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#41
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DSLR vs P&S a replay of Film vs Digital?
Peter Irwin wrote:
In rec.photo.equipment.35mm Wilba wrote: So you're saying that the entire site should not be taken seriously? Their dictionary definition of "Prime lens" is "A lens with a fixed focal length" (http://photonotes.org/cgi-bin/entry.pl?id=Primelens). What's the right definition? Some pedants insist that "prime lens" is best left as the term for the main lens when using a supplementary lens. They may have a point, but it is a widely used piece of slang and rarely causes confusion. But their definition of "zoom lens" is just wrong. There are many lenses of adjustable focal length which are not zoom lenses. For instance, a front cell focussing lens is focussed by changing the focal length, and would not be called a zoom lens by anyone. A zoom lens is one which allows the focal length to be changed and remains in focus when the focal length is adjusted. similarly, the term "telephoto" frequently gets used to describe anything that has a longer focal length than a standard lens, but the term really applies to any lens which is physically shorter than it's focal length. Peter. |
#42
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DSLR vs P&S a replay of Film vs Digital?
On Sun, 18 Nov 2007 01:42:40 +0000 (UTC), Peter Irwin wrote:
In rec.photo.equipment.35mm Wilba wrote: So you're saying that the entire site should not be taken seriously? Their dictionary definition of "Prime lens" is "A lens with a fixed focal length" (http://photonotes.org/cgi-bin/entry.pl?id=Primelens). What's the right definition? Some pedants insist that "prime lens" is best left as the term for the main lens when using a supplementary lens. They may have a point, but it is a widely used piece of slang and rarely causes confusion. But their definition of "zoom lens" is just wrong. There are many lenses of adjustable focal length which are not zoom lenses. For instance, a front cell focussing lens is focussed by changing the focal length, and would not be called a zoom lens by anyone. A zoom lens is one which allows the focal length to be changed and remains in focus when the focal length is adjusted. Peter. That's a parfocal zoom-lens. A zoom-lens need not be parfocal to be called a zoom-lens. There are many telescope and microscope zoom-lens oculars that are anything but parfocal. Though called parfocal zoom-lenses none are truly parfocal. This is why they have to depend on auto-focusing mechanisms after each new zoom setting and always allow for some "slop" at the infinity stop. It's easier to correct for minor difference in focusing than it is to compensate in glass configurations and the more complex internal lens shifting methods that would be required. |
#43
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DSLR vs P&S a replay of Film vs Digital?
"Wilba" wrote in message ... Neil Harrington wrote: John Navas wrote: Moreover tests of these lenses confirm that they do measure up to Leica standards; e.g., "everything you'd expect from Leica glass" http://www.popphoto.com/cameralenses/4597/lens-test-panasonic-leica-d-summilux-25mm-f14-af.html That's "everything you'd expect from Leica glass" by Julia Silber, who in the first paragraph uses "prime" when she means fixed focal length. I think she's the only columnist in Pop Photo who does employ that popular but ignorant misusage. (Herbert Keppler certainly never does.) Someone that careless with language is not to be taken very seriously. So you're saying that the entire site should not be taken seriously? Their dictionary definition of "Prime lens" is "A lens with a fixed focal length" (http://photonotes.org/cgi-bin/entry.pl?id=Primelens). That isn't "their dictionary definitiuon." AFAIK, Photonotes.org has nothing to do with Pop Photo. What's the right definition? "Prime lens" means the camera lens as opposed to some other lens or optical device used with it, such as a close-up lens, tele converter, etc. When used with such a device, the camera lens itself is the prime lens -- whether it's fixed focal length or zoom makes no difference. There are variable focal length prime lenses made by Schneider, Zeiss and others which are catalogued just that way: "variable primes." http://schneiderkreuznach.com/pdf/ki...le_prime_e.pdf http://www.cinequip.com/Category_det...ategory=Lenses http://rentacam.ru/eng/index.php?area=article&id_art=58 http://www.oscars.org/scitech/1998/winners.html (scroll down) Nikon, for example, has NEVER used "prime" to mean fixed focal length in any of its lens literature. Neither have most other camera and lens manufacturers. Neil |
#44
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Anyone not wanting to be trolled by SMS, use this list.
SMS just provided something very useful to all of us. Anyone that doesn't want
SMS poking his ignorant nose into threads and hijacking them for attention for himself with his usual trolling tactics, just use one of these email addresses in your post. This is his block list. How convenient of him to help all of us this way. On Sat, 17 Nov 2007 00:21:27 -0800, SMS ???• ? wrote: Neil Harrington wrote: "GeraldG." wrote in message ... On Fri, 16 Nov 2007 09:43:11 -0500, "Neil Harrington" wrote: "Helmsman3" wrote in message ... BTW, how many different names are you posting under? Haven't hit on one you really like yet? LOL, at least he keeps making everyone's kill-files longer and longer. Hasn't been this much crap since "George Preddy" was around. Here's my most current list: |
#45
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DSLR vs P&S a replay of Film vs Digital?
"Peter Irwin" wrote in message ... In rec.photo.equipment.35mm Wilba wrote: So you're saying that the entire site should not be taken seriously? Their dictionary definition of "Prime lens" is "A lens with a fixed focal length" (http://photonotes.org/cgi-bin/entry.pl?id=Primelens). What's the right definition? Some pedants insist that "prime lens" is best left as the term for the main lens when using a supplementary lens. Yes. When in doubt, go with the pedants, I always say. They may have a point, but it is a widely used piece of slang and rarely causes confusion. "Rarely" perhaps, but it does cause confusion when the term is used properly but is misunderstood by those who think it means "fixed focal length." And that does happen. It's almost certainly how the misusage got started in the first place. But their definition of "zoom lens" is just wrong. Who's the "they" that your "their" refers to? No one in this thread has defined "zoom lens" at all, have they? There are many lenses of adjustable focal length which are not zoom lenses. For instance, a front cell focussing lens is focussed by changing the focal length, and would not be called a zoom lens by anyone. A zoom lens is one which allows the focal length to be changed and remains in focus when the focal length is adjusted. Yes, true zoom lenses are supposed to be parfocal. Whether they are *precisely* so is often doubtful. Many so-called zooms are more properly called varifocal lenses, especially those built into compact cameras, though some SLR "zooms" are really varifocals also. The difference is in the degree of misusage. Many manufacturers use the term "zoom" to mean certain kinds of lenses (esp. projection lenses) and other lenticular devices (binoculars, telescopes, etc.) that are not really parfocal or even approximately so. Nikon, for example, has "zoom" binoculars which I suppose are probably not true zooms in that sense. But Nikon NEVER uses "prime" to mean fixed focal length. Neither did Minolta, when Minolta was still in that business. I think to some extent we should accept the manufacturers' usage as acceptable -- as opposed to a misusage which only started because someone misunderstood the term "prime lens" and that misusage spread via the Usenet. A "zoom" lens may really be a varifocal instead, but it does essentially what a zoom lens does and what people expect a zoom lens to do. The difference as a practical matter is trifling. To take "prime" as meaning fixed focal length when the term never actually meant anything remotely like that is entirely different, and far less acceptable. Neil |
#46
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DSLR vs P&S a replay of Film vs Digital?
Neil Harrington wrote:
Wilba wrote: Neil Harrington wrote: John Navas wrote: Moreover tests of these lenses confirm that they do measure up to Leica standards; e.g., "everything you'd expect from Leica glass" http://www.popphoto.com/cameralenses/4597/lens-test-panasonic-leica-d-summilux-25mm-f14-af.html That's "everything you'd expect from Leica glass" by Julia Silber, who in the first paragraph uses "prime" when she means fixed focal length. I think she's the only columnist in Pop Photo who does employ that popular but ignorant misusage. (Herbert Keppler certainly never does.) Someone that careless with language is not to be taken very seriously. So you're saying that the entire site should not be taken seriously? Their dictionary definition of "Prime lens" is "A lens with a fixed focal length" (http://photonotes.org/cgi-bin/entry.pl?id=Primelens). That isn't "their dictionary definitiuon." AFAIK, Photonotes.org has nothing to do with Pop Photo. Yeah, sorry. I went looking, got distracted, and thought I got there from a link on popphoto. What's the right definition? "Prime lens" means the camera lens as opposed to some other lens or optical device used with it, such as a close-up lens, tele converter, etc. When used with such a device, the camera lens itself is the prime lens -- whether it's fixed focal length or zoom makes no difference. There are variable focal length prime lenses made by Schneider, Zeiss and others which are catalogued just that way: "variable primes." http://schneiderkreuznach.com/pdf/ki...le_prime_e.pdf http://www.cinequip.com/Category_det...ategory=Lenses http://rentacam.ru/eng/index.php?area=article&id_art=58 http://www.oscars.org/scitech/1998/winners.html (scroll down) Nikon, for example, has NEVER used "prime" to mean fixed focal length in any of its lens literature. Neither have most other camera and lens manufacturers. OK, so it's one of those terms that is irredeemably contaminated, like the way people say laptop when they mean notebook, or massive when they mean large. When I searched for "prime lens", none of the first three or four definitions I found mentioned the definition you use, they all referred first to fixed focal length. |
#47
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DSLR vs P&S a replay of Film vs Digital?
"SMS ???. ?" wrote in message ... grant_jiles wrote: About as pathetic as a person with that much time on their hands to compile a list like that. No compiling at all. Just dumping the contents of my Thunderbird filter list for rec.photo.digital. It may help others in setting up their kill files without having to add the e-mail addresses individually. With a good filter list, newsgroups becomes much more readable and more useful. It actually saves time by not having to wade through hundreds of posts by know-it-alls that know nothing. Add one more of course, ". Easier than entering all that stuff into a killfile, which obviously will only grow and grow (and I assume he never bothers re-using his old ones anyway), henceforth I'll just assume any unknown poster supporting that jerk is the jerk himself, and ignore it. Likewise I'll just assume any other idiotic post is from the same jerk, regardless of the subject or name used. It's easy enough to pick him out from his headers, but why waste the time. Neil |
#48
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DSLR vs P&S a replay of Film vs Digital?
In rec.photo.equipment.35mm arnold ziffendorfer wrote:
On Sun, 18 Nov 2007 01:42:40 +0000 (UTC), Peter Irwin wrote: But their definition of "zoom lens" is just wrong. There are many lenses of adjustable focal length which are not zoom lenses. For instance, a front cell focussing lens is focussed by changing the focal length, and would not be called a zoom lens by anyone. A zoom lens is one which allows the focal length to be changed and remains in focus when the focal length is adjusted. Peter. That's a parfocal zoom-lens. A zoom-lens need not be parfocal to be called a zoom-lens. OK. How would you class a front cell focussing triplet? It is designed to be variable in focal length in order to focus. I sure wouldn't call it a zoom. How would you class a variable focal length Dallmeyer Adon? It can adjust to a pretty huge range of focal lengths for different magnifications, but not only do you have to refocus it, you have to calculate the aperture each time you change it. I would hardly call it a "zoom"; it is a fairly difficult lens to use. Though called parfocal zoom-lenses none are truly parfocal. Any zoom lens worthy of the name should be close enough that you can get away without refocussing. Peter. -- |
#49
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DSLR vs P&S a replay of Film vs Digital?
arnold ziffendorfer wrote: On Sun, 18 Nov 2007 01:42:40 +0000 (UTC), Peter Irwin wrote: In rec.photo.equipment.35mm Wilba wrote: So you're saying that the entire site should not be taken seriously? Their dictionary definition of "Prime lens" is "A lens with a fixed focal length" (http://photonotes.org/cgi-bin/entry.pl?id=Primelens). What's the right definition? Some pedants insist that "prime lens" is best left as the term for the main lens when using a supplementary lens. They may have a point, but it is a widely used piece of slang and rarely causes confusion. But their definition of "zoom lens" is just wrong. There are many lenses of adjustable focal length which are not zoom lenses. For instance, a front cell focussing lens is focussed by changing the focal length, and would not be called a zoom lens by anyone. A zoom lens is one which allows the focal length to be changed and remains in focus when the focal length is adjusted. Peter. That's a parfocal zoom-lens. A zoom-lens need not be parfocal to be called a zoom-lens. There are many telescope and microscope zoom-lens oculars that are anything but parfocal. Though called parfocal zoom-lenses none are truly parfocal. This is why they have to depend on auto-focusing mechanisms after each new zoom setting and always allow for some "slop" at the infinity stop. It's easier to correct for minor difference in focusing than it is to compensate in glass configurations and the more complex internal lens shifting methods that would be required. This is an important consideration with moving media. A cinematographer should plan his shot by focusing on the longest focal length to be used and take advantage of the larger depth of field to compensate for any error when going, (or leaving), a wide shot. One of the oldest tricks in the book... JT |
#50
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DSLR vs P&S a replay of Film vs Digital?
On Sun, 18 Nov 2007 04:59:25 GMT, Grumpy AuContraire
wrote: arnold ziffendorfer wrote: On Sun, 18 Nov 2007 01:42:40 +0000 (UTC), Peter Irwin wrote: In rec.photo.equipment.35mm Wilba wrote: So you're saying that the entire site should not be taken seriously? Their dictionary definition of "Prime lens" is "A lens with a fixed focal length" (http://photonotes.org/cgi-bin/entry.pl?id=Primelens). What's the right definition? Some pedants insist that "prime lens" is best left as the term for the main lens when using a supplementary lens. They may have a point, but it is a widely used piece of slang and rarely causes confusion. But their definition of "zoom lens" is just wrong. There are many lenses of adjustable focal length which are not zoom lenses. For instance, a front cell focussing lens is focussed by changing the focal length, and would not be called a zoom lens by anyone. A zoom lens is one which allows the focal length to be changed and remains in focus when the focal length is adjusted. Peter. That's a parfocal zoom-lens. A zoom-lens need not be parfocal to be called a zoom-lens. There are many telescope and microscope zoom-lens oculars that are anything but parfocal. Though called parfocal zoom-lenses none are truly parfocal. This is why they have to depend on auto-focusing mechanisms after each new zoom setting and always allow for some "slop" at the infinity stop. It's easier to correct for minor difference in focusing than it is to compensate in glass configurations and the more complex internal lens shifting methods that would be required. This is an important consideration with moving media. A cinematographer should plan his shot by focusing on the longest focal length to be used and take advantage of the larger depth of field to compensate for any error when going, (or leaving), a wide shot. One of the oldest tricks in the book... JT Exactly. This is why I see no huge compelling argument to the "my camera focuses faster than your camera" childishness. I only use the auto-focus on my camera to quickly find either a nice average to put the subject(s) within the DOF needed or when I use a hyperfocal setting so nothing is missed. The same as I've done for the last 40 years in all my cameras, manual or otherwise. Once that is done I lock it into manual focus so it stays there. Occasionally using the manual adjustment to touch up on what the camera ADVISED for a starting point. No different than the advice you get from the exposure readings. How often that is wrong too. Auto-focus may get me there quicker in most situations but is by no means the answer to worthwhile photography. I do just as well without it if I need to. I'll turn it off completely depending on the shooting scenario. Particularly with macro-photography where it is more of a huge hindrance than any kind of a help. If the "fast auto-focus" admirers only realized how often they reveal their own lack of talent and skills at photography. Snap-shooters that have been brainwashed into thinking that they can buy a camera that will magically bestow them with talent. They need to read Jack & the Beanstalk for hints on how to find some magic beans while they're at it. |
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