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06-05-2010, 12:04 AM   #1
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Catch-in focus with A 50mm f1.7 lens

Hi, guys,

Need your advice on how to get catch-in focus to work with an A50 F1.7 lens. I have enabled the function in the menu (C-3, item 21), but it just won't trigger. I can only manually press the shutter button to take pictures. So what is missing?

Thank you guys in advance,

Sam

06-05-2010, 12:09 AM   #2
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It should work in AFS mode whenever the subject gets in focus, but I'm not 100% sure. Are you able to take pictures at all with it? Make sure you are in P mode with the aperture ring set to 'A', too- you don't need to worry about manually setting it on an A lens.

Adam
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06-05-2010, 03:53 AM   #3
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Hi, I use catch in focus with this lense, so it does work.

Couple of points (forgive me if I am stating the obvious):
1. You must have MF / AF switch set to AF for catch in focus to work.
2. You just hold down the shutter release and slowly turn the focus until it "catches" the in focus subject. This happens when "in focus" indicator shows.
3. Focus can be a little fiddly so I usually approx focus first and then turn focus very slowly until it catches.
06-05-2010, 04:13 AM   #4
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Another remark: you must have the focus function assigned to the shutter, not to the AF-button.

06-05-2010, 08:23 AM   #5
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sucks that it works with center focus point only though.

i find it much better to just use liveview.
06-05-2010, 09:08 AM   #6
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QuoteOriginally posted by RolloR Quote
sucks that it works with center focus point only though.

i find it much better to just use liveview.
I agree, it seems that CIF only works within a narrow set of conditions. However, I've had good success with prefocusing and continuous shooting. Granted, you sort of have to know what's coming in order to do it, but it works well.

FWIW. My D700 didn't exactly snag all the shots my K20D struggled with either. And from what I'm told, panning(passing-by) shots are quite a challenge for pretty much any camera. But I have yet to use the Nikon with a good lens(can't afford it)
06-05-2010, 10:26 AM   #7
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Yes I can take pictures with it manually, but not with catch-in focus. Just scratching my head here.
06-05-2010, 10:31 AM   #8
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In another word, is there a way that the shutter can be released without 100% in focus, i.e., the green indicator is on. Since it's pretty hard to get the indicator to turn on, I just want to be able to take pictures when it's visibly in focus, instead spending a lot of time to focus back and forth to get the indicator on.

06-05-2010, 11:21 AM   #9
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QuoteOriginally posted by dude2009 Quote
In another word, is there a way that the shutter can be released without 100% in focus, i.e., the green indicator is on. Since it's pretty hard to get the indicator to turn on, I just want to be able to take pictures when it's visibly in focus, instead spending a lot of time to focus back and forth to get the indicator on.
That's easy: put your camera to Manual focus. While you still get the focus confirmation, you 'fire' away any time you see fit.
But if I interpret your question correctly, you have actually everything set up for "catch in focus": your camera won't fire until it 'sees' the image is in focus.
That's the catch in focus or focus trap or trap focus. It won't fire by itself. You have to push the shutter button. The shutter will only be released when focus is confirmed.
06-05-2010, 12:36 PM   #10
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QuoteOriginally posted by dude2009 Quote
Need your advice on how to get catch-in focus to work with an A50 F1.7 lens. I have enabled the function in the menu (C-3, item 21), but it just won't trigger. I can only manually press the shutter button to take pictures. So what is missing?
Um, you're aware that catch-in-focus also require you to manually press (and hold!) the shutter button, right? And you're using the aperture ring in the "A" position, right?
06-05-2010, 07:39 PM   #11
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QuoteOriginally posted by Bart Quote
Another remark: you must have the focus function assigned to the shutter, not to the AF-button.
Actually, I just learned the joys of using CIF with focus assigned to the AF-button (as opposed to half-press of the shutter). With this setup:

CIF
1. Press and hold the AF button
2. Press and hold the shutter
3. Focus the lens
Done in this manner, the shutter will trip when focus is achieved.

Focus and recompose
1. Press and hold the AF
2. Focus the lens
3. Release the AF
4. Recompose the shot
5. Press the shutter
Done in this manner, the shutter will trip even if the center is not in focus.
06-05-2010, 07:44 PM   #12
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QuoteOriginally posted by johnmflores Quote
Actually, I just learned the joys of using CIF with focus assigned to the AF-button (as opposed to half-press of the shutter). With this setup:

CIF
1. Press and hold the AF button
2. Press and hold the shutter
3. Focus the lens
Done in this manner, the shutter will trip when focus is achieved.
I never tried it this way, what are the advantages of using CIF with AF button and Shutter over that of using shutter alone?
06-05-2010, 09:38 PM   #13
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QuoteOriginally posted by JohnBee Quote
I never tried it this way, what are the advantages of using CIF with AF button and Shutter over that of using shutter alone?
If all you want to do is make sure that the object in the center of the frame is in focus before tripping the shutter, then there's no advantage at all. It actually takes more steps, so it's marginally slower.

But...

If you alternate frequently between standard CIF as described above and compositions where the subject and focus is off-center, then separating the shutter and AF makes this easy without having to menu dive.
06-05-2010, 09:58 PM   #14
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@Bart: Not so. If you have the AF assigned to the AF button rather than the shutter, cath-in-focus will work if you hold the AF button in and hold the shutter button down at the same time. The shutter will then trigger when the subject comes into focus.
06-06-2010, 02:06 AM   #15
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QuoteOriginally posted by johnmflores Quote
If all you want to do is make sure that the object in the center of the frame is in focus before tripping the shutter, then there's no advantage at all. It actually takes more steps, so it's marginally slower.

But...

If you alternate frequently between standard CIF as described above and compositions where the subject and focus is off-center, then separating the shutter and AF makes this easy without having to menu dive.
QuoteOriginally posted by jbinpg Quote
@Bart: Not so. If you have the AF assigned to the AF button rather than the shutter, cath-in-focus will work if you hold the AF button in and hold the shutter button down at the same time. The shutter will then trigger when the subject comes into focus.
It all depends what you want to use the catch in focus for. For me, having to push the af button as well is not useful.
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