Trying to do this the wrong way. Telescope companies have made the product for years. It is called a telecompressor. It fits between the camera body and lens. Looks just like a teleconverter. Works in reverse. T Makes the projected image smaller. Can't go too small or it won't fill the frame. The one I have is a Celestron. It also makes the lens BRIGHTER!
Think about it- any time you increase magnification without making front element bigger you lose light (teleconverter). Anytime you decrease magnification and leave the lens elements the same size you gain brightness. Camera companies stole the teleconverter from telescope manufacturers. To bad they don't steal the telecompressor. My F10 Celestron becomes a F6.3 with telecompressor. Very little quality loss since you aren't magnifying the prime lens defects (like teleconverter). Center may lose a little sharpness - edges are actually better (has built in field flatner).
thanks
barondla
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