Sunday, October 5, 2008

Focusing Modes-Part 2

When your camera can't autofocus on the subject you want to shoot or you rather focus yourself instead of letting the camera do it, you can always rely on the Manual Focus setting.

In Part 1 I mentioned how in the A200/300/350 you have a lever below the lens release button labeled AF-MF and in the A700/900, the focus lever has a MF setting after the C.

Moving the lever down in the A200/300/350 will switch the camera from AF to MF. All the previously discussed focusing modes CANT be used when the switch is set to MF.

In the A700/900, just moving the lever to MF will do OR press the AF/MF button in the back of the camera, next to the AEL button. (Sorry kids, this function is just available to the A700 and A900)

When you set the camera to Manual Focus, the AF motor the camera has is deactivated and releases the focusing ring of the lens. Do not confuse this with the zoom ring of the lens (if the lens you got has one). The zoom ring is just to adjust the focal length of the lens while the focusing ring works to bring the subject into focus or get it out of focus if thats the effect you want.

Uses for Manual Focus or why you should care at all about it.

Despite how advanced or smart the AF system of your camera is, there will be always a situation which will confuse the camera. But thats not the only reason you should care and learn to use Manual Focus.

Auto focus was introduced in 1985 by Minolta. Before that happened, all the pictures you've seen in books or in albums were taken with Manual Focus.

Manual focus gives you total control of where your focus point is placed in the frame, combined with focal length and f-number. It will also increase the speed you take pictures.


If youre shooting under conditions where the light or the subject distance changes quickly, the camera may not focus fast enough for you to get the shot you want. If you set the camera to MF, you can set the focusing ring to the appropiate distance at which you want to shoot your subject, and when its in that distance, you take the picture and reset it if necessary, this is called prefocusing; setting the focus on a point before the action takes place in it, so by the time it happens, you take the shot without lags.

Imagine youre at an arena and motocross bikes are flying all around. Usually this kind of events are during nightfall. You want to capture the bikers while they are in the air or you want to capture them when they land (or crash) in the ground. If the biker is using a black suit and you try to shoot him in the air against a black background, the camera may be confused because it cant determine whats in there to focus, or if you focus on the landing point, the camera may focus on the ground itself or something behind it (lets say the wall), by the time the biker lands, the camera wont focus on the spot where he is, will be focusing on something else. The biker would need to reach the spot in the ground or the wall for that case to be in the focus zone.

MF is also useful on shots using a macro lens. The AF may hunt too or WAY too much when focusing on tiny subjects, especially when there are plenty of them in the frame. It may focus on everything except what you want or focus on what you want but then move and search for something else to focus. This is really annoying when it happens, and MF solves this problem, you determine the distance and the focus you want on the subject and it remains there until you change it. (You can improve your sight using the viewfinder magnifier when using a macro lens, the FDA-M1AM Viewfinder Magnifier attaches over the viewfinder and enlarges the view inside the VF.

The main advantage of MF over AF is the fact that its up to YOU where the camera focuses. Setting the camera to MF allows you to set the focus where YOU want and to change it if you change of subject. You dont have to wait for the camera to determine where it should focus or what to focus. It all in your control.

Another useful function of MF is that the shutter is not locked. In AF, if the camera determines the subject is not focused, it wont fire unless you change a setting to prevent this (this will be posted in a future entry). There is also the problem of the lag, you may want to take pictures of something happening RIGHT NOW, and if the camera is not ready, youll miss it. In MF, the shutter is never locked, so whenever you set the focus (even if its not razor sharp), the camera will fire.

A lot of photographers from the film days learned to focus manually, and they still do with DSLRs. It pays off to know how to use Manual Focus.

An analogy between AF and MF can be a standard gearbox and automatic gearbox in a car. The automatic gearbox is more comfortable because you just got to step on the pedal and the car does the rest, but if you want to remain on the same gear or go at a certain amount of engine revolutions, you wont be able to. In a manual gearbox you got to do the changes yourself, but you can determine when to do them or how much to force a gear before changing it. Automatic gives you comfort at the expense of total control and Manual gives you total control at the expense of comfort.

So there you have it, your Alpha DSLR has the tools to help you get the shots you want and how to set the focusing mode to make it easier to get that keeper youre looking for. It pays off to know both AF modes and MF, this way youll have the know-how of when to use each of them and what they will do for you.

If you have a A700 or A900 and you wonder whats that AF/MF button for or what the blazes is DMF or what use does it have, read Part 3. (Or if you dont have a A700/A900 but youre a curious one, you can also keep reading) ;)

Next: Part 3-AF/MF and DMF explained.

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