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07-02-2014, 01:40 PM   #1
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A case where you WANT to use a MF lens instead of a modern AF lens

I just realized that the "Catch-in Focus" operation only works with true manual focus lenses but not (regrettably!) when just turning AF off. (Update: Turns out that lenses with a AF/MF switch can be used as well!)

So, if you have a case where you need to rely on a "Catch-in Focus" shooting method, you actually want to have an old lens. Lucky for you that they're cheap (well, usually, unless you want that A* 300 f/2.8 monster)!

An example where I believe "Catch-in Focus" is useful:

When shooting moving objects, e.g. insects in flight (dragonflies), because there you cannot use AF, as it's too slow and would too often try to focus on the background. Instead, you need to preset your focus and shoot at the right moment, using burst mode, preferrably. With the "Catch-in Focus", however, you can just hold down the finger on the shutter and wait for the object to come into focus.

Well, at least that's the theory. Has anyone tried and succeeded in this, or is the focus detection too slow to react? (I'd try myself but I waste all my time with technical experiments at home.)


Last edited by tempelorg; 07-02-2014 at 01:54 PM.
07-02-2014, 01:44 PM   #2
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Catch in Focus also works with lenses that has an AF/MF switch on them. So you can use it on some modern lenses. The bad side of older lenses is that you are restricted to the center point.
07-02-2014, 01:47 PM   #3
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Uh, I had no idea, carrrlangas.

Finally, I see a use for that switch on my DA* lenses!
07-02-2014, 02:10 PM   #4
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I actually just recently tried using CIF with one of my Zeiss MF lenses to shoot hummingbirds. Couldn't get it to work. I'm sure I just did something wrong as it was my first and only attempt and I quickly realized I wasn't really going to be able to get an interesting shot that way, anyway. You have to be able to follow the little buggers around the feeder. I kind of shocked myself that I was able to get quite a few decent shots by actively manually focusing, through the VF. My s-type focusing screen was a big part of why this was possible for me, I'm sure.

07-02-2014, 02:16 PM - 1 Like   #5
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Actually, there is a trick I learned from another PF member, that will allow you to use CIF with screw drive AF lenses.

Leave the MF/AF setting on AF. Hold the camera up to your eye as normal.

Then, press and hold the lens release button down with your right ring finger, or right pinky. This will mechanically disengage the screw drive from the lens.

With the lens release button held down, also press the shutter release with your index finger. The in-body AF motor will spin away, but will not turn the lens. Hopefully the noise will not scare away your subject. Turn the focus ring with your left hand as normal.

A little awkward at first to push two buttons with your right hand, while also holding the camera, but it works.

I don't use this often, but I have a better appreciation for the lens release button being on the right side of the camera.
07-02-2014, 02:58 PM   #6
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QuoteOriginally posted by Tanzer Quote
Actually, there is a trick I learned from another PF member, that will allow you to use CIF with screw drive AF lenses.

Leave the MF/AF setting on AF. Hold the camera up to your eye as normal.

Then, press and hold the lens release button down with your right ring finger, or right pinky. This will mechanically disengage the screw drive from the lens.

With the lens release button held down, also press the shutter release with your index finger. The in-body AF motor will spin away, but will not turn the lens. Hopefully the noise will not scare away your subject. Turn the focus ring with your left hand as normal.

A little awkward at first to push two buttons with your right hand, while also holding the camera, but it works.

I don't use this often, but I have a better appreciation for the lens release button being on the right side of the camera.
Very interesting - never heard of that. Although I'm not sure how much I'd want to have my AF motor spinning around uninhibited, without the expected resistance or damping.
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