[LRflex] Re: R 2x APO Extender Question

I agree that it looks like mechanical vignetting, thus my question about hoods, 
etc.

I use the 400 Telyt with my Nikon 2x and the 1.4x, and no signs of this kind of 
mischief.  Yes, totally different setup.  ( Ditto
the results with my 2x Mutar on my Blad).

I thought the converters spread out the angle of the rays to double, thus 
decreasing the angle of view by a factor of 2.   If I were
to examine the 2x ( non APO) I would look for a big length of distance from the 
rear element to the lens mount..... figuring the
vignetting was caused by the rear of the 2x ( or slightly inside).  I would 
also look at the APO and determine if that same distance
were greater....or lesser. 

I stand very confused.......

Frank Filippone
red735i@xxxxxxxxxxxxx 


Probably.    My suspicion (I have no proof) is that the lens 
diameter, within the 2x is smaller than the lens diameter in the APO 
converter.  But, when I had the APO, I tested it (I had it only for a 
short time) but neglected to measure lens diameters.  In other words, 
I think the problem is mechanical, not optical.  Result is the same!

>I have never seen this effect with all the teleconverters I have had 
>over a number of years.....  (

Neither have I, except for this combination.  As I said, the APO 
converter does not do this.



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