AF assist on 430 EX II

Started Aug 17, 2010 | Discussions
drif8r
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AF assist on 430 EX II
Aug 17, 2010

How do I turn on AF assist on 430 EX II flash mounted on XTi.

The flash fires when required ETTL mode, but never seen the AF assist go on in dark.

Michael Thomas Mitchell
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Re: AF assist on 430 EX II
In reply to drif8r, Aug 17, 2010

Unless your camera offers some additional functionality not addressed in the flash manual, the AF assist beam is automatic and does turn on or off; it is simply always on.

To check your unit, go into a completely dark room. Let your eyes adjust. Then point the camera towards a BLANK wall and press the shutter halfway. You should see a faint red cross-hatch light pattern. The cross-hatch design is there so as to provide contrast for the AF sensor. If it is working properly, the camera should focus very quickly. If you don't see the RED light pattern, then your unit may be defective.

drif8r wrote:

How do I turn on AF assist on 430 EX II flash mounted on XTi.

The flash fires when required ETTL mode, but never seen the AF assist go on in dark.

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Michael Thomas Mitchell

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Lemming51
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XTi C.Fn-5 (p. 104). 430EX II C.Fn-08 (p. 21, 23)
In reply to drif8r, Aug 17, 2010

To turn on the AF Assist, set the XTi's C.Fn-5 = 0 or = 2. Page 104 of the XTi manual.

Make sure the 430EX II's own C.Fn-08 is set to 0 (Enable). Pages 21 and 23 of the 430EX II manual.

drif8r wrote:

How do I turn on AF assist on 430 EX II flash mounted on XTi.

The flash fires when required ETTL mode, but never seen the AF assist go on in dark.

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drif8r
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Re: XTi C.Fn-5 (p. 104). 430EX II C.Fn-08 (p. 21, 23)
In reply to Lemming51, Aug 19, 2010

I changed both settings as you mentioned (Camera was off by default) yet the AF assist does not illuminate in PASM modes, in fact with external flash unit attached lens has trouble focusing in dark, to my surprise AF illuminates just fine in Green and all auto modes.

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Lemming51
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P.S. AF Assist doesn't work with AI Servo.
In reply to drif8r, Aug 19, 2010

drif8r wrote:

I changed both settings as you mentioned (Camera was off by default) yet the AF assist does not illuminate in PASM modes, in fact with external flash unit attached lens has trouble focusing in dark, to my surprise AF illuminates just fine in Green and all auto modes.

The AF mode in Green box and all auto modes other than Sports (running man) is AI Focus or One Shot. In these AF modes, the shutter will not trip until focus is confirmed. So the AF Assist Light is projected, then shuts off at focus confirmation before the shutter opens.

If the AF mode is set for AI Servo, then the AF Assist Light is disabled. AI Servo is continous focus, so the AF Assist Light would be need to be projected continously. And in AI Servo the shutter will trip whenever the user full presses the button, it does not wait for focus confirmation. So if the AF Assist Light was on in AI Servo it would show up in the photos. Thus it's disabled in AI Servo.

It has always been so with EOS cameras, I don't know why there isn't a note to that effect in the manuals for the camera or the speedlite.

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drif8r
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Re: P.S. AF Assist doesn't work with AI Servo.
In reply to Lemming51, Aug 19, 2010

AI servo was the culprit, AF assist works in manual mode with one shot focus; I nearly returned the flash.

Of all flash systems I used, Canon speedlights have the least user friendly interface.

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WilbaW
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Re: P.S. AF Assist doesn't work with AI Servo.
In reply to Lemming51, Aug 20, 2010

Lemming51 wrote:

So if the AF Assist Light was on in AI Servo it would show up in the photos. Thus it's disabled in AI Servo.

That sounds daft. I wonder why they don't just switch off the AF Assist beam while the shutter is open. I hope there's a very good reason why they don't.

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Noogy
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Re: AF assist on 430 EX II
In reply to Michael Thomas Mitchell, Aug 21, 2010

This is my experience as well, it is just always on. Check your AF settings in the camera, you might have disabled it accidentally.

Michael Thomas Mitchell wrote:

Unless your camera offers some additional functionality not addressed in the flash manual, the AF assist beam is automatic and does turn on or off; it is simply always on.

To check your unit, go into a completely dark room. Let your eyes adjust. Then point the camera towards a BLANK wall and press the shutter halfway. You should see a faint red cross-hatch light pattern. The cross-hatch design is there so as to provide contrast for the AF sensor. If it is working properly, the camera should focus very quickly. If you don't see the RED light pattern, then your unit may be defective.

drif8r wrote:

How do I turn on AF assist on 430 EX II flash mounted on XTi.

The flash fires when required ETTL mode, but never seen the AF assist go on in dark.

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Michael Thomas Mitchell

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Noogy
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