Metabones Speedbooster Nikon to BMPCC

Having an issue with the Metabones Speedbooster and was curious if any other users experienced this. When mounting manual Nikkors to the Speedbooster I make sure to set the adapter to 7 per the instructions and close the iris on my lens (f/22). When clicking the lens into place on the Speedbooster the aperture on the lens slightly opens so that 7 is no longer a closed iris and f/22 is never achieved. The workaround is to put the lens on just before it clicks into place and leave it there. It seems like an alignment issue. I can't seem to find anything online about this and Metabones customer support hasn't replied to my emails. Any thoughts?

I have had two Nikon/MFT Metabones Speed boosters, both worked correctly. Try mounting the lens without the SB attached to the camera, so you can see the back side. After it is mounted, is the Iris adjusting tab engaged on the lens Iris tap, look through the lens, it should go from wide open at 0 and atop down to around f/22 at 7. If not, then either the lens, or the SB is not working correctly. Try a different lens to see which one is the issue. This is a mechanical setup, with a Cam on the SB, so the cam might not be engaging the lens Iris tab correctly. Checking the lens/Speed Booster this way will let you work out were the issue is. If it is the SB, then contact Metabones again and give them your tested results.

The Iris is never fully closed on the Nikon lens, it just goes down to f/22 or 32, depending on the lens. The lens has to be set to f/22 or max f/stop for this to work. If the lens is set to f/5.6, then turning the SB Iris ring to 7, will give you f/5.6 only, as the lens Iris f/stop ring actually controls the lens. This is nice, because you can set the max f/stop you want to use, and then open up as necessary. Also, you can calibratedmrhe SB scale to its respective f/stop, by starting a f/3.5 on a 2.8 or faster lens, then turn the SB ring until the iris stops opening, look at the SB index no, and this will be f/3.5 on that lens. You can repeat for additional f/stops.

On a Nikon G lens without a f/stop ring, the G lens is at f/22 until it is mounted on a camera or the Soeed Booster, at which point moving the SB Iris ring from 7 to 1/0 will open up the lens, but you are not going to have a real indication of what the actual f/stop is. The if the camera has a f/stop indicator based on light transmitted, then it will show the actual corrected f/stop based on light transmitted to the sensor.
Cheers

Thanks for the insightful reply Denny. The issue is with all lenses mounted to the Metabones Speedbooster. When attaching a lens to the Speedbooster with a full turn so that it clicks, the iris opens a stop. Not all the way, but enough so that the control ring on the adapter is misaligned. My dilemma is Metabones has not replied to me and the adapter is no longer under warranty. I bought it at B&H in December. The good news is the issue hasn't prevented me from using the adapter, it's just that when I'm out shooting and switching lenses, it takes extra effort to mount the lens carefully, and NOT click it into place. It's purely a mechanical problem with the adapter as far as I can tell, just wish there was an easy explanation/solution. As you know this product isn't cheap for an adapter. You'd expect it to perform flawlessly for the price (or at least have customer support).

If you bought it last December, try contacting B&H Customer support, they might just replace the unit for you, with a try. Sounds like an issue with the Iris Cam mechanism being misaligned. The SB should have a 1-year warranty.
Cheers

One more question about the Speedbooster. I typically leave manual lenses at f/22 and use the Speedbooster iris control ring to adjust the aperture. However, someone told me that I'm not going to achieve correct depth of field this way. They claimed there are elements within the lens that only the lens aperture ring will affect, and the Speedbooster just opens and closes the blades. I'm inclined to think they are wrong, but I would love an expert opinion.

Totally wrong Steven, or they are getting mixed up with adapters that used a Iris in the adapter, sitting behind the lens. The Metabones Speed Booster Iris ring actually controls the Nikon lens Iris, just like a Nikon camera body would, but doing so manually (you rotate the Cam ring instead of a Iris motor in the camera doing so).
So the speed booster is setting the f/stop on the lens, DOF is the same as if it was in a camera. However, the smaller sensor with the SB adjustment is still smaller than the 135sensor, so DOF will be different due to this difference, nothing to do with the Iris control being different.

That said, I would set the lens f/stop to the smallest setting you want to use, like f/8 (not f/22 which you would never want to shoot at, due to lens defraction with the sensor).
Cheers

I really appreciate you getting back to me Denny. I will take your advice and leave the lens f/stop on the smallest setting I intend to use (e.g. f/8). Although it seems that if you mount the lens at the smallest f/stop (e.g. f/22) and have the Speedbooster at 7 (closed position), then once mounted the Speedbooster controls the full spectrum. To me that's more intuitive; even if I don't use f/22 or f/16 , at least I have the option.

You can go either way, but always stop,down the lens and set the SP down to mount and unmout the lens, so the Iris pins align correctly. I prefer,to,set mymlens to f/8, so I know when it stops chasing I am at f/8, and do not accidentally go smaller. But use it the way it works best for you.

Another trick, is to mount the lens on the SB, and set the lens to f/2.8, then while looking through the lens, turn the SB ring until the Iris stops closing, look at the index mark,on the SB, and you know where f/2.8 is. Do the same for 3.5 and 4.0 and you can calibrate the lens Iris to the SB index marks.
Cheers

Great tip, I'll try it. Thanks again for taking the time to reply to my posts with informed responses. I really love the Pocket Cinema Camera but it has been somewhat of a learning curve. I've reached a point where I feel comfortable with my setup and workflow. Really the biggest challenge now is finding time to get out and shoot when the light is ideal.

Yes, yes it is...
Enjoy and cheers.