Somewhat odd technical questions

[ChadS]

Folks,

I'm trying to find information for a bunch of lens mounts regarding the minimum distance between the back element and the sensor. For instance, both the EF and EF-S specification gives the distance from the mount flange to the sensor as 1.4" but the EF-S allows things to intrude further into the camera. I'd like to find this information for as many mounts as possible if someone knows a chart (F-, C-, EF-, etc.).

Also, does anyone have a reference for where the nodal points on the various Canon lenses can be found? Perhaps the location of these points moves as the lens focuses/zooms so let's call it at infinity focus.

Thanks!

[ChadS]

@jrw Thanks for the advice. However, nothing completely obvious jumps out at me. Any direct URLs or charts you could provide would be most helpful.

[ChadS]

@jrw Thanks for the details. I'll dig into them. Sadly, there's nothing interesting about what I'm doing. The company I work for uses off-the-shelf SLR lenses at times as OEM equipment that we incorporate into some diagnostics equipment we make. They're not ideal for what we want but for low quantities getting the equivalent IQ from long working-distance microscopes, etc. would cost a lot more money and still not work as well. Sadly, I'll be taking a couple of lenses, pinning them at infinity focus and locking them in a box. For this application manual focus lenses are actually easier to deal with.

The reason I needed the information about the allowable distance from the sensor to the back element is that for one application we're using the lens backwards. That is, the thing we're measuring is being put where the sensor would be and the light from it comes out the business end of the lens. So knowing how far lenses approach that plane defines my working distance.

Thanks again!

[msowsun]

This chart from the Bob Atkins site may be of some use for you: http://www.bobatkins.com/photography...focus_EOS.html