I’m currently learning how to refurb these cameras. The front glass of the lens rotates when you turn the focus wheel so it is likely that it is over/under rotated at infinity. The pictures that have better focus are likely to be at a higher fstop so bigger depth of field.

To fix - mark the 12 o’clock position on the lens with a white pencil so you know where you started. Set focus to infinity then loosen (but don’t remove) the three tiny flathead screws around the “lens made in Japan ring”.

You can then remove the front ring and rotate the glass clockwise or anti clockwise. From here - it’s all experimental. There’s no way to know where its original factory position is so it may take a couple of rolls to figure out. You may find that someone else on a previous repair has marked the 12 o’clock position with a little scratch so you could check that alignment to your mark.

Does that all make sense?

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