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.
- Panasonic - DMC-GM1
- 30.0 mm
- ƒ/8
- 1/60 sec
- Center-Weighted Average
- Auto exposure
- 0.3
- ISO 500
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.
- Panasonic - DMC-GM1
- 30.0 mm
- ƒ/8
- 1/60 sec
- Pattern
- Auto exposure
- 0.7
- ISO 800
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:
- Panasonic - DMC-GX7
- 200.0 mm
- ƒ/13
- 1/320 sec
- Spot
- Auto exposure
- ISO 1600
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:
- Panasonic - DMC-GX7
- 200.0 mm
- ƒ/5
- 1/500 sec
- Spot
- Auto exposure
- ISO 200
This image was cropped to show the detail of the in-focus drone.