20x zoom lens -- various topics

Douglas Joseph · November 19th, 2005, 04:23 PM

What exaclty is a "floter"? I've never heard this term.

Marty Hudzik · November 22nd, 2005, 02:36 PM

Happens all the time with the 20x lens in low light with bright lights where lens flares are more easily seen. OIS is the culprit. I never experienced this with the 16x manuals lens.

Sprague Theobald · December 7th, 2005, 08:09 PM

Hi. My "Search" function is on the fritz so I apologize if this subject's been covered over and over. I've got the 20X lens with my XL2 and was wondering if anyone has done and testing with the lens to determine the best apertures? Thanks in advance.
Sprague

Ash Greyson · December 8th, 2005, 01:24 AM

Wide open... I like to use it long and wide open is the best way to keep it, that will give you the best DOF and keep the image from getting soft... try to squash light with filters if possible, I try to never go over f4 or f5

ash =o)

Sprague Theobald · December 8th, 2005, 08:16 AM

Many thanks.
S

Miguel Lombana · December 8th, 2005, 02:56 PM

Quote:

Originally Posted by Ash Greyson

Wide open... I like to use it long and wide open is the best way to keep it, that will give you the best DOF and keep the image from getting soft... try to squash light with filters if possible, I try to never go over f4 or f5
ash =o)

Betcha shoot fully manual too huh!

Rob Neidig · December 12th, 2005, 03:31 PM

Hi there everybody!

I just recently got my XL2. I have some previous experience with using other people's XL2s, as well as lots of experience with Betacams, etc.

My question is about focus. When I zoom in and focus on the eye of a person, for example, then zoom back out, the picture looks kinda soft to me. I have seen items in the foreground that actually look sharper than the subject. It's almost like the back focus is off, but the 20x auto lens doesn't have a back focus. Has anybody else experienced this, and is there anything to do about it? Otherwise I might be tempted to look at the 16x manual lens instead.

THANKS!

Rob

Jon Bickford · December 12th, 2005, 05:12 PM

i had something similar at one point and i took the lens to canon to get adjusted, they said it was just fine.

I think what might be happening is that you zoom all the way in and focus, but at the long end ofthe zoom the lens is an f3.5, you focus at that f-stop which has a fairly large amount of depth of field then pull out and the lens opens all the way to f1.6 which has a much shallower DOP so the focus actually has to be more precise on the shorter end which seems backwards, try setting and keeping the aperture at 3.5 all the way through the zoom out and see if you still have the problem, if so you definetely have a back focus problem,

that said, you wouldn't be disappointed with the 16x manual, which keeps a steady f-stop through it's whole range.

-Jon

Jeff McElroy · January 4th, 2006, 08:41 PM

Hypothetical question:
This is kind of silly, but has been bugging me for a while.

If you are in the eye of a, say, 940> mb hurricane with a tight pressure gradient, would the rapidly changing conditions be bad for your lens in the way of bubbles, etc? If there are any weather videographers here, I would love to draw upon your experience in this and a plethora of other regards.

Jeff

A. J. deLange · January 5th, 2006, 06:52 AM

There is a caveat in the XL-H1 manual to the effect that a gas bubble may form in the liquid between the plates in the 20x lens at aircraft cabin pressure altitudes (about 7000 feet). While this is appreciably less than 940 mb I suppose the potential for this to happen is there for any of Canon's OIS lenses that use this basic architecture.

Pete Bauer · January 5th, 2006, 08:05 AM

Haven't traveled with the H1 yet, but I carried my XL2 with 20x and 3x lenses on multiple airplane trips and haven't actually seen any bubbles, even though I know at least once I had cabin pressure altitudes well above 10,000 feet. The barometric pressure in a hurricane would be the least of my concerns -- water and wind-driven objects would be higher on my list of worries!

Jeff McElroy · January 5th, 2006, 09:19 AM

Okay thanks… I was going to segue into the airplane caveat, as you termed it, so I am glad that you covered that.

I do wonder if anyone has ever documented a major hurricane, on the ground, in high def? I think Jim Edds uses a dvx100, and it is only a matter of time before one of these idiots takes the plunge in this regard.

My camera was destroyed along with my house during charley, but the tape survived... which is all that matters!

Shawn McBee · January 5th, 2006, 08:16 PM

Hi all,

I've been trying to figure out (with no luck) if there is any way at all to find out what the focal length is set to in a numerical format on the standard 20x lens that ships with the XL2.

I know there are no markings on the lens itself due to the mag-rings and in the viewfinder it's just a mark between W and T...but if I wanted, for example, to set the zoom to the equivalent of an 85mm prime, is there any way at all for me to set that number exactly?

Thanks for your help,

Shawn McBee

Gerald Godbout · January 7th, 2006, 04:46 PM

I have 2 lens the factory 20X lens and the 3x lens, today I had a shoot and when I connect the 20X lens I had no picture. I then connected the 3x lens and I had picture and everything worked fine. I reconnected the 20X lens, made sure I heard the little pops that the lens does. It did, but still no picture, has anyone else had this problem???

Matthew Nayman · January 7th, 2006, 05:13 PM

Did you take the lens off without turning the power off? You may have blown a lens fuse and it is preventing the iris from opening.

Matt

December 7th, 2005, 08:09 PM	#168
Sprague Theobald Regular Crew Join Date: Aug 2005 Location: Newport, RI Posts: 42	Sweet Spot For 20X Lens Hi. My "Search" function is on the fritz so I apologize if this subject's been covered over and over. I've got the 20X lens with my XL2 and was wondering if anyone has done and testing with the lens to determine the best apertures? Thanks in advance. Sprague

December 12th, 2005, 03:31 PM	#172
Rob Neidig Major Player Join Date: Dec 2005 Location: Eugene, Oregon Posts: 222	Focus Issue with 20x Lens Hi there everybody! I just recently got my XL2. I have some previous experience with using other people's XL2s, as well as lots of experience with Betacams, etc. My question is about focus. When I zoom in and focus on the eye of a person, for example, then zoom back out, the picture looks kinda soft to me. I have seen items in the foreground that actually look sharper than the subject. It's almost like the back focus is off, but the 20x auto lens doesn't have a back focus. Has anybody else experienced this, and is there anything to do about it? Otherwise I might be tempted to look at the 16x manual lens instead. THANKS! Rob

December 12th, 2005, 05:12 PM	#173
Jon Bickford Major Player Join Date: Nov 2004 Location: Las Vegas, NV., Los Angeles, CA, Posts: 220	i had something similar at one point and i took the lens to canon to get adjusted, they said it was just fine. I think what might be happening is that you zoom all the way in and focus, but at the long end ofthe zoom the lens is an f3.5, you focus at that f-stop which has a fairly large amount of depth of field then pull out and the lens opens all the way to f1.6 which has a much shallower DOP so the focus actually has to be more precise on the shorter end which seems backwards, try setting and keeping the aperture at 3.5 all the way through the zoom out and see if you still have the problem, if so you definetely have a back focus problem, that said, you wouldn't be disappointed with the 16x manual, which keeps a steady f-stop through it's whole range. -Jon __________________ Jon Bickford, Trepany Films San Pedro, CA Trephine001@aol.com

January 4th, 2006, 08:41 PM	#174
Jeff McElroy Regular Crew Join Date: Nov 2005 Posts: 91	pressure gradient and the 20x lens Hypothetical question: This is kind of silly, but has been bugging me for a while. If you are in the eye of a, say, 940> mb hurricane with a tight pressure gradient, would the rapidly changing conditions be bad for your lens in the way of bubbles, etc? If there are any weather videographers here, I would love to draw upon your experience in this and a plethora of other regards. Jeff

January 5th, 2006, 08:05 AM	#176
Pete Bauer Wrangler Join Date: May 2003 Location: Eagle River, AK Posts: 4,100	Haven't traveled with the H1 yet, but I carried my XL2 with 20x and 3x lenses on multiple airplane trips and haven't actually seen any bubbles, even though I know at least once I had cabin pressure altitudes well above 10,000 feet. The barometric pressure in a hurricane would be the least of my concerns -- water and wind-driven objects would be higher on my list of worries! __________________ Pete Bauer The most beautiful thing we can experience is the mysterious. It is the source of all true art and science. Albert Einstein Trying to solve a DV mystery? You may find the answer behind the SEARCH function ... or be able to join a discussion already in progress!

November 19th, 2005, 04:23 PM	#166
Douglas Joseph Major Player Join Date: Oct 2005 Location: Zanesville OH Posts: 205	What exaclty is a "floter"? I've never heard this term.

November 22nd, 2005, 02:36 PM	#167
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	Happens all the time with the 20x lens in low light with bright lights where lens flares are more easily seen. OIS is the culprit. I never experienced this with the 16x manuals lens.

December 8th, 2005, 01:24 AM	#169
Ash Greyson Trustee Join Date: May 2003 Location: Tulsa, OK Posts: 1,689	Wide open... I like to use it long and wide open is the best way to keep it, that will give you the best DOF and keep the image from getting soft... try to squash light with filters if possible, I try to never go over f4 or f5 ash =o)

December 8th, 2005, 08:16 AM	#170
Sprague Theobald Regular Crew Join Date: Aug 2005 Location: Newport, RI Posts: 42	Many thanks. S

January 5th, 2006, 06:52 AM	#175
A. J. deLange Major Player Join Date: Jun 2004 Location: McLean, VA United States Posts: 749	There is a caveat in the XL-H1 manual to the effect that a gas bubble may form in the liquid between the plates in the 20x lens at aircraft cabin pressure altitudes (about 7000 feet). While this is appreciably less than 940 mb I suppose the potential for this to happen is there for any of Canon's OIS lenses that use this basic architecture.

January 5th, 2006, 09:19 AM	#177
Jeff McElroy Regular Crew Join Date: Nov 2005 Posts: 91	Okay thanks… I was going to segue into the airplane caveat, as you termed it, so I am glad that you covered that. I do wonder if anyone has ever documented a major hurricane, on the ground, in high def? I think Jim Edds uses a dvx100, and it is only a matter of time before one of these idiots takes the plunge in this regard. My camera was destroyed along with my house during charley, but the tape survived... which is all that matters!

January 5th, 2006, 08:16 PM	#178
Shawn McBee Regular Crew Join Date: May 2002 Location: Sarasota, FL Posts: 69	Focal length on standard 20x? Hi all, I've been trying to figure out (with no luck) if there is any way at all to find out what the focal length is set to in a numerical format on the standard 20x lens that ships with the XL2. I know there are no markings on the lens itself due to the mag-rings and in the viewfinder it's just a mark between W and T...but if I wanted, for example, to set the zoom to the equivalent of an 85mm prime, is there any way at all for me to set that number exactly? Thanks for your help, Shawn McBee __________________ "Keep away from people who try to belittle your ambitions. Small people always do that, but the really great make you feel that you, too, can become great." -Mark Twain

January 7th, 2006, 04:46 PM	#179
Gerald Godbout Regular Crew Join Date: Mar 2002 Location: Orlando FL Posts: 25	Canon 20X lens / No picture I have 2 lens the factory 20X lens and the 3x lens, today I had a shoot and when I connect the 20X lens I had no picture. I then connected the 3x lens and I had picture and everything worked fine. I reconnected the 20X lens, made sure I heard the little pops that the lens does. It did, but still no picture, has anyone else had this problem???

January 7th, 2006, 05:13 PM	#180
Matthew Nayman Major Player Join Date: Feb 2005 Location: Toronto Posts: 917	Did you take the lens off without turning the power off? You may have blown a lens fuse and it is preventing the iris from opening. Matt