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Using Focal Reducers On Full-Frame Bodies

Started Jul 13, 2014 | Discussions thread
CS_63 New Member • Posts: 1
Re: 8mm Fisheye On Focal Reducer On Full-Frame Body

Back to the top of the tread and how lenses for 35mm behave on full frame (a7) cameras and a focal reducer.

I have a Viltrox (0.7x) between a 35mm Nikor PC (shift) lens and my a7 body. The corners vignette the as the Pentax lens shown (near as makes no difference). With the cameras viewing grid turned on it is clear that a 24mm square can be captured in the center.

Another interesting point is that the lens can be shifted by 5mm in either direction horizontally and 8mm vertically without impacting where the vignetted circle is in the viewfinder. This confirms the hypothesis that it is the adapter that is causing the vignetting since if it were not the image would immediately begin to move when shifting the lens. Since the shift lens has an image circle of greater than 68mm (the diagonal of the field of the lens shifted to the maximum in each direction being 58x36mm) it is certain that the principle lens is not responsible for the vignetting.

The new angle of view is equal to that of a 24mm lens, however the depth of field, as well as all other characteristics of the original 35mm lens, is maintained.

Has anyone tried other adapters? It would be great to find one that utilized the full image.

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