camera lense Q
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- JamesBoynton
Looking to learn a little more about photography and planning on getting something from the eos range. Anyway i was looking at this lense (and lots of others like it) and wondered what the 'f/3.5-5.6' referred to? Also do lenses/descriptions normally state the highest f-stop number, my old camera goes from 4-20ish?
cheers
- dibec0
the minimum f-stop for a given focal length generally in "zoom" lenses.
- dibec0
the minimum meaning the largest aperture.
- schjetne0
f/3.5-5.6 refers to the widest apertures at each end of the zoom.
- JamesBoynton0
ahh cool, so the f3.5 is the minimum for the minimum focal length, and the 5.6 is the minimum for the maximum facal length? or have i got that completely wrong?
- JamesBoynton0
Got it, thanks guys!
- dibec0
example ... Canon EF 28-135mm f/3.5-5.6 IS USM Lens
at 28mm you can have 3.5 aperture.
at 135mm you can gave 5.6 aperture.Canon EF 17-40mm f/4.0 L USM Lens
Any where from 17mm-40mm your largest aperture will be 4.0.in case you don't have this link ... http://www.the-digital-picture.c… ... by far one of the best lens review sites for Canon products.
- JamesBoynton0
cool, thanks!
- sikma0
- maybe it will help....sikma
- hey nice ... i always knew what f-stops were but never knew how they came to those numbers. would look great in color!pizzafire
- ... colorpizzafire
- WTF?freitag
- So, if the focal megth was 50, the max apeture would be f2? gah, too hard for me!JamesBoynton
- if your lens if a 50mm f2 would be a 25mm opening.sikma
- dibec0
I love dirty camera talk. It gets my cylinders firing.
- vaxorcist0
The practical meaning is this, an F3.5 to 5.6 lens means you will use a flash more in low light than an f2 or F1.8 lens, because the lens lets in less light at it's most open aperture setting.
Most cheaper zoom lenses make a compromise, they are F3.5-4.5 or 3.5 - 5.6 lenses, whereas non-zoom lenses are often F1.8, and expensive zoom lenses are often F2.8.
In bright light, on a sunny day, you can shoot at F16 and 250th at 100 ISO, in the shade, F8 to F11... any lens will do....
BUT in the shade, or indoors, you may want a faster (i.e. smaller F number, but "larger" aperture)
At F5.6, a lens lets in less light than a lens set to F4 or F2.8 or F2.
At 400 ISO, indoors, you may shoot F2 at 125th shutter, or F2.8 at 60th, or F4 at 30th or F5.6 at 15th. Therefore, your F5.6 lens has a shutter speed that may be too slow, even slow-ish with an image stabilizer.
The other Aperture issue is depth of field. If you want very little depth of field, to get a certain nicely out of focus background look, an F1.8 lens will do this more elegantly than a F5.6 lens, where the background will be less nicely blurry. Depth of field depends on distance and focal length too... if you get as close as possible, and shoot at your longest zoom setting, you will get as little depth of field as your lens can offer if you shoot at the widest (lowest F number) aperture....
A 28-135 lens, if you shoot at 4 feet, F5.6 at 135 zoom, say, for a headshot, the background will be mostly out of focus if it's 10 feet or so away from the subject. If you're using an 85mm F1.8 lens, the background is more easily and beautifully out of focus, even if it's closer to the subject....
sorry for the long note, ... geeky but cool....
- Projectile0
basically, when it comes to both f-stop and angle, the lower the number the better IMO. As your basic lens, you want wide angle, not zoom.. so the 17mm is definitely the better lens. A 28mm angle looks like it was taken with a compact- so generic.
F-stop, you want as low as possible, here the higher number is completely irrelevant. even in direct sunlight you can just up the shutter speed.. but in low light you dont want your shutter speed too slow or it blurs. And the wider your aperture the better your focal depth.
- seeessess0
It's lens not lense.
- ok_not_ok0
Very confusing, this is why I only use prime lenses.