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What is meant by sweet spot in a lens?
Hi,What exactly is meant by sweet spot in a lens? How is it achieved?.

Kind regards,Mil...

Comments (8)

Milbogo wrote:.

Hi,What exactly is meant by sweet spot in a lens? How is it achieved?.

Two definitions here:.

Http://photonotes.org/cgi-bin/entry.pl?id=Sweetspot.

Achieving the first is described here:.

Http://www.digital-shot.com/50226711/find_your_lens_sweet_spot.php.

One way of using the second definition is described here (starting about halfway through the article):.

Http://www.adorama.com/Catalog.tpl?op=academy_new&article=011303.

Sorry not to answer directly, but the above articles probably describe it better than I could anyway...

Comment #1

In zooms, there is usually a focal length where pincushion and barrel distortion are minimized or nil. This is mostly an issue with zooms with larger magnification ranges and/or low f numbers. Of course, some good zooms show virtually no distortion at any focal length but you will likely pay quite a bit for that lens.Leonhttp://homepage.mac.com/leonwittwer/landscapes.htm..

Comment #2

The image quality of a lens isn't the same at all fstops. The sweet spot is the lowest fstop at which the image quality becomes optimal..

Here's an example on 3 lenses. As you can see, at low fstops, most lenses are soft. The sharpness gets better as the fstops increase. I didn't test it all the way, but when you go beyond F16 or so, the quality would decrease again, due to diffraction..

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window.

(Note that these are not the entire image, just a small 100% crop at the center of the frame)..

Comment #3

Hi thanks for your replies.One more question - does a sweet spot change (dependent) on distance to subject?.

Kind regards,Mil..

Comment #4

No, distance by itself does not influence the sweet spot.Leonhttp://homepage.mac.com/leonwittwer/landscapes.htm..

Comment #5

This issue of a sweet spot is intriguing. Shouldn't we always aim to shot in the sweet spot? according to the above examples, one would say yes...

Comment #6

In general, many people do. But notice that Dylan specified that he was showing you an enlargement of a tiny part of the center of the image. The full images at usual sizes might look very similar. There are times, for example, that we need all the depth of field we can get, especially in macro work, to get the entire subject in acceptable focus. We then accept some degradation in small-scale image quality for the sake of the overall image. Or we may be shooting in low light and the need for the highest shutter speed possible trumps the desire for the maximum sharpness..

WillWill PrattBarrick Museum, UNLV..

Comment #7

Yeah I agree with Will. The sweetspot is good if what you need is the utmost sharpness. But most of the time, sharpness has less value than other things that the aperture might affect, including depth of field, shutter speed, ISO speed, etc. Gotta put all of these things into consideration..

Prattw wrote:.

In general, many people do. But notice that Dylan specified that hewas showing you an enlargement of a tiny part of the center of theimage. The full images at usual sizes might look very similar. Thereare times, for example, that we need all the depth of field we canget, especially in macro work, to get the entire subject inacceptable focus. We then accept some degradation in small-scaleimage quality for the sake of the overall image. Or we may beshooting in low light and the need for the highest shutter speedpossible trumps the desire for the maximum sharpness..

WillWill PrattBarrick Museum, UNLV..

Comment #8

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