Is Mark 4 focus system inferior FOR STREET PHOTOGRAPHY to the Mark 3?

[Streker26]

I have upgraded to the Mark 4 from the Mark 3. I do street photography of people. It seems that the Mark 4 works in a very, very different fashion then the Mark 3 when it comes to autofocus. I have tried every single focus setting or combination of settings but I continue to have problems. I am using exclusively a 50mm 1.4 USM lens as I did on the Mark 3 by the way. So it seems like the Mark 4 takes longer to focus. It sometimes hunts. The shutter button as well is not as responsive. But the biggest problem that is driving me up the wall is very often the camera will focus on the background to the exclusion of foreground subjects. And I don't just mean small figures in the foreground but even when I have a person filling one third of the frame in the center of the field! It is weird because this is not always the case but it is often the case. It is especially bad when I shoot fast. If I am slow and deliberate it is less often a problem. But the thing is that this was NEVER an issue with the Mark 3 for me. So I would love to know what settings people recommend as best to quickly catch in focus a a foreground figure in priority over background subjects. And also if others have had similar issues with this camera in relation to it's predecessor. Thanks

[Streker26]

Perhaps ... or perhaps the copy I have is defective in some way. What auto-focus setting wouo you use specifically to prioritize foreground figures over their backgrounds?

[Waddizzle]

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@Streker26 wrote:

Perhaps ... or perhaps the copy I have is defective in some way. What auto-focus setting wouo you use specifically to prioritize foreground figures over their backgrounds?

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One Shot mode, and a manually selected AF point.  The center one is typically the easiest and best one to use.

[jrhoffman75]

AI Focus mode lets the camera decide between One Shot or AI Servo depending on whether or not the camera sees subject motion. But, the camera isn’t smart enough to sense between subject moving or you moving the camera, especyif you are grab shooting. I can’t imagine street photography subjects moving enough to warrant using AI Servo. Set One Shot and Center point and I think you will better success rates. 

[TTMartin]

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 wrote:

One Shot mode, and a manually selected AF point.  The center one is typically the easiest and best one to use.

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Sorry, in my opinion this is BAD advice.

Canon's Rudy Winston's advice is that: 

One Shot should be used for subjects that will not move.

AIServo should be used for moving subjects or subjects that may move.

AIFocus should not be used.

The poster recommending One Shot for everything relies on a large depth of field for moving subjects. 

I expect a lengthy argumentative reply, but, I'll keep my post short and to the fact.

The following photo was taken with AIServo, center AF Point with surrounding helper points.It is forth in a series of a moving subject in front of a cluttered background all of which focused on the subject.

This following photos were taken with the same settings, notice how the shallow depth of field gives a nice blurry background.

If you are going to rely on a large depth of field to capture moving subjects you might as well be using a point and shoot. 

[jrhoffman75]

I don't disagree with what you are advising Tom if the scenario is still camera focusing on subjects that may move; you proved the advise. Camera acquires the subject and tracks possible motion.

But, in the OP's case he is sometimes moving the camera - quick grab shots: "The other day I had two woman talking and they were three feet from me and the camera focused on the background store behind them although they practically filled the frame. Now if I slowly lift the camera to my eye and press the shutter slowly this will happen less." I think in the first case subject acquisition is going to be more difficult; no time for camera to think. 

[Waddizzle]

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@jrhoffman75 wrote:

I don't disagree with what you are advising Tom if the scenario is still camera focusing on subjects that may move; you proved the advise. Camera acquires the subject and tracks possible motion.

But, in the OP's case he is sometimes moving the camera - quick grab shots: "The other day I had two woman talking and they were three feet from me and the camera focused on the background store behind them although they practically filled the frame. Now if I slowly lift the camera to my eye and press the shutter slowly this will happen less." I think in the first case subject acquisition is going to be more difficult; no time for camera to think. 

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I agree with you regarding quick shot and limited movements of street subjects.  Typically, the only time I use AI Servo is when I am also using Continuous drive mode.  For Single Shot drive mode, I almost always use One Shot focusing mode.

One Shot mode simply focuses at the selected AF point, and gives you the fastest focus lock.  AI Servo asks the camera to not only focus, but to also begin analyzing the scene, and tracking subject movement.  Now you have to worry about focus tracking settings.  Street subjects do not move fast or far enough to warrant AI Servo.  One Shot and a fast shutter is all you really need, IMHO.

Tom, those are very nice shots of birds in the wild.  I do not see how using a long, super telephoto in AI Servo mode to shoot birds in flight applies to street photography with a 50mm lens.

[TTMartin]

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 wrote:

Tom, those are very nice shots of birds in the wild.  I do not see how using a long, super telephoto in AI Servo mode to shoot birds in flight applies to street photography with a 50mm lens.

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Both involve moving subjects with cluttered backgrounds and most importantly a shallow depth of field. 

[Waddizzle]

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@Waddizzle wrote:

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@jrhoffman75 wrote:

. 

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One Shot mode simply focuses at the selected AF point, and gives you the fastest focus lock.  AI Servo asks the camera to not only focus, but to also begin analyzing the scene, and tracking subject movement.  Now you have to worry about focus tracking settings..

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I completely forgot to explain the focus tracking settings, which the video does not explain.

The default behavior for AI Servo is NOT to wait for the camera to have a focus before activating the shutter.  But, this behavior is adjustable, but the adjustment only seems to be available when you are in Continuous drive mode.  

This adjustment to AI Servo behavior is called Image Priority.  You can adjust it for Shutter Priority, which does not wait for a focus lock, but allows for the fastest frame rates.  Or, you can adjust it for Focus Priority, which requires the camera to acquire a focus lock before it activates the shutter, but this setting can slow down the frame rate in continuous drive mode.  Or, you can adjust it to a setting somewhere in between the two extremes.  I adjust my cameras for 100% Focus Priority.

If you are using Single Shot drive mode, then you almost certainly want to use One Shot AF mode, because the camera will not refocus between shots in Continuous drive mode.  If you are using AI Servo AF mode, then you almost certainly want to be using Continuous drive mode, because the camera does not have to wait for a focus lock in One Shot mode.

[Streker26]

Yes.. but I am mostly using AI FOCUS and that is supposed to shift between options theoretically being the ideal setting. I am encouraged now to try ONE SHOT however. Hope this will solve the issue. I will say again that I used AI FOCUS on the Mark 3 with no issues. It was simply faster. But with the Mark 3 I was often frustrated because as everyone knows the focus is so central weighted that I rarely could get away with side frameing a subject in the street while quickly walking by. I expected that handicap also with the Mark 4. What I did not expect and still do not understand is how I can line up a standing figure in the middle of the frame and the camera chooses one out of two or three times to focus on the wall behind this figure. 

[TTMartin]

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@jrhoffman75 wrote:

I don't disagree with what you are advising Tom if the scenario is still camera focusing on subjects that may move; you proved the advise. Camera acquires the subject and tracks possible motion.

But, in the OP's case he is sometimes moving the camera - quick grab shots: "The other day I had two woman talking and they were three feet from me and the camera focused on the background store behind them although they practically filled the frame. Now if I slowly lift the camera to my eye and press the shutter slowly this will happen less." I think in the first case subject acquisition is going to be more difficult; no time for camera to think. 

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That is because the OP was using AIFocus.

AIFocus does not work in quick situations as the camera starts assuming a static subject (One Shot)  and then if it detects movement only then does it switch to AIServo for a moving subject.