|
Dennis,
Thanks so much, I am begining to understand. The Camera Lense is like a refractor with a mecahnical mask "Iris" (like the thing on the Stargate), that stops it down (as in reduces its apperture). In a Telescope we usualy use a lense (barlow) either postive or negative to increase or reduce the focal length. In a Camera lense we change the apperture size to do the same thing usin a iris. I got it.
So on my A610 when I change the F ratio I am adjusting the Iris on the lense.
I think i got it now.
So I guess if i add a telephoto lense, I would leave the F ratio on my internal Lense at the max, Iris fully open and adjust the IRIS on the external lense. The question then is at what apperture will my internal Lense itself become a limiting factor, that is act like a obstruction to the external lense. I think I will have to select the apperture and Focal length wisely.
BTW what do you guys recoomend a 52 thread or a 58 thread, which is easiert to get second hand lenses for?
Regards
|