You will never see an 88mm image circle because of baffles in the
converter to limit it's output angle, but that's what is happening
optically and is the reason for the 2 stop (1/4 the light intensity)
exposure effect of the extender. I wasn't trying to say they are 'bad',
only to explain how they work. If we understand our tools and the
alternatives, we can use them more effectively. I've got some old slides
I love taken with a zoom and a little 4 element Vivitar extender. Would
I shoot negative film at 1/30 instead of 1/125 in order to get
magnification of an image in the camera at the clear risk of blurring it
when I can enlarge it later - no.
Moose
C.H.Ling wrote:
I don't think the 2x will produce an image circle of 88mm, I think it
just magnify the center of the image of the prime lens and gives the
same image circle of normal 35mm lenses.
Concerning image degradation, I also have the same thought as you ten
years ago, I expected only the prime lens has resolution, the 2x will
magnify the image but half the resolution. But based on my experience,
Gary's test report and an test essay I read from Pop photo. I have
totally changed my mine. The tele extender perform much better than I
thought, a good matched 2x will give very little lost on resolution.
Give some trial with your lens you will know.
C.H.Ling
dreammoose wrote:
Yeah, my 7 element is a "ROKUNAR 2X MC7 AUTO TELECONVERTER". I've seen
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