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Brad Bussé
lens math
on Jan 15, 2014 at 8:37:49 pm

Hi, I've been tasked with purchasing some new equipment to setup a studio that will heavily use green screen for interviews with 1 or 2 subjects, and I need to get a list of recommended equipment together in the next couple of days. The space I'm shooting in is 26' by 12', and I figure the subject should ideally be about 8' from the screen. And of course the camera will need probably 3' of space from the back wall to be able to operate it comfortably.

So, I was hoping someone could help me do the crop math on whether a Voigtlander 25mm would give a wide enough image to capture the subjects with a midframe shot when connected to either the BMCC or BMPCC.

Thanks.


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Richard Martz
Re: lens math
on Jan 16, 2014 at 12:37:10 am

The BMCC and the BMPCC are very different sensors and will require very different lenses. BMPCC is a large format sensor similar to a "Full Frame Sensor in a DSLR like a Canon 5D or a Nikon D800. The BMCC sensor is an APS-C sensor similar to what is found in a 7D, 60D, T3i, Etc.

As I understand it the BMPCC needs no math since there is no multiplication factor for the lens system. And good luck finding one as they are in VERY SHORT SUPPLY.

The BMCC is a different matter entirely. Take the lens and multiply by 2.4 and you should have the effective composition multiple. If I were you I would find a similar size room and just mark it off. Rent a T3i at a camera store (cheap) with a zoom lens in the 17-300 range. Then try it out in that space or one that is similar making note of the zoom settings at places where you will normally be shooting.

Remember that since the BMCC has a smaller sensor the image comes from the sweet spot in the lens where aberrations are minimal. You can get by without having to use very expensive lenses and you will still have razor sharp images.

Here is a link to a music video we shot using a 17-70 Sigma lens.





Sincerely,
Richard Martz

MagicMartz Media
Atlanta, GA

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Brad Bussé
Re: lens math
on Jan 16, 2014 at 8:35:43 am

Thanks for the reply, Richard.

Isn't the BMCC the larger sensor (1.6 or 2.0) while the BMPCC pocket is 2.3ish?

Those closeups are really nice, I would have guessed they were shot on a prime. What format did you shoot, raw log, cine or video?


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Richard Martz
Re: lens math
on Jan 16, 2014 at 1:05:29 pm

I guess you meant the BMPC, Blackmagic Pocket Cinema Camera (versus Production Camera 4K). And yes… I understand the pocket camera has a very similar sensor to the Cinema Camera.

We shot the video in PRO RES HQ. That was a matter of storage space and budget. We record on San Disk Extreme 480GB cards. Edit in Final Cut Pro 7

And it was pretty amazing. The video had a look much like RAW but we brought out the color by adding color using apple's built in three way color corrector.

I have done some work with Resolve and that program is amazing but I'm just not proficient enough yet to be fast enough to depend on it to meet deadlines.

Sincerely,
Richard Martz

MagicMartz Media
Atlanta, GA

FCP 7
FCP X
Blackmagic Cinema Camera
ADOBE CREATIVE SUITE CC
Premiere Pro
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MAC 8 core
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8' jib arm
20K watts of lighting
Multitrack audio
Teleprompters
Grip Truck/trailer
Location video monitoring
Door and hood mounts
Lots of other Fun Stuff!


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Richard Martz
Re: lens math
on Jan 17, 2014 at 3:23:10 pm

The actual sensor sizes are listed below:

Blackmagic Pocket Camera: Sensor Size 12.48mm x 7.02mm
Blackmagic Cinema Camera: Sensor Size 15.81mm x 8.88mm
Blackmagic Production Camera 4K Sensor Size 21.12mm x 11.88mm (Super 35)

Sincerely,
Richard Martz

MagicMartz Media
Atlanta, GA

FCP 7
FCP X
Blackmagic Cinema Camera
ADOBE CREATIVE SUITE CC
Premiere Pro
DaVinci Resolve 9.0
MAC 8 core
After Effects
PhotoShop
Illustrator
Sony HD Cameras
24' Camera Crane with Motorhead
8' jib arm
20K watts of lighting
Multitrack audio
Teleprompters
Grip Truck/trailer
Location video monitoring
Door and hood mounts
Lots of other Fun Stuff!


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Brad Bussé
Re: lens math
on Jan 17, 2014 at 7:57:04 pm

Cool, thanks for the insight, Richard.


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Peter J. DeCrescenzo
Re: lens math
on Jan 19, 2014 at 8:53:51 pm
Last Edited By Peter J. DeCrescenzo on Jan 19, 2014 at 9:07:17 pm

In DSLR still camera terms, all Blackmagic Cameras have so-called "crop" sensors. They are all significantly smaller than a 135 format size sensor such as in a Canon 5DM3, a "full frame" DSLR camera.

Refer to the sensor size chart on the ProLost website, and the Comparator tool & chart on the AbelCine website:
http://prolost.com/storage/post-images/sensors_003_BMD-context.png?__SQUARE...
http://www.abelcine.com/fov/
http://blog.abelcine.com/2010/08/18/35mm-digital-sensor-comparison-chart/

Concerning BMD camera names and abbreviations, the ones I see used most often are:

BMCC-EF & BMCC-MFT: "Blackmagic Cinema Camera". The original model has an active EF lens mount, and its sister model has a passive MFT lens mount. They have identical specs and sensors (size & type) @ 15.81mm x 8.88mm, with up to 2432 x 1366 recording resolution. The BMCC is known for its relativley high dynamic range and great "look" (color science). These cameras are shipping and are generally readily available.

BMPCC: "Blackmagic Pocket Cinema Camera". The BMPCC sensor is approx. S16 motion picture film size @ 12.48mm x 7.02mm, with up to 1920 x 1080 recording resolution. The BMPCC has an active MFT lens mount. The BMPCC's sensor and "look" are essentially identical to the original BMCC, but at a lower resolution. The BMPCC is BMD's newest camera and is generally readily available.

BMPC-4K: "Blackmagic Production Camera 4K". The BMPC-4K sensor is approx. S35 motion picture film size @ 21.12mm x 11.88mm (also similar in size to "APS-C" stills format), with up to 3840 x 2160 recording resolution. The BMPC-4K has an active EF lens mount. The BMPC-4K sensor and "look" will be similar to the previous models, but with higher res, global shutter, but with slightly less dynamic range & sensitivity. The BMPC-4K was announced April of 2012 but is not shipping yet. Its availability is anyone's guess.

BMD product specs are on their website:
http://www.blackmagicdesign.com

You may find this FOV & DOF tool helpful:
http://www.panavision.co.nz/main/kbase/reference/calcFOVform.asp

---

http://www.peterdv.com
Blog: http://herefortheweather.wordpress.com


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Peter J. DeCrescenzo
Re: lens math
on Jan 20, 2014 at 12:16:16 am

… a slight correction: The BMPC-4K was announced April 2013 (not 2012), although it seems it's been years since it still hasn't started shipping yet! :-)

---

http://www.peterdv.com
Blog: http://herefortheweather.wordpress.com


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Richard Martz
Re: lens math
on Jan 20, 2014 at 1:59:26 am
Last Edited By Richard Martz on Jan 20, 2014 at 2:05:33 am

Yes…It was the same delivery schedule with the Blackmagic Cinema Camera. Promises Promises and a bit of "engineering in the field" with respect to still not having usable audio. I generally love Blackmagic products but their promises are beginning to sound like deja vu.

Sincerely,
Richard Martz

MagicMartz Media
Atlanta, GA

FCP 7
FCP X
Blackmagic Cinema Camera
ADOBE CREATIVE SUITE CC
Premiere Pro
DaVinci Resolve 9.0
MAC 8 core
After Effects
PhotoShop
Illustrator
Sony HD Cameras
24' Camera Crane with Motorhead
8' jib arm
20K watts of lighting
Multitrack audio
Teleprompters
Grip Truck/trailer
Location video monitoring
Door and hood mounts
Lots of other Fun Stuff!


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Peter J. DeCrescenzo
Re: lens math
on Jan 20, 2014 at 3:07:24 am

Despite Blackmagic Design's occasional mis-steps I'm very much looking forward to the BMPC-4K. I've had one on order since last April. If it works as advertised (or very close to) it will be a great value, for me at least. We'll see.

---

http://www.peterdv.com
Blog: http://herefortheweather.wordpress.com


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Richard Martz
Re: lens math
on Jan 20, 2014 at 1:50:35 pm

Ditto. Value means a lot.

Sincerely,
Richard Martz

MagicMartz Media
Atlanta, GA

FCP 7
FCP X
Blackmagic Cinema Camera
ADOBE CREATIVE SUITE CC
Premiere Pro
DaVinci Resolve 9.0
MAC 8 core
After Effects
PhotoShop
Illustrator
Sony HD Cameras
24' Camera Crane with Motorhead
8' jib arm
20K watts of lighting
Multitrack audio
Teleprompters
Grip Truck/trailer
Location video monitoring
Door and hood mounts
Lots of other Fun Stuff!


Return to posts index

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