AI Servo tips, or focusing on walking subjects on 5Ds and 70D

[randomuser74]

I have some older equipment, but it should be fine for this low-key backyard wedding I'm shooting. Canon 70D and 5Ds both are misfocusing in AI Servo mode when doing mock trials of walking-down-the-aisle shots. In One Shot mode with still subjects, things look sharp, so I know it's not a lens calibration/micro-focus adjustment issue. I have a Canon EF24-105mm F4 L IS USM lens, and the minimum aperture is 4 so it's not really a narrow focal plane problem. Shutter speed is 1/250 minimum, but mostly much higher. I use a single AF point and place it directly on the subject's face and try to keep it locked on as they walk. Zone AF points didn't seem to work as well. I'm back-button focusing, holding down the AF-ON button continuously and trying to fire off 8-10 shots. Most are pretty soft and not as sharp as One Shot, and some are downright blurry. I've tried Live View, but the lag is so terrible that I only get 1 or 2 shots and the walk is done, and those are blurry as well. These cameras don't have eye tracking. I've done a handful of weddings with older DSLRs and film cameras and never really had this issue, or maybe resolution was just too low to notice. Honestly, my phone camera does a better job for this one scenario! There must be some technique I'm missing. What other tips can I try or is there some setting holding me back?  I have it set to focus priority.

[stevet1]

randomuser74,

I don't see a whole lot of camera shake, but at f/4, your depth of field is kind of small. I did blow up the picture, and the creases on the man's sweater are definitely blurred out. You might up the aperture setting to about f/5.6 and definitely turn on the image stabilization on your lens. 1/250th should be plenty fast enough for a person walking.

I too seen to have some problem with burst shooting. I think the weight of my hand tends to drag the camera downwards.

You might try using a tripod if you can and see how that works.

Steve Thomas

[randomuser74]

Thanks, stevet1.  But f4 is not typically a narrow depth of field for a single individual, right?  Is that just this particular lens? Or maybe a smidge of back or front focusing that only becomes apparent with motion and not in the stills?  I wanted a bit more blur to the background.  But of course I'll take an in-focus image over blurry background if I have to.

[stevet1]

randomuser74,

I don't know if this has any bearing on your situation or not, but I have a T8i, and I ran across this cautionary note:

It says pretty much the same thing in Live View shooting.

Steve Thomas

[ebiggs1]

"... there is a slight blur and softness to everything that is just confusing."

Since it does seem to be and all over softness, I suspect one or the other or both as the issue(s). First camera settings and secondly you were not steady enough. However, at 1/400 it is pretty difficult to introduce shake but not impossible. I would suggest you turn off all the Ai-focus assist and try One Shot and turn on IS. I almost never turn off IS even when the so-called experts say you should. And, I would suggest you reset your camera to defaults to make sure there isn't a unknown setting change. The shot you offered is really just a simple snap shot. It doesn't require any special settings to capture a good photo. Don't try to make it so. Also, unrelated tip always watch your background for obnoxious objects.

I run this through Photoshop and added a bit of unsharp mask and removed the signs. Nothing else.

Better? 🤔

[ebiggs1]

"... f4 is not typically a narrow depth of field for a single individual, right? "

DOF is dependent on distance not simply the aperture. It could be very shallow if you are very close or could be quite large if you are some distance from the subject. In your sample I suspect f4 was barely (assuming you were 10 feet from subject it would have been a little over 1 and 1/2 feet) sufficient but since your ISO was 800 (way too high for a shot like this), you could drop it to even ISO 200 and up the aperture to f8 (DOF would be about 3 and 1/2 feet). On almost every lens made one stop down is where they are at their best and generally they are not as good wide open.

Someone mentioned, "You might try using a tripod if you can and see how that works." I never use a tripod unless I am at the very back of the church and am using a 300mm, 400mm or 600mm lens. Yes, I have shot weddings from the back and even from the choir loft. Some priests, preachers, reverans, etc., are not photographer friendly.

[randomuser74]

Thanks for your efforts, ebiggs1.  I appreciate the time you took on that!  

Yes, the signs are just because I'm practicing in my yard just for this motion issue and I have limitations on where I can be.  My family can vouch for me that I spend a lot of time noticing and removing annoying objects in the background when it's a real scenario. 😀

The ISO was because it was getting cloudy and dark and that was what the camera needed to have a shutter speed at 1/400, which someone else told me I should try to help with this issue.  I can go back to trying One Shot again.  With a wider depth of field at something higher than f4 that could work.  Thanks again.

[TomRamsey]

Is there any wind that may be moving the ornamental grass and tree leaves in the background,? With servo your focus could jump a little with a moving background.  I take a lot of pictures near the ocean and sometimes have seen that happen.

[Waddizzle]

---

@randomuser74 wrote:

stevet1, it might be camera shake.  It's hand held, but I'm trying to keep as still as possible. I don't have the IS enabled on this lens because I just find it annoying.  But maybe those two things are solutions.

Here's an image.  The face is of course the most important thing to look at, but I've blocked that out.  The hair and ears give a good indication of the blur level of the face.  Hopefully you can zoom in to see that.  

67 mm, f4, 1/400

“ Also just a general clarification: As long as nobody is moving forward or backward out of the plane of focus, slight movement is okay in One Shot, is that correct? “

---

I am going to say incorrect.  Slight movement by whom, the subject or the photographer?  There is a lot to unpack here.  BTW, what was the ISO setting.  Ambient light does not appear to be high noon on a sunny day.  I think your shutter speed is too slow for moving subjects, no matter the AF mode.  But there is another issue that I will get to in a moment.

One Shot is great for still subjects.  For moving subjects, it depends on their speed and distance of their movement.  If the subject is moving, then you need to use Servo.  Up the shutter speed to at least 1/800 of a second.  This is why I am curious about the ISO setting.

Movement by the photographer can cause soft photos.  The photo is almost uniformly OOF, which is a red flag for camera shake by the photographer.  As I look at the grass around his feet, everything is out of focus.  I assume that the photo has not been significantly cropped, which can also lead to soft images.

You must hold the camera steady, with your elbows tucked in close to your body.  No chicken wings.  Besides, when your elbows are sticking out you are making yourself vulnerable to being bumped and dropping the camera.

The primary job of the Image Stabilization in the lens is to stabilize the image for the AF System and the OVF, not compensate for camera shake by the photographer.  Think about it.  The IS spends over 99.99% of its time stabilizing the image for the AF.  It only takes a small fraction of the second to capture an image.  

Because the image seems uniformly OOF, I think the issue here is camera shake.  I am assuming the image has not been severely cropped.

[EDIT]. I did not notice if this question was asked or not.  Were using any lens filters?

[ebiggs1]

"The ISO was because it was getting cloudy and dark and that was what the camera needed to have a shutter speed at 1/400, which someone else told me I should try to help with this issue."

A couple things especially if you want to do a wedding. Most of the time 1/60 or certainly 1/100 is faster that most  humans. Think about it, 60 slices of a second or 100 slices of a second. That's pretty darn fast isn't it? And, 1/200-1/250 will give you that extra safety margin, however these slower SS can cause issues by you since you are the camera holder. You must develop a steady and sturdy hold on the camera/lens combo. Always use IS, too.

As to ISO you always, or most often, want the lowest ISO necessary to get the best quality in your images. Not that ISO 800 is way out of reason it was just not justified in this case. It is perhaps the beginning of being considered a higher ISO. Your camera is probably going to be at its best at ISO 200. Make sure you are using raw for your shots and not jpg. Never use jpg. Raw has the capacity to offer very much increased editing ability which does include increasing exposure or pseudo ISO as matter of fact. Don't over think shots. Your sample is just a simple snapshot and should be thought of as one.

[ebiggs1]

"If the subject is moving, then you need to use Servo.  Up the shutter speed to at least 1/800 of a second."

randomuser74,

I totally, 100% disagree with that advice.