minimum aperture 9.5? at DVinfo.net

Doug Bennett · September 7th, 2006, 03:50 PM

according to the canon specs minimum aperture is f16 - but the actual minimum is 9.5

why would canon do this?

anyone tried using shutter speeds higher than 1/60 - with normal action in front of the lens (weddings) how fast a shutter speed can you use before it is noticeable?

A. J. deLange · September 8th, 2006, 01:17 PM

The sensors on the XL-H1 chip are spaced so close together that the width of the Airy pattern (the spread pattern for a true point source) is comparable to the spacing at apertures in the f/5.6 - f/8 region. Canon thus limits the aperture of the lens on the XL-H1 so that it can't be operated in the "diffraction limited" region. If the lens is fitted to a SD camera with the same size chip the sensors are farther apart and the lens can be stopped down further without the lens's diffraction being the limiting effect (sensor spacing on the chip is the limiting effect in such a case).

Steve Rosen · September 9th, 2006, 07:32 AM

Also, the lenses available for 1/3" cameras don't do well when stopped down too far.. I use the 20x and the 16x and NEVER shoot closed down more than f4.

I just finished a medium high-end corporate (I don't usually like to do them, but they pay the bills - nearly a years worth in this case) and shot the entire show at 1.6 - 2, even though I had a full crew and HMIs.. I used the 16x lens - because I wanted shallow depth-of-field and needed the follow-focus - and it looks terrific - very happy client.

If you are shooting in bright situations, use NDs or a polarizer. focusing is more critical, but the result is superior...

Roy Beazley · December 13th, 2007, 02:01 PM

Is there a jpeg of what this looks like?

Peter Jefferson · December 14th, 2007, 02:28 AM

Quote:

Originally Posted by Steve Rosen

Also, the lenses available for 1/3" cameras don't do well when stopped down too far.. I use the 20x and the 16x and NEVER shoot closed down more than f4.

Sorry to disappoint you mate, but the DVX/HVX goes down to F16 and is not only crystal clear, but has a wider "sweet spot" between f5 and f13.
As for not doing so well, I would have to disagree with you there.

Roy Beazley · December 14th, 2007, 06:36 PM

I really thought the sweet spot on all lenses was F8.....including slr's which I shoot the other 50% of my time....

This censor stuff is a trip...kinda above my head....

September 7th, 2006, 03:50 PM	#1
Doug Bennett Major Player Join Date: Oct 2004 Location: NYC Posts: 260	minimum aperture 9.5? according to the canon specs minimum aperture is f16 - but the actual minimum is 9.5 why would canon do this? anyone tried using shutter speeds higher than 1/60 - with normal action in front of the lens (weddings) how fast a shutter speed can you use before it is noticeable?

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September 8th, 2006, 01:17 PM	#2
A. J. deLange Major Player Join Date: Jun 2004 Location: McLean, VA United States Posts: 749	The sensors on the XL-H1 chip are spaced so close together that the width of the Airy pattern (the spread pattern for a true point source) is comparable to the spacing at apertures in the f/5.6 - f/8 region. Canon thus limits the aperture of the lens on the XL-H1 so that it can't be operated in the "diffraction limited" region. If the lens is fitted to a SD camera with the same size chip the sensors are farther apart and the lens can be stopped down further without the lens's diffraction being the limiting effect (sensor spacing on the chip is the limiting effect in such a case).

September 9th, 2006, 07:32 AM	#3
Steve Rosen Major Player Join Date: Dec 2005 Location: Monterey, California Posts: 895	Also, the lenses available for 1/3" cameras don't do well when stopped down too far.. I use the 20x and the 16x and NEVER shoot closed down more than f4. I just finished a medium high-end corporate (I don't usually like to do them, but they pay the bills - nearly a years worth in this case) and shot the entire show at 1.6 - 2, even though I had a full crew and HMIs.. I used the 16x lens - because I wanted shallow depth-of-field and needed the follow-focus - and it looks terrific - very happy client. If you are shooting in bright situations, use NDs or a polarizer. focusing is more critical, but the result is superior...

December 13th, 2007, 02:01 PM	#4
Roy Beazley Regular Crew Join Date: May 2004 Location: tampa fl Posts: 92	Is there a jpeg of what this looks like?

December 14th, 2007, 06:36 PM	#6
Roy Beazley Regular Crew Join Date: May 2004 Location: tampa fl Posts: 92	I really thought the sweet spot on all lenses was F8.....including slr's which I shoot the other 50% of my time.... This censor stuff is a trip...kinda above my head....