finding a good portrait lens?

Tbini87 · Jun 1, 2010

Hey guys. After getting more serious about photography the last few months my wife has also had a lot more interest in shooting pictures. We usually shoot landscape shots, and we use our D40 with the 18-55 and 55-200 kit lenses that came with it. However, my wife also really likes shooting pictures of people and babies, and really likes getting blurred backgrounds when possible. The 18-55 lens does a decent job, but doesn't get some of the fantastic results she sees on wedding and portrait blogs she looks at.

So, I am looking for an inexpensive lens for her that will be able to get her great shots of people with good bokeh. The problem is that I have no idea what I am looking for. I have been looking at lenses in the f 2.8 range, but is that simply what makes for great bokeh? Can a simple prime like the Nikon 35mm 1.8 do the job i am asking about? Any comments and recommendations would be appreciated!

JustAnEngineer · Jun 1, 2010

Look at the EXIF data for the focal length that you're using for most of your portraits. If it's around 35mm, then the $200 AF-S DX 35mm f/1.8G may be just what you need. If you're shooting most of your portraits around 50mm with the zoom lens, you might prefer the $440 AF-S 50mm f/1.4G or the $500 Sigma 50mm f/1.4 HSM. With their larger apertures, these prime lenses will produce a shallower depth of field than you would get with a zoom lens like the Sigma DC 18-50mm f/2.8 HSM, Tamron Di-II 17-50mm f/2.8 or Tamron 28-75mm f/2.8.

pbelarge · Jun 1, 2010

Tbini
I also was going to mention one of the "nifty fifty" lenses. You can purchase one for a fair price and get a decent lens to boot.

tirediron · Jun 1, 2010

The type of bokeh a lens produces is a combination of several factors, the main ones of which are the focal length, the number of blades in the aperture and the shape of the aperture. The holy grail of shallow DoF lenses for Nikon (IMO) are the 85mm 1.4 and the 50mm 1.2, however both of these are going to cost more than your D40 body.

Typical portrait lenses are most often in the 75 - 90mm length; remember that the longer the FL of a lens, the shallower it's DoF is at a given aperture. For an APS-C sensor, two reasonable options are the 50mm 1.4 and the 60mm 2.8 macro. Both of these produce pleasing bokeh, and are reasonably priced, especially if bought used (Look for the 'D' version - you'll have to focus manually, but you'll save a bunch of cash).

KmH · Jun 1, 2010

Tbini87 said:
I have been looking at lenses in the f 2.8 range, but is that simply what makes for great bokeh?

As tirediron has already alluded to ot sounds like you are using the term bokeh when you really mean DOF (depth-of-field), They're not the same thing.

DOF is a function of 4 things:

the lens focal length
the lens aperture stting
the subject to lens distance
the subject to background distance.

You can achieve nice out-of-focus (OOF) backgrounds with any lens if you set the shot up properly for the camera and lens combination you want to use.
www.dofmaster.com

The visual quality of an OOF background is a function of the physical items inside the lens tirediron mentioned, as well as the various lens elements themselves.

Some lenses have very nice bokeh and some don't, and most fall somewhere in between.

There are 2 distinct types of bokeh too:

Cream cheese bokeh
Hollywood bokeh.

Vinny · Jun 1, 2010

The "standard" lens for portraits is about 105mm on a 35mm camera which would be about a 70mm on a crop sensor DSLR - so figure a 85mm. A small focal length lens can cause lens distortions in photos.

I find it interesting that a lot of people are considering 35mm as a portrait lens. You would be too close to the subject and as was discussed DOF can be an issue.

atraff · Jun 1, 2010

Go long! Get at least a 70 to 200 mm lens, f2.8 if you can afford it. You want to be back from your subject, not in their face. Don't be afraid to crop tight in camera.

JustAnEngineer · Jun 1, 2010

The OP stated that he's using the 18-55mm kit lens with the D40 for his portraits rather than his 55-200mm lens, so I assumed that he's not got the studio space for a longer portrait lens. The same reasoning applies, of course. If he's shooting most of his portraits around 85mm, he should look at an 85mm prime. Once Sigma finally ships theirs, it will be the first 85mm lens that can auto-focus with the D40 camera.

Tbini87 · Jun 2, 2010

thanks guys for the helpful replies! sounds like i probably won't be able to get what i need on such a small budget but oh well. something like the 35mm 1.8 nikon lens looks like a steal for less than $200 but sounds a little short for portrait work. the longer lens we have seems to fit the bill, except for the f 4.5 that it has. getting something that long at 2.8 look way to expensive. we can make do with what we have i guess, might pick up that 35mm prime lens anyways just to have something lower than 4.5.

JustAnEngineer · Jun 2, 2010

There are cheaper lenses available that won't auto-focus with your D40. The $115 AF 50mm f/1.8D comes to mind.

Dao · Jun 2, 2010

Before I got my 85mm f/1.8 or the 100mm f/2.8, I use my 70-300mm IS lens most of the time when I took portrait type shots outdoor. (Even I have the 50mm f/1.8)

So carefully select a scene that the background is far away from the subject. And use your telephoto kit zoom lens (55-200mm) and set it at around 80 to 100mm, or even longer (you just need to have enough distance between you and the subject) and frame your shot that way. You should be able to create a out of focus background type shots. (try to shoot at lower f# if possible)

Mike_E · Jun 2, 2010

Of the lenses mentioned so far, I'd go with the 28-70mm f/2.8 and not use it below 45mm or so. Wide angle distortion below that focal length is NOT your friend.

The effective focal length on a crop sensor has nothing to do with the natural qualities of each individual lens it just means that you have an automatic enlargement of the middle of the image were it on a full frame camera. Using a 50mm lens on a crop body does not make it a 70/75mm lens in regards to compression ( a friendly thing to faces) or distortion.

For OOF shots just have your subject close and the background far away. You can even do this with a 55-200mm.