Diffraction and Macro Adaptors

[Forkbeard]

I was just wondering if diffraction is the same when using an extension tube or macro adaptors etc as it would be for the lens alone? Extension tubes result in the loss of light, so does that mean diffraction will also be less for a particular f-stop?

 

[Kodiak Qc]

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Diffraction is not so much a problem with extension tubes
though there is a cost in ƒ stop.

The better solution is not to close down the lens but to
use focus stacking to improve both DoF and sharpness.

 

[sk66]

"Diffraction" is the size that a point of light/detail is projected onto the sensor. When that point is projected larger than a pixel diffraction is occurring. When it is larger than 2 pixels it is said to be "diffraction limited" and detail/sharpness is lost.

A smaller f-stop (larger #) is one of many things that cause a point of light to be projected larger... that is just the physics of light and nothing is going to change that. So yes, diffraction concerns are the same w/wo tubes. But if the adaptor/filter/etc has glass that can additionally contribute to diffraction (and other optical errors).