Telephoto Lens at DVinfo.net

Tony Marino · August 15th, 2009, 04:03 PM

I'm not sure where to post this, so I put it here. Hope it's okay. My GL-2 is going to cost arount $800 to repair because it needs a new circuit board so I'm either getting a new one or a smaller HD camcorder. Problem is the smaller cameras have weak zooms. Does anyone know if I can buy a 2x optical telephoto lens that has great quality? I used one for my GL-2 before and it distorted the image. Thanks

Don Palomaki · August 18th, 2009, 04:50 PM

In general, the added price for a "great" 2x teleconverter would probably be enough to make a step up in your camcorder buy.

Define the zoom range you need and then start shopping from there.

FWIW: 2x digital zoom on an honest HD signal nets down to nominal SD resolution. Many of the current moderate priced HD camcorders output a very nice image. Just sort out your priorities for features that you use on the GL2, and asses the impact on your decision process if they are not on the replacement camcorder you are considering.

Jason Robinson · August 18th, 2009, 06:21 PM

Quote:

Originally Posted by Don Palomaki

In general, the added price for a "great" 2x teleconverter would probably be enough to make a step up in your camcorder buy.

Define the zoom range you need and then start shopping from there.

FWIW: 2x digital zoom on an honest HD signal nets down to nominal SD resolution. Many of the current moderate priced HD camcorders output a very nice image. Just sort out your priorities for features that you use on the GL2, and asses the impact on your decision process if they are not on the replacement camcorder you are considering.

So a zoom on for example, the A1 destroys resolution and puts it down to SD quality?

Don Palomaki · August 20th, 2009, 03:40 PM

Digital zoom does. It forms the image from only a portion of the CCD/CMOS, discarding the unused pixels.

2x digital zoom on a 720x480 sensor will use 360x240 from the center to gfform the image, and that limits the resolution.

However, optical zoom does not have the same limitation. Its limitations are based on the sensor and the lens quality.

Jason Robinson · August 20th, 2009, 03:57 PM

Quote:

Originally Posted by Don Palomaki

Digital zoom does. It forms the image from only a portion of the CCD/CMOS, discarding the unused pixels.

2x digital zoom on a 720x480 sensor will use 360x240 from the center to gfform the image, and that limits the resolution.

However, optical zoom does not have the same limitation. Its limitations are based on the sensor and the lens quality.

Ok that obviously makes sense. I just thought someone was saying a tele converter on a HD cam reduces its resolution somehow (as if the image was squeezed onto less of the CCD/CMOS and hence using less scan lines)

Don Palomaki · August 22nd, 2009, 07:11 AM

Using a teleconverter may reduce the image resolution if the added glass results in a less sharp image on the sensor. With a quality teleconverter this will not be noticeable to most viewers. With a poor (usually meaning cheap as well) teleconverter there can be a very noticeable loss in image quality. Also, you may see some light loss.

August 15th, 2009, 04:03 PM	#1
Tony Marino Regular Crew Join Date: Feb 2003 Location: St. Louis, MO Posts: 55	Telephoto Lens I'm not sure where to post this, so I put it here. Hope it's okay. My GL-2 is going to cost arount $800 to repair because it needs a new circuit board so I'm either getting a new one or a smaller HD camcorder. Problem is the smaller cameras have weak zooms. Does anyone know if I can buy a 2x optical telephoto lens that has great quality? I used one for my GL-2 before and it distorted the image. Thanks

August 18th, 2009, 04:50 PM	#2
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	In general, the added price for a "great" 2x teleconverter would probably be enough to make a step up in your camcorder buy. Define the zoom range you need and then start shopping from there. FWIW: 2x digital zoom on an honest HD signal nets down to nominal SD resolution. Many of the current moderate priced HD camcorders output a very nice image. Just sort out your priorities for features that you use on the GL2, and asses the impact on your decision process if they are not on the replacement camcorder you are considering. __________________ dpalomaki@dspalomaki.com

August 20th, 2009, 03:40 PM	#4
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	Digital zoom does. It forms the image from only a portion of the CCD/CMOS, discarding the unused pixels. 2x digital zoom on a 720x480 sensor will use 360x240 from the center to gfform the image, and that limits the resolution. However, optical zoom does not have the same limitation. Its limitations are based on the sensor and the lens quality. __________________ dpalomaki@dspalomaki.com

August 22nd, 2009, 07:11 AM	#6
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	Using a teleconverter may reduce the image resolution if the added glass results in a less sharp image on the sensor. With a quality teleconverter this will not be noticeable to most viewers. With a poor (usually meaning cheap as well) teleconverter there can be a very noticeable loss in image quality. Also, you may see some light loss. __________________ dpalomaki@dspalomaki.com