Technique / Sharper Pix

[ilya]

Good read for all ...

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=007iOR

edit: Must read for all

[ssim]

Interesting article. I'll probably have to go through that a couple of times, I'm feeling a little thick tonight.

You sure you didn't pick because the first thing you see is a duck :shock:

[ilya]

You sure you didn't pick because the first thing you see is a duck :shock:

Lol ... I knew why the post felt right at home on this forum :lol: :lol:

[PhotosGuy]

Good article, but I think it’s misleading us on one point. He says,

o Use your lens's optimum aperture.
The sharpness your lens is capable of achieving varies widely as the aperture size changes. If the aperture is too wide, the lens is most subject to loss of sharpness from lens aberrations. If the aperture is too narrow, sharpness will be lost due to light diffraction. Each lens has a "sweet spot": a middle point in the aperture size range where it is least affected by aberrations on the wide end and diffraction on the small end. This range varies by lens model, but is generally somewhere around f/5.6 and f/8. By placing your aperture within the f/5.6-8 range, you will have the potential for achieving sharpeness far beyond what is possible at such apertures as f/1.4 or f/32.

The part I have a problem with is this:
… but is generally somewhere around f/5.6 and f/8.

If I remember correctly, each lens approaches max sharpness when stopped down about 3-1/2 stops from it’s maximum aperture. So, If true, a f 1.4 lens would be sharpest at f 4-5.6 & an f 4 lens would be sharpest at f 11-16.
Someone correct me if I got that wrong – it’s been a while since I read it.

[CyberDyneSystems]

I think it varies widely from one lesn design to another.. so I don't know if there is any hard and fast rule...

Anyways,. a great article.

In a nutshell,.. anything that is conveneint or a short cut.. is wrong! :wink:

[ilya]

Optimum should be construed as that which works for each particular lens.

IF one wants to be precise, take your position in front of a newly built brick wall that has not yet been plastered. Let sunlight fall directly on this wall. Tripod your camera and focus very accurately on the wall. Keep your camera on Aperture Priority mode. Take pictures of the wall at all the apertures of your lens. Do not change the focus setting for any shot. Don’t even touch the camera - use a cable release if your camera permits one or better still use the self-timer for every shot.

Carefully check each shot at 100% crop. You will find that one particular aperture has given you the sharpest image. This is your optimum aperture for this lens. Keep a note of it. Whenever you want a big enlargement to be made of a particular scene, use this optimum aperture. Similarly check the optimum aperture of all your other lenses and keep a note.

N.B. The optimum aperture is not the one to give you the largest depth-of-field. On the focused plane, it will be the sharpest.

[nosquare2003]

Good article, but I think it’s misleading us on one point. He says,

o Use your lens's optimum aperture.
The sharpness your lens is capable of achieving varies widely as the aperture size changes. If the aperture is too wide, the lens is most subject to loss of sharpness from lens aberrations. If the aperture is too narrow, sharpness will be lost due to light diffraction. Each lens has a "sweet spot": a middle point in the aperture size range where it is least affected by aberrations on the wide end and diffraction on the small end. This range varies by lens model, but is generally somewhere around f/5.6 and f/8. By placing your aperture within the f/5.6-8 range, you will have the potential for achieving sharpeness far beyond what is possible at such apertures as f/1.4 or f/32.

The part I have a problem with is this:
… but is generally somewhere around f/5.6 and f/8.

If I remember correctly, each lens approaches max sharpness when stopped down about 3-1/2 stops from it’s maximum aperture. So, If true, a f 1.4 lens would be sharpest at f 4-5.6 & an f 4 lens would be sharpest at f 11-16.
Someone correct me if I got that wrong – it’s been a while since I read it.

Well, I usually do not care much. Yes, the largest aperture is always softer. But if I need the largest aperture, I won't consider the sharpness issue.

[drisley]

I find this tip rather interesting:

"When you can’t lock up the mirror, mount the camera horizontally. "