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12-10-2011, 05:33 PM   #1
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Rule of thirds with manual lenses

Sorry for the dumb question folks.. Was wondering how to apply the rule of thirds using manual lenses (for instance my smc a50mm f1.7 lens) for portrait photography?? That is to say, how can I manually focus on a subject not in the middle of the screen?? I am sorry, but I have just entered the magical realm of photography and cud do with some tips here...)

12-10-2011, 05:48 PM - 2 Likes   #2
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Point the camera at the thing you want to focus on (put it in the center). Focus on it. Re-compose to get the composition you want (so now maybe that subject is no longer in the center) but don't re-focus.
12-10-2011, 05:54 PM - 1 Like   #3
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QuoteOriginally posted by Ali Quote
how can I manually focus on a subject not in the middle of the screen??
I am assuming that you are using a body with AF capabilities. It is rather easy. Just focus on the subject ( middle of screen) then recompose {move the camera}while holding the shutter release button 1/2 way down til the subject is where you want it in the shot .That should lock the focus When the shot is composed like you want it push the shutter button the rest of the way down. That works with my dslr and my slr's I believe it works with all the Pentax bodies. I could be wrong about that but others can correct if some of the bodies work a different way.
There is an indicator in the view finder to tell you when you have focus. My *ist DL has to have that lit to operate the shutter ,with a manual focus lens. I hope this helps.
12-10-2011, 05:57 PM - 1 Like   #4
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"Focus on it. Re-compose to get the composition you want"
+1
Simpler with manual focus than with auto focus really. No chance of the camera refocusing after you re-compose. For portraits focus on the eyes and then compose however you want.

12-10-2011, 05:58 PM   #5
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QuoteOriginally posted by patrick9 Quote
I am assuming that you are using a body with AF capabilities.
Possibly but the OP is using a manual focus lens.
12-10-2011, 06:03 PM   #6
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Set the AF switch on the body to MF (manual focus) and you don't have to "lock focus". The AF assist will still work.
12-10-2011, 06:49 PM   #7
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QuoteOriginally posted by vonBaloney Quote
Site Supporter Join Date: Oct 2011 Location: Denver, CO Posts: 184 | Likes: 0 Set the AF switch on the body to MF (manual focus) and you don't have to "lock focus". The AF assist will still work.
.
Thanks for the reminder about switch. I guess I am getting old and forgetful
12-10-2011, 06:52 PM   #8
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QuoteOriginally posted by jatrax Quote
Possibly but the OP
.
I will now show my stupidity
I see the OP used and know who it is talking about , The thread starter. What do the letters OP stand for?

12-10-2011, 07:08 PM   #9
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OP = original poster
12-10-2011, 07:52 PM - 1 Like   #10
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QuoteOriginally posted by vonBaloney Quote
Point the camera at the thing you want to focus on (put it in the center). Focus on it. Re-compose to get the composition you want (so now maybe that subject is no longer in the center) but don't re-focus.
Yep, it's that simple. With an AF lens with the camera set in AF-S, you focus and holding the shutter half pressed, the focus is locked as long as you don't release it. Re-compose and shoot. I find that far easier than moving the focus point because I'd probably forget I moved it and ruin the rest of my shots for a week.
12-10-2011, 08:25 PM - 1 Like   #11
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Focus-recompose can introduce errors, because the distance is not exactly the same when you change the frame. But the error is usually small enough to ignore in practice. If you use the M50/1.7 really close and at f1.7, remember the error potential; it might be important then.

With a split-prism focus screen, I relied a great deal on focus-recompose and rarely had trouble with it. If you use the focus indicator with a manual-focus lens, remember that only the center AF point is active. When you switch to an AF lens, more points can be used.
12-10-2011, 09:14 PM - 1 Like   #12
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I was schooled to another approach: shoot in the world, compose in the darkroom. If we can get a perfect picture in-camera, splendid! If we need to crop and rotate, that works too. DO WHATEVER IT TAKES TO MAKE THE PICTURE is what I was taught. I think it's called Pragmatism.

So if you're shooting close portraits with a fast lens of hair-thin DOF, and the focus+recompose trick always shifts focus enough that the face blurs, then just center and shoot, and crop later. Our dSLR sensors churn out images with plenty of real estate, ripe for cropping. Don't be shy.
12-11-2011, 04:49 AM   #13
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Dear All,
What a great website and what a marvelous community!! Thank you heaps for your kind replies, and for showing me the way here. I will certainly try both ways - 'recomposing' to see whether I can still get sharp images, and also RioRico's advise of cropping later (without being shy!). I guess this just provides me an excuse to take another couple of hundred shots!!
VonBaloney/Patrick9: my switch is turned to AF, and I have recently found that rather than using the shutter button pressed half-way, I just press the AE/AF button once. The indicator in my view finder comes on whenever I have focus, which is a lot easier than the other way around. I dont fully know the utility of this button and my settings have AE lock disabled...
reeftool: I realized early the focus points were not really my cup of tea either, for the reason you mentioned in your post..
Also, I notice that I dont get good results with my 18-55 mm kit lens - the image is always a bit soft and slightly blurred, even though I use center focus (AF mode). However, the smc A50mm (which I picked up for only 60 pounds off ebay) is razor sharp - I like using an aperture of f2.8, though I am still too raw to get perfect exposure on a consistent basis. O well, will get there!! Anyhow, any comments would be most welcome, and many thanks once again for the help.
12-11-2011, 12:10 PM   #14
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With most zoom lens, you can also zoom in on the thing you want to focus on (to make that focusing easier and more accurate), and then recompose which may include zooming out for a more expansive view in the final composition. Obviously with super-fast lenses wide-open (i.e. the razor-thin DOF) you have to be very careful where your exact focus point is, but most of the time focusing/zooming and then recomposing works fine. Focus is determined by distance from the subject to the film/sensor plane, not by the angle, so it doesn't matter if you are no longer "pointing" directly at the subject if you merely rotate the camera slightly during recomposition you are only changing the distance by millimeters. So it only has a practical effect with close subjects with wide-open apertures, macros, etc. (In cinematography -- for static camera shots anyway -- focus is usually decided with tape measures and depth-of-field charts rather than through the lens -- you decide what you want to be in-focus and out-of-focus and then calculate where the focus ring needs to be set to achieve that.)

You should also learn about hyperfocal distance focusing, a bit of a lost technique in this autofocus age (that's what those marks on your manual lens are for!), but can often give you a more usable DOF than just locking on to the subject. (A bit off-topic, so do a search or google it.)
12-11-2011, 03:20 PM   #15
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VB mentions hyperfocal technique. Technically, it's zone-focus; with hyperfocus, the zone extends to infinity. Here are examples:

I drove to the top of Mt Evans (14250ft / 4275m) in Colorado's Front Range, the eastern edge of the Rocky Mountains that drop precipitously to the Great Plains. Sunlight was intensely bright so I stopped-down my Zeiss 50/2.8 (12 iris blades) to f/11. I prefocused at 10m for DOF from 5m to beyond infinity. I shot features and structures atop the mountain, and vast vistas of the Front Range extending from Wyoming to New Mexico, all without refocusing. For that, 10m was the hyperfocal distance.

I drove down to about the 12000ft / 3600m level and saw a bunch of marmots (sorta like wombats) playing by the roadside. I prefocused to 2.5m for DOF from 1.25m to 5m, and snapped the critters whenever they were within that 1.25-5m zone, all without refocusing. The glare was so bright that I couldn't see to focus anyway. The DOF zone didn't extend to infinity, so it wasn't hyperfocus, just zone focus.

How to use zone focus on a dSLR with old lenses: Those lenses have DOF scales marked for 135/FF cameras. The scales must be interpolated for our APS-C dSLRs. I fudge by a bit over 1 f-stop. So if I have the aperture at f/11, I read the scale just under f/8, maybe around f/7. In the first example above, I set the infinity mark to just inside the f/8 mark. That puts the 5m mark just within the other f/8 mark, and points the index to 10m. Use this technique to define any zone you want in focus.

Our modern lenses no longer have such DOF scales. Bummer. We must rely on software or guesstimation or extreme stopping-down. Bother. When in doubt, make sure the subject is in focus and don't worry about the rest. A basic rule: NAIL THE FOCUS -- EVERYTHING ELSE CAN BE FIXED IN PP.

Last edited by RioRico; 12-12-2011 at 05:32 PM.
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