Blackmagic Cinema Camera 2.5K

[H. Risu]

Hi all, I have 3 questions:

1. Regarding the Blackmagic Cinema Camera 2.5K, I think the crop factor on the sensor is about 2.3x. I read somewhere that because this camera’s sensor is small, it is very hard to get a cinematic shallow depth of field. This confuses me because I read that long lenses and therefore long focal lengths produce shallow depth of field and the longer the lens, the shallower the depth of field. So if a 35mm lens is placed on the BMCC, it will therefore be an 80mm lens. Therefore, would this not produce a shallow cinematic depth of field? Also, a 50mm lens will therefore become a 115mm lens, making the depth of field even shallower! Then, why do people still say that this particular camera is very difficult to produce a shallow cinematic depth of field? Have you used this camera for yourself to be the judge?

2. Between the Blackmagic Cinema Camera 2.5K and the Blackmagic Production Camera 4K, apart from the difference in resolution, price, shutter type and media storage etc. which camera would you choose? Do you think the Blackmagic Cinema Camera 2.5K is great for making feature films that can be played at actual cinemas and look as if they were shot on an Arri Alexa?

3. I have heard of 1080p HD films that were blown up to 2K and 4K etc. without loss of quality. Can you comment on this? Do you think the Blackmagic Cinema Camera 2.5K can blow up a 2K master successfully to 4K without losing quality? I am asking this in the event one wants to meet the Netflix 4K requirements for movie submission.

Thanks!

 

[Aaron Lochert]

Focal length is an actual measurement specific to the lens design. So because your 35mm on the BMCC might look like an 80mm on FF as far as angle of view is concerned, it's still a 35mm lens. Therefore it still has the same depth of field properties as any 35mm.

Think about it this way. If you shot a photo on a Full Frame DSLR on a 35mm and then you cropped it 2.3x in photoshop, did the depth of field change? No. That's all that's happening when you swap out the sensor behind the lens. Nothing changes to the image, you just see less of it.

So what happens is because you'll be seeing less of the image, you'll be picking wider focal lengths to compensate. And wider focal lengths = deeper depth of field.

All this said, when I owned a BMCC it wasn't hard to get some nice background blur. Just buy a fast enough lens. Or you can buy a speedbooster, just be sure to buy the BMCC with the MFT mount, not the EF.

As far as "cinematic" depth of field is concerned, I would simply point to any movie shot on Super 16, which is a smaller imaging area than the BMCC. Those films were plenty "cinematic" to me. Lighting and composition is what's more important.

When the Pocket 4K exists, I would not consider buying either of those old cameras unless you got a screaming deal on one. I would also only consider the 2.5K because the image was always more pleasing to me than the Production camera. But again, the Pocket 4K exists and comes with Resolve studio. It's a no brainer for beginners or really tight budgets.

As far as something looking like it was shot on Alexa, well, that's not really going to happen until you're shooting projects with enough budget to rent an Alexa. What I mean by that is that your lighting package is substantial, your set designers are on point, and your crew is large enough. And when you're at that level, it almost doesn't matter what camera you use anymore - just hire a good colorist.

1080p blown up to 2K isn't far. Up to 4K, I wouldn't bother. You're not really going to see any benefits unless you're aiming to do an HDR pass as well. But for Netflix, the BMCC would not qualify as it doesn't have 4K worth of photosites on the sensor. In fact, the only approved Blackmagic camera is the Ursa Mini and it's revision, the Ursa Mini Pro. I would also expect the upcoming Pro G2 to be included at some point as well.

 

[Dan Kanes]

If you’re in the market and haven’t bought one and are set on an inexpensive BM camera, get the pocket 4K if you’re worried about deliverables and depth of field being deeper. It’s just a great little guy and more versatile than the older ones in like 1 million ways.

 

[David Peterson]

2. Between the Blackmagic Cinema Camera 2.5K and the Blackmagic Production Camera 4K, apart from the difference in resolution, price, shutter type and media storage etc. which camera would you choose? Do you think the Blackmagic Cinema Camera 2.5K is great for making feature films that can be played at actual cinemas and look as if they were shot on an Arri Alexa?

Not at all keen on the BMD Production Camera 4K, the sensor in it was the worst BMD ever used in any of their "cinema cameras". But BMD used that sensor as it allowed them to tick off both S35 and 4K raw quickly at an early date with a very affordable price. With careful handling you can still shoot nice things with the Production Camera 4K, but in 2019 we just have so many other better options to pick instead.

If I was going to shoot a feature film specifically with a BMD camera (just to narrow down our options... as there are tonnes and tonnes of other cameras from other brands I'd consider! Such as Z Cam E2, Kinefinity Terra 4K, Fujifilm X-T30, Sony FS7, Panasonic GH5S, just to give quick smattering of options from a range of prices that I'd seriously consider) then I'd be picking one of the URSA Mini 4.6K cameras (either the OG, or the Pro, or the Pro G2 version. Whichever is the latest version of those three that I could get my hands on, as each newer version improved a bit on the previous one).

I'd also absolutely have a BMPCC4K on set as well as a B Cam, handy for all those times an URSA might not be right.

A BMD Pocket Cinema Camera 4K could also be the A Cam on an ultra low (read: "no") budget film as well! (might consider a BMPCC OG, BMCC 2.5K MFT or BMD Micro Cinema Camera as all being good B Cam options to have for the BMPCC4K. But I'd avoid the BMCC EF if I could, as having the MFT mount of the BMCC MFT just gives so much more flexibility in lens options)

Now as for a film made with any of these BMD cameras can hang with a feature shot with an ARRI?

Yes and No. The end result is going to depend on many many other factors far far more than the camera chosen, such as:

The Story.
The Locations.
The Actors.
The skill of your DoP.
The lighting package and gaffer you get.
The quality of your Sound Department hires & what their sound package is which gets rented.
The entire Post Production process.
etc etc etc etc

3. I have heard of 1080p HD films that were blown up to 2K and 4K etc. without loss of quality.

Important to remember that 1080 (i.e. 1920x1080) is almost exactly the same as 2K (just a few pixels difference between 2000 and 1920 pixels).

So that is a relatively easy blow up.

As to going from 1080 to 4K? Depends on the quality of the HD footage, is it rubbish soft footage from a Canon 5Dmk2 or excellent high quality detailed HD from a Sony F35 / ARRI / etc?

 

[H. Risu]

Thank you so much to the above posters for your reply. Aaron Lochert, you made me understand the dynamics on a greater level now. Thanks for the explanation on the focal lengths and depth of field being the same etc.

To those who have seen and personally used a BMPCC 4K, have you been able to get some nice shallow depth of field with this camera without using a speedbooster? If yes, what lens gave you some nice shallow depth of field results?

 

[David Peterson]

To those who have seen and personally used a BMPCC 4K, have you been able to get some nice shallow depth of field with this camera without using a speedbooster? If yes, what lens gave you some nice shallow depth of field results?

Have you even seen Upstream Color?

This was shot entirely with the Panasonic GH2 (which is the same sized sensor as the BMPCC4K), and there are portions in there which I feel they went overboard with excessive shallow DoF.

You certainly shouldn't have any worry about DoF when filming with Micro Four Thirds, if you select appropriate lens.

Lots of movies get shot on S35 at around T4 or even T5.6+, which is merely the same as T2.8 or slower for MFT.

I reckon you could buy the Panasonic 12-35mm f2.8 and shoot plenty with that while having nice DoF

But if you want to go crazy silly extreme then buy a 50mm f0.95 and shoot with it wiiiide open!

 

[Geran Simpson]

If you are looking at the old Blackmagic cameras because they can be had for cheap, you should be aware of the almost mandatory accessories needed for shooting - which have not gone down in price. You'll need external batteries, you'll need media that you're unlikely to have already, you'll need an external audio recorder/operator since the hardware onboard the camera is awful, even with a good microphone. You'll need some kind of cage support or a cheese plate at the very least. How will you mount the battery? if it's not a Switronix Powerbase then you'll need a battery plate or rod system. Solo operator? Have fun pulling focus while holding this now beast of a rig with one hand. "Oh I'll just shoulder mount it then". HA now you need an external monitor and a handle at the least.

This is the struggle of the original Toaster cams.

The new Pocket 4K alleviates a lot of these problems. The audio of the BMCC 2.5k and BMPC 4K will give you aids. You'll find that once you start adding the accessories for a Toaster, the Pocket 4K is actually cheaper.

Regardless, given the choice between the 2.5K and the Production camera, I would choose the 2.5K in MFT. I own the Production cam in EF and it's a bear. The raw files are enormous as there is no compression, and the lower dynamic range and light sensitivity is painful in the highlights. If you want the advertised 12 stops you have to shoot in raw, too. I would trade that for a smaller sensor.

 

[Andy Jarosz]

Just throwing in experience with the 2.5K as well, and have also found the image quality to be far more cinematic than the original 4K production camera. Your DOF will be about twice that of an S35 sensor camera, so yes you can get your background blurry, but you'll have to either open up or use a tighter lens that you might first assume.

I don't think you'll gain any advantage upscaling to 4K. Here's some .DNG stills from a couple things I've shot with it. https://drive.google.com/open?id=1IqeYVmpA48s_-jfEhvAgNCrXkE-WXgdT

The low light performance of both is not great. You'll definitely want to ETTR. You'll notice the still I linked to are on the cusp of being overexposed, but still show some grain. I've also attached a still that is very overexposed (looks totally white before lowering the raw exposure) to show the lattitude and gradability you can get out of it.

One last thing to mention is they're VERY hackable, if you're into that sort of thing. They're basically a board in a box, and people have done some crazy stuff with them: https://vimeo.com/152792193 https://forum.blackmagicdesign.com/viewtopic.php?f=2&t=33997

This said, the camera can be difficult to use without any external monitoring and audio solutions. I would highly recommend a Pocket 4K, or renting one of the newer Ursas.

 

[David Peterson]

If you are looking at the old Blackmagic cameras because they can be had for cheap, you should be aware of the almost mandatory accessories needed for shooting - which have not gone down in price.

I'd greatly disagree.

Back when the BMCC was first launched then we had relatively few low budget "cinema accessories / gadgets / widgets / etc", as we were still in the early days of the HDSLR Revolution.

Since then we've had an explosion of options, especially in the lower budget range.

And in some areas such as media, the prices have truly fallen through the floor! (for instance I spent a small fortune on SD cards when I purchased my BMPCC, just as much on media as the camera itself! But now those same SD cards are dirt dirt cheap)

 

[H. Risu]

Some further interesting things to know; thank you all - especially great to know about Upstream Color!

Please advise on the below scenario in terms of using cropped sensors:

A 50mm lens is used on a full frame sensor camera and a subject's face is framed accordingly; the camera is on a tripod.

The same 50mm lens is used on a 2.3x cropped sensor camera and the lens therefore becomes a 115mm lens; it is still on the tripod at the same position. The subject's face is therefore not visible fully as before and is out of frame due to the change in focal length. The camera is therefore moved backwards from the subject to achieve the same framing for the subject's face as per the full frame camera.

The question:

If one were to take a screenshot in post-production of each of the two cameras above (with the identical framing of the subject) and compare them side by side, is it correct to say that the full frame camera image frame would contain more detail and quality than the cropped sensor camera's frame of the same shot? I ask this due to the fact that the cropped sensor camera had to be moved backwards and in doing so, loss of detail e.g. on the actor's face including skin blemishes/wrinkles/acne/freckles etc. would be less present than on the full frame sensor camera which was located closer to the actor.

 

[Geran Simpson]

Some further interesting things to know; thank you all - especially great to know about Upstream Color!

Please advise on the below scenario in terms of using cropped sensors:

A 50mm lens is used on a full frame sensor camera and a subject's face is framed accordingly; the camera is on a tripod.

The same 50mm lens is used on a 2.3x cropped sensor camera and the lens therefore becomes a 115mm lens; it is still on the tripod at the same position. The subject's face is therefore not visible fully as before and is out of frame due to the change in focal length. The camera is therefore moved backwards from the subject to achieve the same framing for the subject's face as per the full frame camera.

The question:

If one were to take a screenshot in post-production of each of the two cameras above (with the identical framing of the subject) and compare them side by side, is it correct to say that the full frame camera image frame would contain more detail and quality than the cropped sensor camera's frame of the same shot? I ask this due to the fact that the cropped sensor camera had to be moved backwards and in doing so, loss of detail e.g. on the actor's face including skin blemishes/wrinkles/acne/freckles etc. would be less present than on the full frame sensor camera which was located closer to the actor.

The 50 doesn't become anything else. Get rid of that mindset right away. It's the same lens no matter what sensor is capturing the image it produces. With that said, the detail would depend on the resolving power of the lens, assuming the sensors are the same "quality" for the sake of the question. The more a sensor "crops in" on a lens's native image circle the more it stresses that lens's resolving power.

Detail from the sensor after the lens depends on that particular sensor. The crop factor is not a direct influence over the overall detail. In theory the image would be the exact same but with less light and a deeper depth of field.

As a personal example I have an older 18mp APSC stills camera and a brand new 20mp M4/3 stills camera. The 20mp camera has more detail because it has a better, newer sensor, even when resolution is lowered to like 5mp. The crop factor had a negligible effect on the level of detail captured by the sensor. An early full frame would have even less detail than the APSC camera because it is older and less advanced.

When analyzing sensor sizes the main things to consider are field of view and light sensitivity/noise levels.

 

[H. Risu]

Thank you Geran Simpson. Some interesting points you raised; much appreciated.

 

[David Peterson]

Some further interesting things to know; thank you all - especially great to know about Upstream Color!

Please advise on the below scenario in terms of using cropped sensors:

A 50mm lens is used on a full frame sensor camera and a subject's face is framed accordingly; the camera is on a tripod.

The same 50mm lens is used on a 2.3x cropped sensor camera and the lens therefore becomes a 115mm lens; it is still on the tripod at the same position. The subject's face is therefore not visible fully as before and is out of frame due to the change in focal length. The camera is therefore moved backwards from the subject to achieve the same framing for the subject's face as per the full frame camera.

Does it matter one iota what a 50mm lens looks like on one camera or another?

Only matters if you've very used to shooting on say a 5Dmk2 / D800 / K1 / whatever, and you've got a built in way of thinking "what is a 50mm"

But if you don't, and you're coming to a BMCC MFT / OG BMPCC / BMPCC4K / etc totally fresh then it absolutely doesn't matter what a particular lens looks like on another camera.

I'm firmly of the opinion that the entire concept of "crop sensor" has done far far more harm to the minds of newbie (and not so new!!) filmmakers than it has done any good as a handy tool/analogy.

The question:

If one were to take a screenshot in post-production of each of the two cameras above (with the identical framing of the subject) and compare them side by side, is it correct to say that the full frame camera image frame would contain more detail and quality than the cropped sensor camera's frame of the same shot? I ask this due to the fact that the cropped sensor camera had to be moved backwards and in doing so, loss of detail e.g. on the actor's face including skin blemishes/wrinkles/acne/freckles etc. would be less present than on the full frame sensor camera which was located closer to the actor.

False.

False.

False.

 

[David Peterson]

The 50 doesn't become anything else. Get rid of that mindset right away. It's the same lens no matter what sensor is capturing the image it produces. With that said, the detail would depend on the resolving power of the lens, assuming the sensors are the same "quality" for the sake of the question. The more a sensor "crops in" on a lens's native image circle the more it stresses that lens's resolving power.

The resolving power of even vintage lenses is waaaaaay above the resolution of 2K / 1080

And any half semi decent ish modern lens will resolve greater detail than 4K can.

So while photographers might fret about the resolving power of a lens, as filmmakers it is of less concern for us.

Detail from the sensor after the lens depends on that particular sensor. The crop factor is not a direct influence over the overall detail. In theory the image would be the exact same but with less light and a deeper depth of field.

"Less light"? Well yeah, technically "the total amount of light" is less. But practically speaking folks are much better off just ignoring that. As the exposure is what matters, and the exposure stays the same across all sensor sizes with how we measure it in terms of the numbers we use:

1/50th with f2.8 (strictly speaking... T stop, not f stop) & ISO 800 (assuming the manufacturer isn't fudging numbers, some do slightly) on a S16 / MFT / S35 / FF / etc is all exactly the same.