the size, weight and the cost are more than double for MF compared to FF.</blockquote>

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