Modifiing 58mm Extenders

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mawyatt
Posts: 2497
Joined: Thu Aug 22, 2013 6:54 pm
Location: Clearwater, Florida

Modifiing 58mm Extenders

Post by mawyatt »

Many cheap eBay 58mm extenders are available for various camera mounts but almost all have a sloppy rotational shift when mounted on the Nikon camera body and many even have a translational shift. The translational problem can't be fixed simply and requires a better higher quality F Nikon mount adapter.

When trying to mount lens setups for quality work, like with Raynox's as tube lenses for Mitty's, or PN105, or DImage 5400, some like Robert have built superb setups based upon Thor Labs or others have used MJKZZ components, but many folks have tried creating lens setups that utilize these cheap 58mm extenders.

What I've found is the F Nikon Mount adapter plug pin slot (locks the mount) is slightly too wide to allow a secure fit with a quality mount (like directly on the Nikon body), so this allows a little rotational movement.

I took my Nikon BR-2A, which has a very secure mount and noted the slot details and decided to try and drill a hole into the 58mm supplied F Mount adapter which will mate with plug pin much tighter and thus less rotational movement.

I used a poor quality lens mount ring removed from the screw part as a guide to help locate the hole (see images). The Nikon BR-2A has slots located at 120 degrees apart, which I use to mark the 58mm F Mount adapter. The plug pins are 2mm diameter, and after some trial and test, I used a #47 (0.078 inch) drill since I didn't have a 2mm drill. You can drill a hole or slot depending on what you want and what gives a good snug fit. You need to remove the tiny stop screw on the mount to allow it to rotate around to the new slot/hole.

This creates a very snug fit with almost no rotational shift and as snug as my Nikon BR-2A :D

Anyway, hope this helps some folks.

Image Image Image
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

RobertOToole
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Post by RobertOToole »

Hi Mike,

This is interesting.

Never thought about the topic but I experience the issue all the time.

So basically you moved the stop screw to control the extra rotation in the mount?

Robert

mawyatt
Posts: 2497
Joined: Thu Aug 22, 2013 6:54 pm
Location: Clearwater, Florida

Post by mawyatt »

Robert,

Yes if you remove the stop screw these type of mounts will rotate completely around. With that in mind you can now drill a new "lock" slot or hole which will snuggly fit the pin plug from the other type F mount (camera for example).

These cheap eBay 58mm adapter set F mounts are now as snug as the beautifully machined Nikon BR-2A 52mm adapter, without any rotational play. Well at least the ones with no translational movement, these are still a complete loss :(

BTW I discovered this solution when trying to reconfigure my Raynox 150 and LSA lenses with ~145mm-50mm and 75mm respectively, for your short focus setup. I found some rotational play in every F mount adapter I had, and even researched getting the Thor Labs tubes, clamps and mounts you have.

That's when I looked at the BR-2A and how it's configured with the 3 slot arrangement and realized these 58mm F mount adapters could be modified to do the same and give another pin locking slot/hole which can be a much tighter fit and thus less rotational slop (all the rotational slop is in the adapters when using a quality Nikon mount like the camera body). It works and I'll be modifying all my loose F mount adapters tomorrow.

Hey thanks for all the great work on the lens tests!!

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

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