coy5coy
1.
Canon EF-S 17-85MM f4-5.6 IS USM Standard Zoom Lens
can someone please break this down so I can understand how to read this please?
2.
Canon EF-S 17-85MM f4-5.6 IS USM Standard Zoom
Canon EF 70-300mm f/4.5-5.6 DO IS USM Telephoto Zoom Lens
why would anyone want a zoom lens that stops at 85MM, isnt the larger the number better the zoom? Wouldnt the 300mm be much better because it zooms in better?
Answer
Canon is the manufacturer of the lens, meaning that the lens will mount onto a Canon body.
The focal length (e.g., "70-300mm) is the field of view that the lens can see. A "Normal" focal length is about 35mm on a consumer Canon DSLR and 50mm on a 35mm SLR. This gives roughly the perspective that we, as people, see. A wider lens can see more of a scene (think really big landscapes), but the perspective is exaggerated and as something gets close to the camera is starts to appear much larger. An example of this is the classic image of a dog poking it's nose towards camera; the nose will look really big while the rest of the dog is small because it's further back. A telephoto lens makes a distant scene look bigger (smaller field of view) and also flattens the picture. Think of a telephoto lens as being like a pair of binoculars and a wide angle lens as being those binoculars turned around backward.
EF stands for "ElectroFocus." This means that it is autofocus and will mount on an EOS camera (Any DSLR, recent 35mm SLR's too). An acronym of EF-S means that the lens will only work on cropped-sensor (aka, APS-C) DSLR's such as the Rebel series (or 300D/350D/400D/450D/1000D) and 10D/20D/30D/40D series. It will mount on any EOS camera, but light will not hit the corners of the image sensor or film on a non-cropped camera, and this will result in a big black circle near the edges of the image.
IS stands for image stabilization. This means that there are mechanisms in the lens that helps reduce the shake caused by hand holding it, which in turn makes it easier to shoot sharp images in low light situations.
USM is an UltraSonic Motor. A USM mechanism is virtually silent, and generally focuses much faster than non-USM glass.
DO means "Diffractive Optics" in Canon jargon, and DO lenses can be identified as having a green ring around the lens body towards the front of the lens. Diffractive Optics is a technology that allows very sharp lenses with virtually no chromatic aberration. These lenses are normally a bit smaller than one would expect for their focal length/speed as DO is used to reduce the need for huge pieces of glass, but these lenses are also very expensive. I've never heard of a bad DO lens.
Zoom, of course, means that the lens can change it's focal length -- zoom in and out. Zooms have generally lower image quality than a comparable fixed or prime lens, that does not zoom. A bigger zoom range does not imply better. As lenses are made to zoom more, they lose image quality because you're trying to make the same glass work for a wide range of focal lengths. Basically, you're making the glass perform at an okay level for any given focal length, but never excel at any given one either. A fixed/prime lens will usually give the best optical quality. After that, a small zoom range (16-30mm) will give the next best quality, then a medium zoom range (18-55mm), and a large zoom range (18-200mm or 70-300mm) will give the least optical quality. This is just a general guideline of course, optical quality varies significantly from lens to lens. The 17-85mm IS lens will be a better option if you had to choose just one lens right now, as it covers the "Normal" range, which is where the majority of your shots will come from. The 70-300 DO is an amazing lens, and would be a great second lens.
The f/# is the maximum aperture of the lens. A smaller number is generally better, as the lens can perform in lower-light situations and can also "Sweet spot" (get to it's best working conditions) at a lower aperture as well. A bigger aperture (lower number) means that there is a bigger hole for light to pass through in the lens, which means more light reaches the sensor in a given time, and thus the sensor can record the image faster than with a lens at a lower f/#.
Canon is the manufacturer of the lens, meaning that the lens will mount onto a Canon body.
The focal length (e.g., "70-300mm) is the field of view that the lens can see. A "Normal" focal length is about 35mm on a consumer Canon DSLR and 50mm on a 35mm SLR. This gives roughly the perspective that we, as people, see. A wider lens can see more of a scene (think really big landscapes), but the perspective is exaggerated and as something gets close to the camera is starts to appear much larger. An example of this is the classic image of a dog poking it's nose towards camera; the nose will look really big while the rest of the dog is small because it's further back. A telephoto lens makes a distant scene look bigger (smaller field of view) and also flattens the picture. Think of a telephoto lens as being like a pair of binoculars and a wide angle lens as being those binoculars turned around backward.
EF stands for "ElectroFocus." This means that it is autofocus and will mount on an EOS camera (Any DSLR, recent 35mm SLR's too). An acronym of EF-S means that the lens will only work on cropped-sensor (aka, APS-C) DSLR's such as the Rebel series (or 300D/350D/400D/450D/1000D) and 10D/20D/30D/40D series. It will mount on any EOS camera, but light will not hit the corners of the image sensor or film on a non-cropped camera, and this will result in a big black circle near the edges of the image.
IS stands for image stabilization. This means that there are mechanisms in the lens that helps reduce the shake caused by hand holding it, which in turn makes it easier to shoot sharp images in low light situations.
USM is an UltraSonic Motor. A USM mechanism is virtually silent, and generally focuses much faster than non-USM glass.
DO means "Diffractive Optics" in Canon jargon, and DO lenses can be identified as having a green ring around the lens body towards the front of the lens. Diffractive Optics is a technology that allows very sharp lenses with virtually no chromatic aberration. These lenses are normally a bit smaller than one would expect for their focal length/speed as DO is used to reduce the need for huge pieces of glass, but these lenses are also very expensive. I've never heard of a bad DO lens.
Zoom, of course, means that the lens can change it's focal length -- zoom in and out. Zooms have generally lower image quality than a comparable fixed or prime lens, that does not zoom. A bigger zoom range does not imply better. As lenses are made to zoom more, they lose image quality because you're trying to make the same glass work for a wide range of focal lengths. Basically, you're making the glass perform at an okay level for any given focal length, but never excel at any given one either. A fixed/prime lens will usually give the best optical quality. After that, a small zoom range (16-30mm) will give the next best quality, then a medium zoom range (18-55mm), and a large zoom range (18-200mm or 70-300mm) will give the least optical quality. This is just a general guideline of course, optical quality varies significantly from lens to lens. The 17-85mm IS lens will be a better option if you had to choose just one lens right now, as it covers the "Normal" range, which is where the majority of your shots will come from. The 70-300 DO is an amazing lens, and would be a great second lens.
The f/# is the maximum aperture of the lens. A smaller number is generally better, as the lens can perform in lower-light situations and can also "Sweet spot" (get to it's best working conditions) at a lower aperture as well. A bigger aperture (lower number) means that there is a bigger hole for light to pass through in the lens, which means more light reaches the sensor in a given time, and thus the sensor can record the image faster than with a lens at a lower f/#.
all SLR cameras lens i want to understand?
XDXD
i want to know if all SLR brands can be used the same lens or different ones etc. like a Nikon lens on a canon camera or vice visa or other brands
thats A LOT of money you think anyone has made an extra extension to be place on lets say a canon camera and the extension is allowed to have any lens? because that would be very interesting product to buy
Answer
All camera manufacturers use a proprietary lens mount. Canon lenses for Canon, Nikon lenses for Nikon, Sony lenses for Sony, Penax lenses for Pentax, Olympus lenses for Olympus. The exceptions are Samsung and Fuji. Fuji DSLRs are built using a Nikon chassis and lens mount. Samsung DSLRs are built using a Pentax chassis and lens mount. Sony uses the Minolta Maxxum A-mount that dates back to 1985.
There are adapters that allow you to use a Nikon lens on a Canon or a Minolta SR (manual focus) mount lens on a Sony or Canon or Pentax or Olympus. The problem with adapters is that you have to use the lens in stop-down metering and manual focus. (Each camera requires a separate adapter).
The Tamron "Adaptall" adapters use the M42 screw mount on the lens and an adapter designed for each camera body. With it you could have a Pentax body and a Canon body and use the same lens on both cameras.
Minolta SR mount 250mm mirror lenses go for a premium on eBay and the word is they are being retrofitted with a Nikon mount. I've also seen a couple of SR mount lenses that have had the mount modified to mount to the Sony DSLR, supposedly with full metering.
All in all its still best to buy lenses designed for your camera.
All camera manufacturers use a proprietary lens mount. Canon lenses for Canon, Nikon lenses for Nikon, Sony lenses for Sony, Penax lenses for Pentax, Olympus lenses for Olympus. The exceptions are Samsung and Fuji. Fuji DSLRs are built using a Nikon chassis and lens mount. Samsung DSLRs are built using a Pentax chassis and lens mount. Sony uses the Minolta Maxxum A-mount that dates back to 1985.
There are adapters that allow you to use a Nikon lens on a Canon or a Minolta SR (manual focus) mount lens on a Sony or Canon or Pentax or Olympus. The problem with adapters is that you have to use the lens in stop-down metering and manual focus. (Each camera requires a separate adapter).
The Tamron "Adaptall" adapters use the M42 screw mount on the lens and an adapter designed for each camera body. With it you could have a Pentax body and a Canon body and use the same lens on both cameras.
Minolta SR mount 250mm mirror lenses go for a premium on eBay and the word is they are being retrofitted with a Nikon mount. I've also seen a couple of SR mount lenses that have had the mount modified to mount to the Sony DSLR, supposedly with full metering.
All in all its still best to buy lenses designed for your camera.
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