Canon XSi Basics

The Canon XSI has both fully automatic settings and creative controls for shooting photos. 

The dial on the top of the camera is often times left in the fully automatic modes, usually just the green square.  Taking photos in these modes, ensure a simple use of the camera, but often enable restrictions on the performance of the camera based on what Canon programmers thought to be best.   Often times they’re great, but without moving into the creative zone, one is not taking advantage of the power their DSLR offers.  

So where to begin?  
This is the beginners section, and therefore I will assume this to be your first SLR or first attempt to understand the fundamentals of your shooting. 

Terms you must know to begin:

1)  Aperture: 
2)  Shutter Speed/Exposure Length:
3)  ISO:
4)  Exposure

These are the fundamental terms that a photographer constantly thinks about when composing their photos.  To begin mastering your dslr, you must first get a substantial understanding of these terms, what they do, how they function and are changed. 

Your XSI offers the following creative control modes:  P, Tv, Av, M, A-DEP.
P:  Camera still in automatic modes, but unlocks features of the creative zone.  Camera still sets aperture and exposure time with no user input. 
Tv:  Camera selects aperture based on user defined shutter speed/ exposure time.
Av:  Camera selects shutter speed based on user defined aperture size.
M:  User defines both shutter speed and aperture size.
A-Dep: Camera selects both aperture and shutter speed in an attempt to have the greatest depth of field, and have everything in the viewfinder in focus. 

For our beginning training exercises; you will use the Av – aperture priority mode. 
We start with aperture priority mode because this will allow you to use all of the customizations and options available to you on your XSi, and aperture priority is a good mode to begin with so that you can learn about depth of field and using it to your advantage.   The camera will choose the shutter for you, you can set the ISO, aperture, focus point, white balance and picture style.  Of course most importantly, you can shoot in RAW format and adjust picture style and white balance later on and not worry about it while shooting. 

To begin you will place the camera in Av mode; and then use the dial on the top right of the XSi to select different aperture sizes.  Aperture size has an inverse relationship to what may seem the common sense approach.  For example lets say we own a Canon EF 50mm 1.0 lens, at an aperture stop setting of F 1.0  the aperature inside the lens is WIDE open – the widest it will go and as a result letting in the most light possible with that lens.  Because so much light is being let in, the exposure will occur much faster and result in a much quicker shutter speed then with a lower amount of light let in. 

Lenses state their maximum aperture rating on  them, this means  EF 50mm 1.0 lens  1.0 is the widest, yet the lens will be capable of being “stopped down” which means we can reduce the aperture width from 1.0 to 20.0.   An aperture of 1.0 would provide a blurry background for our subject, while an aperture of 20 would provide a detailed background shot.  Why?   When shooting with a wide open aperture, more light is let in because the “aperture diameter” is the widest possible. The most light is let in, and we get a fast shutter. However, light does not travel in straight paths, this is called being “uncollimated”. At a wide aperture, uncollimated light is let in which causes the blurred background to be captured. Aperture blades are a type of collimator, meaning they collimate the light into a straight path, this is achieved by allowing less light in and only the light which is on a relatively straight path as the same focal length as the focused point of the lens.  When the lens is reduced in aperture width, the shutter stays open longer and allows more light from the “collminated” selection in from distant objects.  The additional light leads to more detail and greater clarity of background (infinity) items .  

OK so that’s a lot to think about right? I think the best way to think of it is…. If we are letting a crowd in to a concert, do we get more efficient and better streamlined results with single file lines or do we get better results with a free for all stampede.

or in letting my imagination run wild here.. lets say we are struggling artists coming up with a new modern painting for the MOMA in NY. If i stand on a 2000 foot diving board over an empty pool and i shoot a bucket of red paint another 500 feet in the air dumping its contents while performing an impressive acrobatic flip or two. Waiting 2,500 feet below in the pool is a 10 x 10 white canvas, the paint is likely going to “disperse” and separate and cover a wide area. Its not going to fall in the shape of the can since its now out of the can. when the paint lands it spreads on the canvas and surrounding area in the pool. Art! perfect

But what if we wanted to have an accurate and controlled piece of art? We’ll do the same exact experiment but instead put a protective cover over the pool. There is a small 2′ circular hole in the cover right above our 10×10 canvas. Well when the paint hits, it’ll be caught by the cover, but some will go through that hole. Since the paint had already begun to disperse, it was on a more consistent trajectory the longer it fell – meaning there would be less dispersion as it continued to fall, so the paint that went through the hole in the cover wouldn’t spread much further than that hole it just went through even if it fell another 500 feet after passing through the hole. So then the paint hits our canvas in a nice and accurate pattern. This is sort of a ridiculous way of explaining, but hopefully really illustrates the idea of collimated light vs uncollimated and dispersed light.

First aperture lesson:
In a brightly lit setting,  focus on an object and take photos at various aperture levels.  If you are using a Kit 18-55IS lens, start at 3.5 and move up to 14 -  try  3.5 , 5.6, 10 , 14.
Look at the photos on your computer and see the change in what is in focus in the background.  If done appropriately, items in the far background should go from being blurred and non distinguishable to sharper and perhaps even in focus.

That’s it, your first lesson in mastering your XSi, you have now learned how to control the depth of field  “DOF”  of your lens.  There are many types of lenses available for Canon SLR’s, they range from “fast lenses” with apertures as high as 1.2   (2.8 is considered a standard fast speed)   to  slower lenses that start at 5.6.   Often times with kit lenses or lower quality lenses, the aperture minimum adjusts based on how far you have zoomed in or out. 

People often buy Canon L series lenses because they are higher end lenses which provide large apertures such as 2.8, 1.4, 1.8 etc..   these faster lenses come at a hefty price but the image quality is much greater than a kit lens.  There are a few fundamental lenses that should be purchased if you want to get serious about your photography.  You need to be able to cover various ranges  using both wide angle lenses – lenses which are designed to capture an entire environment, or telephoto lenses – lenses which are designed to focus on one  subject and not capture its surroundings.

Lesson recap:  every lens contains “aperture blades” within side the lens.  When aperture is decreased, these blades overlap one another to form a shield within the lens.  The shield has a center point which allows light in.  When you change the aperture, the shield center point increases or decreases.  This is what changes in aperture, the blades moving around within the lens, permitting more or less light in. 
Controlling this will change the creativity of your photos based on the depth you want the photo to have.  Its an easy way to start understanding what your camera is doing without having to know shutter speeds.

I will recommend a few lenses but, do so with two warnings
1) Lenses do retain a lot of their value, lenses are expensive, they are a commitment – you have purchased a Canon and will now want to be able to build up your lens collection based on sticking with Canon EOS.
2)  There are EF and EF-S lenses, the kit lens is an EF-S lens, a lens designed to work only with the Rebel XSi / 450d its forefathers, and the 50d and its earlier models.  EF-S lenses do not work on the more professional bodies, so if you ever think you might move into a more professional body  you will likely want to avoid EF-S lenses.
Initial lens recommendations:
EF 50mm II 1.8 – around $90 – a very cheap plastic body, extremely fast and the cheapest lens canon makes.  This lens is great for portraits and is a great beginner lens  – without much investment.  Just be sure to treat it delicately, its not built like a tank.

EF 70-200  2.8   or 4.0:  between $600 – and $1200.  If you can pay the extra amount, spring for the 2.8 with  or without Image stabilisation.  Covers a great range, amazing background blur (“Bokeh”), superb build quality and optics, a common lens good for portraits and sports. 

EF  16-35  or 17-40 ;  the price difference is substantial, between $650 and $1300.  The 16-35 is the faster lens offering 2.8 aperture speeds.  Great ultra wide angle lenses,  perfect for landscape shots and other creative shots. 

Another couple of items you will want to pick up:
1) rocket widget: blows dust off your lenses so you don’t touch them
2)  tripod – can’t take night shots without them, provide much better shots all around – a huge advancement in your shooting alone.