FS7: Metabones SB Focusing Trouble

Joshua Milligan

Joshua Milligan

Well-known member
Hey friends. I just got a Metabones SB Ultra and I immediately noticed upon mounting it on the camera that I cannot focus at infinity. I had my FS7 sitting on my kitchen table and I just had mounted the SB and put on a 16-35mm Canon L lens. I tried focusing on the door on the other end of the house just to play with my new SB when I realized that it would not focus on the door, which was far away. Everything before the door could be in focus, but when I threw my focus out towards infinity to focus on the door, it wouldn't ever reach that point. I hope I'm being clear hear. I'm not sure how else to describe it! Is this a common problem? How do I fix this? Obviously I cannot use the SB this way.
 
Joshua worth a check:

- Make sure you have the latest Firmware for your SB.
- Try pushing 'Focus Mag' to see if it hits the focus u want then punch out. Yr using a f2.8 lens with a SB so focus could look soft, also try stopping down a stop or two to check focus.
- Check the back focus of yr lens. https://www.youtube.com/watch?v=n4m2Vg_4T1Q
 
You need to adjust the backfocus of the Speedbooster. I had to it with mine too when mounting the 16-35. Metabones provides directions on their site, it's easy. When setting the backfocus, Keep in mind most lenses focus past infinity. Better to overshoot it a little to give yourself some wiggle room.
 
Joshua Milligan said:
Hey friends. I just got a Metabones SB Ultra and I immediately noticed upon mounting it on the camera that I cannot focus at infinity. I had my FS7 sitting on my kitchen table and I just had mounted the SB and put on a 16-35mm Canon L lens. I tried focusing on the door on the other end of the house just to play with my new SB when I realized that it would not focus on the door, which was far away. Everything before the door could be in focus, but when I threw my focus out towards infinity to focus on the door, it wouldn't ever reach that point. I hope I'm being clear hear. I'm not sure how else to describe it! Is this a common problem? How do I fix this? Obviously I cannot use the SB this way.
Click to expand...

Don't care what anybody says...you need to have the Metabones back focus calibrated by someone with a collimator. You could do it by trial and error by loosening the tiny screw on the camera mount side of the Metabones and using a chart about 10' away with enough light to get a decent exposure wide open.
But trust one who went through this. It's the back focus on the Metabones and totally fixable.
 
Parfocal is another thing. Unless you want to maximize you minimum focusing distance, overshoot it by a little and you can achieve infinity focus on all your lenses
 
Hi Josh, this is nothing to worry about and isn't firmware related. The backfocus is off which is allowing you to focus a lot closer but not at infinity. It is totally something you can do yourself, most B4 Lenses and PL mounts all have onset user correctable backfocus, no voodoo magic needed.

Typical question is what will it do to the rest of my lenses? answer: it is global, you are correcting the slight irregularity in Flange Focal Distance (or FFD) and not one specific lens. This is often the case with cameras that are adapting lenses, the glass on the sensor is different from various camera manufacture's. Nikon for example has cameras with and without a OLPF so they adjust their FFD ever so slightly outside of thei published FFD spec, your FS7 has ND and a safety window, a BMCC has less IR Cut etc etc and its this minute difference between the lens and sensor that you're often correcting for.

Here is how a cheap Tamron 17-50 F2.8, a middle of the road Sigma 18-35 F1.8 and (once) premium Nikon 80-200 F2.8 should perform with and without a tele extender when mounted to a camera (BMCC) with a speedbooster,


All perform as parfocal zooms just as they do on my Nikon D7100 even though my correction was only performed with the Sigma 18-35 as a control.

instructions are here http://www.metabones.com/article/of/infinity-adjustment-speed-booster-only

Hope that helps :0)
 
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