Blackmagic Pocket Cinema Camera S16 Crop Factor & Choosing Lens

[clanterns]

Hello!

As a student currently learning about imaging, I think the best RAW start up camera would be the Pocket camera. (I have past experience too, but handy-cams and after effects don't look too professional).

 

I am still confused on the best lens for it would be. I am interested in the look that a 24mm gives to a full frame sensor, but don't know how that compares to the crop factor (I heard it's 3x), and the fact that it's a super 16 sensor. It seems like it's basic math, but I'm unsure.

Researching these forums, I see recommendations for this site: http://www.abelcine.com/fov/

but that doesn't answer my question.

If I can figure out the basic math to my problem, I can choose the right lens to get the 24mm, 50mm, etc. look from a 35mm sensor.

 

Would I need a higher, 50mm lens, to get the wide angle look of 24mm, on this camera? Or would I need to go even lower, 8mm to get around a 24mm look?

 

Here's an example of the "look" I'm going for with my future Blackmagic Pocket Cinema Camera:

http://www.pixel-peeper.com/lenses/?lens=567

That example is a 24mm (wide angle) lens, mostly on full frame cameras. The 3rd image catches my eye in particular.

I'm interested in wide angle for music video production.

And yes, those are from a prime lenses, as they are the sharpest, I want the most clarity I can get, and do any distortion in post.

Any help/advice would be appreciated. If I've made any mistakes in my research, PLEASE correct me.

[Rungunshoot]

I don't think anything is going to give you that look on the BMPCC. I've been researching the same thing, and the focal length of lens you're seeking is 8mm.  While those lenses exist for s16mm, they would need impossibly large apertures to equal the wide-yet-shallow DOF in your sample images.

 

You might get something vaguely similar with this combo:

 

m43 speed booster (doesn't exist yet)

voigtlander 17.5mm f/.95

 

That would something be like a 35mm f/1.4 on full-frame.  

 

As far as I know, nothing is equally fast and wide in the m43 arena.

[Zach]

You would need to go lower. I feel like the Tokina 11-16 (canon mount) and the Metabones m43 speedbooster (like he said ^ doesn't exist yet but will soon) would probably give you a similar look. 

[Huuow]

question is, if you want the look of a 24mm full frame, why not go 24mm full frame?

[andy lee]

we already have a thread looking at lenses for this camera here have a read

http://www.eoshd.com/comments/topic/2495-super-16-lenses-for-pocket-cinema/

[Bioskop.Inc]

The picture you're most impressed with is giving what is known as a 3D effect (an optical illusion generated by a v.thin & shallow DOF), but not a v.good example. 

Some lenses create this effect & others don't - its nothing to do with the focal length & it doesn't really translate to video/film (hence why 3D exists).

I could take the exact same picture with a 55mm, but i wouldn't be so close to the car when taking the picture.

[clanterns]

I don't think anything is going to give you that look on the BMPCC. I've been researching the same thing, and the focal length of lens you're seeking is 8mm.  While those lenses exist for s16mm, they would need impossibly large apertures to equal the wide-yet-shallow DOF in your sample images.

 

You might get something vaguely similar with this combo:

 

m43 speed booster (doesn't exist yet)

voigtlander 17.5mm f/.95

 

That would something be like a 35mm f/1.4 on full-frame.  

 

As far as I know, nothing is equally fast and wide in the m43 arena.

I see, what would it be like without the speedbooster, as current models are around $500, then I would have a lens to buy, I'd rather just buy an expensive lens, as the speedbooster quickly makes the "low price" of the BMPCC not so low.

 

question is, if you want the look of a 24mm full frame, why not go 24mm full frame?

Have you seen the price of the BMPCC?

 

we already have a thread looking at lenses for this camera here have a read

http://www.eoshd.com/comments/topic/2495-super-16-lenses-for-pocket-cinema/

Yes, a lot of good information in that thread, I admit I didn't see this thread before, but also I think my thread is more fundamental. I'm trying to figure out the exact calculations I need to make the right purchase.

 

The picture you're most impressed with is giving what is known as a 3D effect (an optical illusion generated by a v.thin & shallow DOF), but not a v.good example. 

Some lenses create this effect & others don't - its nothing to do with the focal length & it doesn't really translate to video/film (hence why 3D exists).

I could take the exact same picture with a 55mm, but i wouldn't be so close to the car when taking the picture.

I realize it has good depth of field, that is not the particular thing i'm getting at. As 8mm lens are very wide field of view (with distortion), 50mm, the human eye is used to seeing (portraits), and on up for telephoto (a "compression" effect).

[Bioskop.Inc]

Realised my mistake, as its the distortion you like! 

Then go as wide as you possibly can - you could even try fisheye lenses.

Just remember that a x3 crop sensor will behave differently with that 24mm than a FF sensor.

[clanterns]

Realised my mistake, as its the distortion you like! 

Then go as wide as you possibly can - you could even try fisheye lenses.

Just remember that a x3 crop sensor will behave differently with that 24mm than a FF sensor.

Correct, I understand that an 8mm is considered "fisheye". So do you know how exactly an 8mm would look on this camera? Would it look more like a 24mm, due to the 3x crop?

[Zach]

Correct, I understand that an 8mm is considered "fisheye". So do you know how exactly an 8mm would look on this camera? Would it look more like a 24mm, due to the 3x crop?

Length wise it'd be about a 24, but there would probably be a little bit more distortion. And not as shallow depth of field

[Ernesto Mantaras]

Correct, I understand that an 8mm is considered "fisheye". So do you know how exactly an 8mm would look on this camera? Would it look more like a 24mm, due to the 3x crop?

 

Exactly!

[clanterns]

Length wise it'd be about a 24, but there would probably be a little bit more distortion. And not as shallow depth of field

And I regain that DOF with a speed booster? Can the DOF change be calculated?

[clanterns]

So an 8mm lens would appear to be a 24mm lens on the BMPCC... This is factoring in the crop factor, and the S16 sensor size? I'm still learning here.

[Huuow]

depth of field is pretty much non existant

 

here´s a calculator:

http://www.dofmaster.com/dofjs.html

[clanterns]

depth of field is pretty much non existant

 

here´s a calculator:

http://www.dofmaster.com/dofjs.html

So the speed booster mentioned earlier would bring it back?

[Zach]

So the speed booster mentioned earlier would bring it back?

 

No, the 8mm lenses don't have hardly any depth of field to begin with. When you stick it on the blackmagic, it is just using the center part of the lens, so even less so. 

[Zach]

is there any reason in particular you want the black magic? Something like the GH2 or GH3 would acheive the look with much greater ease

[clanterns]

is there any reason in particular you want the black magic? Something like the GH2 or GH3 would acheive the look with much greater ease

I have seen the GH2/3 and heard of their modding community. The clarity of the BMCC is incredible IMO, and they don't use a low pass filter for moire, which increases the sharpness. And RAW 1080p video is key. I have not seen anything comparable to the BMCC when it comes to the GH's, maybe you can prove me wrong.

[Rungunshoot]

There's also the imperfect solution of combining the BMPCC with a larger-sensor camera on the same shoot to achieve different looks.  A well-exposed 8-bit image can match nicely to a graded RAW image because ultimately your viewer will be seeing this in 8-bit anyway (unless it's going to cinema, in which case I have no idea).  To my knowledge, all broadcasting and most displays are 8 bit by default.  

 

Someone correct me if I'm wrong here.

[Rungunshoot]

Here's an option for a 24mm-equivalent lens on the BMPCC.  8mm f/1.4 C-mount lens designed for 1" sensors. Roughly $500.

 

http://www.navitar.com/product/navitar-machine-vision-1-format.aspx