Hi, I have Canon 1100D and Canon 50mm 1.8 lens.
I want to buy another lens and i need to take full body shots with it and to have a lot of bokeh (or depth of field)
and i want it to be sharp.
now because i have a crop camera the 85 will be 136mm..
but my question is if to upgrade the 50 to 135 or to go straight to the 135?
there are a lot of difference between the 50 and the 85??
"... i need to take full body shots ..."
You don't want either! These lense have become know as portrait lenses. Although you can take "full body shots" with either, you will need to be back farther from the "body"!
I would pick a EF 35mm f2 IS USM or possibly the EF-S 17-55 f/2.8 IS USM.
Still sticking with your first choice, I would get the EF 135mm f/2L USM. It is a much better lens and performer than the 85mm f1.8.. I sold my 85mm after a short trial with it and bought the Sigma 85mm f1.4. Now that is a Lens with a capitol "L". The best 85mm made, bar none.
"full body shot"
"... it doesnt have to be with legs just like from the stomach and up ..."
"Hi, I have Canon 1100D and Canon 50mm 1.8 lens."
If you don't like the frame provided by your 50mm, the 85mm is going to be worse not better. You will have to step back farther to get the same shot. And even farther back if you go with the 135mm. Not trying to say whether this is god or bad but you must be aware of this fact.
I don't mind going back from the model or person I'm shooting.
but when i go back with the 50mm there is no more depth of field like i want it to be. i want a lens that if i go back and try to capture not only the face, i'll have depth of field and bokeh.. i believe that with the 135mm i will be able to, but will i be able to do that with the 85mm?
I'm a bit confused. Depth of field and bokeh are sort of opposites, aren't they? I.e., bokeh, as the term is generally understood, is a phenomenon that manifests itself in conjunction with diminished depth of field. Am I missing something here?
im not so good in English, but if i understood your saying, I've already taken pictures with depth of field and bokeh as well, so i don't think what you said is accurate..
and I'm 16, so i must be wrong, but that what i was taught so maybe our definitions are a little bit different.
I assure you that you are far better at English than I am at your native language. But let me try to clarify a bit:
A lens's depth of field (i.e., the range of distances between the subject and the focal point at which the subject will be perceived to be in focus) varies with its focal length and with the size of the aperture used. It's greatest for a short focal length and a small aperture and least for a long focal length and a large aperture. In many (perhaps most) cases a large depth of field is desirable; it makes it easier to keep major elements of the image in focus.
But a small depth of field has its own advantages. If you want to emphasize one element of a picture and get rid of other elements that may serve as distractions, one way to do it is to focus on the important element and throw the rest out of focus. That usually requires a small depth of field, so you use a longer lens and/or a wider aperture to achieve it.
The term "bokeh" (a word supposedly adapted from the Japanese language) is a measure of the attractiveness of the out-of-focus portion of the image. Different lenses handle them differently, and what is considered attractive in such circumstances varies from person to person, so "bokeh" is a highly subjective term. But there's enough agreement overall to allow many lenses to be categorized as having good or bad bokeh without too much argument.
In your case, it sounded as though you were looking for both good bokeh and a large depth of field. But in a way, that's contradictory. If the entire image is in focus, the term "bokeh" doesn't apply. If almost all of the image is in focus, the bokeh doesn't matter much. So if you want to be sure that we understand what you're looking for, you need to be more precise about how you're using the terms "depth of field" and "bokeh".
When I was 16, I got my first adjustable camera, an Argus C-3. I'm now almost 77, and I've had a long, sporadic relationship with photography. The advent of the digital camera rekindled my interest, and I'm now a serious photographer for the first time in my life. You're lucky to be starting out with a range of available technology that I couldn't have dreamed of. Work hard at photography, and it will likely bring you great satisfaction all your life.