FT3 won't focus at infinity

[waynecrider]

An FT3 I got awhile back and never shot won't focus at infinity. The split image focusing spot shows lines not aligning at distance. I've tried 3 different lenses. Could the mount be out of register? I had sunk money into a CLA on this at one time and never checked it and now it looks like it needs fixing. Any hints on a DIY

 

[BobD]

Did it focus properly before the CLA?

 

[waynecrider]

Did it focus properly before the CLA?

Can't remember.

 

[Rol_Lei Nut]

1) Shoot something at infinity with one of the lenses (preferably a tele) set at infinity and wide open... Is it sharp?

2) If so, check that your focusing screen is properly seated, and/or

3) Have your mirror resting point adjusted.

 

[LunoLuno]

Get a cheap focusing screen and set it on the film guide-rail, then shoot at infinity with the mirror lock-up setting or with the bulb mode. If the sprit image of the focusing screen on the film guide-rail doesn't match the split you see through the view finder, there's something wrong with the mirror alignment or the placement of the focusing screen. It the two split image match each other, there's something wrong with your lenses or the back-focus alignment of your body.

 

[Trask]

You can actually get some very thin tracing paper and tape that across the film plane, if you've got something at "infinity" to focus on that's out in bright daylight (and maybe you've pulled your jacket over your head like a focusing cloth).

 

[elekm]

If the viewing screen is seated correctly, I think that you need to adjust the angle of the mirror.

 

[waynecrider]

Thanks guys I'll try the GG trick.

 

[John Koehrer]

Something I have seen once was one edge of the mirror out of it's retaining bracket.

 

[2F/2F]

The bayonet mount on the body could be loose or maladjusted.

The mirror could be loose or maladjusted. (This happened with one of my F-1s right after a CLA, and it ruined 90% of the shots on about 20 rolls of film. It is not easy to notice the problem unless you focus on infinity or use your distance scale a lot, and with my 50mm lens, I rarely do that, so I did not notice until near the end of a long trip.)

The focusing screen could be loose or maladusted.

The focusing collar on the lens may not be moving the internals of the lens to the proper position. (My Canon 28mm f/2.0 had this problem. When the collar was set to infinity, the lens was not actually focused on infinity.)

Only the latter is an issue with the lens.

 

[Pumal]

I'm inclined to think is the lens. Some element loose

 

[John Koehrer]

All three lenses are off.
Try the ground glass at the film plane trick.
Put a GG on the film rails & focus. If the lens & image on the GG agree it's the focusing screen. If not look at body for errors.