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Old Dec 15, 2006, 10:52 PM   #1
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Isawa photo taken with the following settings:

Focal length = 34mm, Exposure Time= 1/250s, Aperture f/10, ISO 100, with D200 + 18-200mm f/3.5-5.6G lens.

Two questions:

1. How to achieve this setting? I have the same equipment as above.

2. How is it possible to set the aperture to f/10, when the lens is only f/3.5-5.6? Also for that matter, is it then possible to set the aperture to f/2 (for example)?

Please feel free to be detailed as I am a novice.

I followed the instructions in the manual, but could not achieve the above settings. The manual is not helpful. I purchased Thom Hogan's guide on D200, but the CD has not arrived yet. I am really looking forward to it.
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Old Dec 15, 2006, 11:44 PM   #2
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photino wrote:
1. How to achieve this setting? I have the same equipment as above.
Unless the lighting is identical, you'd probably need to use manual exposure (M position on your mode dial) and set both the aperture and the shutter speed to get the settings identical. The control wheels are designed to let you dial in the desired settings (just watch your viewfinder as you spin them and you can watch the changes).

But, if the lighting is not the same, you'd end up with an overexposed or underexposed image, depending on the ISO speed you used. ;-)

You can't just use settings at random. You have to use settings that match the conditons. In most conditions, Aperture Priority is a better way to go for more control, since you can use the aperture to control depth of field, and let the camera select the correct shutter speed for proper exposure. So, that can be much easier than using manual exposure and watching the meter in the viewfinder to dial in your settings for both variables.

Think of the aperture opening in a lens as a pupil in your eye. If you open up the aperture wider (smaller f/stop numbers), more light gets through, allowing you to expose the image faster for the same lighting and ISO speed (ISO speed represents how sensitive the sensor or film is to light).

If you use a smaller aperture (higher f/stop number), less light gets through (so it will take longer to "expose" the film or sensor, requiring slower shutter speeds for proper exposure for a given ISO speed and lighting).

2. How is it possible to set the aperture to f/10, when the lens is only f/3.5-5.6?
Lenses are rated by their largest available apertures (smaller f/stop numbers), and for most (but not all) zoom lenses, you'll see two aperture ratings... the first one is for the widest aperture at the wide end of the lens (least apparent magnification), and the second is the widest aperture at the long end of the lens (most apparent magnification).

You can still use smaller apertures (higher f/stop numbers). Most lenses can go down to at least f/22 (and some can go all the way to f/45).

The largest available aperture (smallest f/stop number) will fall somewhere in between the two numbers you'll see for a lens' specs at focal lengths in between the two extremes.

Some zoom lenses can maintain a constant aperture throughout their focal range (with f/2.8 being the most common). Of course, a brighter zoom lens is larger, heavier and more expensive. For indoor use without a flash, a lens with a constant f/2.8 aperture is preferred in a zoom (but, a brighter prime is even better, allowing faster shutter speeds and/or lower ISO speeds for the same conditions).

Aperture as expressed by f/stop is a ratio, and is determined by dividing the focal length of the lens by the size of the iris opening.

The aperture scale (in one stop increments) goes f/1.0, f/1.4, f/2.0, f/2.8, f/4.0, f/5.6, f/8.0, f/11, f/16, f/22, etc. With each one stop move to a smaller aperture (represented byhigher f/stop numbers), you will need shutter speeds twice as long for proper exposure.

So, a lens with a larger available aperture (smaller f/stop number) is desired to get fast enough shutter speeds to reduce motion blur (either from camera shake or subject movement) in many conditions.

Of course, the downside to using larger apertures is a shallower depth of field. This can be a pro or a con, depending on what you're shooting. But, for portraiture, you typically want a shallower depth of field (to help your subject stand out from distracting backgrounds). Again, just because a lens has larger available apertures, doesn't mean you need to shoot that way.

Also for that matter, is it then possible to set the aperture to f/2 (for example)?
Sorry, your lens has a largest available aperture of f/3.5 at it's wide angle lens position (least apparent magnification), and f/5.6 at it's full telephoto zoom position (most apparent magnifcation). You won't have f/2 available at any focal length.

In a lens with the zoom range of your 18-200mm, it's just not practical to make a lens that bright (f/2 available). It would be far too large and heavy. That's why a prime (fixed focal length, non-zoom lens) is a popular choice for low light use. You can find them smaller, brighter and sharper than a zoom (but, you give up the convience of a zoom). There are always tradeoffs.

BTW, for more information on how aperture impacts Depth of Field, see this Depth of Field Calculator:


Again, lenses can also use smaller apertures than the largest available (and a lens isn't going to be as sharp at wide open apertures anyway, so "stopping down" a bit can yield sharper photos, and you've got more room to stop down with a prime starting out with larger apertures versus a zoom that may start out at f/2.8 or smaller). But, you need to keep an eye on shutter speeds in less than optimum lighting, no matter what lens you use.

Here is a handy online exposure calculator that lets you see how larger apertures impact shutter speeds, in 1/3, 1/2 or 1 stop increments (you can change this via check boxes at the bottom). Film speed in this calculator is the same thing as ISO speed.


You may also want to get a book on basic photography and read it. The basic concepts of photography are going to be the same for film or digital.

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Old Dec 15, 2006, 11:57 PM   #3
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Dear JimC,

Thank you so very much for your time and your detailed and very helpful explanation!! I appreciate it very much. I've borrowed somebooks from my local library onphotography, and I'm looking forward to reading morebooks.

BTW, the link at the bottom of your message is one of the best readings I have done on this subject. Thank you!!

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Old Dec 18, 2006, 3:32 PM   #4
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The F-stop was F-10 not F-1.0, In program mode the F-stops are set by the computer and could be F-10 which is between F-8 and F-16. It would then tell in the cameras data what the setting when shot was used. The 18/200 is F-3.5 wide open.

Jim C has given you a lot of good information, You should really print it out and keep it.

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