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Lens/aperture


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#1 Rob Ine

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Posted 23 July 2015 - 10:47 AM

Hi,

 

What aperture & focal length do you think these where shot at?

Looking to do something similar with DSLR

Capture.png

 

 

Capture2.png

 


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#2 David Mullen ASC

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Posted 23 July 2015 - 10:55 AM

Looks like maybe a 50mm on an APS-C camera / 75mm on a FF35 camera, fairly wide-open -- there is a 1.5-stop difference in depth of field, just as there is a 1.5X difference in field of view, between APS-C and FF35, in other words, you'd use a 50mm at f/2.0 on an APS-C camera to get the same view and depth of field as a 75mm at f/2.8-4 split on a FF35 camera.

 

I could be wrong, maybe they had enough room to back up and use a 75mm to 150mm range on an APS-C camera.  Certainly everything is on the long side at a wide aperture.


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#3 Rob Ine

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Posted 06 August 2015 - 05:11 AM

Thanks David,

 

Am I right in saying APS-C is more equivalent to 35mm film in terms of focal length rather than full frame cameras?


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#4 Rob Ine

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Posted 06 August 2015 - 05:20 AM

Also what effect would using a EF lens on a APS-C sensor have on focal lenght

 

Appreciate any help


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#5 Mark Dunn

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Posted 06 August 2015 - 05:24 AM

Thanks David,

 

Am I right in saying APS-C is more equivalent to 35mm film in terms of focal length rather than full frame cameras?

More or less. 35mm. Academy is about 22x16mm., APS-C on digital about 24x16. APS-C classic was 25.1x16.7 on film. APS-C AR is a bit wider but not so different as to affect lens choice very much.


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#6 Rob Ine

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Posted 06 August 2015 - 05:33 AM

I thought so, It seems confusing as people always talk about it being cropped and the 1.6 factor where as they seem to be similar to 35mm in field of view compared to full frame. 


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#7 Brian Drysdale

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Posted 06 August 2015 - 06:11 AM

That's because a lot of people are coming in with a stills photograhy background and always comparing to what they're used to.


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#8 Rob Ine

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Posted 06 August 2015 - 07:32 AM

It seems weird that it is sometimes referred to as Full fram 35mm sensor.

 

Would using a 50mm EF lens on APS-C sensor be equivalent of 75mm EF-S on APS-C? 


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#9 Robin R Probyn

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Posted 06 August 2015 - 08:29 AM

Although both 35mm in width .. in a stills camera the film goes through horizontally ..8 perfs.. in movie cameras the film goes through vertically .. 3 perks for s35mm ..APS-C is about the same size as the movie vertical  frame.. .. 

 

Any PL mount lens will correspond to  S35/APS-C..  

 

PS If your going to film Riggsy .. don't take your wife with you..   :)


Edited by Robin R Probyn, 06 August 2015 - 08:36 AM.

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#10 Mark Dunn

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Posted 06 August 2015 - 10:20 AM

You may be confusing FF stills, 36x24mm., and 35mm. cine which is about the same as what stills photographers would have called half-frame.


Edited by Mark Dunn, 06 August 2015 - 10:22 AM.

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#11 John E Clark

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Posted 06 August 2015 - 11:02 AM



It seems weird that it is sometimes referred to as Full fram 35mm sensor.

 

Would using a 50mm EF lens on APS-C sensor be equivalent of 75mm EF-S on APS-C? 

 

If you are truly worried about answering the question, "What length lens do I need to get a full length shot of a 6 foot man, with my camera at 15 feet", then using a calculator, such as pCam will clarify the situation, and give you a clean clear answer.

 

When one hears discussions about whether to use a 35mm or a 36mm lens for a shot... crop factor will not help you 'see' the difference...

 

Especially when 'crop factors' are most often related to 35mm still film which had an aspect ratio of 1.5, and would not match up any standard Motion Picture Film standard, ranging from 4:3 'Academy' to wide screen 2.39.

 

*No, I don't get any kick back for promoting pCam... I think it is a very useful tool that answers many questions that are related to camera work, without having to resort to the ASC Cinematographer's Manual or similar.

 

As it is I shot 35mm stills for years, but when I moved over to digital, I did not ask about crop factors, just determined what was 'normal', which for the camera I had at the time, was about 35mm... that was sufficient for me to then determine what was 'telephoto' and what was 'wide angle'...


Edited by John E Clark, 06 August 2015 - 11:04 AM.

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#12 David Mullen ASC

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Posted 06 August 2015 - 11:03 AM

Most people compare the diagonal length to determine crop factor, but I usually use just the horizontal because the aspect ratio will affect the diagonal dimension.  FF35, Full-Frame-35, 8-perf 35mm horizontal, aka VistaVision, is generally considered to be 36mm wide.  Super-35 cine and APS-C are more like 24mm wide, so that's a 1.5X difference.

 

The focal length doesn't changes when you put a lens on different formats, only the amount of cropping of the image projected by the lens.  So a 50mm is a 50mm whether on a FF35 camera or an APS-C camera.

 

But on an APS-C camera, the view of the lens is cropped by 1.5X, making it tighter.  You'd have to use a lens whose focal length is 1.5X shorter on an APS-C camera to match the same view as the lens you pick for the FF35 camera.  

 

So yes, you'd put a 75mm lens on a FF35 camera to match the view of a 50mm lens on an APS-C camera, or you'd put a 33.33mm lens on an APS-C camera to match the view of a 50mm lens on a FF35 camera.

 

This is one reason why the cheap kit zoom lens that comes with APS-C cameras is often an 18-50mm and the one that comes on a FF35 camera is more like a 24-70mm.


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#13 David Mullen ASC

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Posted 06 August 2015 - 11:08 AM

Thanks David,

 

Am I right in saying APS-C is more equivalent to 35mm film in terms of focal length rather than full frame cameras?

 

This is where terminology matters -- "equivalent to 35mm film" is confusing because traditionally 35mm still photography has been horizontal 8-perf and 35mm movie photography has been vertical 4-perf.  Both are 35mm film.  Hence why adding words like "cine" or specifying a movie format like "Super-35" makes it more clear that you aren't referring to still photography formats.


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