Still Lens Crop Factor on 5K Sensor

[Andrew Rieger]

Quick question. What is the crop factor of a still lens such as the Zeiss ZF on the upcoming MX 5K Scarlet Sensor?

[David Mullen ASC]

The MX sensor is 30 x 15mm; FF35 is 36 x 24mm.

If a 5K recording uses all 30mm of the sensor (it's probably a bit smaller though), then that's a 1.2X factor (36/30 = 1.2) if you are comparing horizontal view.

[Tom Lowe]

It's probably going to end up being similar to the crop factor on the 1D Mark 4 (27.9 x 18.6 mm).

[Andrew Rieger]

Thanks, that is what I was looking for.

[Gary Paul Walker]

Aside from the crop factor of using a lens that resolves for full frame, are there any other issues that should be looked out for when using them? It may seem a stupid question, but if the architecture of the glass is to project to one size 36 x 24mm, and only the exponential centre of the lens is used by the S35 sensor will that effect the image in any way- however small any artifact might be?

[David Rasberry]

Usually you have issues when you use a lens for a smaller image format, say DX specific lenses, on a larger format like FF35 as you can get lower resolution, fall off and vignetting toward the edges of the frame. The center of any lens is usually the sharpest area, so FF lenses work just fine on smaller sensors. Older lenses designed for film cameras may have some issues on digital sensors due to non-telecentric designs, especially very wide angle lenses.

[Gary Paul Walker]

Usually you have issues when you use a lens for a smaller image format, say DX specific lenses, on a larger format like FF35 as you can get lower resolution, fall off and vignetting toward the edges of the frame. The center of any lens is usually the sharpest area, so FF lenses work just fine on smaller sensors. Older lenses designed for film cameras may have some issues on digital sensors due to non-telecentric designs, especially very wide angle lenses.

Ah I see.. many thanks for this David. I'm lucky enough to have access to quite a few FF lenses, so if I'm getting a nice sharp image at its very centre for the s35 sensor I'll be incredibly happy!