XL2 Image is too Soft! at DVinfo.net

Ben Hurst · August 11th, 2005, 11:38 AM

I have always had a problem with my indoor images looking like I've got some kind of diffusion filter on it. Yesterday I was shooting something out side and had the ND filter on and everything was sharper than it has ever been but when I flipped the ND off the image was diffused again. What is going on?

Chris Hurd · August 11th, 2005, 11:58 AM

Hi Ben,

What you're experiencing here is an optical phenomenon known as diffraction, which can affect any higher-end camcorder. Basically this is a softening of the image which occurs at very small apertures (in other words, at large f/ numbers such as f/16). It doesn't usually happen in less expensive consumer camcorders because their aperture ranges tend to top out at f/8 or f/11 or so. You can read my article about diffraction here:

http://www.dvinfo.net/canon/articles/article19.php

I wrote that for the old XL1 but the principle still applies to the XL1S and XL2. Basically you want to avoid shooting at the extreme ends of the aperture range... neither stopped down too far nor opened all the way up... the best, most naturally sharp image will come from the "sweet spot" in the middle of the aperture range, around f/5.6 plus or minus a stop or two or three. Hope this helps,

Ben Hurst · August 11th, 2005, 02:42 PM

Thanks a lot. Usually I don't have a lot of light to work with indoors so I'm always opening the iris as wide as it will go. I'll do some tests, Thanks again.

Ben

Dan Vance · August 11th, 2005, 04:43 PM

I'm probably going to get thrown to the sharks for this, but I have to question the "diffraction" explanation for the softness at high f-stops. I had understood that the reason for degraded images at high f-stops was due to the fact that the light was passing through the thickest portion of all elements, where the tiniest lens imperfections stack up and reduce sharpness.
I'd also point out that pinhole cameras, which have no glass, can produce super crisp images, at effective f-stops way beyond f32. I've also shot stills at f45 and even f64 (with really good lenses) with no softening of images.
So, I agree that the softness is related to the f-stop, but I don't think diffraction effects enter the picture (so to speak, ha ha) even at the extreme ranges found on camcorders.

Ash Greyson · August 11th, 2005, 05:13 PM

Be, sounds like you need to adjust some of your settings, the softness you refer to indoors is most likely the flatness of the image of the XL2 with factory settings. This provides great detail across all ranges. First thing to try, is to set your knee to high and your black to press... then try turning down the master pedestal a couple notches....

Softness can be a factor, as noted above, with the aperature nearly closed but it is MUCH worse on cameras like the XL1s and the DVX100a. It is always best to control light with FILTERS and use the aperture of the camera as "fine tuning"

ash =o)

Ben Hurst · August 11th, 2005, 08:26 PM

Thanks all. I have been working on film for many years now and have been very impressed with the XL2 as a smaller budget option. I'm trying to get used to all of the digital settings. I have my custom presets set exactly where all of the colors and shadows I see with my eye are how they look on screen. I think the softness is definately an aperature problem. I am wondering though, also, if the same diffraction rule applies when the iris is wide open because that is where I am really experiencing softness. I tested the opposite and found that to be the problem. Just not sure the other way around...

August 11th, 2005, 11:38 AM	#1
Ben Hurst New Boot Join Date: Aug 2005 Location: Austin, TX Posts: 22	XL2 Image is too Soft! I have always had a problem with my indoor images looking like I've got some kind of diffusion filter on it. Yesterday I was shooting something out side and had the ND filter on and everything was sharper than it has ever been but when I flipped the ND off the image was diffused again. What is going on?

August 11th, 2005, 11:58 AM	#2
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	Hi Ben, What you're experiencing here is an optical phenomenon known as diffraction, which can affect any higher-end camcorder. Basically this is a softening of the image which occurs at very small apertures (in other words, at large f/ numbers such as f/16). It doesn't usually happen in less expensive consumer camcorders because their aperture ranges tend to top out at f/8 or f/11 or so. You can read my article about diffraction here: http://www.dvinfo.net/canon/articles/article19.php I wrote that for the old XL1 but the principle still applies to the XL1S and XL2. Basically you want to avoid shooting at the extreme ends of the aperture range... neither stopped down too far nor opened all the way up... the best, most naturally sharp image will come from the "sweet spot" in the middle of the aperture range, around f/5.6 plus or minus a stop or two or three. Hope this helps, __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

August 11th, 2005, 02:42 PM	#3
Ben Hurst New Boot Join Date: Aug 2005 Location: Austin, TX Posts: 22	Thanks a lot. Usually I don't have a lot of light to work with indoors so I'm always opening the iris as wide as it will go. I'll do some tests, Thanks again. Ben

August 11th, 2005, 04:43 PM	#4
Dan Vance Built the VanceCam Join Date: Apr 2004 Location: Prescott Valley, AZ Posts: 109	I'm probably going to get thrown to the sharks for this, but I have to question the "diffraction" explanation for the softness at high f-stops. I had understood that the reason for degraded images at high f-stops was due to the fact that the light was passing through the thickest portion of all elements, where the tiniest lens imperfections stack up and reduce sharpness. I'd also point out that pinhole cameras, which have no glass, can produce super crisp images, at effective f-stops way beyond f32. I've also shot stills at f45 and even f64 (with really good lenses) with no softening of images. So, I agree that the softness is related to the f-stop, but I don't think diffraction effects enter the picture (so to speak, ha ha) even at the extreme ranges found on camcorders.

August 11th, 2005, 05:13 PM	#5
Ash Greyson Trustee Join Date: May 2003 Location: Tulsa, OK Posts: 1,689	Be, sounds like you need to adjust some of your settings, the softness you refer to indoors is most likely the flatness of the image of the XL2 with factory settings. This provides great detail across all ranges. First thing to try, is to set your knee to high and your black to press... then try turning down the master pedestal a couple notches.... Softness can be a factor, as noted above, with the aperature nearly closed but it is MUCH worse on cameras like the XL1s and the DVX100a. It is always best to control light with FILTERS and use the aperture of the camera as "fine tuning" ash =o)

August 11th, 2005, 08:26 PM	#6
Ben Hurst New Boot Join Date: Aug 2005 Location: Austin, TX Posts: 22	Thanks all. I have been working on film for many years now and have been very impressed with the XL2 as a smaller budget option. I'm trying to get used to all of the digital settings. I have my custom presets set exactly where all of the colors and shadows I see with my eye are how they look on screen. I think the softness is definately an aperature problem. I am wondering though, also, if the same diffraction rule applies when the iris is wide open because that is where I am really experiencing softness. I tested the opposite and found that to be the problem. Just not sure the other way around...