Photography workshop - day 3

connie

connie

Alumni
Hi all

Well I'm starting today's workshop a little early again as I have some running around to do. I'll be back after lunch if you have any questions.

Today’s topic is F-stops and shutter speeds or how your camera actually works. If you are really serious about taking good photos, a basic understanding of photography is a necessity. Earlier I said that you don’t need fancy equipment to take good pictures. You don’t. All that you need is an understanding of how your camera works. The more you know, the better your chances of taking good pictures. For those of you with automatic cameras, there will be info in here for you as well. This info cost me thousands of dollars to obtain in college so be sure to enjoy it for free. :)

Cameras read the amount of light based on a middle shade of grey. When your camera is deciding what exposure to use, and adjusting the settings in relation to this shade of grey. I’ll explain more as to how this effects your photos tomorrow when I talk about photographing black and red items. For now f-stops and shutter speeds.

To start out with, cameras take in light via a shutter that opens and closes in front of the lens. The amout of light that comes in depends on the f-stop and shutter speed selected - either manually by you or automatically by your camera.

The shutter speed is easy. That is the length of time the shutter stays open. The longer the shutter speed the more light gets into the camera. Shutter speeds are indicated by a fraction of a second (1/2, 1/60th, etc.) or with a long shutter speed, the number of seconds the shutter is open. Manual cameras often have a bulb setting as well. This allows you to keep the shutter open as long as you want.

Shutter speed is important in a couple of different ways. If you are shooting high-speed action photos and want to stop the action, a very fast shutter speed will capture a moment as if it is frozen in time. If you want to indicate movement, you can use a longer shutter speed and you will have a blur of whatever you are shooting.

For shooting clothing, the second aspect of shutter speeds is more important. That is, the longer the shutter is open, the more light gets in the camera. This means , the brighter it is where you are taking your pictures, ths shorter your shutter speed. On the other hand, if is is dark where you are taking pictures, you will have to have a longer shutter speed. The problems comes here if you are shooting indoors and don’t have sufficient light.

The first thing to know is that cameras aren’t nearly as sensitive to light as the human eye. You might be looking around a room and it seems plenty bright to your eye but to the camera it is dark. If you have an automatic camera, it will automatically set the camera with a longer shutter speed. Unfortunatly, if shutter speed is longer than 1/60th of a second you are going to have problems. Anything longer than that is not hand holdable. The movement of your body will show up as blurry photos. You can correct this to an extent if you have a tripod. Remember Kang from day 1:
<img src=http://www.cosmiccatvintage.com/web-data/Components/photoworkshop/day1wotripod.jpg>
without tripod

<img src=http://www.cosmiccatvintage.com/web-data/Components/photoworkshop/day1wtripod.jpg>
with tripod

At a certain point though, if it is too dark, it is too dark and you will end up with dark photos. Your camera will still try and compensate by lightening the photos. You will end up with a greyish photo with very little contrast.

Remember what I said about shadows being your friend. That means that a low contrast, greyish photo is going to look bad. You want to have some contrast so people can really see what your clothing looks like. You can correct this a bit in Photoshop but believe me, it is MUCH easier to get it right in the camera. You can only correct so much post production. There are definite limits to what Photoshop can do.

Here are some quick examples I shot for you in my family room.
The room is fairly bright. The pictures are pretty accurate in that regard. Still, take a look at this first phot taken without a tripod:

<img src=http://www.cosmiccatvintage.com/web-data/Components/photoworkshop/day3wotripod.jpg>
Even though there is enough light to read by here, I couldn't hand hold the photo. It came out blurry.

Here is the same picture done with a tripod:
<img src=http://www.cosmiccatvintage.com/web-data/Components/photoworkshop/day3wtripod.jpg>
not too bad.

For the sake of argument, lets say that I had to hand hold the photo and decided to use my flash. Here is what I got:
<img src=http://www.cosmiccatvintage.com/web-data/Components/photoworkshop/day3wflash.jpg>
Notice how you loose the shadows on the door. (Remember, when pictures are too dark you loose contrast and shadow detail.)

Well say I decided that I would fix that in Photoshop. Well here is what I came up with:
<img src=http://www.cosmiccatvintage.com/web-data/Components/photoworkshop/day3wmanipulation.jpg>
Doesn't look TOO bad on its own but lets do a side by side comparison with the natural light photo:

<img src=http://www.cosmiccatvintage.com/web-data/Components/photoworkshop/day3compare.jpg>
First you should notice how, even though I tried to up the contrast in the door, it still isn't as good as in the natural light photo. The door still seems very glaring, bright white.
Also, when I increased the contrast, I lost all the detail in the radio cabinet. Now it looks like a big dark blob.

Of course, all these pictures came from a not too dark photo. The situation would have been even more difficult if I took these shots in a darker room. Remember, Photoshop is great but its always easier to get these things right the first time rather than messing with them later.

I'm going to look around and see if I can't come up with more examples. In the meantime, Coming up next...f/stops

Connie
 
Connie, I'm woefully ignorant when it comes to the workings of my camera and this will be a perhaps really silly question, but does the
F- stop, etc principles apply to digital cameras as well?

I have a mid-line Kodak and I'm assuming that I'm not understanding
it properly when I look at it, but there doesn't seem to be a lot of adjustments that can be made.

Sue
 
Yes, ALL camera use f/stops and shutter speeds, from the most basic pinhole camera to our fancy new digital ones. The computer technology in modern cameras doesn't change the basic optics involved in how light gets onto the film/disc. This will make more sense later. My last "official" post of the day will be how to use those automatic settings on your camera to get it to change the f/stops and shutter speed for you. Hang in there.:)
Connie

And no, that wasn't a silly question!
 
Now onto f-stops. The f-stop is the diameter the shutter opens when you take your picture. It is also read as a fraction. Think of a shutter as a number 1. When you see a setting of f/16 that means 1/16th, f/4 is 1/4th, etc. So, the larger the f-stop number, the smaller the shutter opening. Generally the biggest f-stop opening you’ll see is f/2. On zoom cameras the biggest f-stop opening will be smaller. This information is always printed on the lens of the camera. On my camera for instance I have an opening of f/2.8 when my camera is set at the widest angle and f/3.1 at the farthest telephoto setting. This is pretty good for a zoom.

Like shutter speeds, f-stops effect your pictures in two ways. The first is the amount of light that comes into the camera. The wider the shutter opens (ie. f/2) the more light that gets in; the smaller the f-stop (ie. f/11) the less light that gets in.

The second aspect of f-stops is very important and something you’ll need to consider all the time. The f-stop also determines the depth of field - how much of your photo is in focus. The wider open the shutter is, the less depth of field; a smaller shutter opening, the more depth of field. The easiest way to remember this is to imagine you have a set amount of water, say 6 ounces. If you pour that water in to a into a containing with a large diameter (f/2) it will only go up a little way in the glass (narrow depth of field). If you put that same amount of water in a glass with a small diameter (f/11) then it will go up farther (longer depth of field).
<img src=http://www.cosmiccatvintage.com/web-data/Components/photoworkshop/day3depthoffield.jpg>

Here is an example I just photographed real quick for you. In the first I have the f/stop at its smallest (f/11 in this case). Notice how all the ladies from front to back are all in focus.

<img src=http://www.cosmiccatvintage.com/depthoffield1.jpg>

In the second picture I opened up my shutter to its largest opening (f/2.8). Here the first lady is in focus, the second lady isn't too bad but the back three ladies are definitely blurry as is the curtain at the back.

<img src=http://www.cosmiccatvintage.com/depthoffield2.jpg>

This becomes very important if you are shooting outdoors or somewhere where you have a busy background. To make your photos look professional, you’ll want to have the focus of the camera - and therefore the focus of the eyes of your potential buyer - on the item your are photographing. You may have the most beautiful lawn in town but if your trying to sell clothes, this is not the time to show it off. What you want to do is set the f-stop at it’s most open setting. Focus on your clothing and the background will be softly blurred.

Ok, well I don't have a yard to shoot it so I'm going to use a sample from one of my wedding pictures (with thanks to my brother, niece and nephew). Here, notice how what could have been a very distracting and busy background is slightly blurry, causing your eyes to focus on the people.

<img src=http://www.cosmiccatvintage.com/web-data/Components/photoworkshop/day3wedding2.jpg>

Now I don't think I explained this clearly enough earlier, but all cameras use f-stops and shutter speeds. Every camera has to have a way of controlling the amount of light that gets in. Someone back in Victorian times came up with this system and it is so good, we still use it now. Basically you have a big hole in the front of your camera with a lens in front of it to focus the light. Behind the lens is a shutter. This shutter opens and closes when you press the button to take the picture. The shutter speed is how long the shutter stays open and the f/stop is the diameter of the opening.

F-stops and shutter speeds work in tandem. Your camera will always adjust the settings so that you get a good exposure. So for instance, if you set the f-stop open wide (letting in more light) then your camera will automatically set the shutter speed faster (letting in less light) to compensate. If you have a manual setting, you can of course override this mechanism. I find that in most cases, your camera’s settings are pretty right on. I’ll get into occasions where your camera might be fooled tomorrow.

Now for those of you who don't have full manual, shutter priority and aperature priority buttons on your camera, don't worry. You can still get your camera to adjust the settings the way you want. I'll go into that in just a little while.
Connie
 
Yes, f-stops and shutter speeds (f-stops in particular) are a bit hard to grasp at first. They are everything in photography though. You literally can't take a photo without an f-stop and shutter speed. I wish there were an easier way to explain all this to you but this is how cameras work and we have to go with what we've got.

This is one of those times where starting out with a manual camera and being forced to adjust it comes in really handy. You really learn things very quickly that way. Its like riding a bicycle though. Once you get the hang of it, you never forget.

If anyone has any questions, feel free to ask. I don't mind explaining things over again. Don't forget, I had a semester to learn all this and I'm throwing it at you in one week.

Coming up in a few minutes, getting your automatic camera to work for you.
Connie
 
One of the things you have to understand about cameras is that (like computers) they are really very dumb. They only know they are programmed to know. They can’t think for themselves. For instance, your camera might have a button on it that looks like a bunch of mountains. This is for taking pictures of landscapes. Or you might have a button that looks like a running man. This is for taking action shots. All that these buttons are doing are telling the camera how to set the shutter speed and aperature for those situtations. I know enough about photography that I don’t even use those buttons. I can do those settings manually using the cameras shutter priority (where I choose the shutter speed and the camera sets the f-stop for me) or the aperature priority (where I set the f/stop I want the camera gives me the appropriate shutter speed). Or if I’m really feeling confident, I’ll do everything manually.

Now the landscape button or the action button are really great if you are taking pictures of mountains or people running, but if your taking pictures of clothing it isn’t so obvious. It would be really nice if cameras had a “little black dress” button on them. This is one of those things though where there are too many different factors involved for your camera to figure it out. Remember, your camera can’t think, it can only do what it is programmed to do. For instance, when you are taking pictures of clothing you have to take into account the color/s of the dress, the texture of the fabric, the color of the background, the amount of light, what kind of light (natural or artificial), where the light is coming from, etc. That is just too much info. Technology is good but it isn’t that good, To get really good pictures, you have to understand what is going on and how to tell your camera what to do.

And what if you have a camera that doesn’t allow for shutter or aperture priority settings. Well you can still get your camera to do what you want. For instance, say you want to take pictues outdoors like I mentioned above. You want your camera to open the shutter as much as possible (blurring out the background) and then have it adjust the shutter speed to get the correct exposure. Here you can take advantage of the Portrait setting on your camera - generally a button with the outline of the head and shoulders of a person. The Portrait setting will automatically open the shutter so that your subject is in focus and the background is blurred. Voila.

Now say it’s a bit dark and you want to make sure that your camera keeps the shutter open for as long as possible. First, make sure you have the camera on a tripod. If you have a night scene mode (a moon and star on my camera) then by all means use it. If you don’t, then use a bit of backwards thinking. Instead you can use the landscape button on your camera - usually a button with the outline of mountains on it. What the camera is doing here is making sure that the shutter opening is small and therefore the depth of field is very long - perfect for landscapes photos. By default, your camera will have to set the shutter speed longer to compensate for the small shutter opening. Now you take take a picture in a darker area without resorting to a pop-up flash.

On a side note, if you have a macro button on your camera your camera generally sets the shutter so it opens very wide. This means that you will have a narrow depth of field when you do extreme close-ups. This shouldn’t effect the quality of your photos but is something to keep in mind when your shooting.

Notice in this example how the earring in front are just a little out of focus but that the bracelet is fine. These items were obviously set right next to each other but because the camera was set on macro and the f-stop was big, my depth of field was very shallow.

<img src=http://www.cosmiccatvintage.com/web-data/Components/dresses/D1228103.jpg>

Some cameras allow you to set the iso. That is essentially the film speed. Those of you who’ve used film cameras know that lower number iso (160, 200) is really only good in brightly lit situations. A high iso (800,1600) is good in lower light situations. If you have an iso button on your camera you can let it know whether your shooting in a low light or high light situation and it will set the exposures appropriately.

Well those are the basics in photography. Sometimes, despite all the camera settings, we still have problems. These mostly have to do with dark items and red ones. I'll talk about ways you can improve pictures of those items , using lighting, backdrops, f-stop and shutter speed adjustments, tomorrow.

Connie
 
::Head twirling::
Ok, so my notes say:
-low f stop #=wider the opening, shallow depth of field

Question-My camera has +0.3 to + 2.0 and then it also has negative numbers in the same range. What are the negative numbers for?

If I am using indoor lighting sources i.e. lightbulbs, do I need to mess with my f stops?

I am learning sooooo much!
Thanks Connie!
Sandra
 
Well I'm not sure what those numbers are Sandra. Where are you seeing them? They don't sound like either f-stop numbers or shutter speeds. It might be that this is a way your camera is setting the f-stops and shutter speeds for you (ie. the "plus" numbers are allowing in more light and the "minus" numbers are letting in less light. I'd have to see your camera/manual to know though.

F-stops and shutter speeds both deal with the AMOUNT of light that is let into the camera. It doesn't matter what kind of light it is. F-stops are simply the size of the hole that the light comes through and shutter speeds are how long that hole stays open. It doesn't matter whether it is sunlight or fluorescant light or whatever.Light is light is light as far as your camera's shutter is concerned.

Indoor lighting is less bright that sunlight. If you are indoors and you might want set your camera so that the f/stop is open wide, letting in more light and allowing you to hand hold your camera. If you have an automatic camera, it is adjusting these things for you. So yes, f-stops do matter when you are indoors.

Does that make sense or do you want me to try again? :)
Connie
 
Well, f-stops and shutter speeds combined are the exposure settings. I'd really have to see your camera and/or manual though to tell you how those numbers relate to the shutter speed/f-stops. I suspect that it is like I said, a short cut for people who don't know about f-stops and shutter speeds. If you can take or scan a picture for me, I 'd be able to help you out more.

Connie
 
This is a little OT perhaps...But what if you want to take a picture of fireworks, stars, or maybe a vintage christmas tree and only want the points of light to show up. Many cameras will give you a washed out sky trying to compensate for the black, or you will just not get the depth of field and will get a good picture of the dust on your lense.

I know you spoke of the landscape setting, but, and i might be dense, will that setting assist in these situations.
 
To really take good night pictures you need to have your camera on a tripod and the ability to open up the shutter for a fairly long time. Some cameras come with a nighttime/fireworks setting. I doubt a landscape button is going to do a whole lot for you. It might help a bit but it is really for shooting in the day light. I could be wrong about this though as I've never used any of these buttons on my camera. I'd try some experiments and see what happened.

In the past, when I've taken night photos, I've always bracketed - that is, taken a bunch of pictures at slightly different exposures and then gone with the best one. This is standard photography technique. My camera will even do it automatically if I set the bracketing button.

I just want to put in an off-topic note here myself - photographers take more "bad" pictures than they do good ones. I remember one of my brothers (a photographer) talking about how if he got 1 or 2 really good shots in a roll he was happy. The rest of the pictures might be ok but they wouldn't be up to his standards. This is a very common attitude so don't feel that every picture you take has to be a masterpiece.

When I'm taking pictures of my clothes, I do two photos of every pose. I do one with the cameras automatic setting and a second on aperature priority. Both of these settings have different white balances so I can pick and choose what looks best to me.

Connie
 
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