Diffraction Limited Aperture (DLA)

[bob_r]

I was reading a review of the Canon 50D on The-Digital-Picture and they added a new field for their camera reviews. With the 50D, your images start losing sharpness due to diffraction whenever you set the apeture smaller than f/7.6. It seems the newer cameras are really going to tax the older, less stellar lenses. Here's a link to the review: http://www.the-digital-picture.com/Revi ... eview.aspx

It makes me wonder if it's advantages to upgrade my 30D. The diffraction limits wouldn't have much affect when I use my primes, since I usually shoot them close to wide open, but it could affect some of my zooms. I think it could come into play when shooting landscapes with my 10-22 if I were to upgrade to a 50D.

Anyone have any thoughts about this?

Bob R

[Edd]

Hi Bob,

I tried shooting a series of images of the same subject but at different apertures to see if I could see this effect after I read the article you kindly steered me towards.

My untrained eye couldn't see any difference on images at with smaller apertures other than the expected increase in DOF.

Is Diffraction really going to impact that much on images ????

I understand from before most lenses have a "Sweet spot" and shooting above this point diffraction starts to cause the image to be less sharp.

Could it be the lower end lense tend to mask this effect ????

Cheers

Ed

[bob_r]

Ed,

I haven't seen sample images of this yet showing how much diffraction will affect them, but as Canon keeps bumping up the megapixels with each new release, I'm sure it will become more of a problem. My 30D is only at 8mp, so I'm not sure if I will see much of a difference, but I may try the 10-22 or 28-135 at various settings to see if I can detect a difference.

Bob

[Edd]

Bob,

If I remember correctly along with that article was an online calculator where you could put in the make and model of the camera and the type of lense you were using and it would give you and idea of what was the smallest aperture you could use with that combination.

Playing around with it I found that the higher the spec of the camera the smaller aperture that could be used. But I suppose that's what we would expect anyway.

Also the article did mention that although diffraction could be present that was only one of a number of other things that could cause sharpness issues, and it seemed to indicate the "other things" would tend to have a bigger impact on the image than diffraction alone.

Unfortunatley I deleted the images that I took, like yourself I'll try and reshoot and see if I can spot any difference.

Ed