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Full body portrait focus technique


keith_lai2

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Hi, all

 

I just joined this group

Now I would like to get some experience from you.

If I want to shoot full body portrait, what technique to focus would be better?

Using camera central focus point to focus the eye, then recompose OR

Move the focus point to the eye, then shoot

If I would like to use aperture 1.8 .

Please kindly share your experience.

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<p>Compose first, then set the focus point on the eye or face. F<a href="https://www.google.com/search?q=focus+and+recompose+error&rlz=1C2LENN_enUS490US562&biw=1031&bih=617&source=lnms&tbm=isch&sa=X&ei=Gh47VYveLsi2ogTrnoGYAw&ved=0CAcQ_AUoAg">ocus and recompose</a> risks throwing off the very shallow plane of focus at wider apertures. The greater the swing arc to recompose, the greater the risk of losing sharp focus on the desired area.</p>

<p>Whether it's significant or noticeable depends on several factors, including DOF, sensor/recording medium size. Focus and recompose error is less noticeable with tiny sensors so occasionally I'll use the trick to isolate focus on a specific person picked out of a crowd. It would be more noticeable with full frame than APS sensor, more with APS sensor than CX sensor and so on.</p>

<p>Face detect AF and focus tracking can help. These work pretty well on small sensor and APS sensor P&S cameras. No idea whether any full frame models offer these or whether these focus aids work reliably on full frame models.</p>

<p>If focus first, then recompose, is unavoidable, you can minimize the risk of error by not swinging the camera. Instead, raise and lower the camera in a vertical line, without changing distance. Easier with a tripod mounted camera, and easier with a geared center column than sliding column.</p>

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<blockquote>

<p>"What do you think the focus point other than the central one. Will that result photo not so sharp?"</p>

</blockquote>

<p>Depends on the camera. Some models have fewer of the more sensitive cross-type sensors, centrally grouped, with the somewhat less sensitive sensors toward the edges. But in good light all should perform well enough. The main differences in AF performance are in dim light or with low contrast subjects. A model's eye in good lighting should provide enough for any AF sensor to lock on accurately.</p>

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<p>In some camera's the center focus points are more effective than the surrounding ones However, I agree with Lex, at 1.4 or 1.8 recomposing can change the distance from sensor to subject and when dealing with only a few inches in dof, eg when using a 135mm at 6 feet you have about 3/4" dof. Locking focus on the shortest distance to the subject then raising or lowering the camera's angle can make the distance increase. Combine that with any subject movement or photographer movement away and you can loose focus. I prefer to compose then move the focus point as close to the eye as possible. Letting the camera use all focus point makes it less likely to select the eye as the correct place for focus. </p>
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I recently switched to full frame with a ten year old Canon 5d classic. I am using manual focus Olympus and other lenses with a focus

confirmation adapter. Lex is on the money when he talks about focusing points along the edges being weaker in low light but not making

much difference in good light. For me, choosing the right lens was key factor full length portraits. I was shooting one person full lengths

and used a 50mm lens in portrait orientation, focused on the eye and shot around f4 using a 1.8 lens. The eyes were tack sharp and the

rest of the body was acceptable.

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<p>Whichever focus point you use, the time honored rule of focusing for portraits is to focus on the eyes -- not just some random place on the face but the eyes -- especially when using a wide aperture. And if the face is at an angle, focus on the eye closest to the camera. Depending on your tatste, it can be acceptable for a nose, ear, chin, etc. to be a touch soft but the eyes have to be sharp.</p>
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  • 3 weeks later...

Can you talk a bit about your lighting setups? This is important to me for portraiture type of work and setting up the

camera correctly. Are you using more than one light or perhaps 2 or more lights? Often I will use up to 5 external lights,

but not very often.

 

I can't ever recall shooting at 1.8 or less, although a few of my lenses go below 1.2, such as a few Rangefinger Leica

lenses. One of the Leica lenses is .95! WOW! The magic F-stop settings for me is around F-4 to F-5.6 for outdoor work. This totally depends

on the lens I'm using. Longer lenses, such as around 200 to 400mm's are almost always at F-5.6. When working outside

the background around the 4 to 6 foot mark will go blurry with longer lenses, out of focus in a very pleasing way.

 

At 1.2 or less, such as with a 50mm or an 85mm lens often the nose and eyes may be in focus, but the ears will be soft, so we need to be very careful. With

shorter lenses, such as a 28mm you should be fine, however I hate the look of 28mm lens portraits. The longer the lens

- the better most people look.

 

For indoor studio work, using 2 or more strobe lights this varies a bit. Such as working with hard high key light compared

to the soft romantic lighting look. With regards to setting up the lights generally I'm around F-4 to F-11. I can't recall ever being over F-11

or under F-4. You actually asked a very difficult question, because of all the rules related to portraits. Hope this helps.

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  • 3 months later...

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