How do I get the whole picture sharp?

[Jack56]

This morning I took this photo with the 100mm L.
Iso 160 - f/13 - 0,5 sec.
Distance about 30 centimetres.
I used a tripod and cable release.
I didn't crop the photo and shot it in raw. Yes, the colour is about that green, that's why I like it.
How is it possible to get everything sharp with this lens even in the corners?

 

[neuroanatomist]

Lenses are always sharper in the center, that's just a basic fact of optics.

Here's the MTF curve from Canon for the 100L Macro:

Sharpness is the thin lines, the blue lines represent percromance stopped down to f/8. The center of the image is the left of the plot and the the corners of the image are at the right – note the fall off in sharpness.

Looking at your image, it appears (altough it's hard to tell for sure with the subject) that the lower right corner is not as sharp as the other three corners. The sharpness fall-off should be symmetrical, if it's not there may be a problem with the lens (e.g. decentering of an element).

 

[Jack56]

Thank you for your reply. What is the best way to test this?

 

[neuroanatomist]

http://www.lensrentals.com/blog/2012/05/testing-for-a-decentered-lens-an-old-technique-gets-a-makeover

 

[surapon]

Lenses are always sharper in the center, that's just a basic fact of optics.

Here's the MTF curve from Canon for the 100L Macro:

Sharpness is the thin lines, the blue lines represent percromance stopped down to f/8. The center of the image is the left of the plot and the the corners of the image are at the right – note the fall off in sharpness.

Looking at your image, it appears (altough it's hard to tell for sure with the subject) that the lower right corner is not as sharp as the other three corners. The sharpness fall-off should be symmetrical, if it's not there may be a problem with the lens (e.g. decentering of an element).

Thank you, Sir, Dear Teacher, Mr. neuroanatomist.
Thanks for your Great Information.
Surapon

 

[surapon]

http://www.lensrentals.com/blog/2012/05/testing-for-a-decentered-lens-an-old-technique-gets-a-makeover

Thank you, Sir, Dear Teacher, Mr. neuroanatomist.
Thanks for your Great Information of great Link.
Surapon

 

[Jack56]

Thanks for your help. That's very kind of you.
I made two other images just to check. Because, when I make other photos, long distance f.e., there is no problem in sharpness. On this flat objects the corners look allright to me.
Is a leaf, because it's not totally flat, different?
Are my settings allright?
I didn't sharpen the next images.

 

[mackguyver]

Your test shot looks okay to me, so here's another possibility. It looks to me like the lens was tilted at a slight angle to the leaf because the top left and bottom right corners look a tiny bit softer than the others. With this kind of magnification, even very slight angles affect depth of field and (even) f/13 in the macro world is about like f/2 when shooting portraits Macro, unless focus stacking, is often about creative choices in terms of what's sharp vs. what's blurred.

Personally I don't find the "softness" to be concerning at all and would be happy with this shot had I taken it.

 

[CarlTN]

This morning I took this photo with the 100mm L.
Iso 160 - f/13 - 0,5 sec.
Distance about 30 centimetres.
I used a tripod and cable release.
I didn't crop the photo and shot it in raw. Yes, the colour is about that green, that's why I like it.
How is it possible to get everything sharp with this lens even in the corners?

I would have tried closing aperture to f/16 to f/20. (Also, with this subject and lighting, ISO 50 would be useful.) The center might get very slightly softer, but the borders and corners get a bit sharper. Then apply some sharpening in post processing. Experiment with the radius of the sharpening...and also balance the application of it, with the "detail" slider. Many times you can have the detail slider above 50 (out of 100), while keeping the sharpening lower. Other times, not. To make full use of the detail slider, it's necessary to bring the luminance noise that gets captured, to an absolute minimum...hence my suggestion for using ISO 50. If you can't go below ISO 100, then use 100.

 

[Jack56]

Thank you all. I've learned something and will try to practice tomorrow again. Thanks again!!

 

[wtlloyd]

What camera are you using? Depth of field with a 7D is only .3cm (1/10th of an inch) at your settings. Much more depth of field at greater distances, as you stated...

 

[Jack56]

Mark5dIII. Thanks.

 

[Keem]

I agree with Mackguyver. In order to comment on corner softness or misalingment of a lens element you should be 100% sure about the following:

i) the subject should be flat (in your case the leaf does not seem to be flat)
ii) the sensor should be perfectly parallel to the flat subject

The other test pictures shows no significant variation among the corners; so if I were you I would not worry about the lens!

For the best results i think you should also consider diffraction limits (before going to a setting like f20):
http://www.luminous-landscape.com/tutorials/understanding-series/u-diffraction.shtml

If you go beyond f11 the image loose sharpness due to diffraction effects!

As a rule of thumb f8 (maybe f11) is the optimum setting you should use. If you use a smaller aperture you may increase the depth of field but the image sharpness will degrade.

In macro photography, if you want to get your subject completely in focus you should try focus stacking:
http://en.wikipedia.org/wiki/Focus_stacking
(here you can find some software solutions to stack the images)

You may need a macro-focus rail (and patience!) to get good results;

Good luck and happy shooting (you have a nice lens)

 

[Canon1]

Your test shot looks okay to me, so here's another possibility. It looks to me like the lens was tilted at a slight angle to the leaf because the top left and bottom right corners look a tiny bit softer than the others. With this kind of magnification, even very slight angles affect depth of field and (even) f/13 in the macro world is about like f/2 when shooting portraits Macro, unless focus stacking, is often about creative choices in terms of what's sharp vs. what's blurred.

Personally I don't find the "softness" to be concerning at all and would be happy with this shot had I taken it.

This is what I was going to suggest.

 

[neal1029]

Perpendicular to the plane of focus.

 

[CarlTN]

In macro photography, if you want to get your subject completely in focus you should try focus stacking:

Focus stacking is both time consuming, and consumes more storage space, and more processing power. Using apertures smaller than f/11 can be perfectly acceptable, in practice...especially for shooting an object that is mostly flat, and parallel with the sensor. If the subject has more depth in the third dimension, that is when focus stacking really makes more sense, and can come into its own. The question really should be, at what point does the image justify the effort spent for focus stacking? Is it really required, or is it more an academic exercise?

For example, magazines such as "Nature Photographer", rarely even include landscape images that were shot at wider than f/14 aperture (whether that is always the right philosophy, might be up for debate...but the editor certainly voices their opinion in favor of it, and very often includes it in the text with the image). In those cases focus distance is not only not in the macro realm, but is usually more than 10 feet from the camera, and on a wider angle lens to boot. Yet at f/14, the lens is yielding noticeable softening at the pixel level, due to diffraction. But the 8.5 x 11 full page (or sometimes smaller) prints in the magazine, do not appear soft. And in most cases, there was no focus stacking.

As photographers, it's our judgment call, based on our experience and our willingness to commit time...as to which technique we use.

 

[privatebydesign]

For example, magazines such as "Nature Photographer", rarely even include landscape images that were shot at wider than f/14 aperture (whether that is always the right philosophy, might be up for debate...but the editor certainly voices their opinion in favor of it, and very often includes it in the text with the image). In those cases focus distance is not only not in the macro realm, but is usually more than 10 feet from the camera, and on a wider angle lens to boot. Yet at f/14, the lens is yielding noticeable softening at the pixel level, due to diffraction. But the 8.5 x 11 full page (or sometimes smaller) prints in the magazine, do not appear soft. And in most cases, there was no focus stacking.

As photographers, it's our judgment call, based on our experience and our willingness to commit time...as to which technique we use.

Clearly the editor doesn't know what they are talking about, had the same problem when they all insisted we had to have 360dpi for magazines. F14 on what format size?

A 135 format f14 gives the same diffraction as f8.75 on an APS-C and f96 on an 8"x10".

 

[CarlTN]

For example, magazines such as "Nature Photographer", rarely even include landscape images that were shot at wider than f/14 aperture (whether that is always the right philosophy, might be up for debate...but the editor certainly voices their opinion in favor of it, and very often includes it in the text with the image). In those cases focus distance is not only not in the macro realm, but is usually more than 10 feet from the camera, and on a wider angle lens to boot. Yet at f/14, the lens is yielding noticeable softening at the pixel level, due to diffraction. But the 8.5 x 11 full page (or sometimes smaller) prints in the magazine, do not appear soft. And in most cases, there was no focus stacking.

As photographers, it's our judgment call, based on our experience and our willingness to commit time...as to which technique we use.

Clearly the editor doesn't know what they are talking about, had the same problem when they all insisted we had to have 360dpi for magazines. F14 on what format size?

A 135 format f14 gives the same diffraction as f8.75 on an APS-C and f96 on an 8"x10".

I suggest you write the magazine a notarized letter of complaint. I'm sure the editor will realize they are wrong and you are right, and will issue a front page apology in the next issue, for the error in judgment over the years. This should fix the problem. If not perhaps organize a protest rally around their headquarters, that will teach them a lesson they will never forget! Those always work exactly as intended...and are never a waste of time.

 

[privatebydesign]

For example, magazines such as "Nature Photographer", rarely even include landscape images that were shot at wider than f/14 aperture (whether that is always the right philosophy, might be up for debate...but the editor certainly voices their opinion in favor of it, and very often includes it in the text with the image). In those cases focus distance is not only not in the macro realm, but is usually more than 10 feet from the camera, and on a wider angle lens to boot. Yet at f/14, the lens is yielding noticeable softening at the pixel level, due to diffraction. But the 8.5 x 11 full page (or sometimes smaller) prints in the magazine, do not appear soft. And in most cases, there was no focus stacking.

As photographers, it's our judgment call, based on our experience and our willingness to commit time...as to which technique we use.

Clearly the editor doesn't know what they are talking about, had the same problem when they all insisted we had to have 360dpi for magazines. F14 on what format size?

A 135 format f14 gives the same diffraction as f8.75 on an APS-C and f96 on an 8"x10".

I suggest you write the magazine a notarized letter of complaint. I'm sure the editor will realize they are wrong and you are right, and will issue a front page apology in the next issue, for the error in judgment over the years. This should fix the problem. If not perhaps organize a protest rally around their headquarters, that will teach them a lesson they will never forget! Those always work exactly as intended...and are never a waste of time.

Well am I wrong?

 

[Menace]

Your test shot looks okay to me, so here's another possibility. It looks to me like the lens was tilted at a slight angle to the leaf because the top left and bottom right corners look a tiny bit softer than the others. With this kind of magnification, even very slight angles affect depth of field and (even) f/13 in the macro world is about like f/2 when shooting portraits Macro, unless focus stacking, is often about creative choices in terms of what's sharp vs. what's blurred.

Personally I don't find the "softness" to be concerning at all and would be happy with this shot had I taken it.

+1