Josh Mitchell-Frey
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I know there are so many threads on this forum about RED speed boosters, and nearly all of them end with "there's not enough room" (except for James Miller's successful DIY Nikon mount solution, which required the removal of the OLPF to work)
But surely whether there's room or not depends on the flange focal distance of the lenses in question - perhaps Pentacon Six lenses, with an FFD of 74.1mm could be workable?
I've been running some numbers, but am no expert on optics, so I've had to make some assumptions that may not be correct.
The main assumption - a 0.71x Speed Booster will reduce the FFD by 0.71x. This may be completely false, and there may be a complex algorithm to figure out the change in FFD.
But if this is correct:
P6 FFD of 74.1mm becomes (74.1 * 0.71) = 52.611mm with a 0.71x speed booster.
The Epic Dragon sensor is recessed 26.45mm past the body plane of the camera (according to this thread). 52.611mm - 26.45mm = 26.161mm. So a speed booster mount for Pentacon Six would need to hold the lens 26.161mm from the body plane. Surely this would be enough room to house the speed booster element.
What I haven't accounted for here is how much the OLPF effects FFD. Most likely this means there'd be a little less than 26.161mm to work with in making a mount that allows focus to infinity.
Any thoughts on the above logic?
*I'm not concerned about problems with vignetting, or with questions of whether a speed booster is really necessary, or with debating the quality of Pentacon Six lenses at this stage, purely whether from an optical standpoint it'd be possible to focus to infinity*
But surely whether there's room or not depends on the flange focal distance of the lenses in question - perhaps Pentacon Six lenses, with an FFD of 74.1mm could be workable?
I've been running some numbers, but am no expert on optics, so I've had to make some assumptions that may not be correct.
The main assumption - a 0.71x Speed Booster will reduce the FFD by 0.71x. This may be completely false, and there may be a complex algorithm to figure out the change in FFD.
But if this is correct:
P6 FFD of 74.1mm becomes (74.1 * 0.71) = 52.611mm with a 0.71x speed booster.
The Epic Dragon sensor is recessed 26.45mm past the body plane of the camera (according to this thread). 52.611mm - 26.45mm = 26.161mm. So a speed booster mount for Pentacon Six would need to hold the lens 26.161mm from the body plane. Surely this would be enough room to house the speed booster element.
What I haven't accounted for here is how much the OLPF effects FFD. Most likely this means there'd be a little less than 26.161mm to work with in making a mount that allows focus to infinity.
Any thoughts on the above logic?
*I'm not concerned about problems with vignetting, or with questions of whether a speed booster is really necessary, or with debating the quality of Pentacon Six lenses at this stage, purely whether from an optical standpoint it'd be possible to focus to infinity*