About the Lens, F1.2 or F1.8? at DVinfo.net

Mark Fan · September 15th, 2004, 05:36 PM

Hi everybody, I always wondering what's the difference between F1.2 and F1.8? wich one is better? or which should be used with a 1/4 inch CCD ?

becasue I have a JVC GR-DV900, (differ from US version 800,which has a F1.8 lense)

and another question is about the size of the lense, is it the same as long as they have same times of Zoom?

sorry I'm a new user , have some silly questions.
Thanks in Advance!!

Jeff Donald · September 15th, 2004, 08:53 PM

The F Number is a measure of the light gathering capability of a lens. The lower the F Number, the more light that can enter the lens (assuming the lens is set to that F Number). F Numbers vary, they can be set manually by the camera operator, or automatically by the camera. In order for the camera to adjust the F Number, it must be in an automatic or semi automatic mode.

The F Number is one of the three variables that determine proper exposure (if the picture is too light or too dark, or just right). Shutter Speed and Gain are the the other variables.

Post back all the numbers you see on your lens and I'll decipher them for you.

Mark Fan · September 16th, 2004, 03:55 AM

Hi there: great to meet u , and by the way, I'm in Dunedin too!New Zealand right ?

I'm doing BA in Otago, well, back to the lens, the No is f=3.8-38mm( and d= 52mm) that's all the number I have on my lens.
and great website.

Thanks for your help !actually I have more questions, I started discover my passion for video and photographing about a year ago, in my school holidays , my principle gave me a chance to make a video, and then I did, and can't drop it off anymore.

Thanks again!

Jeff Donald · September 16th, 2004, 05:28 AM

You lens is a 10X zoom. Zoom, meaning you can change the focal length from a wide angle (wider angle of view, get more in the scene) to a telephoto (less in the scene but the subject gets bigger). Lenses are measured in millimeters. Your lens measures from 3.8mm (it's widest setting) to 38mm (longest telephoto, most magnification). The ratio from 3.8mm to 38mm, is 10 to 1 or it is often referred to as a 10X zoom. The 52 is the diameter of the front of the lens in mm. This is often referred to as the filter size. When you buy filters for your lens, they'll need to 52mm filters.

Nice to meet you too, Mark. I'm in Dunedin, Florida.

Mark Fan · September 16th, 2004, 06:27 AM

Hi Jeff:

Thanks for your reply, so how do u feel about my lens ? is it a good one ? My camcorder has a 1/4 inch CCD, at the time it came out, JVC put an Ads says 1/4 CCD and F1.2 lens is the best match! but new their new product line come out, and most of the lens has been changed to F1.8, regardless of the size of CCD . are they trying to lower the cost, or just simply lied ?

and why so many people think that Canon has the best lens ?
what advantages they got ?

Cheers!

Jeff Donald · September 16th, 2004, 07:37 AM

The best way to judge the quality of a lens is to shoot with it and decide if the images meet your expectations. Use the camera just as you would for shooting your regular work, so the resultant images reflect your actual production work.

The f1.2 lens lets in more light than an f1.8 lens. If everything else is equal (chip, gain, shutter speed etc.) the f1.2 lens will work better in low light levels. In bright conditions the images should be the same.

Mark Fan · September 16th, 2004, 08:09 AM

I did some shooting in the last few weeks, it did appear that in low light condition, this camcorder works perfect! the picture are not dark at all(very bright actually), looks like there was enough lights in the dark room, however,I don't like the feeling that it's not recording what i see, and also I feel it is useing its lens to compromise its disadvatages( not sure what it is so far)

and in day light condition, when i was shooting a white flower under the sun, ( I think at that time , the sun is just above me)
and later when i check the image on TV, the flower appear as a total white shining stuff, ( oh, by the way, why is it that image from my camcorder always look better on TV than on computers ?) so I tried to manual contral the explore, it worked in some extent.

regard to the filter, the guy from the stor told me I'd better buy a filter to protect the lens, is it true? coz, somehow i heard that filter does diminish the quality of pictures. i'm really confused. if i di need to buy one, what kind of filter should i buy?

wops , too many questions, Thank u .........very ........much!!

September 15th, 2004, 05:36 PM	#1
Mark Fan Regular Crew Join Date: Aug 2004 Posts: 33	About the Lens, F1.2 or F1.8? Hi everybody, I always wondering what's the difference between F1.2 and F1.8? wich one is better? or which should be used with a 1/4 inch CCD ? becasue I have a JVC GR-DV900, (differ from US version 800,which has a F1.8 lense) and another question is about the size of the lense, is it the same as long as they have same times of Zoom? sorry I'm a new user , have some silly questions. Thanks in Advance!!

September 15th, 2004, 08:53 PM	#2
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	The F Number is a measure of the light gathering capability of a lens. The lower the F Number, the more light that can enter the lens (assuming the lens is set to that F Number). F Numbers vary, they can be set manually by the camera operator, or automatically by the camera. In order for the camera to adjust the F Number, it must be in an automatic or semi automatic mode. The F Number is one of the three variables that determine proper exposure (if the picture is too light or too dark, or just right). Shutter Speed and Gain are the the other variables. Post back all the numbers you see on your lens and I'll decipher them for you. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

September 16th, 2004, 05:28 AM	#4
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	You lens is a 10X zoom. Zoom, meaning you can change the focal length from a wide angle (wider angle of view, get more in the scene) to a telephoto (less in the scene but the subject gets bigger). Lenses are measured in millimeters. Your lens measures from 3.8mm (it's widest setting) to 38mm (longest telephoto, most magnification). The ratio from 3.8mm to 38mm, is 10 to 1 or it is often referred to as a 10X zoom. The 52 is the diameter of the front of the lens in mm. This is often referred to as the filter size. When you buy filters for your lens, they'll need to 52mm filters. Nice to meet you too, Mark. I'm in Dunedin, Florida. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

September 16th, 2004, 07:37 AM	#6
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	The best way to judge the quality of a lens is to shoot with it and decide if the images meet your expectations. Use the camera just as you would for shooting your regular work, so the resultant images reflect your actual production work. The f1.2 lens lets in more light than an f1.8 lens. If everything else is equal (chip, gain, shutter speed etc.) the f1.2 lens will work better in low light levels. In bright conditions the images should be the same. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

September 16th, 2004, 03:55 AM	#3
Mark Fan Regular Crew Join Date: Aug 2004 Posts: 33	Hi there: great to meet u , and by the way, I'm in Dunedin too!New Zealand right ? I'm doing BA in Otago, well, back to the lens, the No is f=3.8-38mm( and d= 52mm) that's all the number I have on my lens. and great website. Thanks for your help !actually I have more questions, I started discover my passion for video and photographing about a year ago, in my school holidays , my principle gave me a chance to make a video, and then I did, and can't drop it off anymore. Thanks again!

September 16th, 2004, 06:27 AM	#5
Mark Fan Regular Crew Join Date: Aug 2004 Posts: 33	Hi Jeff: Thanks for your reply, so how do u feel about my lens ? is it a good one ? My camcorder has a 1/4 inch CCD, at the time it came out, JVC put an Ads says 1/4 CCD and F1.2 lens is the best match! but new their new product line come out, and most of the lens has been changed to F1.8, regardless of the size of CCD . are they trying to lower the cost, or just simply lied ? and why so many people think that Canon has the best lens ? what advantages they got ? Cheers!

September 16th, 2004, 08:09 AM	#7
Mark Fan Regular Crew Join Date: Aug 2004 Posts: 33	I did some shooting in the last few weeks, it did appear that in low light condition, this camcorder works perfect! the picture are not dark at all(very bright actually), looks like there was enough lights in the dark room, however,I don't like the feeling that it's not recording what i see, and also I feel it is useing its lens to compromise its disadvatages( not sure what it is so far) and in day light condition, when i was shooting a white flower under the sun, ( I think at that time , the sun is just above me) and later when i check the image on TV, the flower appear as a total white shining stuff, ( oh, by the way, why is it that image from my camcorder always look better on TV than on computers ?) so I tried to manual contral the explore, it worked in some extent. regard to the filter, the guy from the stor told me I'd better buy a filter to protect the lens, is it true? coz, somehow i heard that filter does diminish the quality of pictures. i'm really confused. if i di need to buy one, what kind of filter should i buy? wops , too many questions, Thank u .........very ........much!!