Can You Make A Lens Parfocal Using A Speedbooster?

Can you make your lens parfocal using a speed booster? In this video we put it to the test. The glass element inside a focal reducer can often be rotated to either move it closer to or further away from the sensor. This allows for correction if the lens can't reach infinity focus, but can we use it to make our zoom lens parfocal? Lets find out.
Links to popular speedboosters:
Metabones Ultra 0.71x EF to MFT
Amazon: amzn.to/3beGOc9
Metabones XL 0.64x EF to MFT
Amazon: amzn.to/2Gjg6DN
Viltrox EF-M2 0.71x EF to MFT
Amazon: amzn.to/2TuqEnK
Ebay: ebay.us/nDtPwy
Metabones Ultra 0.71x EF to Sony E-mount
Amazon: amzn.to/32R2zeq
Gear I Use:
Camera (A) - Blackmagic Pocket Cinema Camera 4K
Amazon: amzn.to/32LEHZy
Ebay: ebay.us/XOtY2b
Camera (B) - Blackmagic Pocket Cinema Camera (Original)
Amazon: amzn.to/39uRRMI
Ebay: ebay.us/etiuzm
Lens Adapter/Speedbooster - Viltrox EF-M2 Speedbooster
Amazon: amzn.to/2TuqEnK
Ebay: ebay.us/nDtPwy
Lighting - Godox SL60W
Amazon: amzn.to/2xSmCxc
Ebay: ebay.us/OEaBp2
Microphone - Rode VideoMicro
Amazon: amzn.to/3cGxLRl
Ebay: ebay.us/BUtEYW
Monitor - Feelworld F6
Amazon: amzn.to/2TuqLzG
Ebay: ebay.us/w5X3kW
(Some of the links in my video descriptions are affiliate links, which means at no extra cost to you, I will make a small commission if you click them and make a qualifying purchase.)

[@carlscinema7086]

UPDATE: I once again own the very popular Sigma Art 18-35mm and I'm happy to report that i managed to get that lens parfocal aswell!

[@travissuttie]

Thank you for sharing this update. I just bought the sigma 18-35mm and you answered all my questions!

[@bryanbarajasBB]

Yeah, I did that with my Sigma 18-35 and Tokina 11-20, ATX-i with my metabones speedbooster on a Canon m1 eosm using Magic Lantern.

[@tristan6509]

How did you get the 18-35 to work with a speedbooster without vignetting?

[@TheSagnac]

Hello, should the speedbooster be adjusted for each lens or does it work for all lenses with a single adjustment? Thnk

[@thisisbug]

also wondering this since its a cropsensor lens @@tristan6509

[@rm-film]

It worked on my BMPCC4k + Viltrox II + Sigma 18-35 EF. Got it parfocal!

[@hellopsp180]

Wooooah this is like next level tech holy

[@lovefirst6157]

Another banger. Great to have you back.

[@carlscinema7086]

Thanks! Good to be back :D

[@danielramosstudio]

I did this to both my ef canon metabones speedboosters and it worked! Thank you so much!

[@carlscinema7086]

Awesome! Thanks for reporting back

[@samosterlund]

Welcome back!

[@carlscinema7086]

Thanks dood!

[@Loftikaz]

Thanks I did this on my Sigma 18-35 with Metabones ultra x71 on my BMPCC4K, I was able to get the Parafocal effect but not the infinity focus. I can get infinity focus by dialing the first line mark, but not at the very end hard stop, I tried everythign even micro adjustments, but it's ok for me as I'm the only one who uses this lens so I know where infinity is but overall it's awsome to have a Parafocal now I'm very happy I could do quick zooms in and out without losing focus for like a rapper singing or documentary.

[@carlscinema7086]

If you have it focused at infinity when its at the mark for infinity on the focus scale then it is dialed perfectly. Going past is focusing the lens beyond infinity. Lots of still lenses lets you do this to make sure you'll reach even if the mount is slightly off.

[@Loftikaz]

@@carlscinema7086 ok then it's my bad, yes the hard stop is beyond infinity I had it that way before, thanks for explaining. Also I did this on metabones ultra, it's same thing but the glass is adjusted from the back side so you must have the lens inside the metabones so you'll know the limit of the back glass.

[@alexisferrenbach]

Hey, both of my metabones Ultra and Ultra CINE are kinda "stuck". Even with the screw off I can't turn the glass element to adjust the position. Have you got any idea on how it can be fixed ? Thanks

[@thisisbug]

Amazing! Did anyone try this with the Canon EF- RF 0.71x Speedbooster? I would be using the Sigma 24-70 2.8 Lens on a C70

[@aestevesdesign]

Hi, Carl! Thank you for this video. Do you think if it´s possible to use this Viltrox Ef M2ii with the Pocket OG? Have you tried this? Thanks!

[@carlscinema7086]

Yes, it works :) I can't guarantee all lens combos though

[@aestevesdesign]

@@carlscinema7086 I haver the Sigma 18-35 And Pocket OG. Do you think is possible to use with Viltrox EF M2ii?

[@maxyboy4913]

Quick question. What If I had a sony a7iii with a tamaron zoom lens Are there speedboosters for the same mounts on both sides?🤔 (E mount for sony)

[@carlscinema7086]

Just like any adapter there needs to be space for the adapter. So it needs to go from a lens that uses a mount with a longer flange to a mount that uses a shorter flange, from Canon EF to Sony E-mount for example. And to add to that, the A7iii already has a full frame sensor. So using a speedbooster with a full frame lens will only concentrate the light from that lens to a smaller area (to fit it to APS-C/Super35 for example), so the lens would no longer cover the full sensor of the A7iii.

[@khklavs]

Did anyone try this on a Canon 70-200 f2.8?

[@gabrielchen7069]

Hi, just wondering, does doing this mod on the Sigma Art 18-35mm cause it to lose ability to reach infinity focus?

[@carlscinema7086]

Mine still reaches infinity without any problems 👍 but just make sure to test it out in case your combo differs

[@gabrielchen7069]

@@carlscinema7086 Hm... i'm trying to adjust mine, and mine just doesn't want to turn at all :( even after i completely remove the set screw.

[@carlscinema7086]

Which speedbooster do you have?

[@dareckmaurice9435]

I have the Viltrox m2 - wonder if this works on my bmpcc 4k

[@carlscinema7086]

Should work, depending on the lens

[@AveryDelMiller]

wow! very impressive. any idea why this happens?

[@Scyth3934]

Optics- very confusing stuff...

[@tylou4479]

Carl, the Angie Tokina is known for its almost parfocal qualities.

[@carlscinema7086]

I know, but given the fact that it's only "almost" parfocal and I was able to make it more parfocal or less parfocal using the speedbooster I still think there's some merit to this.

[@dittokmediaofficial523]

Sigma 24-105mm F4 works well, too.

[@SamuelBoooth]

Are tv lenses parfocal?

[@carlscinema7086]

Yes, they tend to have an adjustment for backfocus so you can make sure they are parfocal on that specific camera.