Missed focus question - HELP

[Ady]

Camera: Nikon D5000 set to single point focus at fast shutter speed (1/500th ish).

Subject: Usually runners or cyclists so moving targets.

The Nikon viewing software shows a red box that indicates the point of focus but in quite a few cases the point of focus has been out (even though the red box is on my intended target) and the focus point is actually a few feet behind.

I am trying to learn some lessons here and need to understand what is going on so is it likely to be:

A - The software is not 100% accurate and I actually missed the subject in the 1st place?

B - I need to use a different method of focus

C - The camera is subject to shifts in focus even though the target square is aimed true

D - Something else.............


Any help greatly appreciated.

 

[Overread]

First of what mode are you using AF in - if its single/one shot then the camera focuses only once before it locks on. Thereafter if the subject (or you) move the focus remains locked at the point it was focused on. So for action it could well be that using this mode the subject moves out of focus before you hit the shutter.

IF you are in a continuous AF mode it could be that if the subject is moving toward/away from you that they are going too fast for the af (its the most challenging mode for af to keep up with). A burst of shots can sometimes help and get you at least one or two that work.

If not then I would suggest first getting a static subject and using the AF in single shot mode to focus on it without motion. This is to test if your lens has a backfocusing problem. If the subject is properly focused the problem is more user than camera if the subject is incorrectly focused then your lens has a problem and needs recalibration.

 

[Ady]

First of what mode are you using AF in - if its single/one shot then the camera focuses only once before it locks on. Thereafter if the subject (or you) move the focus remains locked at the point it was focused on. So for action it could well be that using this mode the subject moves out of focus before you hit the shutter.

IF you are in a continuous AF mode it could be that if the subject is moving toward/away from you that they are going too fast for the af (its the most challenging mode for af to keep up with). A burst of shots can sometimes help and get you at least one or two that work.

If not then I would suggest first getting a static subject and using the AF in single shot mode to focus on it without motion. This is to test if your lens has a backfocusing problem. If the subject is properly focused the problem is more user than camera if the subject is incorrectly focused then your lens has a problem and needs recalibration.

Thanks for your reply - the focus mode is AF-C which I believe gets focus continually whilst shutter button is half depressed and seems the best choice for my subject matter. What about AF area mode - what implications are there................?
Static subject offer no issues with focusing so I think it is me and need to know how best to avoid this issue going forward.

 

[Overread]

By area mode I assume you mean the AF points on the camera - generally speaking the middle point is the one most people use only for such work - unless they are using good midrange or pro range camera bodies where the outer AF points are also of high quality (entry level and older midrange camera bodies tend to have just a good middle point whlist the others are of lesser quality - good but for action you need the best).

As I said if its the subject moving toward/away from you you might be pushing the camera too far - in that case you can try other ideas. One is to use a prefocus (manual focus) and to hit the shutter as the subject enters focus (some cameras also hav a way to make the shutter fire as soon as the af point registers focus aquisition - done with manual prefocusing this can be quite powerfull though I have no idea how to use this in canon least of all nikon camera bodies).

 

[Vinny]

I think the AF mode should be in 3D tracking. The D90 has it so I am assuming the D5000 has it as well. Try setting the camera to AF-C, 3D tracking and give it a try. Also there is a wide zone etting for moving subjects ... these are all in the D90 and I believe the D5000 has all the same things in it.

 

[Ady]

Yes it has the 3D tracking - would you consider that to be the best option for my subject matter? I looked at it and thought it might be a bit 'too clever' and stuck with the single point but I will def give it a go after seeing a lot of spoilt shots from yesterday.

Can anyone comment on AF-C & 3D tracking versus AF-C & single point?

 

[Vinny]

Now that I am re reading the manual it seems that the proper setting may be dynamic area, can't find where I thought it said 3D tracking.

Take a look at your manual, they give info on what to use for static vs moving objects. There is a mode on the D90 specifically for sports, may also be on the D5000 as well.

 

[HannahRebekah]

Now that I am re reading the manual it seems that the proper setting may be dynamic area, can't find where I thought it said 3D tracking.

Take a look at your manual, they give info on what to use for static vs moving objects. There is a mode on the D90 specifically for sports, may also be on the D5000 as well.

I don't know about yours, but a lot of sports modes will up the ISO to unnecessary heights, producing grainy shots.

I don't know about your question, Ady, they've covered most everything I can think of.

 

[Ady]

I tend not to use the various modes, usually just shoot on speed or aperture - as you said, 'Sports' mode cranks up the ISO so you can shoot at 1/1000 like it or not!
I have Googled 3D tracking and read what Nikon have to say (a little more than the manual) and it does sound very clever which I why I shyed away from it but I am going to give it a whirl - I would have though someone on here could tell me in real terms how the dynamic and 3D area modes compare.................

 

[Vinny]

I just read the manual and it gives priority to high shutter speeds so I guess you're right ... high ISOs if need be. But it does say how it tracks the subject if it moves out of the center and it uses dynamic focus for that.

 

[Derrel]

Please allow the D5000 to demonstrate its high degree of in-built cleverness. The computer's speed and skill at decision-making outstrips that of a human. If you were in one of the more-advanced autofocusing modes, which utilize multiple AF points, what you would do is use the multi-controller (AKA the "thumb-pad") on the back of the camera to move the AF are to the subject you wish to follow or track, and then the dynamic AF will follow that subject wherever it moves in the frame, closer or farther, or however you frame it...by examining the colors of the subject you initially focus on, the Nikon 3-D system will use sophisticated color measurements of the R-G-B and reflectance value to lock on to the subject. By allowing the camera to analyze data from multiple points, the computer can perform differential analysis based upon **multiple data points**. If the camera is crippled by the user merely switching t center AF point only, the camera has only a single data point on which to base its AF predictions, and the result is often worse than allowing the camera to do the controlling. This is vastly different from OTHER camera companies' products, which are typically color-blind and have rather dumb metering results on tricky subjects.

A lot of old-time photographers will tell beginners just to stick the AF on center AF area and use that: that works with many brands, and low-tech systems from other manufacturers and with older-style cameras. A good example would be this: let's say you ask me to predict the weather on the 15th. Single data point. Just ask me to predict the average daily high temperature at noon. Well, with your 11-area AF system, we'll call each data point an AF area. Are you willing to bet me 100 Pounds Sterling what the temperature will be on the 15th, with a 10 degree margin of error allowed??Pleaae note--we have only ONE data point-- "the fifteenth of the month". Right there, big as life, right in "the middle", the 15th of the month, if you get the analogy.

With ONE data point, your chances of a win are not too good. But let's add a second data point. Let's say the 15th of August. Our second data point is the month--August. Ohh.....chances of a +/- 10 degree Farenheit win would go up significantly,almost astronomically if we only had a third data point. Let's add a third data point....the 15th of August in London, England. Bingo...we have three data points now! Day,Month,Location. Let's then add in a fourth data point, the weekly time/temp log data from the London Heathrow airport weather station...now we have a really,really good set of data. Your D5000 has over 30,000 photographs in its memory, from which to compare to multi-point data input.

I guess the point is, trying to out-think the newer smart cameras is not always a good idea, and those who tell you blindly "stick it on center AF point" are typically not Nikon users...or are not familiar with how modern AF and metering works in the new Nikons.

 

[table1349]

For cyclist or any other moving sports for focusing the best setting is going to be a single focus point. Usually the center one, however once you get adept at focusing on action, you can begin to switch to other points as needed.

For focus mode you want whatever Nikon calls their continuous focus mode. Canon calls their AI servo.

If possible get your focus button off of the shutter button to one of the buttons on the back if possible. On Canon cameras there are a couple of programable buttons under the right thumb that serves for this purpose. This will allow you to constantly focus on the action and trip the shutter with out an focus lag. I am assuming that Nikon has custom functions that can be set.

Shutter speed needs to be at least 1/250th to freeze the action and 1/500th would be better.

If you are new to sports/action photography and do not feel comfortable shooting in manual mode then I would suggest Aperture Priority mode. This allows you to easily control your DOF as well as you shutter speed.

A DOF just deep enough to capture the direct action, yet blur the background will make the action pop. It also allows you to quickly adjust the shutter speed by bumping your ISO up or down to keep the shutter speed in the 1/250 to 1/500th range.

Shoot as low of an ISO as possible to keep your shutter speed where you need it, but don't worry about having to bump it up. A shot with frozen action and high ISO noise is better than an shot with no ISO noise and motion blur.

 

[table1349]

Please allow the D5000 to demonstrate its high degree of in-built cleverness. The computer's speed and skill at decision-making outstrips that of a human. If you were in one of the more-advanced autofocusing modes, which utilize multiple AF points, what you would do is use the multi-controller (AKA the "thumb-pad") on the back of the camera to move the AF are to the subject you wish to follow or track, and then the dynamic AF will follow that subject wherever it moves in the frame, closer or farther, or however you frame it...by examining the colors of the subject you initially focus on, the Nikon 3-D system will use sophisticated color measurements of the R-G-B and reflectance value to lock on to the subject. By allowing the camera to analyze data from multiple points, the computer can perform differential analysis based upon **multiple data points**. If the camera is crippled by the user merely switching t center AF point only, the camera has only a single data point on which to base its AF predictions, and the result is often worse than allowing the camera to do the controlling. This is vastly different from OTHER camera companies' products, which are typically color-blind and have rather dumb metering results on tricky subjects.

A lot of old-time photographers will tell beginners just to stick the AF on center AF area and use that: that works with many brands, and low-tech systems from other manufacturers and with older-style cameras. A good example would be this: let's say you ask me to predict the weather on the 15th. Single data point. Just ask me to predict the average daily high temperature at noon. Well, with your 11-area AF system, we'll call each data point an AF area. Are you willing to bet me 100 Pounds Sterling what the temperature will be on the 15th, with a 10 degree margin of error allowed??Pleaae note--we have only ONE data point-- "the fifteenth of the month". Right there, big as life, right in "the middle", the 15th of the month, if you get the analogy.

With ONE data point, your chances of a win are not too good. But let's add a second data point. Let's say the 15th of August. Our second data point is the month--August. Ohh.....chances of a +/- 10 degree Farenheit win would go up significantly,almost astronomically if we only had a third data point. Let's add a third data point....the 15th of August in London, England. Bingo...we have three data points now! Day,Month,Location. Let's then add in a fourth data point, the weekly time/temp log data from the London Heathrow airport weather station...now we have a really,really good set of data. Your D5000 has over 30,000 photographs in its memory, from which to compare to multi-point data input.

I guess the point is, trying to out-think the newer smart cameras is not always a good idea, and those who tell you blindly "stick it on center AF point" are typically not Nikon users...or are not familiar with how modern AF and metering works in the new Nikons.

Well since I am have only been shooting sports for 40 years, admittedly with Canon gear since going digital, explain to me how the Nikon AF works with multiple points when one/some point(s) are on one moving subject and another point or points are on another moving subject shooting a shallow DOF, f2.8 or less, to isolate the action. How does the NIKON know which subject to focus on?

 

[Ady]

I do use the thumb pad to change the position of the focus point for different compositions - am I getting the impression that the centre point is the most accurate and the other points not quite so?

Derrel - I here what you are saying and I am going to give the 3D area mode a whirl in conjunction with AF-C focus mode, would you consider this the best focus set up for my runner/cyclist requirements?

Thanks.

 

[Ady]

For cyclist or any other moving sports for focusing the best setting is going to be a single focus point. Usually the center one, however once you get adept at focusing on action, you can begin to switch to other points as needed.

For focus mode you want whatever Nikon calls their continuous focus mode. Canon calls their AI servo.

If possible get your focus button off of the shutter button to one of the buttons on the back if possible. On Canon cameras there are a couple of programable buttons under the right thumb that serves for this purpose. This will allow you to constantly focus on the action and trip the shutter with out an focus lag. I am assuming that Nikon has custom functions that can be set.

This is the method I have been using and my issues may well be down to lag - would the Nikon view software record pre lag (hence the red square is sometimes on an out of focus area)?
Don't think the D5000 has a seperate button to hold in motion focus, it is by partial press of shutter release.
When shooting at f2 or less (accurate focus even more important) and the small focus square (dynamic or 3D) is aimed at the face on a moving subject it is critical that the lag is allowed for - will the 3D do this?