Wide-angle lens choices for XL1?

Stephen Birdsong · May 26th, 2003, 05:18 PM

we have different lenses i believe.

Jeff Donald · May 26th, 2003, 05:31 PM

What you are both noticing is Barrel Distortion. It is quite common in wide angle lenses. WA adapters seem to exaggerate the effect because the optical design is generic and can't take the original lens design into consideration.

The effect can be reduced by designing rectilinear WA lenses. Rectilinear WA use aspherical lenses elements and floating optical groups to reduce barrel distortion. Straight lines (even at the edges of the image) appear straight in a rectilinear WA.

Josh Bass · May 26th, 2003, 08:00 PM

Yes, but how does that help US? I almost bought the canon WA lens, but decided I wanted the 16x more.

Jeff Donald · May 26th, 2003, 08:15 PM

In my opinion the best corrected wide angle is the Canon 3X. Century Optical makes a special WA adapter just for that lens. While I've not used it, others I know are extremely pleased with the results and shots I've seen exhibit very little barrel distortion.

Barrel distortion is reduced by zooming in slightly. But the more you zoom in, the narrower the angle of view. So, it's all a big trade, reduced angle of view or barrel distortion. Your choice, or new lens and adapter.

Stephen Birdsong · May 27th, 2003, 02:02 AM

Im experiencing a squashed image, its not just the corners. Is that normal?

Josh Bass · May 27th, 2003, 02:13 AM

Are you accidentally in anamorphic mode?

Stephen Birdsong · May 27th, 2003, 02:14 AM

Nope. If it would help, I could upload a comparison.

Nigel Moore · May 27th, 2003, 07:06 AM

Quote:

Originally posted by Jeff Donald : In my opinion the best corrected wide angle is the Canon 3X. Century Optical makes a special WA adapter just for that lens.

I'm probably being unnecessarily thick here, but does this mean that the Canon 3x needs an adaptor to correct distortion, or that you can add an adaptor without distortion? Jim MacAllister's article suggested it was pretty much distortion-free.

Jeff Donald · May 27th, 2003, 08:30 AM

Sorry, I should have been more specific. The 3X is virtually free of distortion. Some users have put a more generic WA adapter on the 3X and the distortion is fairly noticeable. However, using the Century adapter made for the 3X, the images show only slight barrel distortion.

Stephen Birdsong · May 27th, 2003, 12:18 PM

Here is an example of what I am talking about. You can notice the first is a bit squashed horizontally. The first is with the canon 14x manual + .7x century optics, the second is the 14x alone, both at widest focal length.

http://pcp03932387pcs.sthind01.mo.co...istortion.html

I realize the picture is not focused properly and the white balance is not set, but i just had to capture something, and i didnt put a whole lot of thought into it.

Stephen

Jeff Donald · May 27th, 2003, 05:51 PM

I suspect it might be the low camera angle, but I certainly see the distortion in the "normal image." Try to shoot a more controlled test. Shot the cover of a magazine or something similar. Line the camera up so the optical axis is perpendicular to the subject. Shoot it both ways and post the results.

Stephen Birdsong · May 27th, 2003, 05:52 PM

I tried to do that originally, but I wanted to keep the focal length the same. Ill do that as well.

stephen

Stephen Birdsong · May 27th, 2003, 07:08 PM

By doing that test, I found no distortion. intersting enough.

Jeff Donald · May 27th, 2003, 07:18 PM

I suspected as much. The change is a result of the change in perspective (low camera angle vs. normal camera angle). When the camera is low and the subject (your head) is high, this effect becomes noticeable to the eye. If you place your subject near the corners you'll also get an odd perspective that the eye will find unusual.

May 26th, 2003, 05:31 PM	#32
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	What you are both noticing is Barrel Distortion. It is quite common in wide angle lenses. WA adapters seem to exaggerate the effect because the optical design is generic and can't take the original lens design into consideration. The effect can be reduced by designing rectilinear WA lenses. Rectilinear WA use aspherical lenses elements and floating optical groups to reduce barrel distortion. Straight lines (even at the edges of the image) appear straight in a rectilinear WA. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

May 26th, 2003, 08:00 PM	#33
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	Yes, but how does that help US? I almost bought the canon WA lens, but decided I wanted the 16x more. __________________ The Bass' camerawork The Bass on IMDB

May 26th, 2003, 08:15 PM	#34
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	In my opinion the best corrected wide angle is the Canon 3X. Century Optical makes a special WA adapter just for that lens. While I've not used it, others I know are extremely pleased with the results and shots I've seen exhibit very little barrel distortion. Barrel distortion is reduced by zooming in slightly. But the more you zoom in, the narrower the angle of view. So, it's all a big trade, reduced angle of view or barrel distortion. Your choice, or new lens and adapter. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

May 27th, 2003, 02:13 AM	#36
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	Are you accidentally in anamorphic mode? __________________ The Bass' camerawork The Bass on IMDB

May 27th, 2003, 08:30 AM	#39
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Sorry, I should have been more specific. The 3X is virtually free of distortion. Some users have put a more generic WA adapter on the 3X and the distortion is fairly noticeable. However, using the Century adapter made for the 3X, the images show only slight barrel distortion. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

May 26th, 2003, 05:18 PM	#31
Stephen Birdsong Regular Crew Join Date: May 2003 Location: Brooklyn Posts: 125	we have different lenses i believe.

May 27th, 2003, 02:02 AM	#35
Stephen Birdsong Regular Crew Join Date: May 2003 Location: Brooklyn Posts: 125	Im experiencing a squashed image, its not just the corners. Is that normal?

May 27th, 2003, 02:14 AM	#37
Stephen Birdsong Regular Crew Join Date: May 2003 Location: Brooklyn Posts: 125	Nope. If it would help, I could upload a comparison.

May 27th, 2003, 12:18 PM	#40
Stephen Birdsong Regular Crew Join Date: May 2003 Location: Brooklyn Posts: 125	Here is an example of what I am talking about. You can notice the first is a bit squashed horizontally. The first is with the canon 14x manual + .7x century optics, the second is the 14x alone, both at widest focal length. http://pcp03932387pcs.sthind01.mo.co...istortion.html I realize the picture is not focused properly and the white balance is not set, but i just had to capture something, and i didnt put a whole lot of thought into it. Stephen

May 27th, 2003, 05:51 PM	#41
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	I suspect it might be the low camera angle, but I certainly see the distortion in the "normal image." Try to shoot a more controlled test. Shot the cover of a magazine or something similar. Line the camera up so the optical axis is perpendicular to the subject. Shoot it both ways and post the results. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

May 27th, 2003, 05:52 PM	#42
Stephen Birdsong Regular Crew Join Date: May 2003 Location: Brooklyn Posts: 125	I tried to do that originally, but I wanted to keep the focal length the same. Ill do that as well. stephen

May 27th, 2003, 07:08 PM	#43
Stephen Birdsong Regular Crew Join Date: May 2003 Location: Brooklyn Posts: 125	By doing that test, I found no distortion. intersting enough.

May 27th, 2003, 07:18 PM	#44
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	I suspected as much. The change is a result of the change in perspective (low camera angle vs. normal camera angle). When the camera is low and the subject (your head) is high, this effect becomes noticeable to the eye. If you place your subject near the corners you'll also get an odd perspective that the eye will find unusual. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors