About lens again at DVinfo.net

Mark Fan · September 18th, 2004, 10:12 PM

I saw Sony DSR-PD170 has a lens says F1.6to2.4 , but Panasonic AG-DVC30 has a lens of F1.6, does it mean Sony has a better lens ? and about Filter diameter, true that the bigger the better it is ?

Jeff Donald · September 19th, 2004, 06:12 AM

The quality of a lens is not measured by the maximum lens opening (f/1.6 vs. f/2.0 for example) nor is it measured by filter size. Lenses can be compared objectively by their MTF (modular transfer function) and subjectively by your eye (do you like the image your camera produces).

Rainer Hoffmann · September 19th, 2004, 08:41 AM

Jeff,

I fully agree to what you said. However, the maximum lens opening may be important in low light situations and, of course, if you want a shallow depth of field.

Richard Alvarez · September 19th, 2004, 09:01 AM

T-Stops are more relative than F-stops when it comes to lens speed.

Rainer Hoffmann · September 19th, 2004, 09:13 AM

<<<-- Originally posted by Richard Alvarez : T-Stops are more relative than F-stops when it comes to lens speed. -->>>

This is true of course. But for zoom lenses with roughly the same number of elements and similar multicoating the difference in T-stops should not be too large.

Or is there a flaw in my thinking?

Richard Alvarez · September 19th, 2004, 10:27 AM

If there is a flaw, it lies in the words "similar" and "roughly". No guarantee that the t-stops for "Roughly simlilar" lenses would be the same. The question "Does Sony have a better lens" is of course subjective in terms of visual aesthetics, but by measurable quantitites, Jeff's reference to MTF is correct.

September 18th, 2004, 10:12 PM	#1
Mark Fan Regular Crew Join Date: Aug 2004 Posts: 33	About lens again I saw Sony DSR-PD170 has a lens says F1.6to2.4 , but Panasonic AG-DVC30 has a lens of F1.6, does it mean Sony has a better lens ? and about Filter diameter, true that the bigger the better it is ?

September 19th, 2004, 06:12 AM	#2
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	The quality of a lens is not measured by the maximum lens opening (f/1.6 vs. f/2.0 for example) nor is it measured by filter size. Lenses can be compared objectively by their MTF (modular transfer function) and subjectively by your eye (do you like the image your camera produces). __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

September 19th, 2004, 08:41 AM	#3
Rainer Hoffmann Major Player Join Date: Aug 2004 Location: Syke, Germany Posts: 249	Jeff, I fully agree to what you said. However, the maximum lens opening may be important in low light situations and, of course, if you want a shallow depth of field. __________________ Keep rolling Rainer

September 19th, 2004, 09:13 AM	#5
Rainer Hoffmann Major Player Join Date: Aug 2004 Location: Syke, Germany Posts: 249	<<<-- Originally posted by Richard Alvarez : T-Stops are more relative than F-stops when it comes to lens speed. -->>> This is true of course. But for zoom lenses with roughly the same number of elements and similar multicoating the difference in T-stops should not be too large. Or is there a flaw in my thinking? __________________ Keep rolling Rainer

September 19th, 2004, 09:01 AM	#4
Richard Alvarez Inner Circle Join Date: Sep 2002 Location: San Mateo, CA Posts: 3,840	T-Stops are more relative than F-stops when it comes to lens speed.

September 19th, 2004, 10:27 AM	#6
Richard Alvarez Inner Circle Join Date: Sep 2002 Location: San Mateo, CA Posts: 3,840	If there is a flaw, it lies in the words "similar" and "roughly". No guarantee that the t-stops for "Roughly simlilar" lenses would be the same. The question "Does Sony have a better lens" is of course subjective in terms of visual aesthetics, but by measurable quantitites, Jeff's reference to MTF is correct.