Canon’s new 600mm and 800mm lenses

Started 3 months ago | Discussions thread
Jack Hogan Veteran Member • Posts: 7,493
Re: DoF of Canon’s new 600mm and 800mm lenses
1

alanr0 wrote:

... my guess is that this is due to a small focussing error, possibly combined with a change in spherical aberration in the preceding optics. ...

Bill, slightly OT. You know I am a raytracing noob and the first time I tried it recently I was flabbergasted at the amount of spherical aberration from a single lens with perfectly spherical surfaces. That would suggest that the choice of where exactly the bundle intercepts the optical axis on the image side is a range as opposed to a single hard number.

Does raytracing take this into account or does it just use the marginal rays? If it does take it into account, what criterion is normally used to determine the location of the CLC in order to draw the relative rays?

Jack

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