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BMPCC Crop Factor question


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#1 Nik Aberle

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Posted 01 November 2016 - 02:55 PM

Hello all, 

 

Long time stalker, first time poster. So I'm hoping to invest in a BMPCC in the nest 12 months for personal projects and I've been having trouble understanding crop factor. 

 

From what I understand, putting an EF lens on the BMPCC will create a crop factor of 2.88 because the lens was meant for a 35mm camera. But what about lenses meant for the MFT sensor? Will the Vega-9 50mm on an MFT sensor look the same as the Canon 50mm on a full frame sensor? Or does the crop factor apply even when the lens was designed with the smaller mount/sensor in mind? 

 

Sorry if that has been covered before but I couldn't find any concrete answers. 

 

Cheers,

 

-Nik


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#2 Kenny Suleimanagich

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Posted 01 November 2016 - 03:45 PM

"Crop factor" is a confusing term that references field of view.

A 50mm on a 35mm still camera has a wider field of view by 2.88x than the 50mm on the blackmagic pocket (super 16). The reason why there are wider focal lengths for small image areas is precisely because of his.
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#3 David Mullen ASC

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Posted 01 November 2016 - 04:09 PM

A 50mm lens is always a 50mm lens whether it was designed for a Super-8 camera or an IMAX camera, though a lens designed for a smaller format usually cannot fill the larger format and you'll see vignetting. What changes is the field of view... a 50mm lens has a more telephoto effect as the format gets smaller, or has a wider view on larger formats.

So a 50mm made for a MFT camera will have the same view as a 50mm lens made for a FF35 camera if you put both on a MFT camera, but if you put both on a FF35 camera, the MFT 50mm would probably vignette.

If you want the equivalent view of a 50mm on a FF35 camera, you'd need to use an MFT lens that was 2.88X shorter (if that's the correct crop factor.)
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#4 Kenny N Suleimanagich

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Posted 01 November 2016 - 04:19 PM

Here is a helpful tool for understanding field of view. 


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#5 Nik Aberle

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Posted 01 November 2016 - 04:21 PM

Awesome! Thanks for the quick replies David and Kenny. 


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#6 Tyler Purcell

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Posted 01 November 2016 - 09:07 PM

The pocket camera magnifies your glass 2.88x.
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#7 Nik Aberle

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Posted 01 November 2016 - 09:20 PM

The pocket camera magnifies your glass 2.88x.

 

Tyler,

 

I see you've used the BMPCC in a few other shoots. Curious what you think of the MetaBones Speedbooster. I currently have no lenses so I'm not beholden to any mount style. I have a few photo lenses at work I'd have access to but that's it. I'm leaning towards MFT to use the krasnogorsk lenses as well as some other vintage lenses that have adapters due to generally cheaper pricing when looking at cine lenses. is the SpeedBooster worth the extra cash for an extra stop of light and reduced crop factor? I plan on shooting mainly with practicals and small lighting rigs indoors so I should have pretty solid control of lighting. My biggest fear is not having a wide enough lens for indoor shoots with the magnification.


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#8 Tyler Purcell

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Posted 02 November 2016 - 12:11 AM

There really isn't anything bad about the metabones speed booster for the majority of cinematographers. The difference isn't that great though, it maybe brings the 2.88x down to 1.88x maybe? I've done back to back tests and put the results into an editing program to see if it was worth owning one and in the long run, I didn't feel it was useful.

My biggest problem is that I'm old school, I light the crap out of everything and I use the sun for most of my lighting, so the camera is already WAY to sensitive for me. I run IRND .6, 200 ISO, 45 deg shutter and I still have over-exposure issues when shooting outdoors. The metabones just exacerbates that issue even more, increasing the amount of light hitting the imager by a stop.

So for people who need more sensitivity, the metabones adaptor will work great AND give you less magnification, which for some maybe nice.

In the end, you can't make the pocket have a S35 field of view, nothing will do that. The pocket looks like S16, which for some people like myself is great, that's what I'm use to shooting. For others, that look isn't as "cinematic", so the camera may not be the right choice in that case.

I mean, I think it looks great: https://www.dropbox....12-120.mov?dl=0
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#9 Zach Boyce

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Posted 03 June 2017 - 09:08 PM



In the end, you can't make the pocket have a S35 field of view, nothing will do that. The pocket looks like S16, which for some people like myself is great, that's what I'm use to shooting. For others, that look isn't as "cinematic", so the camera may not be the right choice in that case.

 

You sound like you have plenty of experience shooting with the bmpcc camera. I'd be interested in knowing what your favorite lenses are for it, and if you use any of the vintage arriflex, c-mount, of kiev style lenses out there.


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#10 Will Montgomery

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Posted 05 June 2017 - 09:30 AM

I use a PL mount Zeiss 12-120 Super 16 lens (it was originally a Zeiss 10-100 "kit lens" for the SR2) modified to S16 by Charlie Pickel at Serious Gear with truly amazing results. The great thing about the BMPCC is all the Super 16 glass out there that works brilliantly with the camera. PL adapter from Wooden Camera.


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#11 Tyler Purcell

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Posted 06 June 2017 - 11:42 AM

You sound like you have plenty of experience shooting with the bmpcc camera. I'd be interested in knowing what your favorite lenses are for it, and if you use any of the vintage arriflex, c-mount, of kiev style lenses out there.


What Will said! LOL :P

I think the 12-120 is the best Super 16 lens you an get. It's great for 80% of your shooting. For the wider end of things, invest in a few cinema primes.

Honestly, I use the Rokinon EOS mount primes on my pocket most of the time. The kit is cheap, so if something happens, it's nearly throw-away. Plus with the EOS adaptor to M43rd's with me all the time, I can put other EOS glass on the camera anytime I want. I think the Super 16 glass is superior in every way, but do you need that superiority all the time? No... for those one-off occasions yes it's nice to have, but for the bulk work I don't think it's a necessity at all.

I wish there was an inexpensive cinema style manual EOS mount zoom lens.
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#12 Will Montgomery

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Posted 09 June 2017 - 11:41 AM

I think the 12-120 is the best Super 16 lens you an get. It's great for 80% of your shooting. For the wider end of things, invest in a few cinema primes.

Zeiss made a version of their "high-end" 10-100 16mm Zoom for Super 16 and it was an odd range like 11-112. I first used that lens with an SR3 and was completely blown away by it so I made it my mission to buy one. When I couldn't find one for sale I went with the conversion and I've loved it ever since.

 

I just wish there was a 4k sensor in a Super 16 size format so I can keep using that lens! (although I'm using it this weekend with an SR2 for a music video).


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#13 Tyler Purcell

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Posted 09 June 2017 - 08:06 PM

It's an 11-110, it's the "super 16" Gen 2 version of the lens. It's the same glass, it's just got a different last element for the super 16 frame size. 


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