Tube Lens tests - medium format and full frame

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nathanm
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Post by nathanm »

Charlie Krebs lives near me, and he brought over his Mitutoyo 5X and 10X. While there are a few slight differences the conclusion is the same as for mine - some degradation in the corners, while the center is fine.

So it seems that the 7.5X and 20X are different than the 5X and 10X
nathanm

PhotogrAzure
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Location: Southampton UK

Re:

Post by PhotogrAzure »

nathanm wrote:
Fri Oct 28, 2016 11:53 pm
Here is a photo of the 5X Mitutoyo mounted on the Raynox DCR-5320 pair.

They take 72mm filter mount, so we made an adapter that threads to 72mm, it is concave just enough to put the end of the objective about 1 mm in front of the front element of the DCR 5320 pair.

Image

We made this after the optical bench tests.

The DCR 5320 is threaded into a 72-77 mm step down adapter, with the 77 mm end threaded into Thorlabs SM3 tube.
Hi Nathanm,
I really like the concave adapter design idea! I am wondering if you could share the 3D model, I'd like to machine one myself.

Lou Jost
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Re: Tube Lens tests - medium format and full frame

Post by Lou Jost »

Nathanm sadly has not been posting much these days (none since 2017). I miss his posts. Perhaps he will answer, but if not, I would like to suggest a work-around. When I have this situation, I use multiple step-down rings, some mounted INSIDE the outer ones. This can bring an objective as close as you want to the front element of the tube lens, with no machining needed.

PhotogrAzure
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Joined: Fri Jun 04, 2021 2:23 am
Location: Southampton UK

Re: Tube Lens tests - medium format and full frame

Post by PhotogrAzure »

Lou Jost wrote:
Thu Jun 10, 2021 6:22 am
Nathanm sadly has not been posting much these days (none since 2017). I miss his posts. Perhaps he will answer, but if not, I would like to suggest a work-around. When I have this situation, I use multiple step-down rings, some mounted INSIDE the outer ones. This can bring an objective as close as you want to the front element of the tube lens, with no machining needed.
Thanks Lou! That sounds like a brilliant idea. Will try experiment this.

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