Sensor & Lens Limitations - again

[boBQuincy]

I previously wrote about an issue where some of the latest cameras have sensors that are "better" than almost any lens available. This is repeatedly being proven in the lab and in the field.

From a recent article on Canon's 50D in "Luminous Landscape"... "There's little question, however, that this camera marks new territory in the realm of imaging with a 35mm SLR style digital camera. The diffraction-limited resolution aperture for this sensor is around f/7! (The appropriate formula is: diffraction limited aperture equals 1600 divided by the pixel pitch in pixels per millimeter.) Using smaller apertures - say f/11 - will result in images with significant softness."

In other words, any aperture smaller than f/7 will result in increased softness due to diffraction limiting, *but* few lenses are at their best until about f/8. So, there are probably no lenses that will deliver the full potential of this camera, never mind lenses we mortals can actually afford and will carry.

Now of course this is not a total disaster and all sharpness will not be gone at f/11, diffraction is a gradual thing and at f/11 the loss may not be noticed except by pixel-peepers. Still, this does mean that we are not getting sharper images by going to the latest cameras, that "new" does not necessarily mean an upgrade.

For now we have reached (and exceeded) the pixel limit, maybe now the manufacturers will finally concentrate on something else that actually delivers better images! Don't hold your breath...

 

[Groucho]

I dunno, this all sounds like a lot of hand-wringing by the hardcore pixelpeepers to me. All I know is that I can look at my 14.6 megapixel images and see clear detail at 100%, with little to no artificial sharpening applied. I can see a difference in lens quality (for example, my Tamron 28-75mm isn't quite as sharp as my Pentax 50-135mm) but you need to look really closely when comparing decent lenses. Many of my 20-40-year-old prime lenses still look extremely good when viewed at 100%.

I'm not sure exactly what the critics want. As long as ISO noise levels can be held down, what's the problem? There always has to be some bottleneck. It's got to be either the lens or the sensor.

I just took a look at the article. The author appears to be living in a vacuum. He went from a 10mp camera to a 15mp one and declares the 15mp one a milestone because he sees more lens faults. ??? Last time I checked, there's plenty of 12mp cameras, a 14mp one, a couple 14.6 ones, and some full-frame 24mp ones - each of which will have very similar abilities to show the limitations of poor lenses.

 

[webshark3]

Darn, my new 12MP DSLR is just shows the limitations of the photographer.

 

[jann1033]

just hypothetically won't that mean they'll have to improve the lenses? wondering if the newer lenses will be better. i really don't understand this whole topic but makes me look at the 40d closer

 

[seashoreCM]

It has to do with the absolute size of the aperture (you could say in fractions of a millimeter).

For a larger sensor, the same 35mm equivalent focal length means a larger absolute focal length and therefore a larger absolute aperture size for the same f/stop.

It will be the more compact cameras, not counting megapixel count, that experience more diffraction diffusion problems. There is the dilemma of, say, the theoretical best focus being had at f/8 and smaller apertures but diffusion diffraction is negligible only at f/7 and larger apertures.

 

[dpic]

I'm sitting at at work and received a text from my daughter a couple of hours ago that my new 50D arrived and is waiting for me at home. When I get home I can't wait to play with its limitations