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03-25-2010, 11:35 AM   #1
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Catch-In Focus: The solution to slow AF-C?

Note: Lens in question is a Bayonet-Mount Takumar 135mm F2.5

After trying to take manual focus images of the Vancouver 2010 Paralympics (Sledge Hockey in particular), I found my keeper rate really low - even with Katzeye. For some reason, my manual focusing is always off compared to AF on my K20D or K10D. I've come to the conclusion that my eyes are just not as accurate...

I was thinking of some solutions. Initially, I thought about getting a DA*200 or DA*300 but that was a lot of money and a huge investment in what may be a one time photo-shoot. No one was renting anything longer or faster than a DA*50-135 F2.8.

So then... I thought to myself: "Oh yeah, the K20D has Catch-In Focus!" So... I used that and tried it on Catch-In Focus with my old schoo lens and it worked great! It was like the best of both worlds: Manual focus so I can tell it what I want it to focus on (instead of constantly zipping to trees / subject / tree / pole / fore ground / background / subject again / tree...) but also the K-camera's focus confirmation if my image was dead on! This resulted in a lot more sharp keepers than any previous attempts I tried!

I even added on a 2x Kencool (yes, Kencool... some off brand) teleconverter and it still worked great!

Has anyone else had this experience? I think for future sports images, I will be manual focusing with Catch-In Focus

03-25-2010, 11:44 AM   #2
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same boat my friend... would love the sig 100-300mm f4.. but alas, the lottery has proven fruitless... i bought a sigma apo 'a' 400mm f5.6 from b+h recently, and have practiced with catch in focus... and even with this sizable lens... has worked out pretty well so far.....
03-25-2010, 12:11 PM   #3
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QuoteOriginally posted by dcmsox2004 Quote
same boat my friend... would love the sig 100-300mm f4.. but alas, the lottery has proven fruitless... i bought a sigma apo 'a' 400mm f5.6 from b+h recently, and have practiced with catch in focus... and even with this sizable lens... has worked out pretty well so far.....
Hey--what aperture are you shooting at?

F168?

Stunning combination of great DOF and stop action!
03-25-2010, 12:38 PM   #4
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Particularly like the last shot! I have being finding it particularly hard to get good MF shots with my longer lenses. With moving shots there is just not the time to focus properly. Sometimes I focus on a fixed point and wait for subject to come in focus but this is not ideal.
I have just started to try catch in focus and agree it is looking really promissing. Like how it can effectively be turned on / off by selecting AF/MF switch on my K-x. Still get focus confirmation when in MF position, but catch focus in AF position.

I am going to an air show next week end and expect lots of panning shots, so will be a good chance to play with this.

03-25-2010, 01:35 PM   #5
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Ah, a golden dog. A warm sunny day. Playing in the water. I miss those around here.

I've been using CIF (AKA trap-focus) a LOT recently. I've stuck metal tape on a number of lenses to use with infinity-focus adapters. But for closer work, and for screwmount lenses (like M39s) whose bases are too narrow to hold metal tape against the camera's contacts, I use a flanged adapter, which shorts all contacts.

With a flanged adapter, we lose infinity focus. Depending on the lens, far focus drops a little or a lot. With one 35mm at f/2.8 it drops to maybe 1.5m, at f/16 to maybe 2.5m. (That 1mm flange makes a BIG difference there!) With one 200mm at f/4, far focus is about 15m; at f/8 it's about 40-45m. (I just paced it off). So that flanged adapter is for situations where infinity doesn't matter. And of course it pulls in the near focus a little -- on the 200mm at f/4, by about 0.1m.

Some of those older, narrow-base lenses would be rather difficult to use well without CIF/trap-focus. And in any case, the camera reacts faster than I do when I achieve focus. Too often with manual non-CIF shooting, I'll reach focus, then the subject or I move before I can press the shutter. Bummer. With CIF, I find myself sticking with wider apertures on longer lenses. I don't need the DOF safety margin as much. Conversely, I'll stop-down softer lenses that I'd otherwise leave open so I could see better. Yeah, CIF is the poor guy's AF for manuals.

Last edited by RioRico; 03-25-2010 at 01:54 PM.
03-25-2010, 01:39 PM   #6
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I always figured it would be too slow for action shots. Never tried it much because of the firmware not allowing it ot happen on DA lenses (see my firmware request thread!).

However, I do find it interesting that so many people prefer manual focus without split-screens:
split screen or catch-in focus?: Pentax SLR Talk Forum: Digital Photography Review
03-25-2010, 01:48 PM   #7
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QuoteOriginally posted by Eruditass Quote
I always figured it would be too slow for action shots. Never tried it much because of the firmware not allowing it ot happen on DA lenses (see my firmware request thread!).

However, I do find it interesting that so many people prefer manual focus without split-screens:
split screen or catch-in focus?: Pentax SLR Talk Forum: Digital Photography Review
For me, I like the act of MF, and I hate the noise of AF.

Maybe it's an age and nostalgia thing, but for me, they're totally different experiences.
03-25-2010, 02:01 PM   #8
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QuoteOriginally posted by Eruditass Quote
I always figured it would be too slow for action shots. Never tried it much because of the firmware not allowing it ot happen on DA lenses (see my firmware request thread!).
There's always the short-the-contacts trick.

QuoteQuote:
However, I do find it interesting that so many people prefer manual focus without split-screens:
split screen or catch-in focus?: Pentax SLR Talk Forum: Digital Photography Review
It goes both ways. I haven't pulled the Katzeye out since I started obsessing with trap-focus. Lazy, I guess. Whatever works...

03-26-2010, 06:04 AM   #9
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QuoteOriginally posted by Ira Quote
Hey--what aperture are you shooting at?

F168?

Stunning combination of great DOF and stop action!
thanks ira.... the 1st shot was f13.. 1/2000/400mm/iso1600/-0.3ev
the 2nd same, but at 1/1600...
... the k-x makes shootin' easier and more capable than my old k200d..
how i wish the k-x were built like the k200d though.....
04-13-2010, 11:53 PM   #10
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I always nail focus perfectly with MF lenses, but that was when using FF slrs. anyway, focus trap and focus confirmation do increase my chances on getting keepers at a fast rate. but I would prefer focus confirmation rather than focus trap since using the former would still enable me to push the shutter down and able to get a shot even if not focused perfectly, thereby not missing any crucial moments. the biggest help for MF lenses are the focus trap, focus confirm, split-screen, Live-View, magnifying eyepiece and angular magnified eyepieces (1.25x - 3x).

I would say that when it comes to action photography, having an AF lens is still a luxury and helps a lot in those situations that are needed, but you still cannot dismiss manual focusing in situations when or where AF struggles. both have pros and cons , but certainly both are needed. having an AF lens is nice and having an MF lens is also nice, but having a lens with both AF/MF feature would be just great.

anyway, such dilemma was also instrumental for me on considering which lens to go for at 135mm. there had been several times that I had almost bought a K135/2.5, only to pull back at the last minute everytime because I really am in need of an AF. it was really difficult and find myself scratching my head because I really like the lens just looking on how smooth the focus ring is and how it looks sharper atleast at the wide open apertures from f2 to f2.8, slightly brighter, punchier color than the 135/f2.8. it was also a hard choice since the offers were from $130 - $200 which are very tempting prices and I could had easily pulled the trigger if I really wanted to. but anyways, I got an FA135 instead which is really a great lens and what I love about it is it is light and smaller than my FA100/2.8 and also an IF lens.

focusing performance wise, the lens is really great with AF. really really fast although there are occasionally quite several focus hunting issues and failed focus under good and lowlight and tungsten conditions. also don't count your hopes too much on focusing manually because manual focusing can really be disappointing since the focus ring is loose, small and narrow, flimsy and slippery. the lens has a short throw and the focus ring should be tightly gripped or held by 2 fingers in a crablike pinch manner. I find an overhand gripping position on the lens much better as opposed to underhand gripping. I say the my FA100 can be gripped much easier and better compared to the FA135. I'm considering on installing a customized rubber grip for the FA135 focus ring. otherwise, it would only be an exclusive AF only lens, which I think the lens is really for. all in all MF is only the main issue of the FA135 and slight issue with the failed focus. IQ, AF, weight, size and MFD are the key features of this lens. the knock out feature IMO is the MFD at only 70cm which is half of the normal MFD of 135mm lenses.

Jon, when I get the time, I'd be willing to let you have it a lil bit of a whirl.
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