I've ranted and raved against how narrow some usable aperture is, usually because it's a zoom with f/5.6 (or higher!!) at the long end and diffraction setting in at f/8 (or earlier!!).

Quote:

The Olympus 75mm ƒ/1.8 is one of the sharpest lenses we've ever tested. It is tack-sharp even wide open at ƒ/1.8, gets a little sharper through to ƒ/8, and stays sharp even stopped down to ƒ/16. At ƒ/22 there is a bit of diffraction limiting that exhibits a little generalized softness.

The Panasonic 12-35/2.8 seems to be as flexible as the Oly 12/2.0, so the zooms are improving, but the prices sure are going up! :)

Maybe it's *just* a zoom thing? Olympus seems to have resoundly beaten this f/8 diffraction ceiling with their 45/1.8 and 75/1.8. If Olympus does produce the rumored 25/1.8 or 17/1.4 those will be very desirable indeed. (I'm a zoom kind of guy, but I catch myself buying primes when I'm not paying attention, so either of those might accidentally make it into my bag.)

Another rant slips through my fingers.

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OM-D E-M5 || O12-50 | P45-175 | P100-300 | PL25 | O45
Adapted: Minolta MD 28/2.8 Celtic, MD 35/1.8, MD 50/1.4, MD 85/2.0, MD 200/2.8, Nikon 100/2.8 E
Wish List: GH3, 12/2.0, 17/1.8, 75/1.8, Oly ZD FT SHG 300/2.8
Pentax K-5, K-01 || 18-135 WR | Sigma 30/1.4

The aperture at which diffraction begins to be a problem is dependent on the focal length of the lens.

I was taught (admittedly some years ago) that diffraction became significant when the size of the effective opening of the diaphragm reached a certain value in millimetres (or a fraction of an inch). So a lens with a longer focal length will only begin to suffer significantly from diffraction effects at a larger f/number (smaller relative aperture) than a lens with a shorter focal length.

Therefore I am not in the least surprised that, with the Olympus 75mm lens, significant diffraction effects have not yet set in at f/16 and only begin to appear at f/22. I also shoot large format where diffraction only becomes significant at f/32, f/45 or f/64 depending on the focal length of the lens I am using - obviously, the focal lengths are much longer than in m4/3 for comparable angles of view.

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Cub
Panasonic G3, 14-45mm, 20mm, 45-200mm, Olympus E-PL1, 9-18mm, 45mm

Your rant is timely.

I've been looking into improving my landscape photography, and have discovered that most of the photos I aspire to are shot sometimes at f22. I have also read that m43 gear performs particularly poorly in at super small apertures due to diffraction. On the other hand, I have pushed my Oly 14-42mI to f10 with personally acceptable results.

It seems that I have to accept this limitation of the m43 system while keeping in mind that it's the size of my camera that allows me to carry it to places worth capturing.

One shouldn't get too worked up over diffraction limits. Yes, at small apertures sharpness will start to decline, but it's not precipitous, and it doesn't mean that at f11 your pictures are great, but at f16 they look like they came out of a Lomo.

It's entirely possible to get very good pictures from m43 at f22. You might want to apply a little extra sharpening, but if you need f22 (or 16, or whatever) to get the DOF you want, go ahead and take the shot. You might be surprised just how good it is.

There are way too many people who are more concerned with test charts and theoretical limits than they are photography, and they all seem to gravitate to online forums.

DOF is also related to the size of the sensor. So if the shot you're looking at was shot at f22 on a FF camera, you'll get the same DOF on m43 at f11 (assuming you're using a lens with the same FOV, and shooting from the same distance). If the f22 shot was on medium format (which a fair number of landscape shooters use), you'll get the same DOF at even wider apertures on m43. I suspect you'll rarely need to stop down to f22 to shoot landscapes on m43.

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I'm not lazy. I'm energy efficient.

You Cannot Change The Laws Of Physics

The Airy Disk size is a function of light wavelength (color), and lens aperture number. Longer focal lengths do not have any effect on the relationship.

Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks

I believe you're correct. I believe some other aspects of lens design also factor in to controlling loss of detail due to diffraction. For example, the Canon 70-200 family has different diffraction characteristics, depending on whether you're using the f/4L, the f/2.8L, or the f/2.8L II, but all have the same focal length(s).

I think this might all be due to the use of ultra-low diffraction elements and multi coatings. My 14-45 only has one aspherical element - it's sharp but only until f/8 or so. The Oly 75 has 5 fancy elements and a low diffraction coating. The 45/1.8 and 12/2.0 are similar, and have much better diffraction-free range than kit zooms. Focal length plays a part, probably because making fancy elements is easier/cheaper for longer lengths.

This is a new era of lens gear, pro-level image quality and correspondingly higher prices.

I'm with you, and it's a decent trade-off to make. To me, the fact that pro-quality glass is coming very soon means that I made the right trade-off.

Ugh, I think I just talked myself into the 12-35.

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OM-D E-M5 || O12-50 | P45-175 | P100-300 | PL25 | O45
Adapted: Minolta MD 28/2.8 Celtic, MD 35/1.8, MD 50/1.4, MD 85/2.0, MD 200/2.8, Nikon 100/2.8 E
Wish List: GH3, 12/2.0, 17/1.8, 75/1.8, Oly ZD FT SHG 300/2.8
Pentax K-5, K-01 || 18-135 WR | Sigma 30/1.4

On M4/3rds F/11 gives the same Depth of Field as F/22 does on 35mm. Diffraction also has the same relative impact at F/11 on M4/3rds as it does at F/22 on 35mm.

The real difference is your ISO and shutter speed settings because your aperture is wider on M4/3rds. If you are going for a slow shutter speed on purpose then 35mm is better. If you want a faster one though, then M4/3rds is clearly better.

@meyerweb There is a lot of wisdom in your post, and it is much appreciated! Although, I have seen some lens reviews that made it sound like you'd be crazy to touch XYZ lens past f/11 (for example). Overly hyperbolic and dramatic? Quite likely.

Interesting that you bring up depth of field and equivalencies. So my f/5.6 kit zoom example is like a FF lens with f/11-f/64 but diffraction starting at f/16? The math is probably wrong, but I hope it conveys the thought well enough.

Yes, we can be too dogmatic at times. "I always use base ISO." or "I'll never go over f/11." or "I always shoot at 1/125th or faster". I think learning the strengths and weaknesses of our equipment can help us make trade-offs in the field, as long as we don't get too dogmatic about those weaknesses.

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OM-D E-M5 || O12-50 | P45-175 | P100-300 | PL25 | O45
Adapted: Minolta MD 28/2.8 Celtic, MD 35/1.8, MD 50/1.4, MD 85/2.0, MD 200/2.8, Nikon 100/2.8 E
Wish List: GH3, 12/2.0, 17/1.8, 75/1.8, Oly ZD FT SHG 300/2.8
Pentax K-5, K-01 || 18-135 WR | Sigma 30/1.4

Your lens and camera can make things worse, but they can never do better than the diffraction limit. For most of us the diffraction effect goes practically unnoticed.

This is the real solution.

The smaller 4/3 sensor is a HUGE advantage if large DOF is desired. I can't imagine needing f/22 on m43 in a non-macro situation.

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