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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Zoom question

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sbcooler

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I know when they measure zooms, you see numbers like 10x or 3x or 14x...and I know you see the number of millimeters the lense is...30-200mm, etc...and I know the sensor size (1/3", 2/3", 35mm) has some bearing on the actual image as well.

When looking at cameras like the Red or a 2/3" sensor camera is there anyway to compare how much zoom...how close objects will look at their maximum zoom? Is there a formula to figure this out on my own if the industry doesn't make it easy to compare this?

I'm real curious to how much MORE zoom you can get with real high quality glass on a high end camera compared to the inexpensive cameras like the Sony Z1u or Ex-1. Those have 1/3" and 1/2" sensors, 12x an 14x zoom ratio, 30-360mm roughly lenses.

How would this compare to say a Scarlet or 2/3" sensor with a 42x from Canon and a 800mm lense? Would this appear twice as close at max zoom or 3 times closer?

How to figure that out?
 
sbcooler said:
I know when they measure zooms, you see numbers like 10x or 3x or 14x...and I know you see the number of millimeters the lense is...30-200mm, etc...and I know the sensor size (1/3", 2/3", 35mm) has some bearing on the actual image as well.


How to figure that out?
Click to expand...


The mistake you are making here is that you are assuming that the 10x refers to a 10 times magnification....which it in fact does not. the 10x refers to a ratio. So a 10-100mm lens is a 10x lens, meaning that the ratio between the widest to the longest part of the focal length is 10 times.

By the same description, you could also have a 5-50mm lens that is also 10X, but the 10-100 10x would get you closer.

jb
 
I understand the 10x or 3x means a zoom range,not a magnification.

My question still is how does the Sony Z1u 30-390mm, 1/3" sensor, compare to a 2/3" sensor that has a 200-800mm monster zoom on it.

Does my maximum zoom with both cameras make my Sony closer or further away. How do I figure out what I need before I drop 50K on a zoom lense? Isn't there math or something on it comparing different sensor sizes and different focal lengths to the apparent magnification?

I know on a still camera, you see things like crop factor...1.6...and I know this means a zoom on this compared to 35mm, you can multiply the magnification by 1.6 times using the the same focal lenght zoom lense.

Again how do I compare what my "magnification will be" on a 1/3" sensor to 2/3" sensor to Red's 35mm with say the same exact zoom lense (if it were possible) on each?
 
The panavision website has a field of view calculator which wil translate the relative image size equivalents between formats.
 
I checked out that website, but not sure I understand it. If I compare a 1.85, 35mm sensor to a 2/3" sensor it seems the 2/3" sensor will have 2.5 times more zoom for any given zoom lense? Is this accurate?

Kind of like a crop factor on still cameras it seems if I am understanding this right.

I also didn't see a 1/3" sensor which is my current frame of reference and makes everything meaningful to me.

I know I could spend a half a million dollars and do trial and error..and maybe spend a bunch of time experimenting, but that post if a real slow way of learning how much zoom to expect from different lenses and different sensors...plus my budget is not so big!
 
Very cool calculator sight, but not sure what it all means.

Let me restate my question in the simplest terms to see if I can get an answer that makes sense to me.

I am shooting a concert from 360 feet away. If I compare what I am using today...1 Sony Z1U that has a 30-300mm lense on it and uses a 1/3" sensor, I estimate that I at maximum zoom the performer appears to be about 30 Feet away from me...so the zoom magnifies the performer to appear much closer to me.

Now with that same exact 30-300mm lense, but one made to fit on a 2/3" sensor, how many feet away would the performer appear?

Same question with the Red One?

And one more, if I put a 300-900mm monster zoom on the cams, would I expect at maximum zoom with the same sensor that I would appear 3 times closer (again comparing 900mm lense at max zoom vs a 300mm lense at max zoom with the same size sensor)?

Thanks again all for trying to help me understand this-
 
Why don't you use the calculator? Do you want us to do the math for you?

You could simply and roughly say that 1/3" is half of 2/3", so 300mm on a 1/3" camera would give you the same view as 600mm on a 2/3" camera, or 300mm on a 2/3" camera would be like a 150mm on a 1/3" camera.

So the performer would be half as large with a 300mm lens on a 2/3" camera as on a 1/3" camera, or you'd have to use a 600mm lens on the 2/3" camera to match the size of the 300mm on the 1/3" camera. "How many feet away does the performer appear" makes no sense to me as a concept. The issue is degree of enlargement -- do you see the person head to toe, waist up, etc. But if you want, you can think of it as getting half as close.

The degree of magnification between a 2/3" camera and a 35mm / RED camera is 2.5X. But for now, you can simply think of it as 2X to keep the math simple -- you'd have to use a 1200mm lens on a RED camera in 4K mode to get the same view as a 300mm lens on a 1/3" camera (though like I said, I'm fudging the math by using a 2X figure and not the correct 2.5X figure -- the real figure would be 1500mm, not 1200mm, to get the same view on the RED camera as a 300mm lens on a 1/3" camera, i.e. 5X for the difference between 1/3" and 35mm / RED, and as I said 2.5X as the difference between 2/3" and 35mm / RED.)

There are charts to tell you the FOV of different lenses for different sensor sizes.

Whether you want to think of 900mm as "3X closer" as a 300mm is up to you. 600mm would be twice as close as 300mm, but would the "third time closer" be twice as close again from 600mm, i.e. 1200mm? But yes, 900mm is 3X 300mm.
 
Finally...David I understand exactly what you said here and I now understand the exact conversion I can expect from 1/3" sensor to 2/3" sensor. I wasn't sure of if it all worked linearly that way, but now I see it does.

Yeah for my concert footage I pretty much wanted to know if it was possible to get a head shot from 360 feet away, but that seems to be asking to much at full resolution with a 2/3" sensor.

One interesting this with Red is, if I shot something in 4K, in post, I could appear twice as close or twice the magnification and finish in 1080p without softening the image compared to other stuff shot at 1080p natively. IT's like having a 2x extended on, except better in that I can choose in post and digitally zoom slowly to add to the overall feel.

Now with Scarlet, my intended camera, I can appear twice as close as the RedOne but at 3K...but still have 80% digital zoom in to get to 1080p without losing quality.

Yeah I am trying to shoot rock concerts with a a few far away cams so they don't get in the way of the performers or crowd and use huge zooms mixed with far away footage. And maybe only have 2 close up cams in what they call "the pit" before the stage.
 
You have some degree of leeway for cropping a 4K image if all you need is to end up with a 4:2:2 1080P image for broadcast. Just beware of underexposing and having a lot of noise that may be more obvious when cropped & enlarged, plus your lenses will have to be top-notch if cropping the image a lot.

You could also shoot in 2K windowed mode on the RED, which is the same thing as cropping the 4K image in half in both directions.
 
Concert zooms

Concert zooms

Note on shooting concerts, they often use follow spots on the performers that will blow out skin values unless you stop down (or ND). Try and get them to keep the ratio of spotlight to other stage lighting as low as they will tolerate. High key ratios often result in a great deal of the rest of the frame being down in the toe (low exposure) where the noise lives. In some cases you can just crush the blacks for a more cameo style look on the lead singer/soloist but that isn't always appropriate thematically.

If you have any input on the stage lighting I suggest you request lower output or more filtration in any spotlights. You should also push for more fill light, over 4000 kelvin preferred.

Shooting concerts with the 4K sensor area will require some big frakkin' lenses. One workaround might be to imbed some camera positions in the prime seating areas closer to the stage. Of course, the promoter may not sign off on turning high revenue seats into camera locations :innocent: . Perhaps you'll get lucky and the house sound mixing position will be within 100 feet of the stage and they will have room for you to shoot from there :shifty:
 
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