What’s Your Preference?

lostinasia · #1 (**permalink**) 01-29-2010, 01:34 PM

Hello everybody,

After reading around about how to make portrait photos sharper I came across a couple of pieces of information that I, as a beginner, find confusing as conflicting with each other.

One said that usually you can find the sharpest aperture of your lens at one or two stops slower than its maximum aperture.

Another said that f/11 is usually the best aperture for portraits because it ensures, most of the times, the sharpest and the most accurate image -focuswise- that your lens might achieve in that situation.

But f/11 is quite far from the maximum aperture of a lens usually, so, what should I do when shooting portraits?

I am aware that some of you might get amused or even shocked by my question, but at the moment I am clueless and confused.

Any insight would be much appreciated.

Thank you =)

OsmosisStudios · #2 (**permalink**) 01-29-2010, 02:43 PM

I would never go above f/8 for portraits. I spend most of my time in the f2.8 range,

BCampbell · #3 (**permalink**) 01-29-2010, 03:15 PM

So, so much goes into this, it's really impossible to answer your question definitively.

middlingly small apertures (f/9 through about f/16) do produce sharp images, generally. But they also give you a wide depth of field. Those are usually settings recommended for landscapes; you have large areas of the scene in focus and that focus is sharp.

For portraiture you usually want the subject to stand out, so blurring forebround/background areas is ideal. This requires a wider aperture. And it's true that most (if not all) lenses are not their sharpest wide open. But the sharpest and widest aperture (what you're really going for) is different for each lens. You will probably want to read reviews or experiment to find what works for your gear.

For example, I have the Canon 50mm f/1.8, and I find it is very sharp but still produces a relatively shallow DOF around f/4-f/5.6. That's about 2.5-3.5 stops from wide open.

It all depends on what you're using though.

Benji · #4 (**permalink**) 01-29-2010, 03:17 PM

Quote:

Originally Posted by lostinasia

Hello everybody,

After reading around about how to make portrait photos sharper I came across a couple of pieces of information that I, as a beginner, find confusing as conflicting with each other.

One said that usually you can find the sharpest aperture of your lens at one or two stops slower than its maximum aperture.

Another said that f/11 is usually the best aperture for portraits because it ensures, most of the times, the sharpest and the most accurate image -focuswise- that your lens might achieve in that situation.

But f/11 is quite far from the maximum aperture of a lens usually, so, what should I do when shooting portraits?

I am aware that some of you might get amused or even shocked by my question, but at the moment I am clueless and confused.

Any insight would be much appreciated.

Thank you =)

The "rule" of one or two stops down from maximum is the "sharpest aperture" is correct most of the time. This rule is especially true for less expensive lenses. However I have discovered that once you discover the sharpest aperture the lens will be equally sharp for several additional settings. For example I have a lens that has a maximum aperture of f/4.0, so applying the above rule, this lens should be sharpest starting at f/8.0. In reality it seems to be sharpest at f/6.3 and remains sharp at several apertures above that, i.e. f/7.1, f/8.0, f/9.0, f/10 and f/11.

You can buy fancy targets that you photograph in order to find where your lens is sharpest, but I just use a newspaper. I thumb tack it to the wall, put the camera on a tripod and use a cable shutter release, flat light it, and I begin photographing it from wide open down to the smallest aperture. You will of course need to use an off camera flash unit that has variable power. After you get the images, load 'em up in Photoshop and enlarge them about 400%. It will be evident rather quickly where the lens begins to sharpen up.

Benji

lostinasia · #5 (**permalink**) 01-29-2010, 08:07 PM

Thank you all for your reply,

@Osmosis: I will be testing my lenses with a larger aperture and see what happens... :-)

@BCampbell: Thank you for your suggestions. I actually have your same 50mm lens and after trying some quick shots (thanks Benji for the test suggestions!) I am quite satisfied with the sharpness I obtained at f/3.2. I haven't tried under ideal light conditions, yet. I will keep working on that.

@Benji: Thanks for your suggestions, I will have to try the tests for a while. It will take me some time, but it's worth it and I am sure it's gonna pay off.

Thank you all again for your insight.

JD