? About Setting up camera physics to match sensor size

[Netcommercial]

@spaced

At this stage, forget about the horizontal and vertical sensor choice, you just need to worry about the Sensor being set to Horizontal and using the correct Sensor Width.

The Render Resolution sets the aspect ratio of your shot:

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Above shows three different aspect ratios: 4:3 (standard definition TV), 3:2 (common photo camera), and 16:9 (HD, widescreen DVD). The sensor and lens is identical, just the top and bottom of the image gets cropped.

When you change the Render Resolution, Blender will automatically change the height of the camera preview. Below, the top two images show the difference in camera preview between 4:3 and 16:9 when the render resolution is changed from “1920 x 1440” to “1920 x 1080”:

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The bottom two images show what happens when you just change the Sensor Width. In all these images, the render resolution, lens focal length and camera position remain the same. A larger sensor width (eg. IMAX 70mm) results in a wider view, and a smaller sensor width (eg. Blackmagic Pocket Cinema Camera) results in a narrower view.

As we worked out a few posts above, your camera should have a Sensor Width around “3.737” and its lens focal lengths are 4.1mm - 61.5mm.

You can set your Blender camera to that Sensor Width and use those lens focal lengths, or you can use a larger sensor with compensated lens focal lengths.

I mentioned previously about the Depth of Field differences. The following three shots have three different sensor sizes (your camera, 35mm Full Frame camera, IMAX 70mm) with adjusted lens focal lengths to give the same Field of View (the camera’s position remains the same):

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Even though the shot is framed identically, you should be able to see the difference in Depth of Field (what’s in focus). This might be a reason you’d use a larger sensor size for rendering your 3D environment.

So, why is this important to know? If you know the relationship between the sensor size, lens focal length and aspect ratio, you’ll know how to match shots to filmed footage. More importantly for your situation, your camera may not tell you what lens focal length it is set to. You know at the widest setting it will be 4.1mm, and at the other end it will be 61.5mm, but in between you may be forced to guess.

Spaced,
Thanks for the time again you spent on this post, I really appreciate it. I have read it a couple of times. And will come back to it the more I learn about this. I am sure others who google this will appreciate this too!

So from what I am gathering and correct me if I am wrong. Sensor position has nothing to do with render out, that is format Output.
IGE: 16:9 pr 4:3 that is what predicates crop or not. So a NO would be the answer to my quoted question there.

What I am gathering from your Suzanne pics is that sensor choice is really about choosing a look in Blender not so much matching a camera One is shooting with. I would presume when shooting, one is going to use the shot footage as the ‘world’. Where One would track and add a figure like Suzanne and as we change the sensor and her position her DOF will change accordingly.
OR to create a 3d world like Suzanne is in and import an in focus re-sized keyed actor and then when adjusting my Sensor size and position of my actor in said 3d world; would determine in focus or not, pending…

I am a bit hazy and think this why MAYBE one would match a sensor to a camera is if we were shooting an actor on green stage and said actor walks closer to the cam, or pulls back more appropriately to get the same affect in our virtual world IF DOF was a factor at time of shooting.
IGE: Actor walks away from cam and goes out of focus or Vise Verse. If sensors match with the cam and blender and my cam does not show Focal length in MM’s Blender can figure for me. Did I get it?

Thanks again for the help on this. Good grief. It would be awesome to have a hover menu and have some of this info there as you think…“Does this pertain?”
IgE: Horiz or Vert of Sensor size. Hover menu: Selecting Horiz or Vertical is for changing the look of your 3d world. NOT necessarily how it is place in your camera. If you are wanting to match Identical as in tracking for adding a 3d object into shot footage then it would be best to match the sensor and it’s direction it is placed in the Camera. Good luck finding out that info. LOL!

Please let me know if I misunderstood. Thanks again Gents
NC

[Netcommercial]

One other thing I was not cranking up was my DOF value to get that look. It appears though, cranking up the DOF value has a blur affect even a bit on my target object which I would think Blender would keep sharp in focus. No?

[spaced]

@Netcommercial

It seems as though you are stating that SW does not matter to get a DOF in blender as does Spaced illustrations show he only changes the FL from 7mm to 137mm creating the desired DOF…

No, the Sensor Width and Lens Focal Length both have to change to keep the same Field of View (ie, the same shot framing). I’ve included the settings in the images, you’ll see both the sensor and lens values change, but they result in the same field of view.

Blender can calculate the lens focal length for you - change the lens drop-down to ‘Field of View’ and copy the value, then change the sensor width and paste back into the lens’ ‘Field of View’ the copied value. Change the drop-down back to ‘Millimeters’ to see the adjusted lens focal length.

@Netcommercial

Which makes me wonder how do you take an actor have him walk towards you maybe 5 feet, track the 3d world place him in it and then have the FOV or DOF adjust

If you want the Focus to follow someone walking 5 feet towards the camera, set the virtual camera’s focus point to an empty that matches the actor’s position. It’s a lot more complicated to change the field of view or reframe the shot without noticeable perspective distortion - you’re better capturing this in camera.

@Netcommercial

It appears though, cranking up the DOF value has a blur affect even a bit on my target object which I would think Blender would keep sharp in focus. No?

The target will be in focus as will an area around the target, futher out things get blurry. The size of the in-focus area depends on the aperture setting. Check out Wikipedia’s entry: http://en.wikipedia.org/wiki/Depth_of_field

@Netcommercial

What I am gathering from your Suzanne pics is that sensor choice is really about choosing a look in Blender not so much matching a camera One is shooting with.

Sensor Width and Lens Focal Length are critical to matching perspective between your filmed and rendered footage.

If the perspectives don’t match and you add a live-action actor to a 3D set, they won’t look like they’re ‘in’ the set.

[spaced]

Just pondering this thread, at this stage I think you can ignore pretty much everything I’ve said. You certainly don’t need it to have fun, nor get a result.

Try the sensor width we worked out and you should be able to learn by playing with the settings.

It certainly wouldn’t hurt to learn how a camera works (lenses, aperture, depth of field, etc) - Wikipedia has useful information.

[Netcommercial]

Thanks for the further input Spaced, I appreciate your in depth answers/feedback. It takes time to do what you did and I am grateful.
Thanks again. I guess my confusion is not how something works just that it does. I’m OK with that. All I wanted to do was match the Sensor as to the camera I am shooting with. When all kinds of things bombarded me with this and that. It would be nice if say Canon published their sensor width and direction. Then I can match, go shoot and adjust from there. Like I care how a watch works I just want to know what time it is. LOL! I have an understanding of Fstop, Focal length but at the end of the day I pop it on Manual (may cam that is) and find what looks good and shoot it.
Thanks again, I am sure I will revisit this thread over time.
Thanks Gpa as well.
Regards
NC