Basic Photography Class

BLAKEJOHN

Active Member
This is where we will hold the Basic Photography Class. To begin, I would like to establish a few posting rules.

To keep this thread clean and orginized, try to keep posts to a minimum.
At the end of a section I will ask if there is any questions. This is the time were I would like the posts to be made about the previous material. If one person has a question then I am sure there are others with the same question, so please post any question pertaining to the previous material at this time.

Please keep the posts on topic with where we are at in the discusion. If you missed the opportunity to ask your question at the appropriate time then you can email me with your question and I will answer it that way. When the thread (class) is over I will post all the questions and answers that were not able to be posted at the correct time.

Those of you that have sent me your email will aslo have my number so you can call if you have any questions or problems.
 

BLAKEJOHN

Active Member
Our first section will be Basic Film Knowledge and a little history. We need to understand how film works in order to understand how our digital cameras work. After all the sensor is really a digital rendition of film.

I will post this section later this evening..
 

BLAKEJOHN

Active Member
Well I did say later, right?
A little History

The beginning of the camera was as early as 1816, when Frenchman Joseph Nicephore Niepcu and his brother succeded in making a paper that would capture a negative image. It was not until 1826 or 1827 that they would be albe to capture a positive image that was permanent. This was called a “Heliograph” and the exposure took 8 hours.

During this time, Louis Jacques Mande Daguerre was also experimenting with photographs. He and Joseph Nicaphere Nicepcu collaborated until Niepce’s death in 1833. Louis came about with the first practical phtograph in 1837 using silver salts. This was known as the “Daguerreotype”.

Without going into a long drawn out history lesson, I will give you the subsequent processes and if you like to look up the rest of the history, have fun.

After the Daguerreotype came, the photogenic drawing (1839), the calotype (1840) later improved and named talbotype. During this period of time A man named Herschel discovered a fixative in sodium thiosulfate and he called this “Hypo”. This fixer is still used today. Then came the collodion Wet-Plate process, a number of non-silver processes were used (the Heliograph was one of them), Gelatin emulsions and then flexible film base.

In the twentyith century improvements were made to the later and we have the emulsion we call film today. And finally we have digital.
 

BLAKEJOHN

Active Member
Basic Film Knowledge

In the beginning of the history we mentioned that the first photo took 8hrs to expose. As time went on and improvements developed we now have exposure time in the thousandths of a second.

The salts of the emulsion or film is what gives us the film speed and grain. The smaller the salt grains the longer it takes to expose the film but the smoother the image. The larger the salt grains the faster the film can be exposed but the grainier the image will be. This is what causes film grain, we know this as noise in digital photography.

ISO

Film has a rating system to rate its sensitivity to light. This is the ASA or ISO. The ISO numbers in one stop increments is as follows:

25, 50, 100, 200, 400, 800, 1000 and so forth.
These numbers represent the sensitivity to light.

For example: If you are using an ISO of 100 and your camera is set at F8 @ 1/60 to get a proper exposure, you can use an ISO of 200 with you camera set to F8 @ 1/125 and get the same exposure in the same lighting condition.

With an ISO of 200 you can use a shutter speed twice as fast as with an ISO of 100. But it will add a little more grain/noise to your photo.

So with a higher ISO you can take pictures faster and/or with less available light. With higher ISO’s comes more grain/noise in your photos.

Since film is replaced with sensors in our digital cameras, I feel that I should mention that when looking for a camera a CMOS sensor is recommended over a CCD sensor.
 

BLAKEJOHN

Active Member
Section Two Camera Basics

Shutter Speed

Now that we have an idea of ISO. ISO is your film speed (the ability in time to capture light), the higher your ISO the faster you can shoot or the less light you need.

Shutter speed is the time you allow light onto your film/sensor. The shutter speed is mainly used to stop motion or allow moving objects to blur showing motion. Sometimes we use the shutter speed to allow a long exposure to capture a minimal amount of light. Shutter speed in represented in seconds. In one stop increments starting at 1 second are as follows:

1, ½, ¼, 1/8, 1/16, 1/125, 1/250, 1/500, 1/1000 and so forth.
 

BLAKEJOHN

Active Member
What is a stop??

We have been mentioning a “stop”, what is a “stop”? A stop is the amount of light from one setting to the next. One stop is equal to twice or half as much light or time. To put this in a better perspective we need to talk about apature.
 

BLAKEJOHN

Active Member
Apature

What is apature? The apature is a variable opening in the lens using an iris type diaphragm that controls the amount of light entering the lens into your camera. The apature size is refered to as the f stop. The lower the f stop number, the larger the opening allowing more light to enter into the camera. These are the f stops in 1 stop increments:

1, 1.4, 2.2, 2.8, 4.0. 5.6, 8.0, 11, 16, 22, 32, 64

An f stop of f11 allows twice as much light through the lens as compard to an f stop of f16 and half as mush as an f8. The smaller the f stop number, the larger the opening allowing more light through the lens.

apature1.jpg
 

BLAKEJOHN

Active Member
Depth of Field

Depth of Field (DOF) is also controld by the apature and also by the distance between you and your subject. The DOF is how much of the photo, focal point to foreground and background, appears to be in focus. A large apature (small f #) will have a shallow DOF This means that your subject will be in focus but everything else will be a little blurry, or out of focus. As a small apature (higher f #) your foreground and background will appear to be in focus. I said earlier that distance also plays apart in DOF. The closer you are to your subject, the shallower DOF you will have, even with a small apature (higher f #). A zoom lens will increase this effect the more you zoom in.

dof1copy.jpg


dof2.jpg



Most of our images from our tanks will have a shallow DOF. This is because we will most likely be very close to our subject and also be using a large apature (small f #).

all above images are from "Photography: The Concise Guide", Bruce Warren
 

BLAKEJOHN

Active Member
The Light Meter

Most of us will use the in camera light meter. In your view finder you will see a bar that looks similar to this:

+2..i..0..i..2-

This is you light meter. 0 represents a properly exposed image, +2 is 2 stops over exposed and -2 is 2 stops underexposed. Each mark is 1/3 stop in either direction. As you move your shutter speed and/or apature you will see this meter move in one way or the other. When taking photos we try to keep this meter at or near 0. this is done by changing either the shutter speed or apature or a combination of both.

One thing I might note. If you set your camera in the program mode (P) and look at you meter, it should be at 0. If it is at anything other than 0, such as -1, then all of you photos will be 1 stop under exposed even if you set your light meter to 0. So make sure in program mode (P) your light meter is set at zero.
 
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BLAKEJOHN

Active Member
Well enough reading, Lets play with our cameras!!!

Ok, now lets put some of this together and go outside to take a few photos.
Lets set our cameras to manual mode.
Set our ISO to 200
If it is sunny we will set our apature at f 16, If it is overcast we will use f 8
Lets set our shutter speed to 1/200
Look through your view finder and check your meter, is it at or near 0?
Lets adjust our apature until it is at 0
Take a picture,…….

don’t go back in yet we have one more to take.
Now frame roughly the same area and this time adjust your shutter speed to 1/400

And adjust your apature until your light meter is at 0
Take another picture….

Now these two pictures have two different shutter speeds and two different apatures but they both should look the same. If you press the play button and look at the pictures on the back of the camera and then press the info button until you see a bunch on numbers and such, you will see the shot settings. F #, ISO, and shutter speed.

The first will have a shutter speed of 1/200th and which ever apature
The second will have a shutter speed of 1/400th and which ever apature.

Since we made our shutter speed 1 stop faster only allowing half the time for the light to be exposed on the sensor, our apature had to be increased (bigger hole, smaller number) to allow twice as much light in. And we come out with two different settings that are exposed the same.
 

BLAKEJOHN

Active Member
Thats it for now. Try the above exersise. If you have any questions at all please do ask you all should have my email and number.
 

BLAKEJOHN

Active Member
I would like to see the pictures you have taken using the above info. This will help me see how to help improve your photos. Please email me these images. Thanks...
 

BLAKEJOHN

Active Member
If you did the above exersize then you should have gotten two photos similar to this below. Notice that both photos are exposed the same, but have two different settings. (you may get one a little darker than the other due to change in light outside but you get the idea)

sameexp.jpg


Why was this exersise important?

To show you that you can have different settings but get the same exposure.

How is this related to our tank photos?

When photographing fish we are trying to stop the motion of the fish. As mentioned earlier we use the shutter speed to do this. This excersise showed us that if you increase your shutter speed, you have to increase the apature (smaller f #) equally. In my sample photo I increased my shutter from 100 to 200 which is one stop (twice as fast). So I had to allow twice as much light (smaller f #) through the lens to get the same exposure with a faster shutter.



.
 

BLAKEJOHN

Active Member
Just a small summary of what was all explained above.

ISO is the film speed. It allows us to use a faster shutter speed in lower light situations or a smaller apature(larger f #) in the same situation. Remember, the higher the ISO the more grain/noise in your photo.

Apature is the amount of light allowed through the lens.

Shutter speed is the amount of time the film/sensor is exposed to light.

The next session will be on Bracketing.
 

BLAKEJOHN

Active Member
What is Bracketing?

Bracketing is Taking a series of shots and each shot is exposed differently by only changing either the apature or the shutter speed. This is done to ensure you have the right exposure your looking for by having under and over exposed images.

To do this we will set our apature at F5.6 and ISO at 200. Look through the view finder and look at our light meter and set the shutter speed so that the meter shows -2 (underexposed by 2 stops). Take a photo and then change the shutter speed by one step slower and take another. We will do this one step at a time until our light meter is at +2 (two stops overexposed)

It does not matter if your images are blurry. Clarity is not the objective in this excersise. We are only looking at the exposure of the images.
 

BLAKEJOHN

Active Member
In the image below all the photos have the same ISO (200) and the same apature (f5.6). Only the shutter speed has been changed in 1/3rd stop increments. Above each photo is the shutter speed and each full stop is labeled, "0 stops" being the center and properly exposed photo.

This is what Bracketing looks like. You can now select which image looks best to use.

bracketing.jpg


In some camers there is a seting to do this automatically for you. It will only take three photos, 1 will be under, 1 will be normal and 1 will be over. The amount of under or over exposure will be determind by what you set it at, in the range of -2 - +2. This setting is usually labeled as AEB (auto exposure bracketing).

This is useful in creating HDR (high denstisy range) images which we will talk about later.
 
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BLAKEJOHN

Active Member
A little tip on correct exposure.

After you take a picture, view it on you LCD in the info screen. If there is any flashing parts in the image these areas do not have any pixel information. Later in post processing you will not be able to pull any detail out of these areas.

Recompose and try to stop up or down to correct this to a minimum.
 

BLAKEJOHN

Active Member
Some low lighting tips and tricks.

Increase you ISO to allow for a faster shutter speed.
Use a tripod to stabile the camera and allow for a longer shutter speed.
Turn off your pumps to reduce motion in the tank. (I personally try not to as everthing begins to slump).

Panning....This takes practice and patience to get it right, but it delivers a cool effect, showing motion of the subject, using the background.

Using a longer shutter speed we focus on our subject. As you press the shutter you pan (move the camera with the subject) with the subject. The longer the shutter, the cooler the effect but the harder it is to maintain focus on the subject.

Here is a sample of one I did a while back. The tang appears to be zipping throught the tank (well he was).
_MG_0024.jpg
 

tektite

Active Member
After you take a picture, view it on you LCD in the info screen. If there is any flashing parts in the image these areas do not have any pixel information.

Highlighting blown out areas isn't a feature on every camera though. For those that have it, it is quite useful.
 

BLAKEJOHN

Active Member
Now that we learned our basic settings and what they do, our next section will be post processing.

I will go into post processing of RAW files and JPEG's separately.
The sofware I will be using is Photoshop CS3. Most programs have similar functions but may not have as much contol. By the end you should have enough of an understanding that you will be able to use other programs as well.
 
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