Hi, my name is Rob Barron. Welcome to my overview on lenses.
The purpose of this little tutorial is to help you understand a little bit about the differences between the various lenses which are available for you to buy for your camera and to help you to understand what all of those in numbers are about which you see in that lens descriptions.
What I just showed you with the photo that I have taken, with the lens that I keep on my camera most of the time. But first of all let us understand what lens is all about and then you will understand why I use this one and why I might be changing and use others for different purposes.
There are two numbers that are mostly important when you buy a lens. The first number is the number of millimeters and this is describes as the focal length. The focal length of a lens talks about how long the lens is and how close it is going to get to your subject. What we really mean by this is if you imagine just looking around at a scene, what your eyes are seeing is approximately the same as a 50mm lens on a 35mm camera. If we go down from 50mm we get a wider field of view. And so we refer to those with a wide angle lens. If we go above the 50mm then the angle of view is narrow and narrower. And so those are referred to as telephoto lenses.
Putting it in other way because a wide angle gets a lot more information into the picture, it will look like that each subject is a little bit further away. But because a telephoto lens is leaning in close to the image and you have not got a lot of things around it, that image will seem to be much closer. If you have wanted to take a big wide landscape scene with lots of rolling hills and lakes and things then a wide angle lens would be more appropriate. If you have wanted go out and take some photo’s of wild life and you cannot get too close to the animals because you just frightened them away, then a telephoto lens is the lens to go for because you can stay further away but the camera will get you in nice and close to the wild life in the action.
Now, let us look at these four lenses that I have with me today. This will help us to understand a few different things. First of all, this is the photographer’s faithful friend. This lens—I am going to take the lens cap off here. This is called a 50mm F1.8 lens. It has got a nickname. It is called the nifty fifty. The nifty fifty lens is a lens I would recommend everybody who has a 35mm SLR camera to own. They are fondly enough one of the cheapest lenses to buy. They cost nowadays between 50 and 60 pounds and looking around on the internet even cheaper in that sometimes.
50mm remember approximately represents what you will see with the naked eye. 50mm does not get you in close but what it does is it makes it perfect for things like portraits and other said shots. But the great thing about this lens is that it’s F1.8. That is the other number that we most commonly see when we see a listing on details of a lens. We have got that millimeter focal length but then we have got the aperture. The aperture is the—it is like the iris. You would think about opens and closes inside the lens and allows the light to go through. The wider it can open the more light can go through and sort of strangely, that actually means the lowest number of aperture is the widest aperture okay. So, the lowest number is the most widened. So, F1.8 is very, very low and lets lots of lighting so it can be useful for a low light lens. It also affects the depth of field. I am not going to go into that today but I do have another tutorial all about depths of field. So, I hope you will have a look at that and have to understand that a bit more. So that is our nifty fifty, very cheap and very available.
At the complete opposite end of the scale is this one. I will take the lens hood off and maybe open it out to the fullest extent. This is a Cannon L Series 100 mm to 400 mm lens. It is what we call a ‘Zoom Lens.’ It is called a zoom because it goes between one focal length and another. If it only stays at one focal length, like the nifty fifty, it is referred to as a ‘prime lens.’ So we have zoom lenses and we have prime lenses.
This lens is an L Series lens, for Cannon. That is mark down with a red light. And that’s Cannon professional range. Nikon, Olympus and so on all have their own different codes and things for more professional level. If you are not sure, just look at the price. That will usually tell you. L Series and other professional lenses are more expensive but they often have things in them which are the lenses do not.
This one has a thing called image stabilizer. It is actually marked in the lens here, image stabilizer. On other cameras, they call it in different things, I think on Nikon, they are referred VR which is Vibration Reduction. Image stabilizer means it has some clever little gadget for you in there which takes out any shaking. So if my hands are not very steady, when you are using telephotos, the camera will take out those shakes completely and give you a much steadier image.
So that is the kind of lens that you are paying for. You are paying lot money for it but they do make fantastic pictures. So this one go to the top end of the scale, we are not going to go up to that in right now.