Shutter Speed and Aperature

[Quantum_Man]

Right now I have a Canon PowerShot S50. It has a full manual mode with shutter and aperature control. I know what both of these words mean, but I am a bit unsure of how to manipulate them to produce the images that I want. Like say I want to do a close-up shot of something, and I want it to be in clear focus on the subject, but everything in the background is out of focus and blurred. Do I use a large F-stop number?

Also I rarely have a tripod with me when I am taking pictures, mostly I take them at events like family gatherings or social events, and then there's the occassional vacation. If I want to get the natural lighting because either the subject is too far away for the flash to reach or I just want natural lighting, and I don't have a tripod, most of my pictures don't come out sharp and but blurred somewhat. But if I make the shutter speed to fast to compensate, it comes out too dark right? What are general guidelines for shutter speeds in different lighting situations?

Time permitting I'd love to take a class for photography, and money permitting I'd love even more to own a Nikon D70 one day, or something in that league, but I'm leaning towards the D70. Would using at least the kit lens that comes in the package with the D70, 28-70mm I think, would this let me take better shots like how I want? Or can I use my Canon PowerShot to do this?

Most of my pictures come out like everything is in focus, foreground and background. I want a more professional look to my pictures, but am I limited by my equipment?

Thanks VERY much in advance for any help and advice you can offer me.

 

[Piano Player]

Right now I have a Canon PowerShot S50. It has a full manual mode with shutter and aperature control. I know what both of these words mean, but I am a bit unsure of how to manipulate them to produce the images that I want. Like say I want to do a close-up shot of something, and I want it to be in clear focus on the subject, but everything in the background is out of focus and blurred. Do I use a large F-stop number?

Also I rarely have a tripod with me when I am taking pictures, mostly I take them at events like family gatherings or social events, and then there's the occassional vacation. If I want to get the natural lighting because either the subject is too far away for the flash to reach or I just want natural lighting, and I don't have a tripod, most of my pictures don't come out sharp and but blurred somewhat. But if I make the shutter speed to fast to compensate, it comes out too dark right? What are general guidelines for shutter speeds in different lighting situations?

Time permitting I'd love to take a class for photography, and money permitting I'd love even more to own a Nikon D70 one day, or something in that league, but I'm leaning towards the D70. Would using at least the kit lens that comes in the package with the D70, 28-70mm I think, would this let me take better shots like how I want? Or can I use my Canon PowerShot to do this?

Most of my pictures come out like everything is in focus, foreground and background. I want a more professional look to my pictures, but am I limited by my equipment?

Thanks VERY much in advance for any help and advice you can offer me.

Shutter speed and aperture are the two ways we use to record the reflected light of an image to control exposure of the film or digital medium.

Shutter speed is more intuitive. A shutter speed twice as long lets in twice the light for exposure. 1/60th of a second lets in half the light as 1/30 of a second. The slower the shutter speed the more likely you will need your tripod. A rule of thumb is to hand hold a camera with a shutter speed at a speed faster than 1/focal-length-of-lens. Thus, if you are using a 50mm lens, you can probably use a shutter speed as slow as 1/50 (1/60) of a second. The more you know good camera handling techniques, the sharper the image.

There are ways to extend your hand holding shutter technique: brace yourself against a wall; press your arms close to your body; rest the camera on a railing or armrest; squeeze the shutter like a trigger (if you have ever been trained to shoot); Use your arm like a monopod (Rest camera in your hand, elbow on arm rest); press the camera against your face. These all work to varying degrees with different photographers.

Aperture is the opposite of what you think. The smaller the aperture number, the more "open" or larger the lens is, and the more light it lets in at any one instant. A difference of one aperture "stop" lets in twice the light. Thus, a lens set at F5.6 lets in twice the light as F8. Unfortunately aperture stops do not follow a linear progression. You pretty much just have to learn it. A SLR lens usually has the numbers written down on the barrel of the lens. The progression looks like this: f22; f16; f11; f8; f5.6; f4; f2.8; f2.

If you want limited depth of field, first find (through the camera meter) the right combination for proper exposure. Lets say the camera meter tells you 1/60th of a second at f8. The smaller the aperture number, the narrower the depth of field. You decide the background is nicely out of focus at f2.8. F2.8 is three full stops from f8. Thus, you must double the shutter speed three times to have a good exposure. 1/60-1/125-1/250-1/500. Your new exposure setting is now f2.8 at 1/500th of a second. This lets the same amount of light on to your film as 1/60 at f8.

Many a professional picture was taken at 1/60 at f8. Your camera probably does that as well as most cameras. A professional kit just gives you more options in any given situation.

 

[2Bhumble]

I bought a nice aluminum "table top" tripod that is 18" when extended and about 7" when collapsed. It fits nice in my camera bag. I'll admit I don't use it as much as I'd like to. I was experimenting with my digital zoom one day and had it maxed out to 48X. The image in the viewer was shaking like crazy. I leaned my body and the camera against a door frame and the picture came out clear.

 

[michabo]

Unfortunately aperture stops do not follow a linear progression. You pretty much just have to learn it. A SLR lens usually has the numbers written down on the barrel of the lens. The progression looks like this: f22; f16; f11; f8; f5.6; f4; f2.8; f2.

This is way too technical for here, so feel free to ignore me, but for those technophiles...


the f-numbers are actually a ratio of the focal length to the diameter of the camera's aperature. The aperature controls how much light is let into the film, so when the aperature (bottom number or denominator) is very high (large diameter), the f-ratio will be low. When the aperature is very low (small diameter), the f-ratio will be high.

Next, notice that the amount of light that enters varys with the square of the diameter. So when you want to double the amount, you only increase the diameter of the aperature by the square root of 2, or about 1.41. But if you double again, the diameter will be double your starting point. That's why f/11 has four times as much light as f/22 - because the diameter of the aperature is twice as large, it lets in four times as much light.

 

[Piano Player]

Right now I have a Canon PowerShot S50. .... Like say I want to do a close-up shot of something, and I want it to be in clear focus on the subject, but everything in the background is out of focus and blurred. Do I use a large F-stop number?

. . . .

Most of my pictures come out like everything is in focus, foreground and background. I want a more professional look to my pictures, but am I limited by my equipment?

I looked up your camera, and there are limitations to your equipment I didn't talk about before. The web site shows that your lens is a 7.1-21 mm zoom with an aperture range of f2.8-f4.9.

One of the biggest, but least talked about, changes in the advent of digital photography is the smaller imaging area. This many times results in much higher depth of field than 35mm photography. When the imaging area is smaller, the focal length of the lens is also smaller to give a "normal" perspective to the image. For example, a 7.1-21 mm lens would be an extreme wide angle lens on a 35mm camera. The smaller the focal length of the lens, the greater its depth of field. When someone describes a digital lens like yours as being equivalent to a 35-105, they are talking perspective only. At the 21mm setting, your camera still has the depth of field characteristics of a 21mm lens.

To get out of focus background you must try harder. Use the lowest apeture setting of the lens. (AP mode is good for this). Maximize the relative distance between your subject and the background. If you get closer to the subject, the background is proportionately further away. You can also move the subject away from the background. Change your composition so close background elements can't be seen.

 

[Quantum_Man]

Thank you very very much for the tips Piano Player, I tried using the AP mode, called AV on my camera actually, and in macro mode it came out pretty well. With regular mode it was harder to get the background out of focus as much as I wanted, but like you said, working with the composition, I can arrange to have the subject farther away from the background, etc.

 

[rgbivens]

...Time permitting I'd love to take a class for photography, and money permitting I'd love even more to own a Nikon D70 one day, or something in that league, but I'm leaning towards the D70. Would using at least the kit lens that comes in the package with the D70, 28-70mm I think, would this let me take better shots like how I want? Or can I use my Canon PowerShot to do this? ...

I'm really suprised SouthernCross hasn't jumped in here. He is a professional and uses D70's. I talk to him all the time and ask for advice about it. I just got one so he helps me a lot. With the lens kit you get the Nikkor 18-70mm lens. Its a pretty good lens. However if you want to shoot stuff like sports and anything that your focal point will be more than 40-50 feet away you should get the Nikkor 70-300mm lens. I just picked it up about a week ago and love it. It eliminates the need for cropping on every photo which in return keeps your resolution to a maximum.

If your going to get a new one I would most deffinatly recomend a D70. Its a nice chunk of change, espically if you get another lens and don't forget about memory, but for me it was a great investment!

If you have any specific questions regarding the D70 feel free to ask me or SouthernCross.

-Grant

 

[Tiger Lily]

That's what I'm having troubles with right now, shutter speeds and apertures...

I used to know this stuff years ago, and have forgotten some of it.

 

[kranich]

I think of it in this simplified way, and I only use SLR cameras. The aperature setting is a measure of the diameter of the iris. The bigger the opening, the more light gets through and vice versa. That is purely logical.

When the iris is open, more light gets through and the result is reduced depth of field. When less light that gets through, the result is a larger depth of field.

The lower numbers are actually larger aperatures and the high numbers are the lower aperatures.

Very confusing: low is large, high is small, more light is reduced depth, less light is increased depth.

So basically if you want to take a picture of the Grand Canyon and get it all in a lower f-stop is applicable but if you want to take a picture of your sweetie in the foreground of that same picture increase the f-stop to a higher setting.

This really applies to short focal lenghts, which in my opinion is the better way to take photos.

 

[Quantum_Man]

If you were taking a picture of the Grand Canyon, wouldn't you want a large depth of field, so you would use a bigger f-stop number so less light gets through?

 

[kranich]

If you were taking a picture of the Grand Canyon, wouldn't you want a large depth of field, so you would use a bigger f-stop number so less light gets through?

That's what I am saying about it is confusing. A bigger NUMBER is a smaller aperature and a smaller aperature is a larger depts of field. Instead of saying "f-stop", which is the actual number on the dial I meant to convey aperature size. I don't know why I typed the word "f-stop" when what I was trying to say was actual diamerter of the iris. I must have confused myself. If the iris is smaller you will get more depth and you are correct, that would be a lhigher f-stop.

Believe it or not I work for a company whose primary products are cameras and lenses. Pretty ironic isn't it?

 

[Quantum_Man]

lol, can you get me a discount if I wanted to buy a D70?

 

[kranich]

lol, can you get me a discount if I wanted to buy a D70?

I can't afford the consumer cameras we make, even with the employee discount they average around $700. I work in the medical division and those run about 20-grand a piece, just for the cameras.

 

[Southern Cross]

Sorry, I've been extremely busy. We started advertising recently, and the emails and phone calls have been coming in pretty quickly. Plus we're opening a studio in the next month or so. You've received some excellent information from the above posters.

If you need a GREAT reference to how aperture, shutter speeds, film/iso speeds work, I'd like to suggest John Shaw's Nature Photography Field Guide. He gives one of the best descriptions I've seen of how these three aspects of your camera's operation are tied together and how to best take advantage of manual controls to achieve the look you want. While the book is older and geared mainly toward film shooters, the information can easily be translated over to digital photography use. As long as you get used to the idea that you are using aperture and shutter speed to control how much light you are allowing to hit the CCD sensor and how sensitive you want the sensor to be by selecting the correct ISO setting, you'll be well on your way to success.

The only way to really figure it out is to go out and shoot, shoot and shoot some more. If your camera has aperture pritority controls, try shooting at different apertures and see what effect the aperture settings have on your images. Also watch how your shutter speeds change as you change aperture settings.

I don't want to re-explain everything that our friends above already commented on because they've done a pretty good job!

The only thing I want to add about macro photography is that you need to keep the camera really stable (i.e., tripod and use the timer or a shutter release/remote) and macro usually requires a greater depth of field, even if you want some of your image blurred out. Macro photography is kind of tough without a decent macro lens (and those are expensive) but I've seen some beautiful shots captured using small digital cameras with a macro feature. Some cameras offer truly atrocious quality macro images, while others do just fine. Good luck!

 

[rgbivens]

I knew he would show up (SouthernCross)

-Grant