Zoom question

[sbcooler]

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?

[chuck colburn]

http://www.panavision.com/lenses.php

Also look under the technical information heading in the tools section.

[John Brawley]

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?

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

[sbcooler]

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?

[Stephen Williams]

How do I figure out what I need before I drop 50K on a zoom lense?

Hi,

Test, test, test!

Stephen

[Mitch Gross]

The panavision website has a field of view calculator which wil translate the relative image size equivalents between formats.

[sbcooler]

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!

[John Brawley]

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?

Yes.

try this for 1/3
http://www.deepsea.com/lensfield.html


Or if you have a palm...

http://www.davideubank.com/pCAM_Manual_1.95.htm

jb

[sbcooler]

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-

[David Mullen ASC]

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.