LIKES 0. Oct 29, 2. I didn't think it worked this way for camera's with interchangeable lenses, you have no start point. Oct 29, 3. Oct 29, 4. Oct 29, 5. Oct 29, as a reply to beanster's post 6. Oct 29, 7. Oct 29, 8. Oct 29, 9. Oct 29, This site by Canon may help you.
Sibil Sibil Cream of the Crop. To get the binocular-like viewfinder magnification value of a lens, divide the focal length by A formula that is easier for me at least to calculate in my head is to divide the focal length by and multiply by 2. Just move the decimal point two places to the left and multiply by 2. Another example: For a mm lens, divide mm by to get 1.
Multiply 1 x 2 to get 2x magnification. At mm, it is about 8 degrees. At mm the lens will have the equivalence of a mm lens on a 35mm film camera or Nikon FX Full Frame digital camera. Focal lengths such as mm or mm would be a large, heavy telephoto lens for taking photos of birds or airplanes. Just remember — a small number is wide, a large number is telephoto.
Two numbers together, e. The IS is the better wildlife lens. It offers slightly better colors, is just about as sharp as the F4 L, and is built better than the IS. Not to mention it has 50 more mm of reach, which is actually quite important for wildlife.
Thanks Brooks P, I was trying to establish zoom on canon sx20 point and shoot camera. But your explaination make sense. Do you guys have any opinion on the quality of this lens for outdoor shooting nature, landscape, birds etc.
It's a budget lens - and you get what you pay for. I had one and think it was one of my worst photographic purchases. Some people get passable results in really good light and seriously stopped down but you are better off saving the money and putting it towards something better. Having used various lenses, the Sigma APO version is by far the best. I use it for aviation images, so usually good light etc. Well pleased with it. In the Nikon DX world that would probably be the 18mm lens since the and are fairly standard kit lenses.
So if you take and divide it by 18 you get the equivalent of it being a 16x lens, meaning that it goes 16 times what the base mm is. For us in the SLR world, it is basically a useless calculation, but for someone trying to decide what moving to the SLR world would mean, it might have some use.
So you'll get longer range on D So the is only a 4. In my Sony F had a 5x zoom, 38 to mm and its replacement the F had a 7x zoom, 28 to mm. A competing model at the time, the Nikon Coolpix , had an 8x zoom — 35 to mm. The focal length remains the same regardless of the size of the sensor; the focal length is a constant. In simple terms the focal length is a measurement of the distance from the lens to the point where the light rays converge focus. Because the DX sensor is smaller the mm lens functions like a mm lens on the larger sensor found in a FX camera.
That is because the image is being cropped, only a portion of the image is captured by the smaller sensor. The diameter of the lens can be made smaller so that image circle is smaller but the distance from the lens to the point of convergence does not change and therefore objects in the image will still be the same size.
Due to this phenomenon the DX sesnsor has what is called a crop factor, and that crop factor is 1. The focal length of all lenses, whether they are FX or DX, must be multiplied by the 1. The operative word is equivalent, because the actual focal length , the focal length printed on the lens, never changes, no more than does the number of inches in a foot or the number of feet in a mile. I somehow had this idea that we start with a 50mm standard 35mm film camera ; convert to DX equivalent by adjusting with the crop factor; thus 50mm on my old AE-1 is 35mm give or take on DX; then we take the max reach of the lens and divide by So, 35mm is 1x, 70mm is 2x, etc, and mm is what, 8.
That gives a more 'meaningful' comparison because we all know what 50mm equivalent is with our given crop factor. I'm probably wrong and will be flamed to extinction. I think that this thread shows that while photographers have done a great job at establishing a transferable base line for exposure they have not done such a good job at developing a useful standard for lenses.
Any knowledgeable photographer can work his way around any camera--aperture--ISO film or sensor --shutter-speed combination and if armed with a working meter can get a properly exposed image. While I've never used a large format camera I'm reasonably confident that I could make a picture with one as long as I know my film speed and shutter speed and have control of my aperture.
Unfortunately this inter-format continuity does not exist when expressing zoom. When someone on this forum states that they were using their 85mm lens for a portrait it means very little. We need to know the size of the sensor that is being used for a focal length to have any bearing. Every camera has it's own sensor size and subsequent zoom ranges. After a while most of us get a handle on the big conversions that are needed for common DSLRs and we all seem to use a baseline of 35mm film.
I convert quite quickly in my head that the 85mm lens on a D3 is about the same as that same lens on a 35mm film camera. The E3 behaves more like a mm lens on film.
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