Tips for Calibrating a GF670's RF

[SaveKodak]

I have a GF670 that has an odd RF issue. When I first received it the RF was clearly off. The images in the split image line up well but the photos were generally out of focus. I found a tutorial online that helped me find the screw for RF calibration. Using a piece of ground glass and a focusing target I made adjustments that work well for most situations. From medium to close distances my RF is very accurate.

However oddly at infinity it's definitely visually off in the horizontal alignment. I used the moon as a target so no risk of it being actually closer than infinity. I'm worried that if I align for infinity will will throw off the close distances.

Any ideas?

 

[Pedro_fiz]

This camera is difficult for calibration. I sent mine to FOKUS camera repairs in Madrid and did a perfect job.
Another issue I had is that there was a slack when the lens was open and it was possible to move it a little to the right. I think this slack also provoked out of focus pictures.
FOKUS also repaired the slack and now the camera is perfect.

 

[SaveKodak]

Is it possible for an RF to be off at middle distances?

My infinity pictures seem sharp (aided by stopping down usually). Close pictures are tack sharp, even wide open. But when I focus on something that is like 10-20 feet away I seem to be front focusing a ton...

That shop in Spain sounds great but I am in the USA...

 

[Peter_S]

You may have seen this already. If not, it may help...
https://www.youtube.com/watch?v=THz6glfMIXg&t=1188s

 

[SaveKodak]

I did a recalibration today at a distance of about 12-14 feet. Using a GG for confirmation I think it's accurate near to far now. Encouragingly even infinity, or near, targets seem to be closer to the hard stop. I'd need to target the moon to know for sure as I am surrounded by woods, which makes finding true infinity difficult.

The lens is so sharp that it's a shame to have these issue.

Another thing I'm finding is that the meter is wildly accurate! It's just been nailing my Ektachrome exposures in Aperture Program.

What a camera. Cosina if you're listening, put these things back into production! You will sell every single unit that comes off the line even if they're $3k. Just make it so they can take a filter when folded, and make the calibration process a bit easier.