One shot vs. Continuous shooting

[Rafal]

When using continuous shooting mode does the camera's focus quality is as good as in one shot setting?

... on a moving object such as a dancing couple

 

[Big Mike]

I assume you're using a Canon camera...is that correct?

Single shot vs Continuous is the release mode. In single shot, the camera fires once when you press (and hold) the shutter release button. In continuous, it keeps firing. This has almost nothing to do with focus...except that the AF assist light on an accessory flash (maybe on the camera) will only function in single shot.

One shot vs AI-Focus vs AI-Servo is the focus mode. In One shot, the camera will try to achieve focus, then stop or lock the focusing. It won't let you trip the shutter until that focus has been achieved. This may not be a good mode for a dancing couple, as the AF may never catch up to them and you wouldn't get any photos.
AI Servo mode (Canon), when active, will continually focus the lens. This is best for moving subject...although it will allow you to trip the shutter when the lens hasn't achieved focus, so there is a chance of missing your focus.

AI Focus mode (Canon) is a hybrid mode. It tries to achieve focus and then lock it, but if it things your subject is moving, it may try to refocus on it. Sometimes it works, sometimes it doesn't.

 

[LarryD]

This is almost two questions. For a moving object, you should be in AI Servo (Canon), or Coutinuous Servo AF (Nikon). In this mode the camera continuously tracks the subject changing focus as the subject moves and only "sets focus" when the shutter is tripped..

How well this works depends on the ability of the camera and what focus point you have selected or the camera is using... It may be focusing on something different than you think it is if you don't select that point

If you are in AI Servo, it doesn't matter if you are using Single Shot or Continuous Shooting

 

[Rafal]

I do understand the 3 focus modes but I was just wondering when using continues shutter mode the camera does have enough time to focus as well as in single shot mode. Lets put it this way, which one would you use in such situation one shot or continues to get best quality? Assuming that Focus mode is set to Al Servo in both

 

[EPPhoto]

If your subject isn't moving much, you can always just use the AF Lock button and fire away without worry your focus will change. Thats what I do in those situations.

 

[LarryD]

I do understand the 3 focus modes but I was just wondering when using continues shutter mode the camera does have enough time to focus as well as in single shot mode. Lets put it this way, which one would you use in such situation one shot or continues to get best quality? Assuming that Focus mode is set to Al Servo in both

Don't know the camera; I would use the motor drive and take bursts of 3 to 5 at a time in order to pick out the best expression and position of the subject. Just taking one limits you to only that pose and nothing else.

"Best Quality" may be subjective. If the shutter speed is adequate and the aperture has proper depth of field, either method should provide a focused photo..

 

[KmH]

When using AI Servo or AF-C focus is usually in shutter priority mode, meaning in burst mode (continuous) the shutter can release even if focus has not been achieved.

 

[pixilstudio]

not sure what you are asking. do you need a sequence of the subject...? the "drive" shouldnt affect the quality of the pic.

 

[GooniesNeverSayDie11]

My impression is that I believe he is asking if the AF can continuously keep up. But that's really relative to the camera and lens being used as well as focus point selected, lighting conditions, speed of your subject etc. It should be just as good in most cases, other than the fact that one shot will not re-focus or track focus without you releasing and re-pressing the AF button.

 

[Rafal]

My impression is that I believe he is asking if the AF can continuously keep up. But that's really relative to the camera and lens being used as well as focus point selected, lighting conditions, speed of your subject etc. It should be just as good in most cases, other than the fact that one shot will not re-focus or track focus without you releasing and re-pressing the AF button.

BINGO! ) sorry, but I couldn't phrase it as good as you.

 

[Rafal]

So let's say that lighting is not an issue, lens doesn't slow down AF, focus point selected and the couples speed isn't crazy fast, dancing in one spot. My objective is to obtain the best possible focus as well as to pick out the best expression and position of the subject.

One shot focus mode is out of the question since it won't lock on the focus point.
AI Servo mode might give be a bunch of shots that are out of focus because it doesn't wait for focus to be locked.
AI Focus mode refocuses and lockes it before releasing the shutter, for that reason taking longer to get a shot.

So if I want to achieve that objective in the shortest time of shooting i would set my camera to Continuos shutter mode with AI Servo focus mode , correct?
Would smaller aperture help the AF to focus faster?

 

[GooniesNeverSayDie11]

No, the aperture does not engage until you take the shot. A lens with a very fast minimum aperture ( lower f/stop number ) would be ideal because it allows more light into the camera for focusing. Continuous AF would be ideal, but ONE shot would work as well if you could press and release the AF repeatedly. The main hindrance here would be your possible in-ability to focus on the spot you intend to be sharpest. Most people blame AF when in fact they either focused on the wrong area due to fast movement, or used too wide of an aperture resulting in a very shallow Depth of Field. Also, you misunderstood what I meant when I said choose an AF point. Depending on the camera, some AF points are cross-type and may function better than others. Also, typically the center AF point works the best. Remember, you may consider a movement to be slow based on the field of view given by your eyes, however, depending on focal length, that field of view may become very narrow, so things may seem to move much more. An extreme illustration of this would be trying to keep a 400mm lens locked onto a bird in flight as opposed to keeping a 35mm locked on. Sure the 400mm will be closer, but the 35mm would be a breeze to follow in the viewfinder.

 

[Rafal]

No, the aperture does not engage until you take the shot. A lens with a very fast minimum aperture ( lower f/stop number ) would be ideal because it allows more light into the camera for focusing. Continuous AF would be ideal, but ONE shot would work as well if you could press and release the AF repeatedly. The main hindrance here would be your possible in-ability to focus on the spot you intend to be sharpest. Most people blame AF when in fact they either focused on the wrong area due to fast movement, or used too wide of an aperture resulting in a very shallow Depth of Field. Also, you misunderstood what I meant when I said choose an AF point. Depending on the camera, some AF points are cross-type and may function better than others. Also, typically the center AF point works the best. Remember, you may consider a movement to be slow based on the field of view given by your eyes, however, depending on focal length, that field of view may become very narrow, so things may seem to move much more. An extreme illustration of this would be trying to keep a 400mm lens locked onto a bird in flight as opposed to keeping a 35mm locked on. Sure the 400mm will be closer, but the 35mm would be a breeze to follow in the viewfinder.

So I just have to make sure that the DoF is enough to cover area that their in but if choose the center AF point, in a crop that covers them from head to toe, wouldn't I loose focus on the face?

 

[GooniesNeverSayDie11]

So I just have to make sure that the DoF is enough to cover area that their in but if choose the center AF point, in a crop that covers them from head to toe, wouldn't I loose focus on the face?

Yes you would, that was more for general explanation about focus points. Not just for this specific subject. I wasn't saying to use the center, I was saying that which focus point you choose could lead to less accurate AF at times. It depends on your set up also. My 7D with an L lens attached is going to focus much faster and much more accurately than a Canon XSi with a kit lens attached. And yes, you want to be careful with the depth of field. A 85mm lens at f/1.4 is going to require pinpoint accuracy of your focus point and be less forgiving. However, stopping down to say f/4 will give you a little more wiggle room incase you are just barely off the focus point.

 

[Rafal]

So I just have to make sure that the DoF is enough to cover area that their in but if choose the center AF point, in a crop that covers them from head to toe, wouldn't I loose focus on the face?

Yes you would, that was more for general explanation about focus points. Not just for this specific subject. I wasn't saying to use the center, I was saying that which focus point you choose could lead to less accurate AF at times. It depends on your set up also. My 7D with an L lens attached is going to focus much faster and much more accurately than a Canon XSi with a kit lens attached. And yes, you want to be careful with the depth of field. A 85mm lens at f/1.4 is going to require pinpoint accuracy of your focus point and be less forgiving. However, stopping down to say f/4 will give you a little more wiggle room incase you are just barely off the focus point.

Thank you for the help Everything is clear now, I simply need a 7D with a nice L lens

Thank you all for the help again , i've learned a lot with you help!