The sharpest lens in the known universe...

Started 11 months ago | Discussions thread
Mark Scott Abeln
Mark Scott Abeln Forum Pro • Posts: 12,795

As lens become sharper - that is, when their optical aberrations are corrected - you still have to deal with diffraction, and as that is physics, it isn't something that can be overcome.

A lens that is well-corrected is often called "diffraction limited" and so most of the blur at the focus point is due to diffraction. But there are other sources of blur, such as blur due to a lack of depth of field, and that leads us to a much bigger problem: an ultra-sharp lens will only perform at its best at a wide aperture opening, one that may very well give an inadequate depth of field.

As megapixels increase, and sharpness increases, the sorrrow of pixel peepers will only increase, as sharp lenses - in a pixel peeping sense - have a shallower apparent depth of field than do lesser lenses and sensors. Also, you'll have more pixels within the diffraction blur region as the number of pixels increases, and noise will still be an issue.

In order to minimize diffraction, the depth of field will be so small that you'll get blur anyway except for the flattest of subjects.

Apodization lenses, which have a radial neutral density filter located near the aperture, do have a modified diffraction blur more amenable to sharpening, and arguably have better bokeh, but they effectively have a higher T-stop as well.

Focus stacking is now done semi-automatically in some advanced cameras, and this is a possible solution to the sharpness problem, but it doesn't handle motion well.

 Mark Scott Abeln's gear list:Mark Scott Abeln's gear list
Nikon D200 Nikon D7000 Nikon D750 Nikon AF-S DX Nikkor 35mm F1.8G Nikon AF Nikkor 50mm f/1.8D +2 more
Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow