Request: EF SpeedBooster Mount for Ursa Mini Pro

BMD Team,

I'm very excited for the Ursa Mini Pro: especially the full-spectrum ND filters!

But I think the camera's greatest potential is in its interchangeable mount: I would love to see the 4.6k sensor's full potential realized with a "SpeedBooster" (focal reducing) lens mount that would allow the full image circle of full-frame lenses to be focused down onto the S35 sensor. That way, users could take full-advantage of full-frame lenses but also be able to use S35 lenses without the loss-of-quality from shooting in a windowed-mode – simply swap between the EF Focal Reducer and the regular EF mounts!

I realize that the clearances might be a bit tight (especially with the added ND filters; however, even if only a .77x magnification was possible (which would result in a ~1.2x crop factor), that would be a great improvement!

Or: if you don't want to make it, then please open up the mount designs to 3rd parties (like Metabones) so they can make one!

You Wouk shave to build the Speed Booster into the EF mount on the UM Pro. You can not make a EF to EF add on SB adapter, and keep the required EZf FFD.

It is indeed possible to make a speed booster for this new ursa mini pro.
I have measured the sizes from the e-mount back to an ef front on a standard metabones adaptor, and the same distance on a metabones e-mount speedbooster and the speed booster is only a few mm shorter.
Theres a guy thats squeezed a speedbooster element behind the lens of a RED epic camera and it works well.

now that you can remove the whole adaptor, there is enough room for the elements as well as the slightly shorter lens mount distance. It isn't an EF to EF adaptor, more like a EF to BM mount adaptor.

This is a big deal to me as I am a photographer who shoots stills and film together and would like a similar focal length and DOF. They would sell well- almost everyone who I know owns a FS7/ FS700 or FS5 runs a speed booster permanently on their cameras. Also means the camera will collect a stop more light, making it have a usable 1600 iso.

I was looking into selling my URSA MINI 4.6 and get an FS5 with a raw recorder- mainly for two main reasons- the built in ND and the speedbooster capability. I think the Ursa Mini pro is looking like a better option- if someone makes a speed booster.

The possibility of a Sped Booster EF type mount for the UM Pro is going to depend on what the camera's lens mount turret to sensor (FFD) is? The Ursa Mini PL barely measured out with enough room on the Turret to add a dumb EF mount, no room for a EF Speed Booster mount. Until this measurement is known to determine the feasibility, we are all guessing.

Also, on the larger sensor UM 4.6 adding a Speed Booster is a small AOV gain, compaired to smaller sensor cameras, where the Soeed Booster makes sense. So the next question is, will there be a big enough demand for a EF Speed Booster mount, that likely will cost a lot more to make than a simple adapter type speed boosters currently made, to make developing and making one worthwhile? Likely not, given the small response to the UM PL camera EF dumb mount project HitRid cameras looked into making.

That said, only time will tell, once the camera is released and in the "wild".

Paul, I am also not sure of the demand. When BMD produced the 'small' sensor BMCC and BMPCC cameras, the Speed Booster was a very popular way to give small sensors the field of view of APS-C or Super/Academy 35 cameras. The 4.6K sensor already meets that cinematic quality in terms of an angle of view we associate with Cinema. A 0.71x Speed Booster would then match 135 stills film, but is there a need to do that? Having the increase in apparent aperture would be nice of course, and perhaps if RED's 8K Weapon (aka Vistavision) catches on, maybe we'll become accustomed to that view, but even RED isn't totally convinced of that or they would not have offered the smaller Super 35ish 8K Helium sensor. Just wondering.


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Paul, I am also not sure of the demand. When BMD produced the 'small' sensor BMCC and BMPCC cameras, the Speed Booster was a very popular way to give small sensors the field of view of APS-C or Super/Academy 35 cameras. The 4.6K sensor already meets that cinematic quality in terms of an angle of view we associate with Cinema. But that 0.71x Speed Booster would then match 135 stills film, but is there a need to do that? Having the increase in apparent aperture would be nice of course, and perhaps if RED's 8K Weapon (aka Vistavision) catches on, maybe we'll become accustomed to that view, but even RED isn't totally convinced of that or they would not have offered the 8K Dragon with that smaller sensor. Just wondering.


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The 8K super 35 from Red isn't a Dragon, it's a whole new sensor.

Speed boosters and the obsession with super-shallow depth of field are definitely indie things. Usually people who only think in terms of bokeh and lighting + composition that are only suitable for interviews.

The medium format cinematography thing is cool, and I personally love to look of medium format, though compared to what I did landscape photography with for so long, medium format is pretty small.

You don't have to go bigger to be "more cinematic" however. I don't believe that anyone would dispute that the new Blade Runner 2048 trailer looks extremely cinematic, but it was filmed with an Alexa not an Alexa 65.

Denny, as you say, you cannot make an EF-to-EF SpeedBooster (well, theoretically you could using a couple extra optical elements, but there would be severe problems).

As Paul mentioned, it should be possible to build into one of the Pro's new interchangeable mounts an optical element similar to the one found in Metabones .71x EF to E SpeedBooster line. (Those focus the image circle of a Full Frame EF lens down onto the S35 image circle of an E-mount camera (such as the FS-5/7).)

The difference in my proposed implementation in the Ursa Mini Pro is that you would have to change the entire lens mount to switch between S35 and (fully-utilized) FF lenses. So, this wouldn't be as easily field-swappable as an E-mount camera where you could swap between a SpeedBooster adapter and a normal adapter.

A key feature would be to include a back-focus adjustment – this is absolutely key to ensure parfocal lenses work as intended.

A SpeedBooster mount for the Ursa Mini Pro would add tremendous capability – the ability to shoot wider angles of view on longer focal lengths to obtain the "Full Frame Look" and realize the additional light capturing potential of FF lenses – all without the need for buying a new camera with a full frame sensor!

Rakesh, yes, mental slip, corrected to Helium 8K.


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The whole speed booster idea started with the Panny GH 2/3, and then especially the AF100, which had an optimized 16:9 MFT (17.8x10mm) sensor, came out (being marketed to Cinema students and as a low-cost ($4/5K) entry Cinema camera) demand for a focal expander adapter was great enough and The AF100 was fairly well received -- and the short FFD MFT lens mount screamed for adapters to use regular PL Cinema lenses, and DSLR (Nikon/Contax, etc manual lenses). The short FFD MFT Mount was ideal (as ismrhe Sony E mount) for using adapters to expand the lens selection available, including using vintage Cinema lenses.

Super 35mm (24x14)* was replacing Academy 35 (21x12mm)* and a demand to have a similar AOV of S35 on the AF100 was great enough for a Metabones (who was already making standard adapters for MFT and other mounts) to have Brian Caldwell help them develop a MFT to Nikon Speed Booster, followed by other models, and eventually a EF Speed Booster. Brian developed the optical designs of the Speed Boosters and Metabones built them. Their first was a 0.71 expansion of the FOV on a 135 (and APS/C) lens to give the same AOV on the AF100 sensor, that a given focal length would have had on a Super 35mm Cinema camera shooting at a 16:9 aspect ratio. When BM came out with their BMCC MFT and Pocket camera, sales were great enough for Brain and Maetbones to develop camera specific Speed Boosters optimized for these two camera.

And that is the rest of the story....

* Note: Sensor area sizes used are for 16:9 aspect ratio, for comparison purposes, to match native aspect ratio of AF100.

William and Paul, the original .71 Speed Booster was used to match AF100 to Super 35 Cinema format which was and still is a Cinema standard format for most films. So the demand to get a S35 look in smaller sensor cameras was in demand.

I do not know how big the demand is for matching a UM 4.6 sensor to 135mm still camera format, which is Not is wide use in Cinema or a majority of video productions, reallymis. It is very easy to frame any shots done on a 135mm DSLR to match the slightly smaller UM 4.6K (or their S35mm) sensor, and crop the 135 image to match the UM 4.6. To cover the costs of creating a new EF mount for the UM Pro with a built in Speed Booster would be a substantial. You would need a fairly large market demand to get a mount like this developed and made, unless you want to spend $3-5K or more to get a limited production one made.

A Duclos PL to PL 1.4 Extender (tele converter, the opposite of a Speed Booster) costs $5K, are you guys willing to pay that or more for a UM Pro EF Speed Booster to use DSLR EF lenses on,y costing a few hundred dollars? Not me! I would rather put that money on a real EF or PL Cine lens to use on my UM

William and Paul, the original .71 Speed Booster was used to match AF100 to Super 35 Cinema format which was and still is a Cinema standard format for most films. So the demand to get a S35 look in smaller sensor cameras was in demand. ... A Duclos PL to PL 1.4 Extender (tele converter, the opposite of a Speed Booster) costs $5K, are you guys willing to pay that or more for a UM Pro EF Speed Booster to use DSLR EF lenses on,y costing a few hundred dollars? Not me! I would rather put that money on a real EF or PL Cine lens to use on my UM

Denny,

I suspect that the development costs would not be so substantial if Metabones were able to reuse the optical element from the EF to E (FF to S35) adapter. (I think that should be possible, but there could be some vignetting as the BMD 4.6k sensor is larger than Sony's S35.) Those adapters retail for $650 (USD). I would be prepared to pay up to $1000 for the same capability on Ursa Mini Pro. (That would be substantially cheaper than buying a Red VV camera and considerably better quality than a FF DSLR.)

Of course, when you had the proposed mount installed, you couldn't use the ever-increasing array of S35 cine-style zooms that are available. However, therein lies the beauty of the interchangable mount: for documentary or applications where S35 look was desirable, you could use the normal mount; for narrative or to take full-advantage of lenses like Zeiss' Otus, you could have the SpeedBooster mount installed.

There is only one small problem to this. I measuredmrhe .71 speed booster optical block on the MFT to Nikon adapter, it is around 24mm. Looking at the photos of the EF mount for the Ursa Mini Pro, it looks to be less than 10mm thick! Add to that the filter wheel is in front of the sensor, removing another 4mm or more, you are not going to have room for the optical elements required to create a Speed Booster inside the EF mount. I do not think it is going to be possible. A Sony E min to FFD is only 18mm, while the EF is 44mm, so you have room in a E to EF adapter for the 0.71 optical block needed. Not wi the new BM Mini Pro EF mount. Sorry
Cheers

There is only one small problem to this. I measuredmrhe .71 speed booster optical block on the MFT to Nikon adapter, it is around 24mm. Looking at the photos of the EF mount for the Ursa Mini Pro, it looks to be less than 10mm thick! Add to that the filter wheel is in front of the sensor, removing another 4mm or more, you are not going to have room for the optical elements required to create a Speed Booster inside the EF mount. I do not think it is going to be possible. A Sony E min to FFD is only 18mm, while the EF is 44mm, so you have room in a E to EF adapter for the 0.71 optical block needed. Not wi the new BM Mini Pro EF mount. Sorry
Cheers

Denny, looking at the following graphic, I would guess that the Pro's standard EF mount is at least 20mm deep (maybe up to almost 30mm deep):



The specs for the Metabones T Speed Booster Ultra .71x EF to E list that it is 28mm thick. The EF mount flange focal distance is 44mm. That should leave 16mm for the ND and the protective glass in front of it. There certainly wouldn't be a lot of free space left over, but that seems to me to indicate a SpeedBooster of some sort would be possible. Whether or not the same optics from the Metabones EF to E model could be used? I am not sure – it would be a close call. But even if it were not possible to reuse the optics, I think that the volume of cameras BMD sells could certainly spread out the R&D costs across enough units to achieve at least a $1k price.

The mount closest to the Ursa Minui Pro is the PL mount, the middle (thin one) ismrhr EF mount, and the front one is B4. The middle EF mount does not look like 20mm to me? The inside baffle part maybe 20mm (which extends inside the mount tomthe filter setup), but that is still smaller than the 28mm optical block you cited.

But, we are just guessing based on artist illustrations, not actual,measurements of rhemcamera and mounts. So,who knows, until the camera and mounts are actually measured.

Paul, I am also not sure of the demand. When BMD produced the 'small' sensor BMCC and BMPCC cameras, the Speed Booster was a very popular way to give small sensors the field of view of APS-C or Super/Academy 35 cameras. The 4.6K sensor already meets that cinematic quality in terms of an angle of view we associate with Cinema. A 0.71x Speed Booster would then match 135 stills film, but is there a need to do that? Having the increase in apparent aperture would be nice of course, and perhaps if RED's 8K Weapon (aka Vistavision) catches on, maybe we'll become accustomed to that view, but even RED isn't totally convinced of that or they would not have offered the smaller Super 35ish 8K Helium sensor. Just wondering.


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I have to disagree- I really think there would be a very big demand.

I have talked to the rental places that have sony cameras (fs5/fs7) and they say the metabones speed booster almost always get rented with them. People want focus fall off and the full coverage of their stills lenses- that what they were designed for. Very few people use rented s35 cine PL lenses on these types of cameras.
A lot of these people renting are photographers or ex-photographers (like me) and want the coverage they had on their stills cameras and their 5d's that they started shooting with.

Who doesn't want a stop more light, and the option to blur the BG more, or use wider lenses. All of these things are adding user options. They are just more options, its easy to reduce the "blur" of the full frame look, just stop down. and there is an extra stop to allow this without light loss.

paul

There is only one small problem to this. I measuredmrhe .71 speed booster optical block on the MFT to Nikon adapter, it is around 24mm. Looking at the photos of the EF mount for the Ursa Mini Pro, it looks to be less than 10mm thick! Add to that the filter wheel is in front of the sensor, removing another 4mm or more, you are not going to have room for the optical elements required to create a Speed Booster inside the EF mount. I do not think it is going to be possible. A Sony E min to FFD is only 18mm, while the EF is 44mm, so you have room in a E to EF adapter for the 0.71 optical block needed. Not wi the new BM Mini Pro EF mount. Sorry
Cheers

Denny, looking at the following graphic, I would guess that the Pro's standard EF mount is at least 20mm deep (maybe up to almost 30mm deep):



The specs for the Metabones T Speed Booster Ultra .71x EF to E list that it is 28mm thick. The EF mount flange focal distance is 44mm. That should leave 16mm for the ND and the protective glass in front of it. There certainly wouldn't be a lot of free space left over, but that seems to me to indicate a SpeedBooster of some sort would be possible. Whether or not the same optics from the Metabones EF to E model could be used? I am not sure – it would be a close call. But even if it were not possible to reuse the optics, I think that the volume of cameras BMD sells could certainly spread out the R&D costs across enough units to achieve at least a $1k price.

When I brought my UM4.6 I wanted to see if an element would fit, so I ordered a extra new "lens" baffle (the screw in light baffle that fits behind, inside the lens mount- I did this so I wasn't modifying the camera, just screwing in a new baffle. I got my local machinist to bore then inside of this and I mounted the elements form a metabones speed booster inside it. It worked a certain amount, it would cover full 35mm lenses, but would only focus 5m or so. The problem was that the element couldn't either get far enough back (as there is a filter over the sensor- i wasn't keen to touch this!) and/or the ef mount of the ursa is 4mm too far out, so can't back focus enough. The difference between my sony metabones /ef adaptor and my speed booster is 4mm in size.
But this new removable mount would change all of this as it mount the ef plate further back, and there is so much more room. I also thing the elements could be a different design to focus differently. I'm obviously not a optics expert, I have just been experimenting, and its been working to a point. I am convinced this can be done however. I might pop into my local camera store tomorrow and see if there are varying sizes ( e-mount to ef mount distance) between the different manufacturers- Viltron, metabones, aputure, complete and others all make speed boosters for sony to canon. If there are different sizes, then suggests this distance isn't an absolute.

paul

Interesteing, but as you found, you lacked about 4mm of space to get the SB set up correctly. I think this is the issue. On the UMPro, a fi,termpack has been added in front of the sensor, so your soace is going to be even less inside a UM Pro EF mount flange to sensor/filter setup. I do not think the ND filter setup effects the camera"s FFD for a given mount (just adds the filters to the rear of the lens, vice the front.

A given lens FFD is written stone, it is a standard so lenses from different manufacturers will work on a given camera system. EF FFD is 44mm, E-mount is 18mm (the difference is used by the EF/E-Mount for the Speed Booster optical block, same for a MFT/EF SB setup, but the MFT FFD is 19.5mm, which is filled by my BMPCC SB optical,block, which measured about 28mm, subtracting the Nikon F mount space in front of the optical block. Also a lens needs some space behind it for the rear elements to fit into, which depending on the lens, restricts your Space for added SB optical elements.

But this is all academic, until the actual UM Pro and its mounts can be measured, and if Metabones is interested in making a Speed Booster for this mount. I do not think a UMPro is going to sell like a Pocket/Micro camera, and this is (so far) the only camera that will use this mount. You need to make and sell a lot of adapter Lens Mounts to make it profitable for Metabones or some one else trying to make one.
It took Metabones more that a year to develop the MFT/EF SP, and longer for thenpowered BMCC MFT version. No doubt the EF lens users who will, get or rent a UM Pro EF and will want the SB, but how many cameras are we looking at here 100 or 1000? This ball I think will be in Metabone's court to work out.
Cheers

Metabones got back to me and they said they are actively looking into the speed booster for the pro. But I would prefer BM make their own- they would be cheap too..

I also did a quick poll on the FS5 forums to ask who has and uses a metabones speed booster and over 50% said they did. This is a an adaptor that costs 1/5 of the cameras cost, and half own it (according to 60 of so FS5 owner- a small sample, but shows a trend). If 50% or ursa mini pro users brought this, metabones (or BM) wouldn't make good money? its just a few, probably (hopefully) off the shelf elements and a housing. Theres no in adaptor processing to be done, as BM has that already in its ef mount (if that part is reused).

paul

Metabones got back to me and they said they are actively looking into the speed booster for the pro. But I would prefer BM make their own- they would be cheap too..

paul

Optics design and manufacturing is very complicated, take a look at the difference between Metabones' and the chinese ones.
I'd rather Metabones made a Speed Booster for the UMP themselves.

Also, Metabones and Brian Caldwell hold the patents to their Speed Booster designs, and "Speed Booster" is their trademark. So if you want a Focal reducer done right, Metabones and Brian are the best. Demand for a SB EF mount, the Min Pro uses actual lens mounts, not adapters, will depend on how many UM Pros BM sells, to determine what the market could be.
Cheers

As the last post in this thread is from March, is anyone aware yet of progress on the design of an Ursa Mini Pro speedbooster?

This is a "dead horse" as it us not economically, if it is even technically, doable. Also, Not enough room in the UM Pro Turret for the correct Speed Booster glass elements to get the desired focal increase, due to FFD issues.

You normally need a lens mount with a much shorter FFD (in the camera, like MFT) than the mount being adapted (in this case EF) to have enough room for the optical block required to make a focus reducer. This is like wanting a MFT to. fT Speed Booster so you can get wider AOV with MFT lens on a Pocket camera. Not very likely to happen.
DS

All things are possible, given a need, the resources, the money and the will to make it happen. There are some realities to be faced.


BM is a lean organisation with already a large selection of products being made and sold at realtively inexpensive prices. It likely cannot afford distractions which may cost it time, effort and money for a small reward. That is how companies operating in a highly competitive environment go broke.

Metabones/Caldwell are likely in a similar bind.

Depending upon how far forward in the throat of the URSA Mini Pro camera, the ND filter mechanical components have been placed AND if the IR filter and frame mask in the throat of the camera can be removed, it may be possible for a 0.71 speedbooster mod for the URSA Mini Pro but only if :-

The 0.71 optical cell's image circle is large enough to cover the 4.6K sensor area with a satisfactory image.

The ND elements in the two ND filter wheels can be changed to include the IR filtering.

The existing IR filter and support frame can be removed and the remaining orifice is wide enough for diameter of the 0.71 optical cell.


I don't think the 0.71 optical cell's image circle will be large enough. It is tailored for a 21mm approx wide sensor. One might scrape by with the 4.6K sensor if the image is cropped to faux-cinemascope but even then I suspect there may be unsatisfactory rendition of the image into the corners.

The modifying of the optical elements in the ND filter wheels represents a MAJOR invasion of the URSA Mino Pro's privacy, not a benign exchange of existing easily accessable components as the big URSA allows. It would be an operation fraught with very many perils, not the least being the assured voiding of warranty.

For the mod to the big URSA at the costs I estimated, I have had but one enquiry. I doubt when it comes to putting money on the table and facing the risks, that enough URSA Mini Pro owners are really going to embrace a mod to their camera, when in many instances it is their bread and butter workhorse.


I have not received any assistance from BM in my speedbooster adventure with the big URSA PL. I was advised they are fine with other outfits making third party gear for their cameras but caution that venturing inside the camera would become a warranty issue.

I have had no responsive messaging from Metabones/Calwell at all. I think it is fairly apparent that neither entity is really interested in a speedbooster for any of the Blackmagic 4K/4.6K cameras. On the other hand, they may well be examining this and wisely keeping their thoughts and their intellectual property to themselves.

I think Robert has summed this up very well. He is correct, in that the existing .71 Speed Booster optical cell that Metabones uses, will not cover much beyond STD. Cine 35mm or about a 2-mm wvide sensor, the BM UM is 25mm, so youmwould need to be in a window mode to use it, but again is is too deep to fin the in remaining space inside the UM turret anyway.
DS