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03-25-2011, 02:41 PM   #46
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QuoteOriginally posted by The Jannie Quote
I used trap focus last night at a concert and I've never had so many sharp photographs! I didn't set out to use it, it just sort of happened and pleased me no end. The K10d and Tokina 60-300 mf combination - iso 1600, 1/30 at f4 - struggled in the low contrast parts of the stage but I persevered, swore a lot and got lots of useable results. For wider shots I used my istDL2 and 18-55WR and they coped better than the K10. I'm converted and will now have to try it on motorsport. For number freaks I took about 350 and at first flick through I'd say more than 40% are useable - and I like my sharpness.
I am glad you persevered this strange and unusual experience. We tend to get impatient and want the shutter to trigger as quickly as possible. Wait till you get involve with manual Focus prime lenses. You too with love the process and thank CIF feature. Wait till I get my shims done next week and post pictures to enlightened how this can benefit us all. Good hunting.

03-25-2011, 11:10 PM   #47
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QuoteOriginally posted by mjkwee Quote
I am glad you persevered this strange and unusual experience. We tend to get impatient and want the shutter to trigger as quickly as possible. Wait till you get involve with manual Focus prime lenses. You too with love the process and thank CIF feature. Wait till I get my shims done next week and post pictures to enlightened how this can benefit us all. Good hunting.
I "discovered" catch-in focus tonight. My cat fell victim to my 50mm f/1.7. This was taken by framing her then leaning into the shot, so when the camera pulled her into focus the shutter triggered.

I'm going to have to play with my long lenses with this when I get the chance - I have a couple cheap-o Quantarays that have been giving me fits. This could prove the answer to my conquering those things.


03-26-2011, 06:26 PM   #48
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QuoteOriginally posted by Sagitta Quote
I "discovered" catch-in focus tonight. My cat fell victim to my 50mm f/1.7. This was taken by framing her then leaning into the shot, so when the camera pulled her into focus the shutter triggered.

I'm going to have to play with my long lenses with this when I get the chance - I have a couple cheap-o Quantarays that have been giving me fits. This could prove the answer to my conquering those things.


I think this will help you with the longer lenses now that you are able to get CIF to work. Due to a shallow DOF of the 50mm at 1.7, use the center point for your AF. With my K100D you can select off center for your AF point. I have not mastered this one at this time due to having to use the 4 way button. Tough for a single handed photographer like me whenever I have to switch on the fly.
03-27-2011, 12:58 AM   #49
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I've put some of the concert shots I referred to at :

The Enid at The Met, Bury, 24/3/11 - a set on Flickr

03-28-2011, 07:47 PM   #50
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You don't need a camera with a built in feature to enjoy Trap Focus. I posted instructions on this forum a couple of years ago on how to do Trap Focus with a K100D. I set up my camera with a Pentax Macro lens (contacts covered with tape) and aimed just to one side of my squirrel feeder. I locked the shutter and went inside for 90 minutes. When I came out the camera had taken 900 frames! I liked this one:
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03-28-2011, 10:50 PM   #51
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That's a great idea (and pic), thanks!
03-29-2011, 04:59 PM   #52
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I forget if this has been mentioned above, but a limitation of CIF is... darkness. Both low ambient light, and tight apertures, make CIF iffy. I've found the aperture cut-off point to be around f/11 -- f/8-11 on most lenses I've tried, f/11-16 on others. As less light reaches the sensor, CIF works best when the centered subject is sharply contrasty. A uniform subject at f/11 is very hard for the CIF 'bot to capture. Not surprisingly, these are the same situations where AF tends to seek.

I'm too lazy for this, so I'll suggest that some wonderful volunteer(s) might test CIF performance on lenses of various focal lengths, with various apertures and ISO's. Maybe on various cameras too. Are any wonderful volunteer(s) on hand here?
03-29-2011, 08:57 PM   #53
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Well, in a couple of days I'll have the K-5, augmenting my K-x & K-7. I also have a variety of lenses; this might be a good way to practice and play. No guarantees, but it might be entirely possible, drawn out over some time.

@ Leo:
I read your thread about trap focus. It is quite informative. Funny how such things become relevant again.

05-07-2011, 09:44 AM   #54
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Does anyone have a picture of covering the pins in aluminum foil? I am using screw mount lenses and cannot get this to work for the life of me. I have catch-in focus turned on, AF.S selected, the lens switch to manual, center point focus, the camera set to Auto focus, and now aluminum foil on what I believe to be covering the pins on the camera lens mount, and the thing fires the second I hit the shutter, before coming into focus, every time?
05-07-2011, 10:48 AM   #55
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Maybe it's doing what mine did - tore through the stick-on foil at the first turn. I've removed the paint/anodising on the M-type lens mounts for a permanent cure.
05-07-2011, 08:19 PM   #56
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QuoteOriginally posted by chiane Quote
Does anyone have a picture of covering the pins in aluminum foil? I am using screw mount lenses and cannot get this to work for the life of me. I have catch-in focus turned on, AF.S selected, the lens switch to manual, center point focus, the camera set to Auto focus, and now aluminum foil on what I believe to be covering the pins on the camera lens mount, and the thing fires the second I hit the shutter, before coming into focus, every time?
Hi I tried using aluminum tape purchase from my local orchard supply store on some of my screw mount lens. The first challenge is taping a wide enough area underneath the lens rim to cover the pins. Second challenge is the aluminum taped gets caught on one of the AF coupler pin that locks the lens. By depressing the lens unlock button this helps overcome this problem. Finally, the aluminum tape has a thickness (although very small) the lens does not rotate fully all the way. This does not seem to affect the infinity focus by much. I used alum tape on my 100mm macro lens, so infinity is not as critical.

Try switching the Focus mode lever AF/MF to AF rather than MF. I think this lever is tied to some other custom settings that can trigger the shutter when depress..

BTW, which lens are you using with the foil?
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