Re-gain infinity focus on Minolta 50mm f1.7 lens

After you have installed the rear socket, now is time to install the front element and re-gain the infinity focus of Minolta 50mm f1.7 lens.  Before I start the guide , let understand more on infinity focus.

What is infinity focus?

Infinity focus mean a particular lens able to lock focus at infinity distance.

how to focus to infinity?

Set the camera focusing method to center point AF. Point the camera lens to a point which is far far away.Press the shutter button half, focusing begin and lock on the target. if you look at the focusing distance window, you can see the white line is pointing to infinity.

Do you able to understand what is infinity focus?

Let start today’s sharing on re-gain Infinity focus on Minolta 50mm F1.7 lens.

1Prepare to assemble focuing distance ring

As you can see from the picture, the focusing part has been dis-assemble in previous sharing. Next step is to install the focusing distance part.

2Assemble the focusing distance ring

Installing the focusing distance part back to the lens.

3After install the focusing distance ring

Insert the metal ring and tight the screw (3 pc instead of 6pc  is good enough)

4Assemble the front element

Clean the front element with IPA before re-install back to the helicoid

5After front element

Tighten the 3 screw for the front element

6mount it to a digital camera

Mount the lens into the dSLR body. To re-gain the infinity focus , this is the method that I used

  1. Mount the lens in the dSLR body
  2. turn on the camera
  3. lens reset to infinity by camera
  4. Set the camera setting to … AF-S , Spot focusing
  5. Loosen the focusing distance’s screw
  6. Point the camera to infinity and half press the shuttle.
  7. Camera AF screw drive will set the infinity focus for the lens element
  8. distance scale will not show correctly , as show as below.

7after infinity focus

white line show where the focusing distance which is incorrect. it should be infinity focus.

8Rotate the focusing distance scale to infinity

Rotate the focusing distance ring to infinity focus as shown above.

9Screw in all the screw

With out power off the camera, tighten the 6 screw.

10Install the hood

Install the hood back to the body

11Installing the front ring

Installing the front ring cover.


Any precaution steps  needed ?

  • Remember to clean the optic before re-installation
  • prior to tighten the 6 screw for the focusing distance ring, do not switch off the camera

My personal experience

The steps above look complicated,I I have used 4 hour for the first task to completely re-assemble it. It can cut short to 10 mins if you are familiar with the lens repair.


Assemble the helicoid and rear socket to Minolta 50mm f1.7 body

After you have completed re-assemble the aperture blades into the helicoid, now is time to install the helicoid back into lens body.

1aInserting the helicoid to main body

use the left hand finger to hold the outer ring while install the helicoid using the right hand. No specific tip needed, just try and error to install it.

2After inserting the helicoid into main body

Turn the outer ring(Yellow arrow) so that the focus guard can be alligned

3Align the focus guide

After the alignment completed

3aMake sure it is flat

Ensure the helicoid, outer ring and the silver body is on the same level. First, adjust the inner part, second on the outer ring.

4Installing focus guide

Install the focus guard

5After installing the focus guide

This is how it look like after install the focus guard

6Inserting the focusing screw

Installing the focusing screw

7Installing the rear socket

Installing the rear socket, make sure the rear socket’s aperture hook is hook into the aperture moving part’s rod, else the camera will not able to control the aperture of minolta 50mm f1.7 lens.

8Rear socket completed

This is how it look like after the re-assemble of the rear socket. Clean the rear element and cap it with rear cap.


Any precaution steps needed?

  • remember to hook the rear socket aperture hook in to the aperture rod
  • make sure the inner part, outer ring and the body is on flat position before install the focus guard. We will restore the infinity focus in next topic
  • Please clean the rear optic after re-assembly rear socket.

My personal experience

These step is pretty straight forward and you should not face any problem in repairing the minolta 50mm f1.7. Time needed is 15 minutes  should able to finish it.

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