The ONAG® SC is optimized for APS-C chips, up to 28mm in diagonal, the ONAG XM for full frame (FF, 24x36mm) chips having 43mm in diagonal.
However the ONAG® XM can easily be used with chips having up to 50mm in diagonal, such as 36x36mm chip formats.The plots below provide the chip illuminations for the ONAG SC and the ONAG XM at different F/# and for various sensor sizes.
The total back focus from the ONAG scope port (SP) to the sensor plane is a assumed to be 120mm unless otherwise noted, which includes the ONAG back focus. This is a typical value for most set-ups with one imaging camera and one filter wheel, or a DSLR.
The color code expresses the level of chip illumination %, assuming that any stops before the ONAG® SP are not a limiting factor.
The right color bar gives the color code reference for each plot.
Most of the vignetting, if any, is at the extreme corners of the image and can be easily compensated for using a simple flat frame calibration without any visible effect on S/N ratio.
Please feel free to contact us for custom calculations, we will be glad to help.