Mark2929 wrote:BM did make the mount correct in the first place using CN-E lenses as their guide
No.
They used the EF mount standard FFD. Not CN E lenses as their guide.
Mark2929 wrote: Had this remained the case My lenses would have worked fine.
While many many wide wide angle canon and non canon users lenses wouldn't be able to hit infinity.
Mark2929 wrote:They then overcompensated for the tokina 11-16mm which was out
No.
That was a lens that commonly showed up as not hitting infinity, but if you search these and other forums, you'll find many lenses especially wider angles one wouldn't hit infinity, including Canon lenses.
The Tokina already had a bad reputation for not even hitting infinity on many bodies before the BMCC was introduced.
Mark2929 wrote:As a result of this no witness marks on pro lenses would ever be right.
Well no lens witness marks were ever right anyway on any stills lens. Unless you had a Zeiss CP or a CN-E lens in EF mount that was collimated to the target body. Witness marks on most still lenses are incredibly minimal and most don't even have lines for their distances.
Mark2929 wrote:However that hasn't stopped BM from plastering pictures all over their advertising buff using CN-E lenses
And there's nothing at all stopping you from using those lenses Mark. You can also use them with the correct witness marks by collimating your lenses to your body, something that's been SOP in PL mount lenses and cameras for many decades. You could also mark up and laminate a follow focus disc with the "right" markings as well, something many 1st AC's do with lenses that don't have good markings.
Mark2929 wrote:You're right I could get my lenses collimated for BM's wrongly sized EF mount and then recollimated again if I buy another camera in the future.
Yep. That's exactly what you do and what many others do with PL lenses.
Mark2929 wrote:Yes BM got slated for those lenses wrongly made and with infinity issues so lets not mention that Lets blame the idiot who went out and spent all he had on a set of pro lenses That's far better isn't it.
Well Mark, did you actually do the research ? You don't seem to understand that it's normal to have to collimate lenses for each camera. I just spent a week in testing. Two of those test days was testing each prime and zoom lens on the bodies I have so that I could be sure they'd all hit their marks. These are Panavision Primos, which have shot countless amazing films and won many academy awards. We still rejected a few.
I'm not blaming you but you, yeah you're kind of ignorant of what normal practice is for cinema lenses. Maybe take the hit for a second and get on with what you can do about it. Like I said, you can easily collimate your lenses to work with your body. It doesn't take long to do.
Mark2929 wrote:
Yes the CP2's are shimmable with a kit and instructions how to do it So no problem there then.
Indeed. If you've only just received your CN-E lenses perhaps you may be able to return them if this is so important to you. In my opinion the CP's are the equal optically to the Canon CN-E's from what I've seen (and I've shot both) and you have the advantage of interchangeable mounts that are user shimable.
CP's are more future proof and will allow you to grow into other cameras and mounts. EF is a closed system that has little chance of growth.
Mark2929 wrote:After testing ALL my CN-E lenses now match with two layers of thin tape.
As I mentioned, a terrible solution that will not be consistent over time.
Mark2929 wrote:A lens can be OUT but still hit the right witness marks on a body that's also out.
Two wrongs make a right?
Yeah they sure can if the lens collimates and the witness marks line up. Absolutely.
Mark2929 wrote:Putting your specific issue aside for a second, the EF lens mount is highly problematic.
No its not Its only problematic when information is not given Like for example "Buy a BM camera and use the worlds best lens crafters
You keep referring to canon as the "worlds best lens makers". You're making this a very emotional argument. Lenses are highly subjective.
Mark2929 wrote:but dont forget we made the mount to cater for the lens most out so your witness marks wont work and you will need to recollimate your lenses so their not accurate to the EF spec.
Yeah. That's exactly what you need to do. Collimate your lenses to the camera so your witness marks line up. You'll also find they are probably closer to accurate on any other EF mount camera you care to use.
Mark2929 wrote:Yes but BM cited using Canon CN-E lenses and indeed made the EF mount using them as a reference. Only changing it after complaints fromTokina users who also seem to have issues with the canon c300
Mark. you've answered your own issue. BM show a range of lenses on the camera. You can use the CN-E lenses on the camera right now. If you want accurate witness marks then get the lenses collimated to your camera. Just like you'd have to do if you bought a C300 or a 5Dmk3. And it wasn't Tokina users. It was a lot of users with canon lenses under 50mm.
Mark2929 wrote:No the reason witness marks cant be used on the EF mount is because the mount is out.
No.
It's because the lenses often don't even have witness marks, don't have any more than three distances, only have 20-30 degrees of rotation before a clutch engages an infinite rotation ring that means you can never accurately repeatedly pull to them, plus their super lightweight loose construction means that even if the mechanical coupling was accurate they never land in the same spot anyway.
Mark2929 wrote:Initially BM made the mount according to the EF spec.
And then many many many user complained so they matched what CANON ALREADY DO and shortened their mount.
So far, in 2 1/2 years you're the only guy I can think of that has complained about this.
Yes. You're right. Yes, if it was at spec and the CN-E lenses were at spec then the witness marks would line up. No canon camera does this. Why should BM, at the expense of the rest of their users ?
Instead, do what we've been doing for years and collimate your lenses to the camera. You have in effect already done this with your bit's of tape.
Mark2929 wrote:This allows Canon to make lenses less expensively with less precision.
Not so with their CN-E lineup though.
Indeed. You're starting to come to grips with why cinema lenses cost so much.
Mark2929 wrote:That was the reason they introduced the M4/3 mount Or at least it should have been.
Correct. That was the fastest way for them to get to PL mount, which would allow shimming, plus allow a lot of other vintage lens options.
Mark2929 wrote:No they shouldnt screw other users They should screw me instead. I think where the problem lies is the advertisement guff and the lack of information
Well like I said Mark, anyone who's worked around cinema lenses knows about shimming and the need to check it. Research. The onus is on you to do that research and be informed. You could have asked here for example and I would told you to seriously consider not buying CN-E lenses in EF mount for exactly these reasons.
Mark2929 wrote:
Yes I understand they needed to please those buying the cameras and I agree But just not with the way they did it. You see if I had known this I would never have bought the CN-E lenses.
Well as I've just said, I wouldn't either.
Mark2929 wrote:
BM could though get their factory to make a flange plate that is the correct thickness and sell it to us. Although you believe BM's mistake however good intentioned should be my problem.
It wouldn't work Mark. Did you look at the shim sizes ? They are measured in thousands of a mm.
You could try asking BM to reset your mount with a "correct" FFD, though that would then mean any other EF lenses would probably have trouble on your camera hitting infinity below 50mm. I imagine if you plead with them you might be able to do this, but I don't think it can be done retrospectively. It has to be set during manufacture.
Mark2929 wrote:
I think it would very helful if BM could make a flange plate of the correct thickness.
Which won't work because it's too thick.
Mark2929 wrote:Well At least you didnt call me a liar! Its a workaround for now. Thanks BM.
Where have you been called a liar ?
Mark2929 wrote:Whatever the thickness and I believe it is far more than a few microns It could easily be done by BM's factory Not a piece of ultra thin metal But a properly sized flange plate to replace the old on Just unscrew it and screw your new one on,
Like I said Mark. They measure shims in thousands of a mm. The act of tightening a screw on a sheet of metal is enough to change the FFD. metal is too thick. Most shims are made of poly / plastic.
Mark2929 wrote:It commits you to a mount that usually can't be shimmed and has other issues with use in motion imaging. For example, you'll find that a heavier cine lens will rotate int he mount when used with a follow focus. There is no way of locking the rotational torque that that follow focus introduces on the lens.
So you're saying I couldnt get my CN-E's collimated anyway
No. Not at all. I'm saying theres ANOTHER issue with using EF mount lenses. Collimation aside, the lens will move in the EF mount because a large diameter focusing ring on a large lens driven by a follow focus has enough leverage to rotate the lens in the mount.
Put any EF lens on your camera and grab it like you're about to have a pull. Then rotate clockwise and counter clockwise. You'll notice it MOVES. That means image shift in your image
Mark2929 wrote:Really? So why does the lens lock into place on the BM mount?
It locks in, but you can still rotate it in the mount.
Mark2929 wrote:I prefer the CN-E's as they are sharper better colour rendition and open wider.
And so the price you have to pay, like for any cinema lens, is to get the lenses collimated if you want the witness marks to line up. Or the camera. But you can't shim an EF mount camera.
Mark2929 wrote:No Vitriol coming from me JB Just a request to BM for a new flange plate that works to the correct tolerances so I can use the lenses they advertise the camera for in a professional way
Yeah there is mate. You're the one who calls people for trolling. You yourself have shown you're totally ignorant about using cinema lenses, issues of collimation and shimming lenses. You've googled a few documents and you're argumentative to those that are trying to explain the complex issues of lens camera body interoperability. Your solution also reveals your ignorance of how lens collimation works. It's fine....I'm really not trying to be insulting, but you keep aggressively responding and banging the table when someone tries to explain any of the detail.
All of your responses show only knowledge gleaned from reading someone's posts from a blog (most of which is wrong). You're not speaking with any previous experience. I do. With both the issues being discussed and how they pertain to BMD specifically.
I actually almost never ever respond here any more for exactly this reason. I've spent over an hour of my own time the day before I start shooting to tell you what you can do to fix the problem. Because it's not the solution you want to hear all I get back from you is agro.
This is precisely why I don't generally bother to engage anymore. Mostly I get told my opinion is biased towards defending or apologising for BM. I'm certainly not the be and end all of lens mounts and knowledge. But I've addressed your issue and told you the painful truth. I truly empathise with your position and can understand why you'd be upset.
I actually felt your pain as I'm sure you've spent a bucket of money on lenses and you want them to work. I was only trying to help mate.
Mark2929 wrote:When Blackmagic designed the BMCC, they designed it to match with Canon’s cinema lenses.
No.
They designed it to work with the EF mount and they've done it to maximise the compatibility with the vast majority of EF lens users. Unfortunately that's not you right now, but doing what we've done for decades, you can collimate the lenses to work with your body perfectly.
Mark2929 wrote: These lenses are pricey, and made to much more exact measurements than Canon’s photo lenses, even their L series.
And are designed to be re-shimmed.....
Mark2929 wrote: Most of the high-end lenses with EF mounts have very precise focus marks on the barrel. They stop at exactly infinity.
Yes. They have hard stops, unlike most other EF canon still lenses which focus past infinity. Yes, they have better witness marks and more of them. And they are designed to be re-shimmed.
Mark2929 wrote:So they performed a recall, and every lens mount they made afterward was adjusted to allow for the wider tolerance of photo lenses. This is how our BMCC is set, to the manufacturer’s revised specifications.
No.
They didn't perform a recall.
They allowed people to return their cameras if they could show that they weren't hitting infinity. Not the same as recall.
JB