BMCC shooters tips

The place for questions about shooting with Blackmagic Cameras.
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Bernie Ryan

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BMCC shooters tips

PostSun Dec 23, 2012 1:16 pm

Hi since I just got my camera and they are shipping, can we have one thread from people using the cameras with tips and recomendations.
This is good for people who have them and those unfortunately still waiting, to get a heads up on ssd issues, lens, software, settings etc..

The first lens I tried was an 85mm, wow don't underestimate the crop factor. You really have to change your thinking from 35mm film, I use a 7D for recce's and thought it would be a bit more but it's heaps.
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malbrand

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Re: BMCC shooters tips

PostSun Dec 23, 2012 1:54 pm

hi, Bernie
this seems like a useful thread
thanks for starting it
according to aberlcine fov calculator crop factor for fullframe is 2.3, and for aps-c is 1.5

I would like to start asking for tips then

scene: outdoors, sunny day, street
I want to have as much large depth of field as possible, so I can see one car coming from behind the actress (which is in a MS), any recommendations? thanks in advance
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Marcel Beck

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Re: BMCC shooters tips

PostSun Dec 23, 2012 4:00 pm

This deserves to be a sticky!

I would suggest more once I get the camera in my hands haha
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Thomas Schumacher

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Re: BMCC shooters tips

PostSun Dec 23, 2012 5:57 pm

malbrand wrote:according to aberlcine fov calculator crop factor for fullframe is 2.3, and for aps-c is 1.5


Please correct me if I'm wrong, but there is no APS-C lens which has a "1.6-crop-factor-focal length" written on it - it's always the focal length according to full frame, so to see what focal length a 17-50 mm APS-C lens will have on the BMC you still have to multiply that with the factor 2.3 - same of course with full frame lenses.
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Thomas Schumacher

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Re: BMCC shooters tips

PostSun Dec 23, 2012 6:03 pm

malbrand wrote:scene: outdoors, sunny day, street
I want to have as much large depth of field as possible, so I can see one car coming from behind the actress (which is in a MS), any recommendations? thanks in advance


Thank god you don't have a full rame sensor here, as the smaller the sensor the more depth of field there will be available. But it's dependent on the focal length as well as the aperture, too. So the wider your lens is, the more depth of field you get - if you close the iris further, depth of field increases. So on a sunny day you might be using a ND-filter nevertheless as lenses tend to get worse once the aperture comes to the lense's end of its spectrum, like f1:16 on old, f1:22 on newer lenses e.g.. Best bet is you learn to know the range of "best results" apertures on your lens and then help yourself with a ND filter.

Hope that helps.
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Jason R. Johnston

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Re: BMCC shooters tips

PostSun Dec 23, 2012 6:16 pm

There's also usability. I generally stay in T4/5.3 on super35 because it gets harder to pull focus on anything more shallow and backgrounds don't generally need to be a blurry haze for the brain to understand a background's separation from the subject. I've also shot around T8 on a 5D and F2.8 on a 1.6x FOVCF 550D to get about the same results. I imagine I'll be happy with T2.9-5.6 most of the time with normal fields of view (wide lenses = normal lenses on the BMCC) as I generally use normal to telephoto lenses for portraits and short lenses for wide. With BMCC, I'll need to consider ~11mm lenses at maybe max 3.6 to get an equivalent ~25mm since I usually won't go wider than that.
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adamroberts

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Re: BMCC shooters tips

PostSun Dec 23, 2012 9:16 pm

gmf wrote:
malbrand wrote:according to aberlcine fov calculator crop factor for fullframe is 2.3, and for aps-c is 1.5


Please correct me if I'm wrong, but there is no APS-C lens which has a "1.6-crop-factor-focal length" written on it - it's always the focal length according to full frame, so to see what focal length a 17-50 mm APS-C lens will have on the BMC you still have to multiply that with the factor 2.3 - same of course with full frame lenses.


Focal length is an optical measurement. It has nothing to do with the sensor size.
http://en.m.wikipedia.org/wiki/Focal_length

A 50mm is a 50mm no matter what camera you put it on- a BMCC, Super35/ASP-C, Full Frame, Medium format, Large Format etc. still a 50mm.

What changes with the sensor/film size is the crop into the image circle.

So if you are used to shooting on Super35 film cameras with PL lenses you don't say "oh this is a 50mm on a Canon 5D so it must now be a 75mm on my Arri Alexa". It's still a 50mm.

So the crop factors are there to give you a guide as to what your lens crop will look like based on your point of reference. For many coming from the 5D that point of reference is Full Frame 35mm (2.3x) and for those coming from arri Alexa or a 550D it would be Super35/ASP-C (1.5x).

So your 17-50mm from a 550D will have the 550D image cropped by 1.5. Where as the 16-35mm from the 5D will have its image cropped by 2.3.

Both lenses at 17mm would look the same on the BMCC.
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David

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Re: BMCC shooters tips

PostSun Dec 23, 2012 9:40 pm

Adam Roberts said:

So if you are used to shooting on Super35 film cameras with PL lenses you don't say "oh this is a 50mm on a Canon 5D so it must now be a 75mm on my Arri Alexa".



Actually, thats EXACTLY what I would say. At least thats how my feeble little head works. Maybe I'll get used to it after a while but thats the reference I'll use for the time being.
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Thomas Schumacher

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Re: BMCC shooters tips

PostSun Dec 23, 2012 10:26 pm

adamroberts wrote:
A 50mm is a 50mm no matter what camera you put it on- a BMCC, Super35/ASP-C, Full Frame, Medium format, Large Format etc. still a 50mm.

...

So your 17-50mm from a 550D will have the 550D image cropped by 1.5. Where as the 16-35mm from the 5D will have its image cropped by 2.3.

Both lenses at 17mm would look the same on the BMCC.


Maybe I don't know how to tech-talk, but I guess I didn't say anthing opposite to what you stated. I just wanted to point out, that there is no APS-C-focal length written on APS-C-lenses, so that people don't think their 10mm-APS-C-lens gets them a crop into the image-circleon the BMC with equals 1.5x10mm but 2.3x10mm.

Not that the OP seemed to misinterpret that, but there was some confusion on this on the forum lately.
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Michael Beck

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Re: BMCC shooters tips

PostSun Dec 23, 2012 10:29 pm

adamroberts wrote:A 50mm is a 50mm no matter what camera you put it on- a BMCC, Super35/ASP-C, Full Frame, Medium format, Large Format etc. still a 50mm.


This is an important distinction by the way. I use to think that this was just silly because I didn't understand that a 50mm looks different than a 35mm in other ways than how close an object looks, and how much you can see. This animation helps me understand this.

http://en.wikipedia.org/wiki/File:DollyZoomTest.ogv

You have to think in terms of how different focal lengths effect the whole composition (foreground and background) not just how close or far away things seem.
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Peter J. DeCrescenzo

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Re: BMCC shooters tips

PostSun Dec 23, 2012 10:29 pm

David wrote:Adam Roberts said:
So if you are used to shooting on Super35 film cameras with PL lenses you don't say "oh this is a 50mm on a Canon 5D so it must now be a 75mm on my Arri Alexa".

---

Actually, thats EXACTLY what I would say. At least thats how my feeble little head works. Maybe I'll get used to it after a while but thats the reference I'll use for the time being.


Just a reminder that a lens' perspective distortion isn't changed by sensor crop. The crop affects FOV/AOV, not perspective distortion.

FredP posted a really good example in an earlier thread:
viewtopic.php?p=21581&sid=c87aa75769ad7b8118400e6f858080ae#p21581
http://stepheneastwood.com/tutorials/le ... ippage.htm
http://www.peterdv.com
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Michael Beck

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Re: BMCC shooters tips

PostSun Dec 23, 2012 10:32 pm

Peter J. DeCrescenzo wrote:
Just a reminder that a lens' perspective distortion isn't changed by sensor crop. The crop affects FOV/AOV, not perspective distortion.

FredP posted a really good example in an earlier thread:
viewtopic.php?p=21581&sid=c87aa75769ad7b8118400e6f858080ae#p21581
http://stepheneastwood.com/tutorials/le ... ippage.htm

Nice, that is another issue as well. its not just how it changes the foreground vs background it changes your subject as well!
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Peter J. DeCrescenzo

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Re: BMCC shooters tips

PostSun Dec 23, 2012 10:41 pm

Yep. The solution is, if you like how a particular lens focal length renders your subject -- let's say a 100mm lens used for portrait -- then if possible use a 100mm focal length lens and increase the distance between the subject and camera, instead of using a ~45mm lens with a 2.3x crop.

Of course, one doesn't always have enough space available.
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adamroberts

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Re: BMCC shooters tips

PostSun Dec 23, 2012 10:59 pm

gmf wrote:
Maybe I don't know how to tech-talk, but I guess I didn't say anthing opposite to what you stated. I just wanted to point out, that there is no APS-C-focal length written on APS-C-lenses, so that people don't think their 10mm-APS-C-lens gets them a crop into the image-circleon the BMC with equals 1.5x10mm but 2.3x10mm.

Not that the OP seemed to misinterpret that, but there was some confusion on this on the forum lately.


No worries about the tech talk. thats why most people are on forums like these, so they can get a better understanding. :-)

You are partly correct. The lens labelling is based on math. Has nothing to do with the sensor size.

So if a user has only ever used a 550D and never used a full frame DSLR they won't know what 17mm looks like on FF. Their only point of reference is ASP-C and therefore a 17mm on the BMCC would have a crop factor of 1.5 from their point of reference.
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Thomas Schumacher

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Re: BMCC shooters tips

PostMon Dec 24, 2012 7:52 am

Adam,

haha, you're right! I never think about all those young dudes, who never had an analogue camera to take photos with back in the days. On the other hand, did we care taking pictures on analog film about all that stuff? At least I didn't, I knew there was some medium format thing as well, that's all. And people not coming from taking photos but doing film all the time, might shake their heads anyway.

But very valuable points made about FOV/AOV and perspective distortion. Actually those crop-factors should be a divisor not a multiplier, as you get less out of your lenses. But more speaking of corner sharpness. ;)

Oh, happy christmas to everyone. May the BMC finally arrive at all of our places.
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Nick Bedford

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Re: BMCC shooters tips

PostMon Dec 24, 2012 11:48 am

May the black magic be with you. - Grant Skywalker
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