what lens for full body portrait on a crop body?

Hi guys
I know that to get the same FOV on full frame and crop-body, e.g.
85mm for cropper and 135mm for full frame, at the same aperture, full frame will have less DOF due to the longer focal length.

i have a 7D and most of the portraits I've done are waist-up. I saw this picture and it looks great to me.

http://farm5.static.fl​ickr.com …88794461_100425​8c11_o.jpg

My question is that : can you achieve similar result with a 85mm f1.8 lens or 200mm f2.8 lens on a cropper? I'm inclined to say yes since in this photo, background is far away from the subject. But I'm not sure what if the background is close to the subject, can you get great full body portrait that seperates the background away on a cropper? can it be achieved on a 85mm f1.8 lens? or 85mm f1.4 lens is needed? how about 200mm f2.8?

sorry for so many questions. I'll do some test myself later when I have time. In the meantime, it'll be great to hear from you guys.

Cheers!

i think the "separation" you see in this photo is the result of sweet light (coming from back right in the frame) in conjunction with shallow DOF

but yes technically due to the nature of the FF sensor and a 135mm f2 lens that DOF is gonna be thinner than with 85 1.8 on a crop - but as far as the "look" is concerned a lot has to do with lighting as well as apertures and focal lengths

If that image has not been cropped I am inclined to say no. You would not get the same shallow in focus area and the rate the in focus areas fall off into blur.

I have used the 85/1.8 on a crop and now on a FF.

I love this kind of picture outside with a 200mm 2.8. You'll get a very creamy background and some compression which I find appealing. Any focal length from 85mm on up will give you a nice shot in this situation, but the longer focal lengths will seperate your subject better from the background.

genjurok wrote in post #9685584
My question is that : can you achieve similar result with a 85mm f1.8 lens or 200mm f2.8 lens on a cropper?

Hi genjurok, That image was (according to the EXIF) was shot with a 135 len and 5D MKII which is a killer combination to begin with, and tough to compete with. You should be able to get similar separation for full body shots with your 85mm lens if you have enough room to play with, and shoot at F/2.8 or less.
As an aside, I changed your image to a link, as posting other people's images here without permission here on POTN is strictly forbidden, sorry.
-Bruce

Ballen Photo wrote in post #9686615
Hi genjurok, That image was (according to the EXIF) was shot with a 135 len and 5D MKII which is a killer combination to begin with, and tough to compete with. You should be able to get similar separation for full body shots with your 85mm lens if you have enough room to play with, and shoot at F/2.8 or less.
As an aside, I changed your image to a link, as posting other people's images here without permission here on POTN is strictly forbidden, sorry.
-Bruce

Thanks to you and others for your kind replies.

Sorry for breaking the rule here. I wasn't aware of it. Appologize for that. Won't happen again.

Cheers!

It's a 135mm at 2.0 on a 5D. a 1.6 crop will give at least 1.6x the DoF.

So, to get about the same DoF, you'ld need a 85mm f/1.1 or thereabout on a 7D I think (1.6 stop).
Maybe the 85L wide open would cut it.

http://photo.net/learn​/optics/dofdigital/

Alternatively, shoot multiple images with a 135L (or your 85mm, but that would give a different perspective, since you'ld need to be closer) wide open.
One of the subject as a whole (about filling the frame), and the rest of part of the subject and the surrounding (IOW: Move the camera around). Then stich all those together. There's a wedding photographer who does that to get a shallow DoF with a wide FoV. Sorry, forgot the name.

René Damkot wrote in post #9687266
It's a 135mm at 2.0 on a 5D. a 1.6 crop will give at least 1.6x the DoF.

So, to get about the same DoF, you'ld need a 85mm f/1.1 or thereabout on a 7D I think (1.6 stop).
Maybe the 85L wide open would cut it.

http://photo.net/learn​/optics/dofdigital/

Alternatively, shoot multiple images with a 135L (or your 85mm, but that would give a different perspective, since you'ld need to be closer) wide open.
One of the subject as a whole (about filling the frame), and the rest of part of the subject and the surrounding (IOW: Move the camera around). Then stich all those together. There's a wedding photographer who does that to get a shallow DoF with a wide FoV. Sorry, forgot the name.

hmmm, interesting technique!!! Never heard it before , will try it later, sounds interesting!

Thanks!

René nailed the solution with 85mm f/1.2 on APS-C.

135mm f/2 on FF at 40' shooting distance provides 10.5'x7' framed area with DOF of 2.6'
85mm f/1.2 on APS-C at 40' shooting distance provides 10.5'x7' framed area with DOF of 2.6'
200mm f/2 on APS-C at 94' shooting distance provides 10.5'x7' framed area with DOF of 4.2'

135L on a crop would not look the same, but it would not be bad either

That is framed rather loosely, so if you imagined 1.6x being cropped out of the middle (so lose all the cool tree framing) then you would get the same picture of the girl and less background with the same blur.

The shot was done with s 135L @ 2.0

On a crop a 85mm 1.8 (or 85mm 1.4) would be the focal equivalent. To get the colors and contrast of that shot however you'll probably need to invest in an L lens. Also, you probably won't get the same depth of field since the example picture was taken on a full frame.