Close focus helicoid adapter question

[Dr. G]

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I've noticed that my Hoage close focus helicoid adapter is shorter than my Leica M to L adapter.  Can anyone tell me what effect having the lens closer to the sensor than it was designed would be?  I imagine having the back of the lens the distance from the sensor it was designed for would be the best scenario for standard shooting.

The Hawk's factory adapter has an adjustment that can be locked in place when you're not using it for close up work, but I can't find that one for sale anywhere.

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[BernardC]

7 minutes ago, Dr. G said:

I've noticed that my Hoage close focus helicoid adapter is shorter than my Leica M to L adapter.  Can anyone tell me what effect having the lens closer to the sensor than it was designed would be?  I imagine having the back of the lens the distance from the sensor it was designed for would be the best scenario for standard shooting.

The Hawk's factory adapter has an adjustment that can be locked in place when you're not using it for close up work, but I can't find that one for sale anywhere.

Having a shorter adapter means that your lenses will focus "past infinity." Lenses are closest to the sensor at infinity, and move farther away as they are focused closer. A simple lens with no internal focus will be extend by its focal length at 1:1, and half its focal length at 1:2. Incidentally, that's why a 55mm macro lens that focuses to 1:2 needs a 27mm extension tube to reach 1:1. Leica's old 60mm macro Elmarit-R came with an extension tube that measures 30mm, since it reached 1:2 without the tube.

Have you tried contacting Hawk's factory through their web site: www.hawksfactory.tw ? That's how I got my adapter. I think it's a single-person operation.