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#121
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Canon digital bodies and Nikon lenses
Rich wrote:
On Wed, 16 Nov 2005 21:19:21 -0700, "Roger N. Clark (change username to rnclark)" wrote: Rich wrote: Single coated filters reflect about 1.5% of the light at each surface, which doesn't amount to much in terms of transmission, But reflectance increases off axis. It would certainly contribute to vignetting on a wide angle lens, but how much I do not know (I don't have a camera with such a filter with me at the moment). It would be an interesting measurement though. Roger Probably not enough to see visually? But one day they'll be able to lay down coatings that will accommodate the angle change (due to curvature) across the face of a lens. -Rich Probably. Especially the reflection off the back side. See: http://www.janostech.com/files/Optic...ign%20Data.pdf The above are not multicoated curves, but it gives an idea. At angles of 35 degrees off the back side of an uncoated filter, reflectance is 20%. Multicoating will reduce that, but we need to see a plot to see how much. At large angles, the destructive interference distances in an AR coating are breaking down (not valid for visible wavelengths), so it could actually be worse! Roger Roger |
#122
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Canon digital bodies and Nikon lenses
Joseph Chamberlain, DDS wrote:
My impression is that this is being caused (at least in part) by the filter I am using. When I purchase my camera I asked for Heliopan multicoated UV filters for both lenses. The reseller gave me by mistake the single coated filters and I didn't notice this until I got home. When I hold the multicoated filter I have on my Nikkor 17-35mm and the single coated filter I have on my Canon 16-35mm both against the light in a angle it is easy to see that the single coated reflects a lot more light than the multicoated. Could this associated with the curvature of the lens and the light fall off effect that has been discussed here in the past for full frame sensors cause this problem ? What are your opinions ? A filter doesn't reflect enough to cause vignetting. If a filter causes it, it's due to not having enough clearance -- the ring on the filter blocks the light. Using a wide angle lens wide open causes vignetting because that's just how it works. Obviously they can try to minimize it in the lens design, but when you have light from a wide circle exposing each part of the image, the edges are going to lose something due to part of the circle being outside the image area. (There seems to be a lot of confusion between this and the "soft corner" effect you sometimes see with digital sensors; they are two different things. Corner falloff is not a "digital" artifact.) Last but not least, I have spoken to some photographers who say they don't use any filter at all with wide lenses such as this 16-35mm because any type of filter independent of how good it is will cause image problems at such wide angles. How many of you use lenses without filters to protect them ? Isn't that a little risky since you can damage the front element of the lens ? How many of you have actually had lenses damaged because of the absence of a protective UV filter ? I don't use them, but I do use lens hoods quite a lot, which offer much the same protection while not hurting image quality (and usually helping). I pretty much always have a hood on the lens. -- Jeremy | |
#123
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Canon digital bodies and Nikon lenses
"G.T." wrote in message ... Lester Wareham wrote: Joseph I think you have come in for some unfair comments from some on this group, well done for accepting it in good grace. Now I note you exchanged the 16-35 for another lens which was more saticfactory. Can you share with us which lens that was please. I guess top-posters can't comprehend simple English. Greg "Joseph Chamberlain, DDS" wrote in message .. . After using a few others 16-35mm the reseller had in his inventory it was apparent not only to me, but to a few specialists that the lens was definitely flawed. I was able to exchange it for a different one that produced images that were noticeably better. It sounds to me like he EXCHANGED it for another Canon 16-35. |
#124
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Canon digital bodies and Nikon lenses
"It sounds to me like he EXCHANGED it for another Canon 16-35"
I thought so too but it was ambiguous - does your reply clarify it. No. Then why not let him answer for himself. "G.T." wrote in message ... Lester Wareham wrote: Joseph I think you have come in for some unfair comments from some on this group, well done for accepting it in good grace. Now I note you exchanged the 16-35 for another lens which was more saticfactory. Can you share with us which lens that was please. I guess top-posters can't comprehend simple English. Greg "Joseph Chamberlain, DDS" wrote in message .. . After using a few others 16-35mm the reseller had in his inventory it was apparent not only to me, but to a few specialists that the lens was definitely flawed. I was able to exchange it for a different one that produced images that were noticeably better. It sounds to me like he EXCHANGED it for another Canon 16-35. |
#125
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Canon digital bodies and Nikon lenses
Thanks for the clarification Joseph.
"Joseph Chamberlain, DDS" wrote in message .. . On 11/13/05 6:49 AM, in article , "Lester Wareham" wrote: Joseph I think you have come in for some unfair comments from some on this group, well done for accepting it in good grace. Now I note you exchanged the 16-35 for another lens which was more saticfactory. Can you share with us which lens that was please. Lester Lester: I have exchanged it for the same lens. Apparently the one I originally purchased with my camera had some manufacturing issue with heavy geometrical distortion towards the edges, specially at the 16mm focal length end of the zoom range. I went back to the reseller and tested a few others and all of them provided better images than the one I had. My new Canon 16-25mm lens has improved dramatically after I exchanged it for another lens. However, I continue to notice a great deal of vignetting primarily when the lens is wide open at 16mm focal length. I took a shot with the blue sky in the background and the vignetting was so intense that after using the vignette correction under lens correction in Camera Raw to its maximum it could still be noticed. My impression is that this is being caused (at least in part) by the filter I am using. When I purchase my camera I asked for Heliopan multicoated UV filters for both lenses. The reseller gave me by mistake the single coated filters and I didn't notice this until I got home. When I hold the multicoated filter I have on my Nikkor 17-35mm and the single coated filter I have on my Canon 16-35mm both against the light in a angle it is easy to see that the single coated reflects a lot more light than the multicoated. Could this associated with the curvature of the lens and the light fall off effect that has been discussed here in the past for full frame sensors cause this problem ? What are your opinions ? I have also looked at B+W's Kaesemann multicoated polarizer and it barely reflects any light on its surface. It seems it would be a good aid in avoiding or reducing this vignetting I am seeing. The only trade-off is the 2 f-stops lost using this polarizer. What are your opinions on this subject ? How many of you have the same Canon lens or a similar lens and have experienced this type of problem ? What solution have you found ? Last but not least, I have spoken to some photographers who say they don't use any filter at all with wide lenses such as this 16-35mm because any type of filter independent of how good it is will cause image problems at such wide angles. How many of you use lenses without filters to protect them ? Isn't that a little risky since you can damage the front element of the lens ? How many of you have actually had lenses damaged because of the absence of a protective UV filter ? Thank you in advance for your replies and help. Best regards, Joseph --- Dr. Joseph Chamberlain Oral and Maxillofacial Surgery |
#126
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Canon digital bodies and Nikon lenses
On 11/16/05 11:59 AM, in article QcMef.512876$oW2.95067@pd7tw1no, "Robert
Brace" wrote: I don't work for them either, but I do use RRS equipment for both film & digital and it is outstanding. I'm surprised at your comparison with Manfrotto for price comparison. I've never encountered anything with the name Manfrotto on it (and I've owned much, and still own some of it) which I didn't consider roughly cast, poorly machined and of inferior design!! RRS is so far ahead of Manfrotto in every area of comparison it doesn't even deserve comment. Their newly re-designed B-150 macro focusing rail (it's now designated the B-150B, I think) is not available yet. They have been saying "late fall" since I first called them on the disappearance of the B-150 last April. I considered the Kirk rail, but decided to wait. That's the result of being impressed with their quality. Bob Bob: Now you have ME surprised. Manfrotto (or Bogen as it is known in the US) makes some of the best tripods, heads and general studio and lighting support equipment I have seen to date. It is one of the most sought by professionals and the one with the most comprehensive product line. Their equipment is sturdy and built like "tanks" - something that is really built to last. I own Manfrotto tripods that are 20 years old and they look as if they were purchased yesterday (in part because of the proper care I provide without exposing them to unnecessary punishment). I don't have one single piece of equipment from Manfrotto that has even a single rust spot or has ever failed to perform as I have come to expect it to. Since I don't own any RSS' equipment I can't compare the two. If their equipment is of similar quality to that of Manfrotto's products they really are good equipment. If they are in fact much better as you describe then they must be the top-of-the-line. I think the roughly cast description you attribute to Manfrotto's products is in fact an intentional design feature aimed at providing consumers with products that "feel" and "behave" sturdy. Joseph --- Dr. Joseph Chamberlain Oral and Maxillofacial Surgery |
#127
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Canon digital bodies and Nikon lenses
"Joseph Chamberlain, DDS" wrote in message
.. . On 11/16/05 11:59 AM, in article QcMef.512876$oW2.95067@pd7tw1no, "Robert Brace" wrote: I don't work for them either, but I do use RRS equipment for both film & digital and it is outstanding. I'm surprised at your comparison with Manfrotto for price comparison. I've never encountered anything with the name Manfrotto on it (and I've owned much, and still own some of it) which I didn't consider roughly cast, poorly machined and of inferior design!! RRS is so far ahead of Manfrotto in every area of comparison it doesn't even deserve comment. Their newly re-designed B-150 macro focusing rail (it's now designated the B-150B, I think) is not available yet. They have been saying "late fall" since I first called them on the disappearance of the B-150 last April. I considered the Kirk rail, but decided to wait. That's the result of being impressed with their quality. Bob Bob: Now you have ME surprised. Manfrotto (or Bogen as it is known in the US) makes some of the best tripods, heads and general studio and lighting support equipment I have seen to date. It is one of the most sought by professionals and the one with the most comprehensive product line. Their equipment is sturdy and built like "tanks" - something that is really built to last. I own Manfrotto tripods that are 20 years old and they look as if they were purchased yesterday (in part because of the proper care I provide without exposing them to unnecessary punishment). I don't have one single piece of equipment from Manfrotto that has even a single rust spot or has ever failed to perform as I have come to expect it to. Since I don't own any RSS' equipment I can't compare the two. If their equipment is of similar quality to that of Manfrotto's products they really are good equipment. If they are in fact much better as you describe then they must be the top-of-the-line. I think the roughly cast description you attribute to Manfrotto's products is in fact an intentional design feature aimed at providing consumers with products that "feel" and "behave" sturdy. Joseph --- Dr. Joseph Chamberlain Oral and Maxillofacial Surgery To add my opinion to the cacophony, RRS stuff really is a lot better than Manfrotto/Bogen. That being said, I've always felt that RRS made their stuff better than it really needs to be, and charges WAY too much. Manfrotto, on the other hand, charges just a little bit more than their stuff is worth, and it generally gets the job done. I have two M/B tripods with heads, and one QR plate of theirs. The QR plate lacks an antitwist feature, but for the difference in price, I just make sure it's good and tight. -- Skip Middleton http://www.shadowcatcherimagery.com |
#128
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Canon digital bodies and Nikon lenses
In article ,
Joseph Chamberlain, DDS wrote: Manfrotto (or Bogen as it is known in the US) makes some of the best tripods, heads and general studio and lighting support equipment I have seen to date. It is one of the most sought by professionals and the one with the most comprehensive product line. Their equipment is sturdy and built like "tanks" - something that is really built to last. I own Manfrotto tripods that are 20 years old and they look as if they were purchased yesterday (in part because of the proper care I provide without exposing them to unnecessary punishment). I don't have one single piece of equipment from Manfrotto that has even a single rust spot or has ever failed to perform as I have come to expect it to. In my opinion, Manfrotto stuff is usually properly engineered, but it is not high-end. For video, I work with some 20 year old Manfrotto tripods and an about 15 year old one from Sachtler. The latest IBC last September was an obvious opportunity to see whether there was any news in tripod land. Manfrotto didn't bring anything that comes even close to a Sachtler head. Recently, I was looking for an affordable, 2nd hand, 'big' ball head. One of the older Manfrotto designs was a complete disaster. Not that it would break, but movements were anything but smooth. (I bought a Gitzo, but I doubt that it is as good as the more high-end stuff). -- That was it. Done. The faulty Monk was turned out into the desert where it could believe what it liked, including the idea that it had been hard done by. It was allowed to keep its horse, since horses were so cheap to make. -- Douglas Adams in Dirk Gently's Holistic Detective Agency |
#129
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Canon digital bodies and Nikon lenses
"Joseph Chamberlain, DDS" wrote in message .. . On 11/16/05 11:59 AM, in article QcMef.512876$oW2.95067@pd7tw1no, "Robert Brace" wrote: I don't work for them either, but I do use RRS equipment for both film & digital and it is outstanding. I'm surprised at your comparison with Manfrotto for price comparison. I've never encountered anything with the name Manfrotto on it (and I've owned much, and still own some of it) which I didn't consider roughly cast, poorly machined and of inferior design!! RRS is so far ahead of Manfrotto in every area of comparison it doesn't even deserve comment. Their newly re-designed B-150 macro focusing rail (it's now designated the B-150B, I think) is not available yet. They have been saying "late fall" since I first called them on the disappearance of the B-150 last April. I considered the Kirk rail, but decided to wait. That's the result of being impressed with their quality. Bob Bob: Now you have ME surprised. Manfrotto (or Bogen as it is known in the US) makes some of the best tripods, heads and general studio and lighting support equipment I have seen to date. It is one of the most sought by professionals and the one with the most comprehensive product line. Their equipment is sturdy and built like "tanks" - something that is really built to last. I own Manfrotto tripods that are 20 years old and they look as if they were purchased yesterday (in part because of the proper care I provide without exposing them to unnecessary punishment). I don't have one single piece of equipment from Manfrotto that has even a single rust spot or has ever failed to perform as I have come to expect it to. Since I don't own any RSS' equipment I can't compare the two. If their equipment is of similar quality to that of Manfrotto's products they really are good equipment. If they are in fact much better as you describe then they must be the top-of-the-line. I think the roughly cast description you attribute to Manfrotto's products is in fact an intentional design feature aimed at providing consumers with products that "feel" and "behave" sturdy. Joseph --- Dr. Joseph Chamberlain Oral and Maxillofacial Surgery Joseph: As I mentioned, I am still using some Manfrotto. One item is a Proball 468RC ball head which has held up not too badly -- but at the first opportunity I replaced their quick release with an early RRS lever release Arca-Swiss type (marked AS-A on the end). Now it works the way it should have originally. I have owned their tripods in the past, but lately have settled on Gitzo tripods, ball heads and monopods and I also have an older Linhof which holds its own very capably. Someone else mentioned that things with Manfrotto seemed "acceptable" but there was always something that seemed "overlooked" (and I don't mean well-scrutinized)!! You could easily make the "over priced" case for RRS, but I don't find myself having to "accommodate" any of their equipment -- it just works and continues to work on & on. What is that worth? There is an old saying my Grandfather used to quote from time to time: "The world is full of people who know the price of everything and the value of nothing". It's still true, in my experience. Bob |
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