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06/23/2006 05:12:12 PM · #1 |
I don't think I am using my lens correctly. Is there only one piece on the lens that I should be working, the part that zooms in or out? Is there another ring on the lens that I should be working as well?
Also
How is it that my lens only goes between 4-5.6 and when I have the lens on I can still change the F stop on the camera to 7 or more?
Sorry for the dumb questions, this is all so new to me.
Thanks |
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06/23/2006 05:18:00 PM · #2 |
4 is the WIDEST aperture on the wide end. 5.6 is the WIDEST aperture on the telephoto end. People don't normally care about the narrowest aperture as much, so it's not specified on the lens.
Your lens has a zoom ring and a focus ring. You can use the focus ring for manual focus if you set the camera appropriately (I think there's one switch on the camera body and the other on the lens itself?). You can't do anything with it if the camera is set on autofocus.
Other lenses can also have an aperture ring. |
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06/23/2006 05:20:42 PM · #3 |
OK, the one that zooms it is right, you're working that correctly. It should also have another ring for focus, but only use it if you are using your camera in Manual focus.
The f/4-5.6 thing:
F/4-5.6 Is the most the lens will open at a given focal length. At 70mm it should be able to go down to f/4 at 300mm it will go down to f/5.6. But for any focal length it can still stop-down (bigger number) to up to f/22.
Edit: darn I was slow. :-(
Message edited by author 2006-06-23 17:21:33.
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06/23/2006 05:21:00 PM · #4 |
| There should be a switch on the barrel of the lens for manual/auto focus. If the lens is not focusing, check that switch... |
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06/23/2006 05:29:37 PM · #5 |
Thank you for not making me feel like a complete idiot :-)
"4 is the WIDEST aperture on the wide end. 5.6 is the WIDEST aperture on the telephoto end."
Does the above mean that I can use both ends of the lens?
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06/23/2006 05:31:35 PM · #6 |
Originally posted by Karalew:
Thank you for not making me feel like a complete idiot :-)
"4 is the WIDEST aperture on the wide end. 5.6 is the WIDEST aperture on the telephoto end."
Does the above mean that I can use both ends of the lens? |
Both ends of the Zoom not the lens.
70mm = f/4
300mm = f/5.6
Maximum Aperture
Message edited by author 2006-06-23 17:33:45. |
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06/24/2006 11:52:28 AM · #7 |
Thank you! Can we do F/stops again.
The lower the number 2.8 means that you will have a blurred background? So 2.8 is a high or low F stop? I don't think I am totally understanding F stops.
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06/24/2006 12:00:00 PM · #8 |
| The f-stop refers to how big of a 'hole' (if you want to call it that) is in your lens. The lower the number, the bigger the opening. That's why it lets in more light at a given shutter speed. And yes you are correct, larger f stops (meaning smaller numbers such as the 2.8 example you gave) result in a shallower depth-of-field, resulting in blurred backgrounds etc. |
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06/24/2006 12:14:29 PM · #9 |
I remember it as f/stop is really a fraction...
1/2.8 is a larger number than 1/8, larger the number the bigger the openning of the aperture. f/2.8 allows more light, where as f/22 is a smaller openning allowing less light.
When we say stop down we mean choose smaller apperture or larger f/number (i.e f/11 or f/22)
When we say open up the apperture it really means to choose a smaller f/number (i.e f/2.8)
Squint your eyes and focus on something...that is like f/2.8, focus on the same subject but with your eyes wide open and the scene is brighter and more objects are in focus...that is closer to f/11.
and thats my non-technical explaination... |
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06/24/2006 12:19:45 PM · #10 |
Your f/stop is a ratio that describes the relationship of the physical diameter of the aperture itself to the focal length of the lens. In other words, a 25mm aperture in a 50mm lens would be f/2.0, and the same 25mm aperture in a 200mm lens would be f/8.0.
Most consumer zoom lenses have a fixed largest aperture, so the longer you zoom them, the smaller the f/stop is; if that makes sense? Many more expensive lenses have a variable largest aperture, so as you zoom longer the aperture actually is expanded in order to maintain a constant f/stop.
Hence, one lens might be "10-22mm f/3.5-4.5" (fixed maximum aperture = variable maximum f/stop) where another might be "28-75mm f/2.8" (variable maximum aperture = constant maximum f/stop).
Regarding which is largest and which is smallest, it helps to visualize your f/stop as a reciprocal: f/4.0 = 1/4 the focal length in size, while f/22 = 1/22 the focal length in size; clearly, 1/4 is a larger fraction than 1/22, and just as clearly f/4 is a larger aperture than f/22.
Hope this helps.
Robt.
I see Pollard beat me to the same thought...
Message edited by author 2006-06-24 12:20:31.
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