How do you shoot people walking towards you with thin dof?

Hi all..

I know this is a pretty basic thing to do, but for some reason I never quite learnt how to do this properly

I usually set my f stop to about 7-8, crank up the ISO and keep a fast shutter speed and hope that they are still in focus from the time I focus to the time I snap

Would you normally use AI Servo if you wanted to use a wide aperture?

Ai servo with camera which can track.

AI Servo is good with any moving subject as well as using back button focus.

I just started using AI Servo and now that is my default setting.

Thanks.. I have tried using AI Servo but didn't get good results with my 5d2

LucasCK wrote in post #16097549
Thanks.. I have tried using AI Servo but didn't get good results with my 5d2

are you using center point? which lens are you using? if a person is just walking and not flying at you at say 45 mph it should be simple.

With a 5DII, depending on the subject, enabling expanded focus points can help in Al-Servo (it's a menu option under focus settings).

Should work fine with the lenses you have (don't know about the sigma though).

Here is my take. On 5dc/5dmk2 if using outer AF points with fast prime I didn't have much luck in AI servo. If you use center AF point then face is going to be OOF unless subject is far.

On 5dmk3 everything worked so much better.

What if you want to use center point focus but want to recompose?

Pre focus on a point where you know the people will be walking through and somewhere you want them to be and wait until they get there.

I have my DOF preview button set to AI servo as most it the time I'm on single shot. Then with BBF and AI servo I just track the subject if they are walking to me. Comes in handy if I'm at an event and I want to catch someone moving.

LucasCK wrote in post #16097480
Hi all..

I know this is a pretty basic thing to do, but for some reason I never quite learnt how to do this properly

I usually set my f stop to about 7-8, crank up the ISO and keep a fast shutter speed and hope that they are still in focus from the time I focus to the time I snap

Would you normally use AI Servo if you wanted to use a wide aperture?

For a shallow depth of field, use a long focal length and a large aperture.

Actual examples from a 70-200mm f/2.8 lens.

LucasCK wrote in post #16097764
What if you want to use center point focus but want to recompose?

If using AI Servo and wanting to do focus and recompose technique, you have to use Back Button Focusing. If you don't use this, when you recompose in AI Servo the camera will refocus onto whatever the active AF point happens to be covering.

However, another way is to not recompose, but simply frame slightly loosely so that you have room to crop the images a little off-center later, in post-processing. 5DII gives you ample image to allow for some cropping.

With 5DII, I mostly use just the center AF point. It's the only visible, dual-axis point in the camera... more sensitive and better at tracking movement than the others.

Actually there are two more dual-axis points, but they are among the six "hidden" assist points that you can optionally enable, clustered close around the center point. The assist points aren't displayed in the viewfinder, sort of make the entire Spot Metering circle one big AF point, when enabled. However only two of them are dual-axis type, and all the hidden assist points only work in AI Servo.

My other cameras are a pair of 7Ds, which have 19 points, all of which are dual-axis type. It's much better for off-center compositions with moving subjects, but that's a good thing because with an APS-C camera there's not as much to work with cropping images in post processing.

Due to the 5DII's AF system (which wasn't changed from the original 5D's and is more akin to 20D/30D and some older Rebel AF systems), it's just not a great camera for action and moving subjects. Walking speeds shouldn't be a problem, but it just doesn't keep up well with faster movement. I tend to use the 7Ds more for action/sports, the 5DII more for stationary types of subjects.

But, hey, you just never know what might fly by when you have one camera or another in your hands....

This is where AF on 5dmk3 comes handy. Center AF with someone moving and shooting at f1.4/f2, good luck IMHO.

bobbyz wrote in post #16099155
This is where AF on 5dmk3 comes handy. Center AF with someone moving and shooting at f1.4/f2, good luck IMHO.

True enough. But, you don't need a 5D3 to accomplish that. Any digital Rebel should be able to handle that with a decent lens and center point only AF. As AMFOTO1 says, BBAF is essential in this situation. I don't have any f/1.2 or 1.4 lenses, and notorious slow-focusers like the 85 1.2 may present a problem, but probably not at f/8, on a walking target.

My XSi, T1i and 60D can track my dogs on a dead-run, straight at me with mediocre glass like the 28-135, 18-135 and 15-85. My Sigma 70-200 f/2.8 OS works just fine for tracking, even at f/2.8. Admittedly, the aperture can make a big difference at f/1.2. I believe the OP was talking about f/8, though. I am pretty sure this is a technique issue, not a hardware problem.