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Photo Forum / Film Photography / 35 mm / November 2006What does 2.8-4.3 mean ??
Sorry for the simple question. But im just a novice. Just trying to understand lenses. What does it mean when a lense gives two f stops in a range. eg when buying a lense. Is this the largest and smallest that the lense will go eg from to ? 2.8 to 4.3 I have searched on the net but cannot find anyone who has answered this simple question. Thanks. > Just trying to understand lenses. What does it mean when a lense gives > two f stops in a range. eg when buying a lense. > Is this the largest and smallest that the lense will go eg from to ? > 2.8 to 4.3 It is for zoom lenses: the lens will be f2.8 at it's shortest focal length and f4.3 at it's longest.  SignatureNicholas O. Lindan, Cleveland, Ohio Darkroom Automation http://www.nolindan.com/da/index.htm n o lindan at ix dot netcom dot com >> Just trying to understand lenses. What does it mean when a lense gives >> two f stops in a range. eg when buying a lense. [quoted text clipped - 3 lines] > It is for zoom lenses: the lens will be f2.8 at it's shortest focal > length and f4.3 at it's longest. That is the wide open f-stop as well (maximum apeture). In short, the maximum apeture for the shortest focal length is f2.8 and the maximum apeture for the longest focal length is f4.3. Having said that, I haven't seen a f2.8 - f4.3 lens before. SignatureThomas T. Veldhouse Key Fingerprint: D281 77A5 63EE 82C5 5E68 00E4 7868 0ADC 4EFB 39F0 > Sorry for the simple question. But im just a novice. > [quoted text clipped - 8 lines] > > Thanks. It is as Nicholas describes, but those numbers represent the sizes of the aperture. The smaller that number is, the larger the aperture is, and as well reverswise, the larger the number, the smaller the aperture. So the smaller that number is, the more expensive the lens will be because of larger glass and barrel. It relates to how much or how little light can reach the film, or CCD / CMOS chip in a digital camera. Zoom lenses have either changing or non-changing apertures. Usually if a zoom has a single, it is constant, which means it is a more expensive and fast lens. I have an old Tamron that is a constant 3.5 aperture, which is 1/2 stop slower than 2.8, but the list price was $710, still a poor design for some reasons. As well, the speed of the film is faster or slower, or sensitivity of the CCD / CMOS such as it's own ISO speed setting. It all relates to "exposure" and the speed or slowness of it. A smaller aperture requires a slower shutter speed, and allows for a finer, sharper image resulting from deeper depth of field and finer rays of light. A wider aperture allows for faster shutter speed and shallow depth of field, where only the subject will be in focus, both forground and background out of focus. The faster shutter speeds stop action that is moving as well, or it is a desireable effect. Depth of field changes as aperture changes. Speed can be increased with the use of a flash and faster film or higher CCD / CMOS sensitivity (ISO) setting. Did that help? Signature}<)))*> Giant_Alex cravdraa_at-yahoo_dot-com not my site: http://www.e-sword.net/ It is the MAXIMUM aperture of the (zoom) lens, at the wide end (f/2.8) and at the tele end (f/4.3). Not half bad numbers, by the way. Minimum aperture is not indicated. For most consumer zoom lenses, max aperture is bigger (smaller number) at the wide end than at the tele end, this simplifies construction. f/3.5-5.6 is a typical specification for such a lens. Pro lenses tend to have a constant max aperture throughout the zoom range as indicated by a single number, this is far more convenient for the photographer but costs you money, weight and size especially in the case of constant f/2.8 lenses. > Sorry for the simple question. But im just a novice. > [quoted text clipped - 8 lines] > > Thanks. Thanks for all your responses. That makes sense, the longer the lense the less light will come down the barell. I have a slr camera but wanted to get a lense that could do some wide angle and zooming and is "fast" because I get tired of having crumy shots indoors, and my flash skills are poor. Bonus is that it is a macro too. Thanks for your help. > Thanks for all your responses. > [quoted text clipped - 5 lines] > > Thanks for your help. No... check your first sentence there. Some lenses have a constant widest aperture. AAvK "steve" <stevesemple@lycos.com> wrote in news:1161096356.473262.299190 @h48g2000cwc.googlegroups.com: > That makes sense, the longer the lense the less light will come down > the barell. I have a slr camera but wanted to get a lense that could > do some wide angle and zooming and is "fast" because I get tired of > having crumy shots indoors, and my flash skills are poor. Bonus is that > it is a macro too. When you say SLR I am presuming you mean film camera. I will point out that unless you are using black and white, you may have colour cast issues relying on ambient light. Most colour emulsions are balanced for daylight but you can get tungsten balanced film. This is balanced for studio lighting, though which is a different shade of white to household lights. Flourescent lights are just plain wierd (all odd peaks and troughs in the spectrum which is almost impossible to filter). Flash is balanced the same as midday light, actually a bit cold for portraiture. If you're using black and white and choose a really fast emulsion (there are a few 800ASAs that can be pushed up to 3200 - with uprating at processing time - ask your lab about it). And with that and a lens less than f/2 you'll be taking photos of black cats in the coal cellar at night during a power cut. ;-) By all means go out and get a really fast lens. If that is what you need you may be better off looking at a prime (ie. single focal length as opposed to zoom) lens as you can get a 50mm f/1.4 or faster lens for a lot les money than a zoom lens that fast. It isn't bad to use a prime lens; it is good practice and good training to learn to use a prime lens well. It teaches one to pay attention to their position and the overall framing without resorting to simply zooming in. At a given price point a prime lens will usually give better picture quality and be faster to boot. Alternatively, learn to use the flash. There is no substitute for a decent flashgun, one with enough power and a tilt/swivel head that allows you to "bounce" it off the walls or ceiling to get a softer light. Modern cameras, with suitable flashguns, can meter the flash through the lens, off the film, during exposure so will not require any thought other than switch to program mode. If that is not true for you, maybe you have an older camera, then using flash is really just a matter of using chart/calculator on the flashgun to work out the correct f/stop for the required distance. It'll take a little practice but it really isn't rocket surgery. Another skill worth learning as it'll help understand the whole photo taking process. At least you can ignore the shutter speed for most purposes. Just set it to X-sync, whatever that is on your camera. Rich > Thanks for all your responses. > [quoted text clipped - 5 lines] > > Thanks for your help. Well, the longer the lens, the larger the diameter of it has to be to maintain a large maximum aperture. Max aperture number is pretty much defined as length divided by diameter, after all. Canon made a 200mm f/1.8 lens once, it was nicknamed "the Eye of Sauron" just to give you the idea. Same thing for their old 50mm f/0.95 (!), the diameter of the front element was huge, quite the cyclops' eye. This drives up weight and cost, of course. Large slabs of optical glass do not come cheap. It sounds like you want a large-aperture superzoom, something like an 18-200 f/2.8 or f/4. Doesn't exist I'm afraid. And it would cost a fortune even if it did. Get two fastish lenses instead, one wide-to-normal (17-40 f/4 for digital or one of the many good something-like-28-to-75- f/2.8s for film for example) and a moderate tele zoom (70-200 f/4) - examples given are Canon but similar stuff is available for other systems. Be prepared to spend money, fast is not cheap. And macro is a separate application, zoom lenses which claim to be 'macro' are not, really. Real macros are fixed focal length, there are some good ones available at moderate cost in the ca 100 mm focal length which should be good for both digi and film. As for indoors, even an f/2.8 zoom is not fast enough to be universally useful without flash, and zooms don't come much faster than that. Fixed-focal lenght lenses are the way to go for this kind of work. You could try to get a 50 mm f/1.8 for this use, build quality is so-so and it gives you a pretty narrow field of view on most digital SLRs but it can be had for a pittance and is fast enough. Or you could go for a 50mm f/1.4 instead if you want to spend three-four times as much money for a more solid and 50% faster lens. Be aware though, depth-of-field rapidly approaces zero as you open the aperture up past f/2.8. We are in "sharp eyes, blurry ears" territory now. Oh, and be prepared to jack ISO up through the roof to keep shutter times down as well, even with fast lenses, noise can be corrected in software but blurriness cannot. Thanks again. All the info is helpfull. Steve St?le Sannerud wrote: > > Thanks for all your responses. > > [quoted text clipped - 35 lines] > open the aperture up past f/2.8. We are in "sharp eyes, blurry ears" > territory now. then there is an 85 mm f/1.4 Nikkor if you want a telescopic macro. > Oh, and be prepared to jack ISO up through the roof to keep shutter times > down as well, even with fast lenses, noise can be corrected in software but > blurriness cannot. can you explain this statement in greater detail? If my aperture is constant, and am shooting indoors (portrait) -(preferably in constant aperture mode), how does a faster ISO help? I know it helps for action pics where the subject is fast moving -but not sure of this. thanks -kamal blurriness cannot. > can you explain this statement in greater detail? If my aperture is > constant, and am shooting indoors (portrait) -(preferably in constant > aperture mode), how does a faster ISO help? I know it helps for action > pics where the subject is fast moving -but not sure of this. If you use a shutter speed slower than 1/100s handheld you are likely to get a blurred picture due to camera movement. If you cannot correctly expose a picture in the given light at your widest aperture without resorting to show shutter speeds then you have two options:- 1. increase the light. 2. increase the sensitivity of the medium - use a faster film or set a higher ISO rating for your sensor. The downside of 2 is that invariably you will get either more grain or noise (depending on whether it is film or digital). Signatureinvalid = com > blurriness cannot. > > [quoted text clipped - 5 lines] > If you use a shutter speed slower than 1/100s handheld you are likely to > get a blurred picture due to camera movement. looks like VR provides something to help out with that. Or maybe one needs a tripod for min shutter speed. > If you cannot correctly expose a picture in the given light at your widest > aperture without resorting to show shutter speeds then you have two [quoted text clipped - 6 lines] > The downside of 2 is that invariably you will get either more grain or > noise (depending on whether it is film or digital). So, does a faster film help in low light? I know about graininess -btw and I use film. thanks -kamal > looks like VR provides something to help out with that. Or maybe one > needs a tripod for min shutter speed. To a certain extent, yes. If you're trying to capture a moving object, however, no amount of VR or IS will help. > So, does a faster film help in low light? I know about graininess -btw > and I use film. Well yes. That is what film speed means = speed of reaction to light. Manufacturers go to great lengths to ensure that the characteristic curve of a film is flat for a given exposure range that conforms to a known rating - ISO rating. That way you can think of one stop of ISO change as having the same affect as one stop of shutter speed or aperture. 1 stop wider aperture = twice the light entering camera. Meaning that half the exposure time or half as sensitive film is required for correct exposure. 1 stop longer shutter speed = twice the exposure to the incoming light Meaning that a half the incoming light or half as sensitive film is required for correct exposure. 1 stop faster film = twice the sensitivity to the incoming light Meaning half as much incoming light or half the exposure time is required for correct exposure. This reciprocity means that:- To get a 1-stop faster shutter speed either open aperture 1 stop or use a 1 stop faster film (100 -> 200 ASA for instance). To get a 1-stop smaller aperture (for greater depth of field) either use a 1-stop slower shutter speed or 1 stop faster film. To get less grain, use a 1-stop slower film (100 -> 50 ASA for instance) and either 1 stop wider aperture or 1 stop slower shutter speed. This continues through to the development as well. As long as your exposure range falls within the flat part of the characteristic curve of the chosen film, you can also get a stop or two's adjustment by over- or under-developing the exposed film. Known as push (or pull) processing, this usually results in harsher, more contrasty negatives when overdeveloping, or smoother, more pastel images when underdeveloping (you can switch these for reversal - slide - film.) I rather like the pictorial effect of the increased grain and contrast resulting from 400ISO Ilford HP5 underexposed by 2 stops (as a 1600ISO film) and commensurately overdeveloped by 2 stops, although I am experimenting with some superfast B&W emulsions. Signatureinvalid = com Thanks for the info. Im thinking of switching to digital for nature photography. Do you think that the technology is good enough? How expensive a camera wuld give me reasonable images? I have an N75 with 24-120mm f/3.5-5.6 Nikkor and a point and shoot 28-120mm canon film camera thanks -kamal http://www.flickr.com/photos/kamalpr > > looks like VR provides something to help out with that. Or maybe one > > needs a tripod for min shutter speed. [quoted text clipped - 45 lines] > film) and commensurately overdeveloped by 2 stops, although I am > experimenting with some superfast B&W emulsions. > Thanks for the info. Im thinking of switching to digital for nature > photography. Do you think that the technology is good enough? How > expensive a camera wuld give me reasonable images? I have an N75 with > 24-120mm f/3.5-5.6 Nikkor and a point and shoot 28-120mm canon film > camera I don't use digital myself but from what I've seen pretty much ANY of the current crop of digital SLRs will give outstanding results. I suppose the advantage for nature is the smaller sensor gives a narrower angle of view for a given focal length, so a 200mm lens will give the same magnification factor on the frame as a 300mm lens on a 35mm camera. You could spend about 500 pounds on a body but you'd need to splash out a bit on a longer fast lens. As you already have Nikon kit, I suspect you'll be better off sticking with them as your existing lenses should be compatible, if effectively a bit longer. Signatureinvalid = com > > Thanks for the info. Im thinking of switching to digital for nature > > photography. Do you think that the technology is good enough? How [quoted text clipped - 13 lines] > be better off sticking with them as your existing lenses should be > compatible, if effectively a bit longer. great advice. I ordered for a D50 body. Im curious what is the multiplication factor from film to analog? Is it constant across manufacturers of lenses/bodies? thanks -kamal > great advice. I ordered for a D50 body. Im curious what is the > multiplication factor from film to analog? Is it constant across > manufacturers of lenses/bodies? Excellent! A fine purchase. The multiplication factor varies with the size of the digital sensor:- Canon EOS Full Frame (1D and 5D): 1x Canon EOS Consumer 400D, 30D et al: 1.6x APS-C cameras (Most, including your Nikon): 1.5x 4/3 (four thirds) system (Olympus): 2x These are approximate and depend on whether you're interested in the width, the height or the diagonal as they are all slightly different shapes, and they all relate to 35mm film SLR format of 24mm x 36mm. Enjoy. Rich Thanks. Does the angle of coverage also get halved when focussing distance increases by 2? regards -kamal > > great advice. I ordered for a D50 body. Im curious what is the > > multiplication factor from film to analog? Is it constant across [quoted text clipped - 16 lines] > > Rich > Thanks. Does the angle of coverage also get halved when focussing > distance increases by 2? Not sure what you mean. Comparing your APS-C format D50 camera with 35mm. The same 200mm lens has the same covering power (that is the image circle) on the film/sensor plane, it is just that your sensor only covers 2/3 of the area the 35mm film covers from the middle of the picture area. It is actually all about cropping; take a photo from 35mm and crop 1/6 off all the way round. The resulting picture is the same frame that you'd get from the D50 using that lens. Which means that the photo taken through a 200mm lens would give the same frame that a 35mm camera would take through a 300mm lens (200 x 1.5 = 300). All relative calculations stay the same, so an object twice as far from the camera will still be half the size on the sensor. Rich > > Thanks. Does the angle of coverage also get halved when focussing > > distance increases by 2? > > Not sure what you mean. The specs for lenses mention the angle of coverage (FOV?). so a 35 mm lens has a higher angle of coverage, and as the focal length increases to 50 mm, the angle decreases from 62 degrees to 44 degrees. ref:- http://www.nikonusa.com/template.php?cat=1&grp=5&productNr=1923 http://www.nikonusa.com/template.php?cat=1&grp=5&productNr=2137 > Comparing your APS-C format D50 camera with 35mm. > [quoted text clipped - 3 lines] > about cropping; take a photo from 35mm and crop 1/6 off all the way round. The > resulting picture is the same frame that you'd get from the D50 using that lens. yeah i meant cropping by 1/<multiplying facotr> when focal length increases by given multiplying factor. regards -kamal > Which means that the photo taken through a 200mm lens would give the same > frame that a 35mm camera would take through a 300mm lens (200 x 1.5 = 300). [quoted text clipped - 3 lines] > > Rich > Thanks for the info. Im thinking of switching to digital for nature > photography. Do you think that the technology is good enough? How > expensive a camera wuld give me reasonable images? Sure, unless you are doing very large prints. I get nice results with 6MP at 13x19 inch. > I have an N75 with > 24-120mm f/3.5-5.6 Nikkor Is that the VR lens? If not it may not be all that useful. If so, it would be handy but you would still probably want a wider lens such as the kits lenses. A used D70 with the 18-70 lens is your best affordable option though the D50 is smaller if you like that and a tad better low light performance but a lesser kit lens. Or look at a D80 for the big bright viewfinder and then maybe just get the body & wait till you can afford a 12-24 lens. Some of the 3rd party wide zooms are not bad. For nature photography (wildlife) you'll want a fast expensive long lens some day but the digital crop frame will give you a 1.5x advantage on your old lens to start with. > and a point and shoot 28-120mm canon film > camera [quoted text clipped - 53 lines] >>film) and commensurately overdeveloped by 2 stops, although I am >>experimenting with some superfast B&W emulsions. SignaturePaul Furman http://www.edgehill.net/1 Bay Natives http://www.baynatives.com > Is that the VR lens? If not it may not be all that useful. If so, it > would be handy but you would still probably want a wider lens such as [quoted text clipped - 3 lines] > bright viewfinder and then maybe just get the body & wait till you can > afford a 12-24 lens. Some of the 3rd party wide zooms are not bad. I think the Tokina 12-24 is supposed to be pretty good. I have been very impressed with the Tokina 80-200mm and I don't expect that the 12-24 will disappoint me if I should get hold of it. SignatureThomas T. Veldhouse Key Fingerprint: D281 77A5 63EE 82C5 5E68 00E4 7868 0ADC 4EFB 39F0 > > Thanks for the info. Im thinking of switching to digital for nature > > photography. Do you think that the technology is good enough? How [quoted text clipped - 7 lines] > > Is that the VR lens? If not it may not be all that useful. If so, it yes -its a VR lens. Its still not useful in low-light conditions. > would be handy but you would still probably want a wider lens such as > the kits lenses. A used D70 with the 18-70 lens is your best affordable kit lenses? The ones that are bundled with the dslr body? More often than not, they are the cheaper ones and don't function well in low-light. Its a marketing stunt to bundle the cheapest lens with the body and show them that we are giving you a giant zoom lens which is all you will ever need. > option though the D50 is smaller if you like that and a tad better low > light performance but a lesser kit lens. Or look at a D80 for the big [quoted text clipped - 4 lines] > some day but the digital crop frame will give you a 1.5x advantage on > your old lens to start with. which of the Nikkors would you recommend? I like sunset shots [and sunrise too -but can't get up on time] and some lit-up architecture. thanks -kamal > > and a point and shoot 28-120mm canon film > > camera [quoted text clipped - 61 lines] > Bay Natives > http://www.baynatives.com >>>Thanks for the info. Im thinking of switching to digital for nature >>>photography. Do you think that the technology is good enough? How [quoted text clipped - 9 lines] > > yes -its a VR lens. Its still not useful in low-light conditions. Useful in low light but not for action in low light. >>would be handy but you would still probably want a wider lens such as >>the kits lenses. A used D70 with the 18-70 lens is your best affordable [quoted text clipped - 4 lines] > body and show them that we are giving you a giant zoom lens which is > all you will ever need. The D70 18-70 kit lens gets good reviews and it's not particularly cheap at around $300. It's not a fast lens, for that get the $1,700 17-35, 24-70 and 70-200 f/2.8's. >>option though the D50 is smaller if you like that and a tad better low >>light performance but a lesser kit lens. Or look at a D80 for the big [quoted text clipped - 7 lines] > which of the Nikkors would you recommend? I like sunset shots [and > sunrise too -but can't get up on time] and some lit-up architecture. See above if you don't have budget constraints. Another option is prime lenses, that's the only way you'll get faster than f/2.8 anyways. And any f/2.8 zoom will cost you a mint. I just bought an old manual 28mm f/2.0 AI-S for $200 or for AF on a budget look at the 35mm f/2 used or a 24 or 28mm f/2.8. A classic 50mm f/1.8 is nice & cheap but too long on digital for normal field of view landscapes. I have a 12-24 and I just love that wide andgle for architecture and certain landscape scenes. It's rarely necessary to have a fast lens that wide. If you aren't shooting wildlife, you don't need a particularly fast or long telephoto and your 24-120 should be fine. If you want low light performance get a fast normal prime. SignaturePaul Furman http://www.edgehill.net/1 Bay Natives http://www.baynatives.com > >>>Thanks for the info. Im thinking of switching to digital for nature > >>>photography. Do you think that the technology is good enough? How [quoted text clipped - 11 lines] > > Useful in low light but not for action in low light. No -it looses on many details in low-light even for still subjects. > >>would be handy but you would still probably want a wider lens such as > >>the kits lenses. A used D70 with the 18-70 lens is your best affordable [quoted text clipped - 6 lines] > > The D70 18-70 kit lens gets good reviews and it's not particularly cheap I haven't decided to move to a DSLR as yet. Maybe I will first buy some lenses, and then switch at the right time. > at around $300. It's not a fast lens, for that get the $1,700 17-35, > 24-70 and 70-200 f/2.8's. Yeah the problem with inexpensive lenses is that they aren't fast. Im looking for fast lenses , some wide-angle, some macro and some telscopic. Wide-angle would be for landscape in low-light, macro for architecture with dim lighting and telescopic could be a slower one -but for shots of wildlife. > >>option though the D50 is smaller if you like that and a tad better low > >>light performance but a lesser kit lens. Or look at a D80 for the big [quoted text clipped - 9 lines] > > See above if you don't have budget constraints. Another option is prime I very much do have budgetary constraints. > lenses, that's the only way you'll get faster than f/2.8 anyways. And > any f/2.8 zoom will cost you a mint. I just bought an old manual 28mm > f/2.0 AI-S for $200 or for AF on a budget look at the 35mm f/2 used or a > 24 or 28mm f/2.8. A classic 50mm f/1.8 is nice & cheap but too long on > digital for normal field of view landscapes. I have a 12-24 and I just Ive asked someone to get me a 50 mm f/1.4 brand new and this is for my N75 film slr. > love that wide andgle for architecture and certain landscape scenes. > It's rarely necessary to have a fast lens that wide. If you aren't Agreed. > shooting wildlife, you don't need a particularly fast or long telephoto > and your 24-120 should be fine. If you want low light performance get a > fast normal prime. Yeah -Im looking around for suitable primes for <$500. -preferably with AF. thanks -kamal > -- > Paul Furman > http://www.edgehill.net/1 > Bay Natives > http://www.baynatives.com > The D70 18-70 kit lens gets good reviews and it's not particularly cheap > at around $300. It's not a fast lens, for that get the $1,700 17-35, > 24-70 and 70-200 f/2.8's. While not a fast lense, it is not horribly slow either. At f3.5 wide open, it does a pretty decent job. The Canon equivalent is MUCH slower throughout its range. SignatureThomas T. Veldhouse Key Fingerprint: D281 77A5 63EE 82C5 5E68 00E4 7868 0ADC 4EFB 39F0 |
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