Metabones Speedbooster Ultra lens adapters are widely used with Sony’s Super 35 E-mount cameras like the FS7, FS5 and FS700. They contain a specially designed optic that brings a near full-frame field of view to smaller sensors, and the sensor also benefits from a one stop gain in exposure value. They come in different mounts but the most popular is Canon EF.
For many users the Speedbooster will be just fine the way it comes from Metabones. However, there are occasions though where the EF lens mount can exhibit a little too much wiggle due to differences in tolerances of the mount and the locking pin mechanism. If focussing by hand this isn’t too much of a problem most of the time. If you’re using cinema lenses like the Zeiss CP2s in combination with remote focus motors or follow focus units with high torque then it can be more of an issue.
This troubled our friend, Director and DP Jason Wingrove so much that he turned to Polish lens mount adapter maker Foto Akcesoria for a custom solution. In his words he “loved the full frame look it (the Speedbooster) offered on the Sony FS7 / FS5 etc. but I always felt a bit dirty putting my cine modded lenses on it, quite a sloppy fit.”
He asked them to make a new casing for the Speedbooster optics with a special locking EF to E-mount. The result is the new Speedlock. It looks a bit like a PL cine mount and locks EF lenses securely in position. Canon use a similar solution for the C500 and C300 mkII, as does Chinese maker Kinefinity on their KineRAW cameras.
You simply thread the optics from the Speedbooster into the Foto Akcesoria mount and adjust the position until the infinity focus is correct. Then you tighten a small grub screw to hold the glass in place. You can do this yourself, or pay the company to fit and calibrate the optics for you at a cost of 36 Euro.
The mount comes with a small mounting foot with a 1/4 20 screw thread on the bottom. This can be attached to a rail mount to lock the adapter securely in place on your rig. Jason uses a quick release rod clamp from Chinese maker Smallrig.
There is one downside of the adapter. It has none of the electronic contacts of the Metabones, which means that any electronic EF lens cannot have its aperture adjusted while on the camera. This pretty much limits the use of the Foto Akcesoria adapter to cine lenses and manual stills lenses adapted for video use. Jason points out that “if you already know you need this adapter, you probably don’t care about that.” If you have a lot of Zeiss CP2s, Samyang VDSLR or XEEN lenses then this might be just the ticket.
I personally prefer to use manual lenses where possible with my EF to E-mount Metabones Speedbooster because the electronics can lead to occasional lock-ups and errors with some Sony cameras. This has improved with recent Metabones firmware updates, but still causes me problems from time to time.
You can also have the Speedlock made with locking Nikon, Leica R and Pentax K mounts.
The Speedlock costs 500 Euro (+ tax if applicable), and requires your existing Metabones Speedbooster Ultra. Visit the Foto Akcesoria website for more details.