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Chronos User Discussion / Re: Effective focal lengths/f-stops for lenses with various Chronos mounts

« on: September 10, 2023, 07:22:01 PM »

basket random

Is there a nice shorthand way to calculate effective focal length and f-stop for lenses mounted on the Chronos using adapters?

For instance, I know that using the EF-to-C mount adapter increases the lenses' effective focal length (making it less wide) and raises the effective f-stop (making it slower).  Presumably, so does the new MFT mount due to increasing the distance from the sensor to the lens.  Even more so if using an EF-to-MFT adapter stacked onto the MFT mount.

I was hoping there would be simple conversion factors/ formulas you could use to predict how any given lens will end up when using various adapters on the Chronos.

For example using a 9mm F2.8 EF-mount fisheye with an EF-to-MFT adapter on the MFT mount might end up as a factor of 2, resulting in an effective 18mm F5.6 lens.  I was hoping there would be a nice easy multiplier you could use like that.

Determine the crop factor between the original lens's intended mount and the Chronos's sensor size. For example, if the Chronos has a Micro Four Thirds (MFT) sensor and you're adapting an EF lens, the crop factor is approximately 2x. This means the effective focal length will be roughly twice the original focal length.