~SparkyArt

A friend of mine, well, I thought they were a friend, said some pretty screwed up things to me and it really upset me. Thought we were friends. We've been 'friends' for like, 14 years. Well, I think it's time to move on and start a new adventure, which is why I will be migrating my account to araine86. This is what I have been promoting myself in real life (actually just araine) so, if you watch me, please move over to this account. That would be much appreciated. This new account will be photography only. I may be not known to the USA as a professional, but I am considered and known as a professional in this town. I have a college education, a nice beginners camera, and an eye, whether some of you want to admit it. And, if you don't think my work is professional and you don't like it, then don't comment on it. I will only want nice comments and critiques that could and would help me in the future. People are not born knowing, they have to learn. So, teach me my friends, and help me become a better artist.

New Account:

More photography knowledge for the beginner's soul.

When you look at the technical specifications of a digital camera, one of the very first specification mentioned is its maximum aperture and/or its aperture range.

What is 'aperture,' what is a good aperture range, and how is aperture relevant when it comes to choosing a digital camera?

What Is Aperture?

The main function of a camera lens is to collect light. The aperture of a lens is the diameter of the lens opening and is usually controlled by an iris.The larger the diameter of the aperture, the more light reaches the film / image sensor.

Aperture is expressed as F-stop, e.g. F2.8 or f/2.8. The smaller the F-stop number (or f/value), the larger the lens opening (aperture).

[Note: Many camera user manuals today will refer to the aperture in terms of "aperture value" instead of f/value. I'm not sure when this trend started but don't get confused between "aperture" and "aperture value." Aperture value" is simply another way of saying f/value.]

In practice, unless you are dealing with a fixed-aperture lens (many simple point-and-shoot cameras have only one fixed aperture), the aperture of a lens is usually expressed as a range of fstops.

When you read the specifications of a camera, the aperture may be expressed in a number of different ways, the following three being the most common:

* Maximum Aperture:

Max. Aperture F2.8

This simply states that the maximum aperture for the lens is F2.8.

* Aperture Range:

Aperture Range F2.8-F8.0

This states the max. and min. aperture, the assumption being that there are standard increments between them.

* Maximum Wide-Angle and Telephoto Apertures:

Aperture F2.8-3.5 or F2.8(W)-F3.5(T)

This gives the max. aperture for the wide-angle (F2.8) and telephoto (F3.5) focal lengths of a zoom lens.

It is usually not too difficult to figure out that a stated range deals with maximum apertures and not max and min apertures: the mimimum aperture should be quite small at F8, F11, F16 or F22.

A "fast" lens is one that has a large maximum aperture (F2.4, F2.0 for current digital cameras; F1.4, F1.2 for 35mm film cameras).

A Good Aperture Range

My personal preference for a 'good' aperture range is:

F1.8 - F16
F1.8 F2.8 F4 F5.6 F8 F11 F16

This tells us that the camera has an aperture range of F1.8 to F16; the maximum aperture is F1.8, and the minimum aperture is F16.

There are 5 f-stops between the max and min aperture. If your camera's lens is currently set at an aperture of F5.6, closing it by 1 f-stop would mean selecting F8; opening it up by 1 f-stop would mean selecting F4.
F1.8 F2.8 F4 F5.6 F8 F11 F16

How Is A Large Maximum Aperture Relevant?

A large maximum aperture is preferable to a smaller one since it gives the photographer more latitude in the kind of pictures that can be taken.

For example, it is pretty obvious that the larger the aperture, the better your digital camera will perform in low-light situations, since a larger lens opening is able to admit more light than a smaller lens opening.

A larger max. aperture also allows you to use a faster shutter speed to freeze action.

So, let's say the light meter in your digital camera calculates that for proper exposure in that indoor arena, you need an aperture of F4 and a shutter speed of 1/60 sec.
F4
1/60

To use a faster shutter speed (say, 1/250 sec.) to freeze action, you have to open up the aperture to allow more light in for that shorter amount of time.

For every shutter speed increment we go up, we need to open up a f-stop of aperture. From 1/60 sec. to 1/250 sec. there are 2 increments, so we open up the aperture by 2 f-stops, going from F4 to F1.8. Note that the camera would give proper exposure at 1/60 sec. at F4, 1/125 sec. at F2.8, and 1/250 sec. at F1.8, since all three aperture/shutter speed combinations allow the same amount of light into the camera. [Some digital cameras provide a 'rogram Shift' function to allow that very shifting of aperture/shutter speed combinations in tandem.]
F1.8 F2.8 F4 F5.6 F8 F11 F16
1/250 1/125 1/60 1/30 1/15 1/8 1/4

Of course, in a digital camera set on Auto mode, you can select Sports scene mode, and the camera will automotically select a fast shutter speed and the appropriate aperture. Likewise, in Shutter-Priority mode, you can choose which shutter speed you want (fast or slow), and the camera will select the appropriate aperture for proper exposure.

In our example above, let's say the lens on your digital camera only opens up to a max. aperture of F2.8. If you now select 1/250 sec. (in Shutter-Priority mode), the camera will not be able to select an aperture larger than F2.8 (in our example, it really needs F1.8). It would then give you an "underexposure" warning. If you go ahead and take the picture anyway, your picture would be 1 f-stop underexposed (i.e. you really needed to open up the aperture by 1 more f-stop for correct exposure).

Similarly, if you select a shutter speed of 1/4 sec. and the lens only closes down to a min. aperture of F8 (in our example, it really needs F16), the camera would give you an "overexposure" warning. If you go ahead and take a picture anyway, your picture would be 2 f-stops overexposed (i.e. you really needed to close down the aperture by 2 more f-stops for correct exposure).

[Editor's note: There is a third variable in the above example which we have purposefully not introduced. This is the sensitivity of the image sensor -- the ISO. We'll cover this in a later tutorial.]

How Is A Small Minimum Aperture Relevant?

A small minimum aperture is preferable to a larger one since it also gives the photographer more latitude in the kind of pictures that can be taken.

Suppose we want to take a picture of flowing water. As mentioned above, to depict flowing water, we usually want to use a slow shutter speed so that the water blurs. It is this blurring that makes the picture so effective in depicting water motion.

So, let's say the light meter in your digital camera calculates that for proper exposure on a bright sunny day, you need an aperture of F8 and a shutter speed of 1/125 sec.
F8
1/125

Well, if you decide to use a slower shutter speed (say, 1/30 sec.), this means that you have to compensate by closing down the aperture to allow less light in.

It makes sense really. Since you have increased the time the shutter remains open to allow light in, you must compensate by allowing less light in to expose the image sensor in that longer amount of time, if you still want a properly exposed picture.

But, what if the lens on your digital camera closes to a minimum of F8? You're stuck at the shutter speed of 1/125 sec. If you use 1/30 sec. at F8, your picture will be overexposed, i.e. burnt out. At 1/125 sec. and F8, your picture will be properly exposed but the fast shutter speed will freeze the water motion and you won't obtain the blurring effect you desire.

If the lens in your digital camera closed down to F16, presto, your problem is solved! 1/125 sec. at F8 is equivalent to 1/30 sec. at F16, which means that you would have a perfectly exposed purposefully-blurred-for-effect flowing water shot. [If your lens does not close down to F16, you could use a Neutral Density (ND) filter to reduce the amount of light coming into the lens, and thus allowing you to use a slower shutter speed.]
F1.8 F2.8 F4 F5.6 F8 F11 F16
1/2,000 1/1,000 1/500 1/250 1/125 1/60 1/30

[Editor's note: There is a third variable in the above example which we have purposefully not introduced. This is the sensitivity of the image sensor -- the ISO. We'll cover this in a later tutorial.]

Aperture and Depth of Field (DOF)

We mentioned this above but feel it is important enough to repeat in its own paragraph.

The Depth of Field is the distance wherein objects are in focus.

There are times when you desire a great depth of field, i.e. where objects both close to you and far from you are in focus. This is especially true when you are taking a landscape picture and want as much as possible to be in crisp focus.

Then there are times when you want to isolate your subject, as when you are taking a portrait and want your subject to be in sharp focus but the background to be out of focus. In this case, you desire a shallow depth of field.

One way to influence DOF is by selecting the appropriate aperture.

The rule of thumb is this:

* Select a large aperture (or small f/value or small aperture value), e.g. f/2.8, to obtain a shallow DOF
* Select a small aperture (or large f/value or large aperture value), e.g. f/8.0, to achieve great DOF

Resource: [link]

This was brought up earlier, and since I didn't know, which explains my noisy pictures when downloaded full verisions, but I figured I would post this as well. To help others out that don't know.

ISO sensitivity expresses the speed of photographic negative materials (formerly expressed as ASA).

Since digital cameras do not use film but use image sensors instead, the ISO equivalent is usually given.

What ISO denotes is how sensitive the image sensor is to the amount of light present. The higher the ISO, the more sensitive the image sensor and therefore the possibility to take pictures in low-light situations.

And, where you would have needed to physically change to a different roll of film if you wanted a different ISO speed, digital technology allows you to simply dial one in. In this way, you can record images taken at different ISO speeds on the same memory card.


ISO Speed & Exposure

ISO speed affects the shutter speed / aperture combinations you can use to obtain correct exposure.

Suppose your digital camera's light meter warns you there is not enough light to correctly expose a scene. You could use the on-board flash, but let's suppose again it's not allowed (like in a concert or indoors recital).

You would then need to use a higher ISO. Set on "ISO Auto" mode, your digital camera will automatically select a higher ISO. Otherwise, you can manually select the next higher ISO and see if the increased sensitivity allows you to obtain a correctly exposed picture. If it does, you can now take a correctly exposed picture.

Similarly, if you find the camera is using a shutter speed that is too slow (1/60 sec. and slower) to handhold the camera steady and shake-free (thus resulting in blurred pictures), and you cannot open up the aperture anymore, and you do not have a tripod or other means to hold the camera steady, and you want to capture the action, etc. etc. -- then you might select the next higher ISO which will then allow you to select a faster shutter speed.


ISO Speed & Noise

However, all this increase in sensitivity does not come free. There is a price to pay with your image appearing more noisy.

See, when you boost the sensitivity of your image sensor by selecting a higher ISO, the image sensor is now able to record a fainter light signal. However, it is also true now that it will record fainter noise, where noise is any signal that is not attributed to the light from your subject. Remember that an image sensor is still an analog device and it generates its own noise, too! The increased sensitivity allows the image sensor to record more light signal and more noise. The ratio of light signal to noise (S/N ratio) determines the "noise" in your resultant image.

An image sensor is usually calibrated so that it gives the best image quality (greatest S/N ratio) at its lowest possible ISO speed. For most consumer digital cameras, this value will be expressed as ISO 50, ISO 64 or ISO 100. A few digital cameras use ISO 200 as their lowest ISO speed.

Just as with its film counterpart, an image sensor will exhibit "noise" (comparable to "graininess" in film) at the higher ISO speeds. Unlike film, where graininess can sometimes contribute to the mood of the image, noise produced by an image sensor is undesirable and appears as a motley of distracting coloured dots on your image.


ISO Speed & Image Sensor Size

The size of the image sensor determines the ISO speed range that a digital camera can use without suffering from undue noise. One reason for this is because the pixels on the larger image sensor can be larger and therefore receive more light, and thus have a greater signal-to-noise (S/N) ratio.

Most consumer digital cameras use 1/1.8 in. (and smaller) image sensors, so noise at high ISO is a problem. Though they will allow you to use a high ISO (such as ISO 400), the resultant image will usually be very noisy.

A digital SLR (dSLR), on the other hand, uses a large image sensor, usually full frame (24x36 mm) or APS-sized (half-frame). Noise is rarely a problem and the use of a high ISO 400 results in images with barely noticeable noise.


Practical Considerations

You obtain the best image quality by using the lowest ISO possible on your digital camera. If you want to ensure your digital camera always uses the lowest ISO setting, switch the ISO setting from the default "Auto ISO" (this setting is usually found in the Menu) to the lowest possible on the camera, say ISO 50.
If you mostly take pictures where there is enough light for a correct exposure, i.e. sunny outdoors, then using the lowest ISO on your digital camera will give you the best image quality your digital camera is capable of.
If you want to take pictures indoors where light may not be sufficient and in other low-light situations, then you would need to supplement existing light with flash or studio lights. Either that, or select a higher ISO. Of course, depending on your digital camera, a higher ISO may mean a noisy image.
A large image sensor (APS-sized and larger) means that you are able to use a high ISO speed without unduly worrying about noise. This means that you can take pictures in low-light situations without your pictures being under-exposed. It also means that in situations where it is required, you are able to use a fast enough shutter speed to prevent camera shake. All, again depending on your camera, without much noise.

This information was taken on March 29th, 2008 from [link] I did not write this material nor claim to have written it, it was posted for research material only.

It's official guys! I now have a hardbound 20 page book containing some of my best horse pictures here on DA! I am selling them for $60, and trust me, I am not making as much profit as you think, it costs quit a bit to have these little buggers made! I also make custom books, so if you would like to choose 20 pictures from my gallery and placed into a book, just let me know and I can do custom orders for $75. High price cause it will be more work to get the images right. If you are interested, please note me with your name, address, and we will discuss payment through paypal, check, or money order.

Dear Dogs and Cats:
The dishes with the paw prints are yours and contain your food. The other dishes are mine and contain my food. Please note, placing a paw print in the middle of my plate and food does not stake a claim for it becoming your food and dish, nor do I find that aesthetically pleasing in the slightest.

The stairway was not designed by NASCAR and is not a racetrack. Beating me to the bottom is not the object. Tripping me doesn't help because I fall faster than you can run.

I cannot buy anything bigger than a king sized bed. I am very sorry about this. Do not think I will continue sleeping on the couch to ensure your comfort. Dogs and cats can actually curl up in a ball when they sleep. It is not necessary to sleep perpendicular to each other stretched out to the fullest extent possible. I also know that sticking tails straight out and having tongues hanging out the other end to maximize space is nothing but sarcasm.


For the last time, there is no secret exit from the bathroom. If by some miracle I beat you there and manage to get the door shut, it is not necessary to claw, whine, meow, try to turn the knob or get your paw under the edge and try to pull the door open. I must exit through the same door I entered. Also, I have been using the bathroom for years --canine or feline attendance is not required.

The proper order is kiss me, then go smell the other dog or cat's butt. I cannot stress this enough!

To pacify you, my dear pets, I have posted the following message on our front door:

To All Non-Pet Owners Who Visit & Like to Complain About Our Pets:
1. They live here. You don't.
2. If you don't want their hair on your clothes, stay off the furniture. That's why they call it "fur"niture.
3. I like my pets a lot better than I like most people.
4. To you, they are an animal. To me, he/she is an adopted son/daughter who is short, hairy, walks on all fours and doesn't speak clearly.

Remember: Dogs and cats are better than kids because they:


1. Eat less
2. Don't ask for money all the time
3 Are easier to train
4. Normally come when called
5. Never ask to drive the car
6. Don't hang out with drug-using friends
7. Don't smoke or drink
8. Don't have to buy the latest fashions
9. Don't want to wear your clothes
10. Don't need a gazillion dollars for college, and...
11. You don't have to pay for their wedding
12. And If they get pregnant, you can sell their children