Blackmagic Pocket Cinema Camera: Yes there will be housings!

I just spotted that the Nauticam housing for the BM pocket camera is on the Nauticam Australia website as coming soon. Here's the link:

 

http://www.nauticam.com.au/products/housings/pro-video/blackmagic-pocket-cinema-camera/index.html

 

So now I am wondering about a WA lens again. Does anyone know how to figure out what the 8mm FE would look like on a Pocket Camera? Can you just use the same crop factor as for a rectilinear lens with a fisheye?

 

Tim

Exciting!

So now I am wondering about a WA lens again. Does anyone know how to figure out what the 8mm FE would look like on a Pocket Camera? Can you just use the same crop factor as for a rectilinear lens with a fisheye?

 

Tim

Check this link:

http://forum.blackmagicdesign.com/viewtopic.php?f=2&t=7219

Yes 8mm = 24mm on the BM Pocket and you'd probably loose a lot of the FE effect as you'd be using the centre of the lens, which for video would be great! I've got a Samyang 8mm FE that I'm planning to use for topside WA, but its a manual lens so not so easy to use underwater unless the housing/port is designed for controlling it.

Yeah, I'm hoping that it would lose some of the FE effect. But I'm not sure that the 8mm refers to full frame equivalent. Anyway, hopefully now that the camera is shipping, albeit apparently only a few, before long we'll see some samples. I guess Nauticam must have one so lets hope they post a few - not only the 8mm but also the 7 - 14mm zoom would be good to see.

The crop factor you are showing for the BMPCC camera are more than a bit misleading since I don't recall ever seeing a 24mm FISHEYE lens. This needs to be approached from the standpoint of angle of view. A 15mm fisheye on a full frame Fisheye lens is 180 degrees, a 15mm rectilinear lens on full frame is 110 degrees.

The Samyang 8mm has an AOV of 180 degrees on the Nikon APS-C 1.5X sensor and an AOV of 167 degrees on the Canon 1.6X APS-C sensor so with this lens you need to do the crop from the APS-C size not the full frame size, it would be a circular fisheye on full frame like the Canon 8-15 fisheye zoom.

The Panasonic 8mm fisheye M43 lens has an AOV of 180 degrees on the M43 size sensor, these lenses have about a 1.3X crop on the BMPCC so you would be going from an AOV of 180 degrees to an AOV of around 135 degrees for the Panasonic 8mm, still quite fishy.

The Panasonic 7-14 rectilinear zoom M43 lens has an AOV of 114-75 would would come out at around 87-57, give or take a few degrees.

If you just take your 8mm full frame circular image and divide by 3 you don't really get a true picture of the final AOV of the lens. That would make the 180 degree fisheye a 60 degree fisheye, a 24mm rectilinear lens is 84 degrees so not even close. You would have to think in terms of a 60mm fisheye and I don't know how you do that. If you take the difference between the 15 Fisheye and 15 rectilinear and divide 180 degrees by 110 degrees you get 1.636 times the 60mm fisheye would make the AOV about a 98 degree fisheye also no where near the 84 degrees of a 24mm.

Phil Rudin

The m43 sensor size is 17.3 x 13mm and the pocket camera sensor size is 12.48 x 7.02mm, so if I take a sample shot on an m43 camera and open it in Photoshop with a size of 17.3 x 13 and then crop it by reducing the canvas size to 12.48 x 7.02 will that show me what the lens used would look like on a pocket camera?

That, I think would work. My above post for AOV is based on the 3:2 and 4:3 formats of the cameras involved. My post on page two of this thread would be based on the lenses being used on the 16:9 format which will further reduce the AOV of these lenses.

Phil Rudin

Thanks Phil. That is really cool. So it looks like getting wide establishing shots is not going to be a problem after all and with careful framing the Panasonic 8mmFE should be a nice lens to have.

A picture is worth a thousand words. The BMPCC is also 16:9 so this pic approximately illustrates the crop factor:

It's not what people think it is. Going to a C mount or S16 lens like the Ernitec 6.5mm Fisheye will get you back some wide angle, but it won't be 180°. But then again what moving picture looks good with 180° fisheye look? C mount probably won't be as sharp either. Test before buying!

Yes, big difference between a lens made for a 35mm full frame and a M43 lens which is made for M43 at full frame. Olympus attempted to point out this difference when they first started selling the 43 cameras but it went over most people's heads.

Olympus and Panasonic 43 and M43 lenses really have no crop factor because they were made for the 17.3 X13mm sensor.

Using the same logic you would find that a 35mm sensor has a 2X crop factor if I mount a Hasselblad medium format lens on it.

The new Canon and Nikon lenses made for APS-C cameras really have no crop factor because they won't work on 35mm sensors using the full frame. They can be used but at the APS-C size not the 35mm size.

At some point someone decided that 35mm should be the format by which all other cameras are judged and to me it makes far more sense to talk about what AOV you get with any given lens and sensor size which is really what matters when you are buying a lens along with the other obvious issues of build and image quality.

Phil Rudin

Thanks Phil,

Really nice post

Phil, the 35mm "full frame" standard is a relic from the Kodak's 135 film for stills, which is 35mm across including perfs. That is how this whole 35mm full frame started.
S35 film is closer to APS-C sensor size, as is S16 film is to 1" sensors. 35mm full frame is closest to Vistavision 8/35mm film.

We all know that 35mm cine film turned on its side was the basis for 35mm still film photography. The image size when shot on 35mm film and now 35mm sensors of 24mm X 36mm is where the idea of crop factor v. Full frame ( full frame being 24 X 36 mm) came from. In the 3:2 format a 1.5 X crop factor is releated to the 24 X 36 mm image size not the original film size. So a Nikon APS-C sensor is 23.5 x 15.5 about 1.5 and the Canon 1.6 X APS-C size sensor is 22.5 x 15 mm image area compared to the 24x36 35mm image area.

The crop factor idea with 43 and M43 is even less relevant because it is a different 4:3 format v. the 3:2 35mm format. If you had a 2X crop v. 35mm it would be 18 X 12mm, because the 4:3 format is three units of length X four units of length you end up with a 17.3 x 13 mm sensor area or 4.333 x 3= 13mm and 4.333 x 4= 17.3mm for the 43 and M43 sensor image area. Some of the sensors like film are larger but the image capture area is what is relevant.

No one ever talked about full frame or crop factors other than 35mm half frame before digital.

Regarding Drew's photo illustration it would help to mention that the photo is in the 4:3 format with what looks like some type of fisheye and it might help to also illustrate the use of a fisheye or other W/A lens on the 3:2 format for comparison.

Phil Rudin

Just remember if you are planning on putting Olympus or Panasonic glass on the BMPCC then there is NO in camera processing of the (distorted) image. Again it should be helped a little by the crop.

Just remember if you are planning on putting Olympus or Panasonic glass on the BMPCC then there is NO in camera processing of the (distorted) image. Again it should be helped a little by the crop.

And add to this the fact that Optical Image Stabilization OIS is not granted as discussed on Blackmagic forum:

http://forum.blackmagicdesign.com/viewtopic.php?f=2&t=11036&p=69425&hilit=Bmpcc+OIS&sid=e92bbdeb16a8b8aaaed0fbfb70787ca4#p69425

Here is an excerpt"

Kristian Lam

Blackmagic Design

Posts: 183

Joined: Tue Aug 21, 2012 1:11 pm

Re: Stabilization from Panny lens on BMPCC?

Thu Aug 15, 2013 10:35 pm

I would like to issue a correction.

There will be no stabilisation enabled if the lens, such as the Panasonic 14-42mm, does not have a physical switch. The protocol for enabling stabilisation is not part of the MFT standard so it not work right now.

We'll have to see if Panasonic is willing to share with us what we need to tell the lens in order to turn stabilisation on.

For lens with physical switches, it will work fine."

[lazy]

1. So which MFT lenses are not designed to have their distortion corrected in-camera? SLR Magic etc.? Any Panasonic/Olympus?

2. So which MFT lenses do have a physical OIS switch?

[/lazy]

Personally I don't think I'm so worried about distortion correction or even the lack of stabilisation. CA might be a problem though. Anybody know how to deal with that in post?

[lazy]

1. So which MFT lenses are not designed to have their distortion corrected in-camera? SLR Magic etc.? Any Panasonic/Olympus?

 

2. So which MFT lenses do have a physical OIS switch?

[/lazy]

Is it MFT or M43? I only ask because if I say MFT and it is M43 I'm sure there will be someone out there ready to correct me!!

Anyway basically all manual lenses are fine Nick, only the electronic ones will have an issue. However the crop MTF>FF is around 2 I think while the crop BMPCC>FF is around 3, so again even on lenses designed for MFT you would be using the glass towards the centre of the lens (although obviously not quite as much as say an EF lens). This should reduce any problems with using a FE or an electronic MFT lens, but it probably wont get rid of all the distortion. Until people actually get their hands on these cameras it is hard to say exactly what it will look like, but from the tests I've seen online so far it looks pretty good and probably good enough for underwater use even if you want a rectangular look rather than a FE (which for serious video IMO is pretty much a no no apart from for a special effect / intentional different look).

No idea which lenses have a manual OIS switch. I know the two MFT lenses that I own don't have a switch so I'd guess this is pretty common.

Cheers, Simon

You could also say Micro Four Third or µ4/3.

Is Metabone still coming out with a lens booster? Would be ace if there is one for MTF from EF lenses

cheers

David

Nick, of the lenses pertinent to UW use, the Pana Elmarit 45mm and 12-35mm have a OIS switch. I know the 14-140 does too but that's too difficult to house. OIS can also screw up a shot if it "misinterprets" underwater movement.