f stop mystery at DVinfo.net

David Herman · May 8th, 2006, 02:57 PM

XL2 I cannot manually close my aperture below f8 - if I try the shutter closes down completely. If I use the exposure lock I can get f11 or f22, but can't dial the aperture down with the aperture lever. I found the same on a friend's H1. Any ideas?

Miguel Lombana · May 8th, 2006, 05:13 PM

Quote:

Originally Posted by David Herman

XL2 I cannot manually close my aperture below f8 - if I try the shutter closes down completely. If I use the exposure lock I can get f11 or f22, but can't dial the aperture down with the aperture lever. I found the same on a friend's H1. Any ideas?

since someone is going to ask, I'll do it first, are you shooting outside? Are you shooting with the ND filter on or off? Are you zoomed in or out? Let's start there.

David Herman · May 9th, 2006, 01:54 AM

Miguel, the answer is yes. ND on or off, shooting outside (have never found myself inside needing anything beyond f8 inside) I am shooting 25P and a shutter speed of 50. I usually shoot in TV mode, allowing for just aperture adjustment after I lock exposure. So I will be shooting TV shutter speed 50 and lock exposure. The camera gives me, let's say, an f8 aperture. Turn to a brighter part of the scene and try and close the aperture manually and the shutter closes completely - black. Exp lock off and then on again and the camera will have adjusted to f11 or 16 or 22. Can't dial it in manually. Tried the same in manual mode with the same result. Can't dial in exp below f8. (By the by I also have a beautiful wife.)

Tom Hardwick · May 9th, 2006, 02:28 AM

The first point to note is that when using 1/3" chips (even with SD) you should always avoid shooting at an aperture smaller than f/8 simply because diffraction losses become very noticeable - and especially so at short focal lengths (wide-angle).

My Sony VX2000 will shoot at f/16. f/22 and f/32 in the auto exposure mode but you'll sure as hell wish you'd switched in the ND that was screamed for when you see the results.

I don't have working experience of your XL2's 20x zoom, but I'm guessing Canon make the diaphragm blades close fully to stop these small apertures being used. Sony's FX1 and Z1 have an extra two-bladed internal shutter within the element lineup that does just this.

So stick to wide apertures, Dave. And take lots of beautiful wife footage; I do.

tom.

David Herman · May 9th, 2006, 02:35 AM

Tom. I'm not suffering the problem as much as mystified by it. Absolutely spot on that the ND filters allow me not to be driven to use very small apertures, but, the camera will access the smaller apertures on its own (ie when exposure lock is off and then switched on again the camera has chosen f11 16 etc) but won't allow ME to do that. Whose the boss here? (aside from the wife that is)

Tom Hardwick · May 9th, 2006, 02:50 AM

Your Canon, like my Sony, is programmed to give correct exposure whatever fool is using the camera. Both our cameras will shoot at smaller and smaller apertures as it gets brighter and brighter in the auto mode, giving presedence to exposure over sharpness. In the manual mode sensible stops are put on the smallest aperture available as they assume we'll use ND.

Lots of cameras will up the shutter speed in an effort to control exposure, but I invariably lock mine off at 1/50th, not liking the choppy effects that using high shutter speeds bring. The HC1/A1 only stops down to f/4 (1/3" CMOS chip). After that point internal ND takes over - though hitting 'display' will have you believe smaller apertures were used.

Can your lens actually shoot at f/22? Have you had a look at the results when this happens? If so, do you intend letting the camera do this again?

I thought not.

tom.

Rainer Hoffmann · May 9th, 2006, 07:22 AM

David, I'm not really familiar with the 20x zoom of the XL2 because I (almost) exclusively use the 16x manual lens. I can stop that lens down to f16, after that it closes the iris completely. I wonder why this should be different on the 20x lens when the camera is in manual mode. What's more, I never heard anyone on this board complain about this.

As you say, who is the boss here. I expect a camera in manual mode to do what I want, even if it doesn't make sense.

Greg Boston · May 9th, 2006, 08:48 AM

I don't have the PAL camera but I will try to duplicate what you are seeing. I do know that certain shutter and aperture values are not available in the semi auto modes. You have to be in full manual to get at the other values. Just looking at the XL2 manual (NTSC), in manual or auto, the listed values available for setting are F11 and then CLOSE. The camera may indeed have internal access to smaller apertures, just not you and I.

I just duplicated what you have seen on your camera with my XL2. F11 then CLOSE, but in Tv mode, with a bright subject, the camera had chosen F22. If I toggle down one time I get F11 and then it goes back to close while in EXP LOCK.

So, what you are seeing is normal operation and is nothing to be concerned about.

-gb-

David Herman · May 9th, 2006, 09:19 AM

Gentlemen - I truly appreciate the responses and am glad that I'm
no longer sitting with the feeling that I have the one off lemon XL2.
The XL2 is certainly as good and usually better than me as a tool,
but I have a low tolerance of idiot devices in my equipment.

May 8th, 2006, 02:57 PM	#1
David Herman Regular Crew Join Date: Sep 2003 Location: gloucestershire uk Posts: 93	f stop mystery XL2 I cannot manually close my aperture below f8 - if I try the shutter closes down completely. If I use the exposure lock I can get f11 or f22, but can't dial the aperture down with the aperture lever. I found the same on a friend's H1. Any ideas?

May 9th, 2006, 01:54 AM	#3
David Herman Regular Crew Join Date: Sep 2003 Location: gloucestershire uk Posts: 93	f stop mystery Miguel, the answer is yes. ND on or off, shooting outside (have never found myself inside needing anything beyond f8 inside) I am shooting 25P and a shutter speed of 50. I usually shoot in TV mode, allowing for just aperture adjustment after I lock exposure. So I will be shooting TV shutter speed 50 and lock exposure. The camera gives me, let's say, an f8 aperture. Turn to a brighter part of the scene and try and close the aperture manually and the shutter closes completely - black. Exp lock off and then on again and the camera will have adjusted to f11 or 16 or 22. Can't dial it in manually. Tried the same in manual mode with the same result. Can't dial in exp below f8. (By the by I also have a beautiful wife.)

May 9th, 2006, 07:22 AM	#7
Rainer Hoffmann Major Player Join Date: Aug 2004 Location: Syke, Germany Posts: 249	David, I'm not really familiar with the 20x zoom of the XL2 because I (almost) exclusively use the 16x manual lens. I can stop that lens down to f16, after that it closes the iris completely. I wonder why this should be different on the 20x lens when the camera is in manual mode. What's more, I never heard anyone on this board complain about this. As you say, who is the boss here. I expect a camera in manual mode to do what I want, even if it doesn't make sense. __________________ Keep rolling Rainer

May 9th, 2006, 02:28 AM	#4
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	The first point to note is that when using 1/3" chips (even with SD) you should always avoid shooting at an aperture smaller than f/8 simply because diffraction losses become very noticeable - and especially so at short focal lengths (wide-angle). My Sony VX2000 will shoot at f/16. f/22 and f/32 in the auto exposure mode but you'll sure as hell wish you'd switched in the ND that was screamed for when you see the results. I don't have working experience of your XL2's 20x zoom, but I'm guessing Canon make the diaphragm blades close fully to stop these small apertures being used. Sony's FX1 and Z1 have an extra two-bladed internal shutter within the element lineup that does just this. So stick to wide apertures, Dave. And take lots of beautiful wife footage; I do. tom.

May 9th, 2006, 02:35 AM	#5
David Herman Regular Crew Join Date: Sep 2003 Location: gloucestershire uk Posts: 93	Tom. I'm not suffering the problem as much as mystified by it. Absolutely spot on that the ND filters allow me not to be driven to use very small apertures, but, the camera will access the smaller apertures on its own (ie when exposure lock is off and then switched on again the camera has chosen f11 16 etc) but won't allow ME to do that. Whose the boss here? (aside from the wife that is)

May 9th, 2006, 02:50 AM	#6
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	Your Canon, like my Sony, is programmed to give correct exposure whatever fool is using the camera. Both our cameras will shoot at smaller and smaller apertures as it gets brighter and brighter in the auto mode, giving presedence to exposure over sharpness. In the manual mode sensible stops are put on the smallest aperture available as they assume we'll use ND. Lots of cameras will up the shutter speed in an effort to control exposure, but I invariably lock mine off at 1/50th, not liking the choppy effects that using high shutter speeds bring. The HC1/A1 only stops down to f/4 (1/3" CMOS chip). After that point internal ND takes over - though hitting 'display' will have you believe smaller apertures were used. Can your lens actually shoot at f/22? Have you had a look at the results when this happens? If so, do you intend letting the camera do this again? I thought not. tom.

May 9th, 2006, 08:48 AM	#8
Greg Boston Wrangler Join Date: Oct 2003 Location: DFW area, TX Posts: 6,117 Images: 1	I don't have the PAL camera but I will try to duplicate what you are seeing. I do know that certain shutter and aperture values are not available in the semi auto modes. You have to be in full manual to get at the other values. Just looking at the XL2 manual (NTSC), in manual or auto, the listed values available for setting are F11 and then CLOSE. The camera may indeed have internal access to smaller apertures, just not you and I. I just duplicated what you have seen on your camera with my XL2. F11 then CLOSE, but in Tv mode, with a bright subject, the camera had chosen F22. If I toggle down one time I get F11 and then it goes back to close while in EXP LOCK. So, what you are seeing is normal operation and is nothing to be concerned about. -gb-

May 9th, 2006, 09:19 AM	#9
David Herman Regular Crew Join Date: Sep 2003 Location: gloucestershire uk Posts: 93	Gentlemen - I truly appreciate the responses and am glad that I'm no longer sitting with the feeling that I have the one off lemon XL2. The XL2 is certainly as good and usually better than me as a tool, but I have a low tolerance of idiot devices in my equipment.