Taken in Saltsjöbaden, Stockholm, Sweden using Nikon D70s and Nikkor AF 50/1.8D. Post processed in Adobe Lightroom.

One of the greatest things with a SLR type camera is that it is possible to control the focus in the picture. This area is known as the DOF or the Depth-of-Field, or the Depth of Focus. This the space in a picture where things are in focus. In front of the DOF is the near out of focus field and beyond is the far out of focus field. There are certain things that controls this field and this article will describe them and how you can use them to improve your pictures. Without going into the actual optics, I will try to explain how to achieve the desired DOF and what it can be used for.

What affects DOF?

The DOF is actually the part of an image that is in focus. Any lens have a certain volume where things are percieved to be in focus and this volume or field of focus is referred to as the DOF. There are several factors that influences this, one of the most important factors is the aperture setting of the camera.

The aperture

The aperture controls how much light that falls into the camera at a given moment, it is a diaphragm in most cameras it is located inside the lens or just behind it, in the SLR type cameras it is located in the detacheable lens that is part of a camera system.

The aperture can generally be set in several steps. Earlier lenses permitted a limited number of steps but modern lenses and digital cameras permits the aperture almost always to be set in steps of 1/3 of a EV. The aperture is expressed as a ratio between the focal length and the diameter of the diaphragm and therefore it is written as f / 5.6 for example.

Cheaper lenses have a more narrow range of apertures than more expensive lenses, this means you can “open up” the aperture more on the expensive end, this is sometimes called “fast” lens (because they give shorter shutter times for the same scene during same conditions as a less expensive lens does) or more “sensitive”.

If you are using a good lens and you are setting it to the  lowest f-stop permitted then you will have the most narrow DOF that this lens can produce. This is a start and a setting you might want to use during low light conditions but remember that your shallow DOF can make it difficult to get the full scene in sharp focus.

The focal length

The focal length plays together with the aperture of course as we have already talked about. The focal length is what you “zoom” to when you zoom, or the fixed focal lenght of your prime lens. The smaller the focal length, the wider the field of view and the deeper the DOF becomes.

The greater the focal length, the more you “zoom in” the shallower the DOF becomes.

The focus point

The focus point is the last part of our equation. The closer to you the focus point lies the shallower the DOF is. The further away you focus the deeper the DOF will become.

It is all about rations between these three, the aperture, the focal length and the distance of the focus point. If you want to create a shallow DOF you should open the aperture, zoom is as much as possible, go close as much as possible and then focus closely.

Remember also that most of your DOF is behind the point of focus, when you focus on somethin the DOF arranges so that you have 1/3 of the range in front of your focal point and 2/3 behind it. Make use of this!

Portraits

This is used in portrait photography to create a sense of depth in the image. Typically you see the model in sharp focus and the background cast in blurriness, this is due to using the DOF properly.

Portrait optics are usually in the range of 90-135 mm focal range and can often be used with an aperture up to f / 2,8 which allows the photographer good control over the DOF and to photograph in the low light of dawn and sunset.

Hyperfocal charts

Finally

These are the things that affects your DOF:

• Focal length
• Aperture setting f / x
• Distance to focus point

When you focus on something the DOF extends 2/3 beyond that point and 1/3 in front of it.

There is a lot of confusion among people on the net who recently bought a Nikon digital camera. So I was trying to clear up this concept once and for all. Please link to this site if you run a mailing list or similar where this question comes up now and then.

Nikkor is the brand of lenses produced by Nikon corporations. A lot of people refer to them simply as Nikon brand lenses or Nikon lenses. Don’t get confused, the trading name these lenses are sold under are Nikkor.

Over the years Nikon have mande many different types of lenses, some are compatible with your digital DSLR, some can be used with some effort and a few are not useable or is painful to adapt to the DSLR.

Nikon is however the camera manufacturer with the best compatibility of old lenses on new cameras. Most of the lenses since the fifties and forward can actually be used on a modern Nikon DSLR, I am talking about the D70(s), D50, D100, D1x and such cameras. I personally own a D70s and I am very happy with this camera, it is a great photographic instrument. Perhaps matrix light metering may not work or you have to focus manually but the lenses would actually fit with a few exceptions that you can find in the table below.

I will skip some historical lenses from the eighties in this article, because you will most likely never have to deal with them, and if you do you can always check this article out where the author discusses this problem in more detail. This article is just to give you a quick summary and help at a glance.

Nikkor lenses have a lot of different designation letters to tell the user what type of lens it is, what kind of glass, type of focus and so on and pretty much any other feature. I will try here in a form of a table just very briefly try to describe the different versions and I will not go into too much detail. After all this page is just trying to answer questions like “Will my lens of type <insert type here> work with my Nikon DSLR” and “I have this Nikkor 35-70 mm AF-S ED lens from my old Nikon F-series camera, can I use it with my new D70?”. So here we go.

Lenses and Mechanics

These describes the mechanical differences between the lenses made by Nikon over the years. Almost all lenses can be used with a modern digital body, however you really want the autofocus lenses with built-in motors. They are great in the field and manual focus lenses is only really practical in a studio environment because they do not give you proper metering cababilities with the camera.

Optical differences

These should not impact the compatibility on your lens, they are mainly to do with the optics itself and how to distinguish a more expensive lens from a cheaper one

Help me update this list if you find any omissions or errors, please let me know immediately. Thank you.

More information here.