F stop for landscapes w/ em-5

Being new to mft I am not sure about f stop settings for landscape photos. With my DSLR f8 -f11 was pretty good for most situations unless it was really bright or in failing light. I don't know at what point diffraction  becomes a problem with mft. Or is it the same as with what I could expect with a Canon 7D? I will primarily be using the 12-50mm or the 25mm for landscape. Thanks for any suggestions.

In M43 landscape world, I'd say F stop begins from 4.5 and up to 11

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Looking for equilibrium...

I'd say more like f/4 - f/5.6 (f/8 - f/11 FF equivalent) would be more ideal.  By f/11 (f/22 in terms of FF), diffraction softening is beginning to take a terrible toll, though DOF constraints might make f/8 (f/16 FF equivalent) the number you need.

Normally I find myself in the f/4 to f/8 range for landscapes as well.

Agree strongly - I mostly use the Panasonic 14-45mm lens on Oly bodies and it works best in the f/4 to f/8 range but I generally seem to leave it on f/6.3 or f/7.1 as a general use aperture at all focal lengths for scenery.

At f/8 diffraction definitely is starting to reduce fine detail, at f/11 getting quite noticeable. But of course if doing close-up and macro then you may end up at f/16 of f/22 as the increased depth of field over-rides the effect of loss of resolution in the final appearance of the shot.

The interactive graphs at  http://www.slrgear.com/reviews/showcat.php/cat/7 (not responding at the moment, may be doing maintenance) and the lenses marked as (Tested) do have graphs to play with to help determine best apertures for image quality.

Usually better quality for scenery comes with setting focus on the furthest thing in the scene and using as small as necessary aperture diameter to give sense of foreground detail. That's Merklinger's method and it does work.

Regards...... Guy

On m43 the "optimal" compromise between enough DOF and avoiding diffraction is somewhere around f/5.6. Fast lenses will give optimal sharpness around f/4 but that may not give enough DOF for landscapes. On APS-C the optimal sharpness is obtained at f/5.6 but for landscape f/8 is good. (For full frame f/8 is sharpest and f/11 gives most DOF without showing diffraction.)

The main problem with for instance the E-M5 with 12-50 is that the lens cannot do f/4 in most of its range and not even f/5.6 at the long end. With this lens f/8 may be needed for optimal sharpness from the lens whereas f/4 to f/5.6 is better to avoid diffraction.

I have used Canon (a 450D) with the 17-55IS lens and there f/5.6 was clearly optimal: 2 stops down from wide open. But for landscapes I mostly used f/8 to get best DOF.

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Slowly learning to use the Olympus OM-D E-M5.
Public pictures at http://debra.zenfolio.com/.

I think it starts with the lens. I don't own the 25 but find the 12-50 sharpest closed two stops (regardless of zoom value) and that's what I try to do with landscapes. My other lenses, the 20, 45 and 40-150, can also be used with this rule of thumb, but the primes sharpen up rather quickly, so don't need stopping down unless the light's too bright or I want more DOF.

As a side note, most of my 4/3 lenses can be shot close to wide open with good results.

Cheers,

Rick

I'd pretty much agree. Usually I shoot at F4 to F5.6 for landscapes. A person can go to 8 as GB said...without too much adverse effect. I have used F11 with a manual wide angle and zone focus, at events in order to be able not to wait for focus and have a long DOF..works well in combination with auto-ISO...but I wouldn't use it (F11) where extreme detail is of utmost importance, such as macro or landscape, 'usually'...mostly because of diffraction. There is a site (I lost my bookmarks back a while ago, in a hard drive crash) that shows the effects of diffraction at various F stops with a given lens. Maybe someone will have the name.

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Why so serious? :The Joker

Yep as Guy stated, sometimes for extended DOF a higher numerical F stop does do better in macro...at the risk of diffraction. Been a while, and mostly use my old Canon for macro at present (where diffraction occurs slightly later in the F stop range).

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My Gallery is here -
http://www.pbase.com/madlights
Why so serious? :The Joker

I think you want more DOF while shooting landscapes

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Looking for equilibrium...

...this is plainly not the case:

http://www.lenstip.com/334.4-Lens_review-Olympus_M.Zuiko_Digital_12-50_mm_f_3.5-6.3_ED_EZ_Image_resolution.html

in terms of the sharpness of the optics themselves.

However, depending on the scene you are photographing, stopping down may put more of it within the DOF and result in an overall sharper photo, if the portions of the photo that were outside the DOF at a wider aperture that were brought into the DOF at a smaller aperture outweighs the overall effects of diffraction softening.

Well, the test linked above shows the 12-50 to be sharpest in the center by f/4 (just barely sharper than wide open at f/3.5) and sharpest in the edges at f/5.6 (f/8 -- one stop down from wide open -- at 50mm).

Sure.

So he doesn't find it sharpest closed down two stops?

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hi Luca, most M4/3 lenses have their sweet spot for sharpness around F4, in general shorter than what is common for DSLR glass, some even wider.

A simple rule for landscapes could be to use the widest aperture compatibly with the required DOF.

With a M4/3 12mm FL lens at

- F2.8 conventional DOF goes from 1.7m to infinity

- F4.0 conventional DOF goes from 1.2m to infinity

with a M4/3 17mm FL lens at

- F4.0 conventional DOF goes from 2.5m to infinity and

- F5.6 conventional DOF goes from 1.7m to infinity

with a M4/3 20mm FL lens at

- F5.6 conventional DOF goes from 2.4m to infinity

- F8.0 conventional DOF goes from 1.7m to infinity

calculators at: http://www.dofmaster.com/dofjs.html and

http://www.dpreview.com/glossary/optical/depth-of-field

reliable lens reviews at: http://www.photozone.de/m43

Regards, Vittorio

As I said:

However, depending on the scene you are photographing, stopping down may put more of it within the DOF and result in an overall sharper photo, if the portions of the photo that were outside the DOF at a wider aperture that were brought into the DOF at a smaller aperture outweighs the overall effects of diffraction softening.

Yeah, I read your post.

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This never would have happened if Tedolf was still alive.
http://www.flickr.com/photos/smrlabs/

A feather in your cap.  I'm at a loss, then, to know what you were asking when you asked if "he doesn't find it sharpest closed down two stops", since the above paragraph in italics directly addresses that point.

Whether or not diffraction is a problem at any given f-stop depends a lot on how large the image display will be, whether on screen or in a print.  For example, on a recent trip I used f/8 a lot with the Pan 14-45, which is sharper at f/5.6.  On screen at 100% I can see slight softening, but viewing the entire image at 9.5" wide it's only at 20%.  In this case, and in an 8x10ish print, the image compression eliminates the softness.  Everything looks sharp as a tack.  With a large print (a 16mg file makes an 18x23" print at 200 dpi), it would normally be viewed from further away, which again, negates the issue.  This is one of those cases where there can be a big gap between theory and practical reality.

In landscape work DOF is the most important thing.  I use whatever aperture is required for the scene.  I don't make giant prints, so I don't worry about diffraction.  What good does it do to limit the f-stop for diffraction purposes if the resulting DOF isn't enough?

How to know what aperture to use?  I use a hyperfocal distance chart.  This link contains a set of charts for 4:3 at a range of focal lengths from 12mm to 150mm, and instructions on how to use it

http://cjcom.net/articles/hyperfoc.htm

The chart is about half way down the page, and there's also a link to download a file for printing.  I carry a copy in my camera bag.

With 4:3 sensors f/8 is usually enough for even the most extreme scene.  For example, with a 20mm lens f/8 delivers 6 ft to infinity when focused at 11 ft, and at 14mm it's 2.8 ft to infinity.

Regards,
Clayton

Info on black and white digital printing at  
http://www.cjcom.net/digiprnarts.htm
I-Trak 3.0   http://www.cjcom.net/itrak.htm

My "loop" if you will, is reviewing results at home then modifying my technique in the field based on what works best. Test results are merely a starting point while my results are my own.

I didn't address ultrawide, but shooting with very wide lenses it's often advantageous to stop down to get a very close foreground object in focus while still capturing the background (e.g., a flower with distant mountains. You might give up some ultimate resolution to gain the vast DOF of, say, 7mm@ f: 11 or even 16 with a lens that resolves "best" at f:5.6.

Cheers,

Rick

...DOF, diffraction, and lens aberrations all serve to affect shaprness one way or another, and display size figures equally into all of them.

For example, we know that f/22 result in massive diffraction softening.  Display the photo at 800x600 on the web, and it's not very noticable.

Same with DOF -- f/5.6 has less DOF than f/11.  But display the photo small enough, and you won't notice the difference.  In fact, it is unfortunately a little known fact that the display size of the photo is used in the calculation of the CoC, which is an integral parameter in calculating the DOF (online calculators, for instance, use a CoC based on an 8x10 inch print, or any photo displayed with a 13 inch diagonal, a viewing distance of 10 inches, and 20-20 vision).

So, clearly we want to get the important elements of the scene (which, depending on the scene, can mean the entire scene) within the DOF so the will be rendered sharply.  However, coming with the deepening DOF is increasing diffraction softening.  Where the balance point lies depends on the scene and the artistic intent of the photographer.

Myself, I select a focal point, set the aperture to my best guess, take a pic, and chimp at 100% view.  If it's good, I might try a wider aperture.  If it's not so good, I try a different focal point and/or different aperture.

I can't remember ever needed more than f/16 on FF (f/8 on mFT) myself.

Again, those charts are based on an 8x10 inch print, or any photo displayed with a 13 inch diagonal, a viewing distance of 10 inches, and 20-20 vision.  So, if you're printing 24x36 inches, for example, and still viewing from 10 inches away with 20-20 vision, the DOF will be less.  But if your viewing distance scales with the display size (e.g. 20 inches for a 16x20 inch print, 30 inches for a 24x30 inche print, etc.) then they'll work just fine.

...and for those types of pics, PC lenses are very useful. I'm surprised there aren't any for mFT yet, but I'm sure they're coming.