Digital Camcorder Question - DPChallenge Forums

Tamron AF 28-300mm f/3.5-6.3 XR Di LD Aspherical IF for Canon

06/29/2009 04:55:51 PM · #1

How do you figure the Optical zoom on a camcorder in mm.
My wife and I have been looking for a camcorder and we have found a non-HD camera by JVC at bestbuy.

Here is the model
Here is a tour of the camcorder (click the play button that overlays the picture) from wolfcamera.com site but it is $25 more and only has a 30GB HD where the one at BB has a 60GB HD.

It has a 1/6" CCD image sensor and 40x Optical zoom. Does anyone know how to calculate that in mm.

Thanks in advance.
Scott

ETA: From FAQ Sheet
� CCD: 1/6� � No. of CCD Pixels: 680k � Effective Pixels for Capture (Moving images - 340k-pixel) (Still images - 340k-pixel) � KONICA MINOLTA LENS
� Zoom Ratio Optical (35x) � Zoom Ratio Digital (max.) (800x) � Focal Length (mm) 2.2 - 77.0 � F Stop - F1.8 - F4.0 � Filter Diameter (mm) - 30.5
� Video Image Stabilization � Full Range AF/Manual Focus � Full-Auto/

Message edited by author 2009-06-29 17:06:52.

Mal37

Canon EOS-5D Mark II

Canon EF-S 18-55mm f/3.5-5.6

06/29/2009 05:01:25 PM · #2

On B&H

KONICA MINOLTA Lens
Focal length=2.2-77mm
F/Stop=1.8-4.0

06/29/2009 05:12:22 PM · #3

35mm equiv.

32mm - 1100mm

Tamron AF 28-300mm f/3.5-6.3 XR Di LD Aspherical IF for Canon

06/29/2009 05:13:24 PM · #4

Originally posted by Mal37:

On B&H

KONICA MINOLTA Lens
Focal length=2.2-77mm
F/Stop=1.8-4.0

I found that after posting and edited the original post. But still don't know how to figure out the optical zoom based on the focal length. I guess whats throwing me off is the fact that I know 1x can't equal 2.2mm that would be an impossible wide angle. So if 1x doesn't = 2.2 that would stand to reason that 40x would not = 77mm. So if I can figure out what 1x equals then I should be able to times that by 40 to get the appropriate mm.

Tamron AF 28-300mm f/3.5-6.3 XR Di LD Aspherical IF for Canon

06/29/2009 05:20:59 PM · #5

Originally posted by JH:

35mm equiv.

32mm - 1100mm

JH how did you get that range? 3mm less than 35mm equiv. I know I seem to be asking dumb questons here. But we only have x amount of $ to spend and I want to get the best I can for the money.

Main features that we want in order.

1. Longest zoom possible.
2. HD and optional memory card
3. Great night capture or low light capture.
4. 16.9 ratio
5. The above without loosing super DVD quality. Would like to have HD quality cam but out of budget and does no have a long zoom.

Message edited by author 2009-06-29 17:21:37.

Mal37

Canon EOS-5D Mark II

Canon EF-S 18-55mm f/3.5-5.6

06/29/2009 05:22:30 PM · #6

2.2mm*35=77mm

It's a 35x optical zoom / 40x dynamic zoom (whatever that means)

Edit: sorry misread, I was working on the math, JH beat me to it :)

Message edited by author 2009-06-29 17:32:04.

06/29/2009 05:27:14 PM · #7

Originally posted by SDW:

Originally posted by JH:
35mm equiv.

32mm - 1100mm

JH how did you get that range? 3mm less than 35mm equiv. I know I seem to be asking dumb questons here. But we only have x amount of $ to spend and I want to get the best I can for the money.

Here's the calculation. The two things you need to know are the diagonal size of the sensor, and the focal range of the lens.

First get the multiplier based on the size of the sensor;

43.3mm (diagonal on 35mm sensor) divided by 3mm (diagonal on 1/6" sensor) = 14.43 multiplier

Then use the lens focal length to arrive at the 35mm equivalent values;

Focal range of lens = 2.2mm to 77mm = (2.2 X 14.43) to (77 X 14.43)

Giving a 35mm equiv focal range of 32-1100mm

Tamron AF 28-300mm f/3.5-6.3 XR Di LD Aspherical IF for Canon

06/29/2009 05:31:47 PM · #8

Originally posted by JH:

Originally posted by SDW:

Originally posted by JH:
35mm equiv.

32mm - 1100mm

JH how did you get that range? 3mm less than 35mm equiv. I know I seem to be asking dumb questons here. But we only have x amount of $ to spend and I want to get the best I can for the money.

Here's the calculation. The two things you need to know are the diagonal size of the sensor, and the focal range of the lens.

First get the multiplier based on the size of the sensor;

43.3mm (diagonal on 35mm sensor) divided by 3mm (diagonal on 1/6" sensor) = 14.43 multiplier

Then use the lens focal length to arrive at the 35mm equivalent values;

Focal range of lens = 2.2mm to 77mm = (2.2 X 14.43) to (77 X 14.43)

Giving a 35mm equiv focal range of 32-1100mm

Thanks for your in depth information. So your saying that it would be like a dSLR with a 1100mm lens attached. But with less quality of course.

06/29/2009 05:32:58 PM · #9

Originally posted by SDW:

Thanks for your in depth information. So your saying that it would be like a dSLR with a 1100mm lens attached. But with less quality of course.

Yes, exactly. The sensor is so small compared to dSLR sensors that they can offer that kind of zoom range.

Tamron AF 28-300mm f/3.5-6.3 XR Di LD Aspherical IF for Canon

06/29/2009 05:42:56 PM · #10

Originally posted by JH:

Originally posted by SDW:
Thanks for your in depth information. So your saying that it would be like a dSLR with a 1100mm lens attached. But with less quality of course.

Yes, exactly. The sensor is so small compared to dSLR sensors that they can offer that kind of zoom range.

Let me see if I understand. Smaller sensors can allow for longer zooms but with a tradeoff of having a higher noise ratio.
A larger sensor does not offer as large zoom range but the trade off is better lower noise; better quality.

06/29/2009 05:57:14 PM · #11

Originally posted by SDW:

Originally posted by JH:

Originally posted by SDW:
Thanks for your in depth information. So your saying that it would be like a dSLR with a 1100mm lens attached. But with less quality of course.

Yes, exactly. The sensor is so small compared to dSLR sensors that they can offer that kind of zoom range.

Let me see if I understand. Smaller sensors can allow for longer zooms but with a tradeoff of having a higher noise ratio.
A larger sensor does not offer as large zoom range but the trade off is better lower noise; better quality.

In camcorders the still image quality is not as important as in dSLRs. For example, the CCD in the camcorder you're looking at is a tiny 3mm diagonal chip with 340,000 effective pixels - that's an image area of 580x580 pixels (don't know the exact pixel dimensions, lets say 580x580 for arguments sake). For moving images, that's acceptable quality.

Now imagine using your 40D to take a shot, using all 10,000,000 pixels at the 135mm end of your 28-135 lens, and then cropping a section in the middle of the shot 580x580 pixels square and calling that your photo. Hey, impressive zoom you've got there! :)

Tamron AF 28-300mm f/3.5-6.3 XR Di LD Aspherical IF for Canon

06/29/2009 06:03:08 PM · #12

Thanks for your information