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Using Canon AI Servo for Macro Shooting?


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#1 BurBunny

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Posted 18 November 2007 - 09:06 AM

In getting to know my new Canon 400D, I can definitely see the potential benefit of shooting AI Servo if shooting big critters such as large fish or sharks while they or I are moving. Larger movements, covering lots of space, it'll hold lock until the critter swims into a nice overall frame.

But what about with macro and supermacro? How much benefit might it be with something like a juvenile sweetlips which is flitting around like crazy? Or a juvenile filefish? I'm used to getting focus lock with half press and once locked on what I want, immediately taking the shot. Is AI-Servo sensitive enough that I can focus with the * button and the critter can flit 1/8" inch away from where it was to begin with, but into a perfect orientation for the shot, and it'll refocus so I can get the shot?

For this type of shot, would be using center focus point only. Likely with my 60mm lens, possibly with a woody or Inon 67mm lenses (perhaps double stacked) if that makes a difference.

How do you all use AI Servo... or have you tried it and found it just wasn't what you were looking for?
-Amber

#2 Stewart L. Sy

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Posted 21 November 2007 - 11:28 AM

But what about with macro and supermacro? How much benefit might it be with something like a juvenile sweetlips which is flitting around like crazy? Or a juvenile filefish? I'm used to getting focus lock with half press and once locked on what I want, immediately taking the shot. Is AI-Servo sensitive enough that I can focus with the * button and the critter can flit 1/8" inch away from where it was to begin with, but into a perfect orientation for the shot, and it'll refocus so I can get the shot?

I've been using AI Servo for a lot of my super macro shots. Canon designed algorithm to be able to track a vehicle at around 50mph about 30 yards from camera, pretty darn fast, so if it can do that, how hard can it be to track a diver breathing in and out?

Here's a shot taken with the 10D, uncropped, Tamron SP90mm Macro and Woody's diopter, I would guess this is pretty much a 2:1 magnification 1:1 x 1.6 x 1.2 (approx. magnification of a Woody's) = 1.92:1

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Edited by scubastu, 21 November 2007 - 11:28 AM.

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#3 BurBunny

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Posted 21 November 2007 - 01:41 PM

Thanks, Stu - was what I was hoping to hear! Knew it was fast, but wasn't sure if it was sensitive enough on such a small target focus point. If I can finally get my pygmy seahorse shot which is crisp, I'll be a very happy camper. Tired of "almost, but not quite" shots, but haven't tried one yet with the new DSLR.
-Amber

#4 james

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Posted 21 November 2007 - 03:20 PM

Hi Amber,

Sorry I haven't been able to answer sooner, but I'm away for the holidays.

I use AI-Servo all the time for wideangle fast action shooting, but I prefer one-shot for Macro. I have tried it for macro, but I find it doesn't select an area of the critter that I want to focus on. It looks like it worked OK for Stu though!

I prefer using the * button w/ one shot to focus, on just about any part of the critter. Then I move in and out until the eye is in focus.

Oh, forgot to mention that I have a 1D series body which has excellent autofocus.

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#5 pakman

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Posted 21 November 2007 - 07:16 PM

Amber, good to see you spending more time over here in wetpixel where you don't have to deal with that resident crackpot on SB :)

I remember vaguely trying the AI Servo on my 400D and wasn't too satisfied with the results. Again, it might have been a case of using it for the wrong occasion. Maybe it would work with a dominant subject with little or no distracting background. I agree with James in that the potential problem is what the camera wants to lock focus on may not be what you want in focus. The center focus on the 400D, especially coupled with a fast lens, performs pretty well though. Take Scubastu's great pygmy shot above, I'd be worry that the camera would decide to focus on the belly and not the head.

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#6 yahsemtough

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Posted 22 November 2007 - 06:08 AM

I find that for the critical focus that I want for macro I use half press focus lock. I either use it on the subject or on something near the subject and recompose.

IMHO

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#7 Cerianthus

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Posted 23 November 2007 - 02:09 AM

this is interesting stuff.

For me the main disadvantage of servo is that the focus marks dont light up in red when focus is achieved. With macro, i like to aim one focus point at the eyes, so I know it's sharp when it lights up red (mostly practiced near my aquarium though).

I know you can select one focus point, but is there a way to see which focus point is chosen ?



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#8 BurBunny

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Posted 25 November 2007 - 09:48 PM

Amber, good to see you spending more time over here in wetpixel where you don't have to deal with that resident crackpot on SB :rolleyes:

I remember vaguely trying the AI Servo on my 400D and wasn't too satisfied with the results. Again, it might have been a case of using it for the wrong occasion. Maybe it would work with a dominant subject with little or no distracting background. I agree with James in that the potential problem is what the camera wants to lock focus on may not be what you want in focus. The center focus on the 400D, especially coupled with a fast lens, performs pretty well though. Take Scubastu's great pygmy shot above, I'd be worry that the camera would decide to focus on the belly and not the head.


Yeah, I need to break myself of the habit of replying to him, but with Alcina on holiday, and the fact he's maligning me personally, feel I have to respond so those who don't know him don't think he actually has a clue.

Actually, at least with the 400D, you can set a focus point other than center. I've been playing with it offset (to be able to frame on the rule of thirds) and it seems to work beautifully, at least with C.Fn4-1 as the mode. But of course that means playing with the focus point shot to shot, and loosing the cross point of the center focus point.

this is interesting stuff.

For me the main disadvantage of servo is that the focus marks dont light up in red when focus is achieved. With macro, i like to aim one focus point at the eyes, so I know it's sharp when it lights up red (mostly practiced near my aquarium though).

I know you can select one focus point, but is there a way to see which focus point is chosen ?
Gerard


If you have just a single focus point chosen, instead of all points, it does flash when that point gets focus lock. When you set the single focus point, look through the viewfinder or the LCD (if your camera supports this on the LCD) whilst twirling the dial to set. It will show you which focus point is currently selected.
-Amber