This is just an informational posting about how to set infinity focus on the Fujifilm GX617 cameras so people can do that is needed.
Actually, if you haven't ever tested your camera, it would be a good idea to test this to ensure that you don't have one that is off. It may result in better images and permit using larger apertures when shooting.
The lenses all have a helical in them and the focus collar on the helical is a metal ring that has a rubber grip ring glued to the focus collar. Underneith the rubber collar are several screw locations. One pair of screws attaches the infinity limiter chuck which keeps the collar from rotating past the infinity point so you can safely throw it out to infinity and not have to be checking on a GG to ensure proper infinity focus. There are also three very small set screws at 120 degrees around the focus collar. They may be hidden in the glue used to adhere the rubber grip ring to the focus collar. They require a micro straight screwdriver. If you loosen those, you can get the focus collar to move freely on the helical (except for the infinity focus limit stop).
Here's the procedure to test the focus at inifinity:
1. Focus at infinity.
2. Open the shutter using the B setting and use a GG to check the focus with the lens WIDE OPEN on a very distant subject. Trees are easy to see the branches against the sky. That willl set the DOF the shallowest and highlight any focus errors.
3. If the focus looks good enough to you, you probably don't need to change anything, but this is a bit of a case of Goldilox because if it is slightly short of infinity, the infinity focus stop will not permit you to see that it could possibly be sharper. If it is past infinity, you will be able to see it get a touch sharper when you focus the lens closer than the infinity stop. Basically, while looking at the GG, work the focus collar and see if it gets sharper when shorter than infinity.
4. If it gets sharper when closer than infinity, then find the sharpest place and stop. Then, you will need to decide if the error is far enough out to pull off the rubber ring and adjust. If so, peel up the rubber ring and find the three set screws and loosen then a turn or two and then turn the collar so that the infinity stop hits and then retighten the set screws.
5. Then find a suitable adhesive to re-glue the rubber collar back on the lens.
If the lens is not clearly focusing past infinity, then you have to decide if the infinity focus point is "right on" the infinity point. To do this, look at the infinity focus and then see if you can focus on something that is clearly closer than infinity (but still out near infinity) so that you can estimate if that "nearer than infinity" object appears sharper than what you were able to get at infinity. If it looks like it is, then it may currently be set closer than infinity when at the infinity stop and you will need to adjust the focus collar. The directions are a little different than above.
3. You need to get it back to infinity and then pull off the rubber collar.
4. You need to loosen the three set screws and rotate the focus collar to the right (from above) slightly so that the infinity limiter is not engaged.
5. Tighten the set screws again temporarily. Not real tight, just snug.
6. Now, it should be focusing past infinity when you rotate the collar so that the infinity focus limit is engaged. Verify that on the GG.
7. Re-focus while looking at the GG so that you can see when the object is the sharpest. It should be slightly short of infinity now on the focus collar.
8. Re-loosen the set screws and turn the focus collar until the infinity stop engages. Tighten the set screws for the last time. Good and tight.
9. Glue the rubber collar back into place on the focus ring.
All done. It's easier than it sounds, but you will need to find a suitable adhesive.
I don't know exactly what adhesive it should be, but I think a flexible contact adhesive should work well. The rubber is semi-tight anyway, so you just need to keep it from slipping around. I put the rubber collar back in place and the lifted a spot and put a few drops of G-S Hypo Cement under and let the rubber collar squeeze it flat. A small amount in a few points around the collar should be good. It will dry in a few days.
Actually, if you haven't ever tested your camera, it would be a good idea to test this to ensure that you don't have one that is off. It may result in better images and permit using larger apertures when shooting.
The lenses all have a helical in them and the focus collar on the helical is a metal ring that has a rubber grip ring glued to the focus collar. Underneith the rubber collar are several screw locations. One pair of screws attaches the infinity limiter chuck which keeps the collar from rotating past the infinity point so you can safely throw it out to infinity and not have to be checking on a GG to ensure proper infinity focus. There are also three very small set screws at 120 degrees around the focus collar. They may be hidden in the glue used to adhere the rubber grip ring to the focus collar. They require a micro straight screwdriver. If you loosen those, you can get the focus collar to move freely on the helical (except for the infinity focus limit stop).
Here's the procedure to test the focus at inifinity:
1. Focus at infinity.
2. Open the shutter using the B setting and use a GG to check the focus with the lens WIDE OPEN on a very distant subject. Trees are easy to see the branches against the sky. That willl set the DOF the shallowest and highlight any focus errors.
3. If the focus looks good enough to you, you probably don't need to change anything, but this is a bit of a case of Goldilox because if it is slightly short of infinity, the infinity focus stop will not permit you to see that it could possibly be sharper. If it is past infinity, you will be able to see it get a touch sharper when you focus the lens closer than the infinity stop. Basically, while looking at the GG, work the focus collar and see if it gets sharper when shorter than infinity.
4. If it gets sharper when closer than infinity, then find the sharpest place and stop. Then, you will need to decide if the error is far enough out to pull off the rubber ring and adjust. If so, peel up the rubber ring and find the three set screws and loosen then a turn or two and then turn the collar so that the infinity stop hits and then retighten the set screws.
5. Then find a suitable adhesive to re-glue the rubber collar back on the lens.
If the lens is not clearly focusing past infinity, then you have to decide if the infinity focus point is "right on" the infinity point. To do this, look at the infinity focus and then see if you can focus on something that is clearly closer than infinity (but still out near infinity) so that you can estimate if that "nearer than infinity" object appears sharper than what you were able to get at infinity. If it looks like it is, then it may currently be set closer than infinity when at the infinity stop and you will need to adjust the focus collar. The directions are a little different than above.
3. You need to get it back to infinity and then pull off the rubber collar.
4. You need to loosen the three set screws and rotate the focus collar to the right (from above) slightly so that the infinity limiter is not engaged.
5. Tighten the set screws again temporarily. Not real tight, just snug.
6. Now, it should be focusing past infinity when you rotate the collar so that the infinity focus limit is engaged. Verify that on the GG.
7. Re-focus while looking at the GG so that you can see when the object is the sharpest. It should be slightly short of infinity now on the focus collar.
8. Re-loosen the set screws and turn the focus collar until the infinity stop engages. Tighten the set screws for the last time. Good and tight.
9. Glue the rubber collar back into place on the focus ring.
All done. It's easier than it sounds, but you will need to find a suitable adhesive.
I don't know exactly what adhesive it should be, but I think a flexible contact adhesive should work well. The rubber is semi-tight anyway, so you just need to keep it from slipping around. I put the rubber collar back in place and the lifted a spot and put a few drops of G-S Hypo Cement under and let the rubber collar squeeze it flat. A small amount in a few points around the collar should be good. It will dry in a few days.
