Home made lens tools

[Tom Caldwell]

A thread for illustrating tools made to assist with lens repairs:
Here is my jig for making screws from threaded bar stock.

 

[Tom Caldwell]

Home made adjustable lens spanners

 

[petrochemist]

I've brought a couple of e-bay lens spanners but I think your homemade ones look better!
I will have to keep an eye out for more of these compasses

 

[Tom Caldwell]

I've brought a couple of e-bay lens spanners but I think your homemade ones look better!
I will have to keep an eye out for more of these compasses

Normally called "dividers" and used by carpenters/engineers for precision measuring and transcribing measurements. Hence made/sold with points. They are not that expensive. As sold they might have too much flex in their legs and point ends are not as secure as flat slots ends in my opinion. Therefore I have generally shortened the ones I have made and ground different shapes of flat slot ends on them. Because they are cheap, compact, easily made, and keep their settings well I can use several of them with different settings in a disassembly and be able to use them in reverse order to re-assemble the lens.

 

[petrochemist]

Normally called "dividers" and used by carpenters/engineers for precision measuring and transcribing measurements. Hence made/sold with points. They are not that expensive. As sold they might have too much flex in their legs and point ends are not as secure as flat slots ends in my opinion. Therefore I have generally shortened the ones I have made and ground different shapes of flat slot ends on them. Because they are cheap, compact, easily made, and keep their settings well I can use several of them with different settings in a disassembly and be able to use them in reverse order to re-assemble the lens.

Thanks I've often seen them at car boot sales, but agree they'll typically need shortening.
Your quite right compasses are only when there's a pencil/pen fitting on one arm.
Most of the dividers I have at the moment are not of the bow design (sprung with a screw adjustment, like the ones you've shown) one pair is designed to be used single handed, with a section to squeeze to open the tips - quite helpful for navigation in rough seas where you need the other hand to hold on!

 

[ken53]

A thread for illustrating tools made to assist with lens repairs:
Here is my jig for making screws from threaded bar stock.

View attachment 1400

Wow, nice post. Thank You for sharing this interesting subject. Very nice supporting photos and visuals. Great addition for a new forum site.

 

[Tom Caldwell]

Not strictly an adapted lens tool but a home made device and possibly ok as an 'invention'

Here is the low profile mount for a red dot sight. In a country that has licensed guns quite strictly we can still buy red dot sights for pistols and re-purpose them for less serious use.

Here is the mount what was based on a standard weaver rail design but made on a small manual milling machine from a very small piece of stock aluminium bar.



The object of course was to try and make the mount as low-profile as possible to minimise the parallax effect. The machining itself needs to be true to the hot shoe guide with standard clearance. There is no parallax adjustment as that would make the part too complex. There is a slight directional wiggle in the hot shoe clearance which was accidental but comes in handy in centring the RDS with the pinpoint focus system in the camera body.

Obviously a RF-Style body also helps immensely with parallax - combined with the mount the parallax even at distance is minimal.



Here is the Red Dot Sight mounted. (I replaced the thumb adjustment wheel with another later to give better clearance with the camera body - it was ok but a little too tight-clearance for my comfort)

Note that the RDS fits snugly in between this lens (PL 200/2.8) and should also fit behind most other lenses.

Set up is pretty simple - set pinpoint focus and focus on a reasonable distant object then align the red-dot with the in-focus marker on the camera using the firm but moveable wiggle in the hot shoe.

Note that the red dot sight is not a laser sight and does not emit any beam. But instead puts a dot up on the surface of the RDS screen which represents the target. Fascinatingly the dot does not otherwise need to be aligned otherwise on the target - no matter where your eye might be behind the camera if you can see the red dot it is on target. Simple.

Accuracy?

I used my son's jinking drone as a test target and no matter where it was when it was in the highlighted dot spectrum I could rely on the camera pinpoint AF to make good AF without checking the lcd screen. Just by using the RDs as point of focus indicator.

An example:




Here the drone was near, in front of, and among trees and at least 150 metres distant. The actual original image shows that the drone was sharply in focus.

Another example:



This image was cropped to show the detail of the in-focus drone.