Focal Reducers / Speed Boosters | Explained

💭 Comment - Let us know what you want us to explain next below!
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Sources / Further Reading
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Production Kit
Canon C200 (Piece to camera)

RED Gemini (Studio B-Roll)
CueScript EMC15 Teleprompter
Sachtler Video 18 S2
Sennheiser MKE600
Zeiss Otus EF Set - 28, 55, 85
Zeiss Milvus 100mm
Nanlite Forza 500
Aputure Light Dome II
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00:00 - Intro
00:11 - What Is A Focal Reducer
01:30 - How They Work
08:11 - Why Should You Use One?
11:14 - What Mounts Do They Come In?
12:08 - What Is Flange Distance?

#FocalReducer #Speebooster #Mythbusting

[carneritochiquito]

I think this is the best video about focal reducers on the entire internet.

[mack_solo]

What an EXCELLENT video! I'm just chipping-in to wake the algorithm up to push it higher up the attention ladder. This is not only valueable to videographers but photographers as well - that table at 13:05 is a treasure! Thank you and cheers!👍

[thatcherfreeman]

I would definitely appreciate a similarly technical video on the "full frame look". Too often you see bs on youtube that attributes it to some magic qualities of a larger sensor, and it would be good to have a comprehensive reference of specific technical advantages of the larger format.

[mosswareproaudio]

A lot of us choose to not use focal reducers as they add glass. We feel that just adapting a 645 to a FF35mm is enough. This way you eliminate glass edge distortion. The best part of the lens is in the middle.

[floriankochvisuals]

I wish this video would have been around when I started shooting. This is the greatest Video on the topic I've ever seen! Thank's for giving so much Information!

[thesurfacelevelgamer]

I just discovered your channel, and it's great. There's a few things i want to say:

A factor that would enter into the equation of DoF would be the circle of confusion which is what makes that, with lenses that give both systems the same field of view (25mm for m4/3; 50mm for FF), a 1/4 of FF sensor like a m4/3 has not 4x the DoF of Full Frame, but only 2x. If you want to hear an explanation look at min. 4 of Filmmaker IQ's Hyperfocal video. I don't know how focal reducers affect circle of confusion.

The other thing I want to say is that it'd be great to see a video about the FF look you mentioned. I've found it very difficult to comprehend what are the things that differentiate a FF image from a crop sensor's with an increased aperture.

[edwardhuang]

This is the best explanation so far I see, kudos to you, CVP!👍

[sopp]

I've had my C70 and FR 0.71 for a few weeks now.

Thank you for this video, I now know it's science and not just magic that makes it work. :)

[davidjohnbalce]

Great and informative video. More of these please, valuable information like this is very hard to come by. Really love the effort put into these. And it's very helpful for people wanting to know what products to buy for what reason. Keep up the good work.

[suhaib]

Im here to advocate the large format look video!

[EYECRAFTVideo]

Great Video = QUESTION - I have a RED Super 35 camera with an EF mount & I use EF Lenses, what would be the best Focal Reducer for this ? Please can answer this?

[aristomenis_k]

Such a clear and detailed explanation. Thank you!

[mosswareproaudio]

The Mamiya 645 and RB67 are similar. Can a speed booster made for the 645 be also used on the RB67 lenses if mounted on a dumb adapter?

[randomgeocacher]

Great overview and lots of details!

I just wish there was an option to disable the “transformation” of f-stops and focal length, and just have the camera show what the lens is really set at.

I think the “speedboosting” of metadata is the cause of 99% of the confusion about speedboosters ... and primarily done to tout/market the capability of the device rather than being helpful to the operator. Especially when an adapter is semi-permanently screwed on it’s fairly obvious the operator likes to work with adapted lenses terms rather than the native mount terms.

[mrenovatio]

9:06 ... Large format look. It's worth elaborating on this. Using longer lenses on larger sensors to get a wider fielld of view with less distortion.
Other factors, maybe the fall off from forcus to out of focus, etc...

[miguelgaggiotti]

Hey Jake. Amazing vid! Best explanation of focal reducers I’ve seen. Please make a vid comparing the Otus and Milvus sets! Thatd be sweet!! Thanks!

[myxomop]

I'm attempting to adapt the Canon f/2.8 65mm 1x-5x MP-E onto an Olympus OM-D E-M1X. If I understand the video correctly, there will be no difference in DOF in either direction (increased or decreased), whether with the use of a straight EF-MFT adapter, or with an EF-MFT focal reducer, but the use of a focal reducer will recover one stop of lost light. Assuming that's correct, my biggest remaining question is whether or not the AOV and/or working distances will change with a straight adapter vs. a focal reducer. When mounted on a FF Canon body (such as my older 6D), the MP-E's normal working distance is rather shallow/small, particularly at higher magnifications. It would be beneficial to see those working distances increased to allow for more light, and more room for flashes other than a ring flash between the front element and the subject. Lastly, I'm wondering if models like the VILTROX EF-M2II, Commlite CM-AEF-MFT and Fotodiox Pro Fusion Redux Adapter are actually suitable alternatives to the significantly more expensive Metabones T Speed Booster ULTRA, or if they are underperforming in some way. Thank you in advance!

[paulloth]

I genuinely love this channel, one of the best channels for filmmakers.

[naratt]

Great video. But at 5:50 you mentioned that the f-number and focal length are cancelled out, so the DoF will be the same. However, from the formula, the focal length is powered by 2 while the f-number has no multiplication. Should the DoF change? Did I miss something?

[markjob]

Thank you for the review. Now I'm completely confused. I get the focusing more light into the lens circle of coverage, thus the extra stop of light, but the rest was a nebulous black hole. Felt like a math test.