T2i Zoom lens vs. prime lens --- DOF question???

singleframe

singleframe

Well-known member
So I received my T2i with the kit lens (just b/c I don't own any lenses...but def interested in acquiring some new glass!), and although not totally crazy about the kit lens, it does have a decent look when I zoom in some.

When not zoomed at all and standing near a subject, the face looks a bit odd and the background not so out of focus. I'm told the Canon EF 50mm f/1.4 USM is a solid all-around lens. My question is: with a fixed lens, am I going to have the same look I'm getting with my kit lens when not zoomed in? Are there any great, must have lenses that zoom that I should be considering?

Sorry for the noob question...just don't have much experience with lenses, since my days of working with dvx's and hvx's....

thanks in advance!!!
 
What kit lens do you have? Is it the 18-55mm?

When you're wide (18mm) most things will be more focused than if you were zoomed in around the 55mm mark.

The Canon 50mm 1.4 is a great lens so yes, look into it. Also, look into the Tamron 17-50mm lens. It's awesome!
 
A 50/1.4 lens set to f/5.6 will look similar to a 18-55 zoom set to 50mm and f/5.6. The thing your zoom can't do are aperture values below 3.5 (I think). Long story short:

To get the background/foreground out of focus:
-Use a larger focal length. For zooms, this means zooming in
-Use the largest aperture value available. For zooms, this is the largest available at the longest focal length
-Get as close to your subject as possible. This is called minimum focus distance.

The opposite will give you deep DOF.

Your question doesn't make any sense to me. I hope the above explanation helps. You should cruise around wikipedia and search for Depth of field, focal length, etc, etc. Follow the links as deep as you can.
 
dof 101 !

dof 101 !

The more you zoom in (increase focal length) the more the dof (depth of field) will get shallow

The more you zoom out (decrease focal length) the more the dof will get deep and everything
will be in focus.

When you stay on one focal length (eg, try 50mm and focus on something 10 feet away) try taking a few stills at different apertures.
Look at f5.6 then try f16 (and boost the iso to compensate). See how the dof changes? The wider the aperture the shallower the dof.
 
Set to a similar aperture value it will look similar.

However, prime lenses are valued because they are typically optically superior to zoom lenses (although this is certainly not always the case, even within similar quality levels.) They are usually sharper, less prone to problems like chromatic aberration, various distortions, and flare or ghosting issues. Generally the optics are higher quality.

Generally. Most of the time. Usually. Typically.

I am over simplifying it a bit, but that's the G-2.
 
I have the Canon 50mm f/1.4 and its a great lens. Due to the crop of the camera this lens is like a 80mm. So, at times it does get a bit difficult to shoot in smallish rooms. I only have this one lens, but its a great one, and I'm happy I got the f/1.4 over the f/1.8. More light and shallower dof.

As I said, I dont own any other lenses, but I would get something with the lowest f# possible - which you ca afford. It get really useful. I'm not sure which zoom lens it was that many recommend, I believe it was the Canon 70-200mm? and/or the Tokina 11-16mm. Something like that.
If you have the time, stick with primes. Its a lot better than a zoom lens - well, most cases... I wont be getting any zooms myself, just primes, all under f/2.
 
I have the 50mm 1.8 and use that almost exclusively. It is cheap ($90) and plastic but looks great. I get great shallow DOF pictures all the time indoors and out with using a variable ND.

Other than that I would probably look at some of the Nikon 50mm ones, I'm thrifty.
 
singleframe said:
When not zoomed at all and standing near a subject, the face looks a bit odd and the background not so out of focus.
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The face looks odd because of perspective distortion. Here's a rule of optics: The closer you are to a subject, the more distorted it will look. When you use a lens with a longer focal length to achieve the same framing as with a lens with a shorter focal length, you have to stand farther away from the subject. This results in less distortion.

I'm told the Canon EF 50mm f/1.4 USM is a solid all-around lens.
Click to expand...
Because of the crop factor due to the smaller sensor on the 7D versus a full-frame camera like the 5D, 50mm would not generally be considered a good "all-around" focal length for the 7D. It'll probably look too "zoomed-in" for you. 30mm, on the other, hand is a versatile focal length for the 7D. The Sigma 30mm f/1.4 has many, many fans.

My question is: with a fixed lens, am I going to have the same look I'm getting with my kit lens when not zoomed in?
Click to expand...
The "look" of a lens, aside from things like color, contrast, and sharpness, is determined by the focal length and the aperture. You really need to learn about focal lengths and stop thinking about "zooming." Different focal lengths give you different angles of view, which is why a lens appears to be more or less "zoomed-in/out." The short end of your kit lens is 18mm. The Canon prime lens that you mentioned above is 50mm. The prime lens will give you a much narrower angle of view. "Zooming" is just another word for changing the focal length of a zoom lens. You can get zoom lenses of different ranges of focal lengths. So a 17-50mm lens will not give you the same range of angles of view as your 18-55mm lens.
 
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