Apr 21 2009

How to Find Your Lens’ Sweet Spot

Published by at 6:24 am under Intro to Photography,TUTORIALS

max6 How to Find Your Lens Sweet SpotIn this photography tutorial, I’ll give you a few tricks to find your lens’ sweet spot. First off, what does the “sweet spot” mean? Simply put, the sweet spot is the aperture at which your lens is at its sharpest.
vide How to Find Your Lens Sweet Spot
You’ve probably noticed that some of your images weren’t as sharp all the time and you may have shrugged it off as camera shake. Maybe it was, but it could’ve also been softness caused by your aperture setting on your lens. You see, your lens doesn’t have the same sharpness throughout its complete aperture range. So just changing apertures will change you lens’ sharpness. Hence the importance of finding its sweet spot.


Before I get into the details, I would like to mention that, because of the lack of zoom, prime lenses are usually sharper than zoom lenses. Yes, even prime lenses have their sweet spot but the differences are minuscule and can barely be seen by eye (for quality primes). I have 2 prime lenses, the Nikkor 50mm and the Sigma 105mm, and they’re pretty sharp throughout their complete aperture settings. That said, let’s get back to the sweet spot.
vide How to Find Your Lens Sweet Spot
There is a general rule that can be applied to most, but not all lenses, when it comes to finding it’s sharpest aperture setting. Generally speaking, your lens’ sweet spot is 2 stops above its widest aperture. I won’t get into the whole f-stop theory here because I’ll bore you to death but it’s important to at least know your full f-stop settings on your lenses. Basically, each f-stop increments reduces the amount of light entering the camera by half which means the circle’s surface area is reduced by half.  Here’s a diagram to better explain it.

fstop How to Find Your Lens Sweet Spot

vide How to Find Your Lens Sweet Spot
Ok, now that you understand basic f-stop increments let’s look at an example of the 2 stops theory. If your lens’ widest aperture is f 2.8, your sweet spot should be f 5.6. If your lens’ widest aperture is f 4, it’s sharpest aperture should be…. come on, you know it….. right! f 8. icon smile How to Find Your Lens Sweet Spot So this is easy, right? Tutorial done, right? You’re now a sweet spot expert, right? Well, not really. All rules are made to be broken. icon wink How to Find Your Lens Sweet Spot
vide How to Find Your Lens Sweet Spot
Once you’re done with the theory, it’s time for the practice. There aren’t any shortcuts for this. If you really want to find each of your lenses’ sweet spots, you’ll have to shoot the same scene at various apertures. I recommend setting up your camera on a tripod in a bright environment and using a remote triger like the MC-30 or the RS-80N3 to prevent camera shake. Put your camera on aperture priority mode and start shooting each frame at 1 stop increments (your camera might be set to 1/2 or 1/3 stop increments). Then open them in Photoshop or another photo software and view the image at 100%. That’s how you’ll find your lens’ sweet spot.
vide How to Find Your Lens Sweet Spot
Another option is to look at lens review sites.  DPReview has great lens reviews with interactive charts where you can scroll through different apertures and see the various sharpness. It’s so cool! icon smile How to Find Your Lens Sweet Spot If you know of other great lens review sites that test aperture sharpness, please share them in the comments.
vide How to Find Your Lens Sweet Spot
To be completely honest and practical, my first suggestion is for you to buy good lenses right away. This way you won’t have to compromise your aperture for relative sharpness. Remember that you’ll change your camera body but your lenses will stay. I would rather compromise sharpness over aperture any day since aperture is a means to my creativity.  Not to mention all the available sharpening softwares out there like Photoshop and Lightroom.

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5 responses so far

5 Responses to “How to Find Your Lens’ Sweet Spot”

  1. Rhondaon 21 Apr 2009 at 12:36 pm

    Thanks for the link to DPReview. My favorite site for Canon lens reviews has always been http://www.the-digital-picture.com/Reviews/.

  2. Davidon 21 Apr 2009 at 3:07 pm

    This site:

    http://www.slrgear.com/reviews/index.php

    Has great interactive charts for sharpness (blur index), CA, distortion, and vignetting at different apertures and focal lengths. It also has good writing. Be sure to use the sliders on the interactive graphs.

    It’s my go-to site for lens reviews.

  3. leeon 24 Jul 2009 at 4:29 pm

    thank you for your suggestions.. I realize that each lense has a sweet spot.. how does your suggestions affect depth of field..? as long as you fill the frame with the subject then sharpness is important. but what about sharpness in full figure with some background affect the sweet spot.. with all of my lenses, I shoot in apature priority using F8.. this is how I can assure that everyone will be in focus …I do wedding shots and I never know what will be framed.. Please any advise you can add Id appreciate …

  4. somphongon 11 Nov 2010 at 2:05 am

    This is my first time to know “sweet spot
    of lens” really useful to me, only my work is to
    go back and keep practicing it,

    many thanks for your valuable advice mr.Yanik

  5. 4orty 9ineon 30 Mar 2012 at 4:31 pm

    Here’s a lens sharpness guide that loads into your camera and displays your lens’s sweet spots on the camera’s display screen: www.http://slrlensguides.com

    Read more: http://www.digital-photography-school.com/sweet-spots-why-your-f1-8-isnt-so-great-at-f1-8#ixzz1qdNanYbz

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