Request for Ursa Mini

I know that several of us have mentioned on this forum before that we would very much like an m43 mount version of the Ursa Mini to facilitate the use of various other lens mounts and adapters. I have another suggestion that will be even easier to implement. Make a version with no mount at all. Just a mounting surface as close to the sensor plane as possible, and some mounting holes would be plenty. If BM were to do so, I'm confident that within days third parties like Wooden Camera would have a full range of interchangeable lens mounts available. They made an interchangeable mount system for the BMPC by replacing the entire front of the camera. Save them a step.
I really want to use this camera if it works as advertised. But it has very limited use to me if I can't change lens mounts. It would allow so much more creative flexibility, from being able to use all flavors of stills and motion picture glass, from c-mount to Leica M to BNCR to PL to PV. To using speed boosters, or allowing third parties to make built in NDs, or behind the lens filter/net holders. And I honestly think that you would gain many more customers/users if you provided such an option.
Just my opinion : )

See:
viewtopic.php?p=217191#p217191

A MFT version of the 4K URSA mini is doable (they did this to the original Cinema camera after the EF version came out). However, as John B. Pointed out in several other threads, interchangeable lens mount not doable, mostly for cost reasons, and the fact that BM URSA (big one) sensor is mounted to the lens turret as an optical block, the Mini is probably a similar one unit design. So a complete redesign of the the camera front end would be required. It would be less expensive, just to buy another Ursa Mini with the lens mount you want, one camera for EF, one for PL, etc. think of the URSA Mini as a "unibody" design, rather than a modular design concept like the Micro cameras are. Also, MFT mount/lenses only just cover the 4K sensor, the 4.6K sensor is too large for a MFT mount system.

I also would like to see a MFT version of the URSA Mini 4K, but not holding my breath!

A MFT version of the 4K URSA mini is doable (they did this to the original Cinema camera after the EF version came out). However, as John B. Pointed out in several other threads, interchangeable lens mount not doable, mostly for cost reasons, and the fact that BM URSA (big one) sensor is mounted to the lens turret as an optical block, the Mini is probably a similar one unit design. So a complete redesign of the the camera front end would be required. It would be less expensive, just to buy another Ursa Mini with the lens mount you want, one camera for EF, one for PL, etc. think of the URSA Mini as a "unibody" design, rather than a modular design concept like the Micro cameras are. Also, MFT mount/lenses only just cover the 4K sensor, the 4.6K sensor is too large for a MFT mount system.

I also would like to see a MFT version of the URSA Mini 4K, but not holding my breath!

Sure it's doable, but it wouldn't make any sense as it would be unusable out of the box. The mft mount/lenses won't cover the entire sensor area. They did it with the BMCC because the sensor wasn't too far off. The MFT lenses would cover the sensor on the BMCC. They wouldn't even come close with super35.

It's not that hard to make non electronic interchangeable mounts. I have an Epic and use a $400 aluminum Canon FD mount on a daily basis. It works great. And there are $400 PL mount options various places as well. I use the $2000 titanium one that came with my camera, but many many people use the $400 aluminum ones without issue. Yes, I know, as people have mentioned the Epic has adjustable back focus. But shims will work just fine for both pl-mount options and whatever other mounts people may make.

And as I mentioned before, it's also entirely possible to make a mount with a helicoid or other method of backfocus adjustment built in. I just found a B4 to m43 mount on ebay for $115 with adjustable back focus. So, while that mount is not particularly useful to me, it does show that it's not that hard or expensive to make. Someone also made $400 adjustable FD mounts for the Red One (before Red stopped them), and they worked great. And that was a much harder mount to replace.

These options may not necessarily be field changeable, but all you need is a measuring tape and focus chart. If that. I changed the back focus on my Epic last July while crammed in the back of a Cessna while flying over Tanzania. I used the widest lens I had with me set at infinity and the focus peaking on my monitor. Then gave it a touch of leeway beyond infinity for safety. Worked just like a canon L series(in terms of focusing past infinity) and worked fine the rest of the trip.

You can't accurately focus from marks on stills lenses anyway, and most modern stills lenses focus past infinity, like the L series I mentioned above. So when using those lenses you don't necessarily need the most accurate back focus. It just needs to err on the side of focusing past infinity. And if you're using PL lenses you're hopefully doing a proper camera check out and checking/adjusting back focus anyway. These reasons are, I would assume, why BM offers shims with the PL mount and not the EF.

And like I said, I'm not asking BM to make a bunch of mounts. Just a neutral surface from which to allow others to jump in. It really shouldn't be any harder than making PL or EF or m43 options. It should be easier in fact, because the precision would fall on the third party mount manufacturers.

And one other thing... people in other threads, like the one linked above, keep mentioning that Reds mounts cost $2000. Which is true for the titanium PL-mount. But the aluminum EF and Leica mounts are $700. And they all have electronic contacts. Third party dumb mounts are as little as $400, as I mentioned before. But the thing that is not mentioned is that any Red mount is a separate cost above the base price for the camera body. So if we're going to use Red as our example, the Ursa Mini with no mount should cost less than the PL or EF versions. Not more.

I understand people's arguments perfectly well. But other manufacturers have shown that it needn't be expensive or complicated.

Just my opinion and experience.

"Sure it's doable, but it wouldn't make any sense as it would be unusable out of the box. The mft mount/lenses won't cover the entire sensor area. They did it with the BMCC because the sensor wasn't too far off. The MFT lenses would cover the sensor on the BMCC. They wouldn't even come close with super35." Paul DelVecchio

Paul, you are correct, a MFT lens or Mount will Not cover a Super 35 sensor like the 4.6K BM sensor. But, the 4K sensor is Not a super 35, it is closer to Std. 35 at 21x12mm with a lens image circle of 25mm. Normal MFT sensor (AF 100 in 16x9) image circle is 20.5mm. But most third party MFT mount lenses like the SLR Magic, and Veydra have larger image circles. Veydra lenses cover 31-33mm (depending on the lens) so it would most definitely cover the BM 4K sensor without using the outer edge of the lenses image circle. No the MFT mount would not work on the URSA Mini 4.6K camera, but it would with the Ursa Mini 4K sensor, just making it. Of course, adapted lenses like the Zeiss ZFs would also more,than cover the 4K sensor. It would need to be a "dumb" MFT mount to prevent the use of the smaller Panny and Olympus still lenses, which might not cover the sensor. But the Cine MFT lenses and APC/Std 35mm lenses out there that will cover the 4K sensor. I think this makes sense for someone coming from a Pocket camera with already invested MFT Cine lenses, or adapted Nikon/Zeiss lenses. Yes you can readapt the Nikon mount lenses to EF, but not the cine lenses from SLR Magic or Veydra.
If BM made a MFT URSA Mini 4K camera, perhaps Metabones would come up with a Mini specific Speed Booster? Anything is possible, the issue is, is there a big enough demand to make it worthwhile.
Cheers

These reasons are, I would assume, why BM offers shims with the PL mount and not the EF.

EF flange depth is very difficult to set out of the factory on any camera. There's no such thing as lens shims for EF mounts as far as I know. It'e either a factory adjustment or done by moving the sensor. It was never designed to be used as a cinema mount and they never envisaged needing to shim or adjust it once it left the factory.

You’ll notice that Canon themselves on the C300/500 don’t offer interchangeable mounts ? They are fixed. You buy one version or the other.

And again I’ll draw your attention the the fact that the PL mount version in BM’s camera line up is more expensive from a manufacture whose whole Raison D’être is to keep things at a lower cost than the equivalent of other brands.

That reflects the fact that to make a mount that is user shim-able and to maintain it’s precision over time to the high standards that users of PL lenses would expect, then it’s going to cost more. End of story. There is no escaping that.

Your alternatives are certainly less expensive, but they use metals that are more likely to change and deform with temperature, thus changing their precision.

You’re suggesting that because users want to use lenses that don’t have accurate witness marks then it kind of doesn’t matter.

I can see that argument too, but as you say, if you setup a lens where it’s just going past infinity and you do it in the cold, and then you go out shooting in a different temperature and your mount expands and changes your flange depth again…?

Of course they can make it work. Of course there’s always a cheap way to do it. Of course someone will always make something for a low enough cost.

But we’re talking about something that is measured in thousands of a mm. yeah we can kludge around that precision, but I don’t want that for my PL mount camera thanks….

And to design an interchangeable mount that is good enough for PL mount, cinema lens repeatable precision as well as the cheaper stills mounts where that precision doesn’t matter so much is still going to be very difficult.

I happen to think that BM should go and make their own short flange depth mount that can be adapted to others rather than going down the mFT mount path which make no sense at all.

But it’s gunna add cost to do it well, cause nothing causes hysteria like back focus and flange depth issues. If you go back to a couple of years ago there were hundreds of posts about the original EF mount flange depth that BM went with right here on this forum that caused outrage. Having an interchangeable mount system will GUARANTEE that people will come here, not having any knowledge of what they're are doing expecting to be able to whack lenses on their camera and have them all work perfectly. Let alone what happens when parfocal lenses suddenly become not parfocal...

Many of the users of BM cameras haven’t got any experience at all with what it means to collimate, project or even how to check a lens and mount alignment.

I think this is something they need to get absolutely right. Not cheap. Just right. Even when they do there will still be headaches for all of us here on forums that try to help people with problems.

JB

I posted a response to some of your comments in another thread. I suppose I should delete them and post here to keep things on topic.

Maybe go and COST those mounts you refer to.

Wooden camera is making various mounts for AJA Cion cameras for $399 a piece. I use a $400 Canon FD mount on my Epic daily and it works great. There are several third party PL-mounts for various cameras for $400 or less.

And, yes, The Epic has adjustable back focus in camera. But I also just found a B4 to m43 mount on ebay with adjustable back focus in the mount for $115 (yes, in addition to the back focus adjust in b4 mount lenses, before anyone misunderstands). There was also a $400 Canon FD mount for the Red One which had adjustable back focus. So other than a few of the mounts that Red makes out of Titanium or Magnesium, most dumb mounts don’t cost much and aren’t very complex to manufacture. Even with back focus adjustment built in. So I just respectfully disagree that the cost would be prohibitive.

So the question really is....how much EXTRA would you be prepared to pay for an interchangeable mount ?

It seems that the base price for a camera body with interchangeable mounts should be less, not more, if we're going by the pricing structure of every other manufacturer that I'm aware of. Particularly if there are no electronic contacts. In my opinion, it wouldn't make sense to charge more for a neutral surface on which to attach mounts than for an EF mount with electronic contacts. It would certainly be cheaper to manufacture. And not only should it be easier and cheaper to manufacture, but the precision for the mounts would fall on the third party mount manufacturers like Wooden Camera, not BM.

Look at BM's current price. The EF mount is not user shimable. The PL mount IS user shimable. It costs $500 more for a PL mount even though it's not even got the electronics and power contacts of the EF lens to worry about.

I would guess that that would have more to do with economies of scale than the cost of the precision of the lens mount. They will sell many more times the number of EF mount cameras than PL-mount cameras. But I could easily be wrong.

Canon doesn't charge any more for the PL-mount version of the c300 or c500. I can't imagine that the cost difference would have to do with the difficulty in getting the FFD correct on the mount. And if it was so precise that it increased the cost then it wouldn't make sense that they would need to include shims.

The shimming has to do with the lenses being used.

The EF mount version doesn't need shims because EF mount lenses focus past infinity. Because they are made to be focused electronically or by eye. And the markings are too small and too inaccurate to focus by anyway. So as long as you err on going past infinity you’re usually fine.

Shimming or back focus adjustment is necessary for PL mount lenses and any other lenses that have accurate focus marks, or any lenses that hold focus through their zoom range, because the marks need to be accurate and the zooms need to hold focus (Most stills zooms don't hold focus through their zoom range so that's another reason why that mount doesn't need to be as precise). So, yes, interchangeable PL mounts would need to have that ability. But shimming isn’t terribly difficult or expensive. And has been standard practice for a very long time. I don’t understand why it would be harder to shim an interchangeable mount than a permanent one. It seems to me it would be much easier.

Again these are just my opinions and experience. I’m not trying to ruffle any feathers. I’m just trying to make suggestions for what I believe would be a more useful and versatile creative tool.

I understand all of your points. And I agree with most of them. And I certainly know the pain of hordes of uninformed or misinformed users. I've been using Red cameras and on that forum since the painful beginning.

And I will fully concede that I'm not thinking of BM customer service having to deal with the users who don't understand the equipment and complaining about any number of variables. That's certainly something they need to consider as a business. I'm only thinking of my own selfish needs and wants, knowing that I do understand all of the variables and deal with them daily. I regularly use PL mount lenses, if I didn't I wouldn't care in the least about interchangeable mounts. I'd get an EF mount version and be done with it. So I know very well the need for tight tolerances and properly set up cameras and lenses.

But for certain projects, I unashamedly love using imperfect old stills lenses, and have learned to deal with the quirks and flaws in forcing them into a job for which they were not made.

I've just become very accustomed to being able to change mounts based on each project's, or even each shot's requirements. And I'm loving everything about this new 4.6k sensor, at least the little we've seen from it. So I'm just trying to lobby for what it would need to work for my needs : )

At this point BM and Canon seem to be the odd people out on interchangeable mounts. AJA, RED, ARRI, SONY all have interchangeable mount systems. And the Cion and FS7 are in the same general price point as the Ursas.

I just can't justify buying two cameras to be able to have one for each of the two types of work that I tend to do. Especially, and I don't mean this to be overly harsh or critical, with the current reputation of professional reliability of BM cameras. Trust me, I had an early Red One. I know the drill. But the only way I will be able to try to work this camera into professional gigs, would be to have the ability to change mounts. And if I'm renting, I simply can't take the risk of using a BM camera at this point.

... But the only way I will be able to try to work this camera into professional gigs, would be to have the ability to change mounts. And if I'm renting, I simply can't take the risk of using a BM camera at this point.

Paris, we all respect each other's selfish interests and no doubt others would find the same things useful to them as well. I for one thought an MFT mount made sense on the URSA 4K since most of the Veydra MFT primes would cover the sensor, but I've moved on from that wish as the new 4.6K sensor trumps everything for me.

So that's a little sad to hear you say you won't be able to enjoy that wonderful 4.6K sensor this year that you know is exclusive to BMD. Oh well, at least that RED Forged Weapon Dragon 8K will have ProRes, eventually.


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Paul, you are correct, a MFT lens or Mount will Not cover a Super 35 sensor like the 4.6K BM sensor. But, the 4K sensor is Not a super 35, it is closer to Std. 35 at 21x12mm with a lens image circle of 25mm. Normal MFT sensor (AF 100 in 16x9) image circle is 20.5mm. But most third party MFT mount lenses like the SLR Magic, and Veydra have larger image circles. Veydra lenses cover 31-33mm (depending on the lens) so it would most definitely cover the BM 4K sensor without using the outer edge of the lenses image circle. No the MFT mount would not work on the URSA Mini 4.6K camera, but it would with the Ursa Mini 4K sensor, just making it. Of course, adapted lenses like the Zeiss ZFs would also more,than cover the 4K sensor. It would need to be a "dumb" MFT mount to prevent the use of the smaller Panny and Olympus still lenses, which might not cover the sensor. But the Cine MFT lenses and APC/Std 35mm lenses out there that will cover the 4K sensor. I think this makes sense for someone coming from a Pocket camera with already invested MFT Cine lenses, or adapted Nikon/Zeiss lenses. Yes you can readapt the Nikon mount lenses to EF, but not the cine lenses from SLR Magic or Veydra.
If BM made a MFT URSA Mini 4K camera, perhaps Metabones would come up with a Mini specific Speed Booster? Anything is possible, the issue is, is there a big enough demand to make it worthwhile.
Cheers

Definitely valid reasons there. I could see that being a nightmare, though, as some users will still try to get those smaller Panny and Olympus lenses to work and then there'd be a whole load of people asking for an active MFT mount.

If enough people say they want it, I guess it would get BMD thinking about it. I wonder if the demand is out there.

Yes, an active mount would be nice, but would increase the cost. When the AF100 came out, it became apparent, not all MFT lenses were created equal, and only the two slow zooms in the Panny Pro Line, latter added to with the "HD" line. However it became apparent that these lenses were Not cut out for high end video/cine productions, and AF shooters wanted better lenses, hide all the adapters, and the rest is history. I use the Panny Leica 15mm and 45mm micro(with IS) for handheld shots with the Pocket, and they work OK and are useable, where as most of the rest have too much distortion, or CA issues for serious work. When Four Thirds first came out, Olumpus did make a few "Pro Line" lenses in Four Thirds, that were optically corrected (not in camera corrected,which FT cameras lacked), to compete with Nimon and Canon pro lenses. I got the Olympus 14-35 f/2.0 lens for my AF100, simply a stunning Parfocal zoom, but still not a Cine zoom as it needed additional lens support and it changed length when zoomed in or out.

So an Active MFT mount would allow the use of the Olympus Four Thirds Pro zooms, but since then Sigma, Tokina and others have come out with an even better manual zooms in Nikon Mount, and some rehoused for Cine work on MFT mount too, so better options are out there that do Not require an Active mount, and using a "Dumb" mount like BM did on the Cinema camera, would prevent anyone from trying to use the cheaper Panny/Olympus lenses that are Not going to work on the 4K sensor. Besides its a URSA, not a pocket camera, so you want a physically larger lens anyway, which the non-active manual MFT lenses are. For me the biggest advantage is to be able to use my Veydra MFT lenses on a URSA Mini (4K sensor).

Firstly, thanks for tons of valuable info here all that have been posting. Been reading tons over the past few weeks. Here's a setup to my question. I sold the farm in preparation to purchase the Ursa Mini 4.6k EF, cards, etc... (whoot, just made the pre order!!!). My reason to upgrade from the BMCC was/is two-fold. Client work. And shooting an indie film I've recently completed. Really, the timing for the camera (assuming it's coming this year) couldn't be better.

From here, I'm considering a few new lens purchases. The SLR Magic 50mm to be released has caught my eye thanks to Rick, links and others providing landslides of solid info. My wonder is whether pulling focus alone on client work will be a tremendous challenge? Curious for thoughts on that.

Thanks for any input!

Cris

Cris, pulling focus alone is going to be a challenge if the camera is not rigged. If you are doing it by sight as a sole operator, you may get good results using the BMD Viewfinder with peaking turned ON. If you are on rails, a follow focus with hard stops at the beginning and end makes changing the focus easier if you talent hits their marks. But even that will be hard if the talent is in motion and you want to match their movement with a change in focus. Practice and multiple takes. It can't be easy but you can do it. At least you are going to have a decent cinema lens and not a photography lens with a tiny focus throw.


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I shot a short that has one scene that we chose to shoot handheld. I had the camera on my shoulder, and I had three marks, plus one if the actors had three marks. My ac had four marks set on the controller, and we found that if I was off by a foot with my mark, focus was way off.

The long focus throw is worth it. I don't think that we'd have been able to make that shot work without it, the focus had to be very precise or it wasn't going to usable.

Hey Rakesh how's the film doing?

Editing is moving forward, the rough cut looks pretty nice so far. We'll hopefully be moving to color grading and sound design and composing soon.

Niiice...can't wait to see it.

AAAAALL of this is why I'm buying a PL camera and never looking back. I am done with the imprecision and general wankiness of vanilla stills lenses for motion picture work. Even cine-vized stills lenses can be pretty bleh a lot of the time (my love-hate for Rokinon Cine lenses, for example). Everything has to be a step forward...

Going PL makes for a bigger investment up front, but it makes things like precise focus pulls much easier.

You'll be glad in the long run. Plus, they're easier to find renters for.

Cris, pulling focus alone is going to be a challenge if the camera is not rigged. If you are doing it by sight as a sole operator, you may get good results using the BMD Viewfinder with peaking turned ON. If you are on rails, a follow focus with hard stops at the beginning and end makes changing the focus easier if you talent hits their marks. But even that will be hard if the talent is in motion and you want to match their movement with a change in focus. Practice and multiple takes. It can't be easy but you can do it. At least you are going to have a decent cinema lens and not a photography lens with a tiny focus throw.

Rick,

Thanks for the response. I pull alone on simple gigs a lot using photo lenses with tiny throw (always using focus peaking and viewfinder). I have little to no experience with true cinema lenses so I'm curious if in those solo-shoot circumstances would pulling be significantly more challenging with the larger barrel of the SLR Magic. Or is it essentially the same. I suppose the answer to this has to do with whether my hand can crank the focus all the way around (with our without focus gear) in one go without readjusting my hand to continue the pull.

Again, thanks for the response.

Cris

The SLR Magic APO lenses aren't huge as cinema lenses go, but you could likely manually turn the distance you need with your hand on the focus ring, unless you are trying to focus from infinity to MOD which is a bit extreme. It's easier to focus larger lenses like the APO than a lens with a significantly smaller barrel which one would tend to over focus because the changes happen too quickly for your brain to put on the brakes. If you've already done that, then you are going to be fine.


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Going PL ... they're easier to find renters for.

Nailed it.