How to find your DSLR camera lens' SHARPEST aperture.

So I went ahead and conducted a little experiment the other day compliments of Jim over at He's got an article all dedicated to getting your photos as sharp as possible. I am always looking for ways to sharpen my skills (no pun intended) and Jim's article hit the spot. Here it is in all of its glory. He goes ahead and describes a good way to get to know your lens functions in particular, in tip #3. It goes a little something like this:

(The following text is quoted from

Sharpness Tip #3: Determine your sharpest apertures

Just as the zoom dramatically impacts sharpness, so to does the aperture.

Many photographers learn that the sharpest aperture on many lenses is f/7.1 or f/8, but it totally depends on the lens.  That is a good general rule, but it is foolish to accept this as 100% true.  Just take a minute to lock your lens on a tripod and shoot a subject at all of your aperture levels to see what photo is sharpest.  If you are a landscape photographer, you will likely notice that many wide-angle lenses are significantly sharper at slightly higher apertures, because they are made that way.  This test will only take you 5 minutes to perform and will improve your photos for the life of the lens.

To test sharpness, make sure to shoot from a distance that you commonly shoot that lens, shoot in lighting conditions similar to what you will shoot in the field, and do common-sense things like shoot on a tripod with a cable release and mirror lock-up.

So I have my results below here and as you can see from the captions, I have an EF-S 18-135mm f/3.5-5.6 Canon lens. It works decent as a middle-of-the-road lens so I am just trying to get the best photos out of it I possibly can. I have it attached to my Canon T2i Rebel. A gem amongst the others in the Rebel family in my eyes. 

So if you look closely below I did a couple trials of this experiment shooting in Av mode for both, and on the first set if you take notice of the capital "G" throughout, it definitely has an increase in clarity as we approach an aperture of 10.0, which seemed to be my best in this trial, with 9.0 being very close as well. Not sure what happened on 11.0 there. I may have bumped the tripod in all of the monotonous excitement of shooting paper scotch-taped to my bedroom wall. JOYYYYY!!! (To get a better view just click the images below.)

So then we come to the second trial of the experiment. This one is a small business card from Griffith University here in Gold Coast, Queensland. I visited their campus the other day so that was awesome. With this one, You can focus once again on the capital "G" if you'd like and notice that we gain more clarity as we approach 10.0 and 9.0. Seems to be a trend here if I may be so bold. This one has an odd jump from unfocused to focused again if you look from 8.0 to 7.1. Hm, odd... 

So I tried to get Bill Nye to help me wrap up this experiment conclusion with an awesome rap performance about science and cameras and such but he was unable to pencil it in due to prior engagements. No, I am not going to rap and try to steal his thunder. You'll just have to wait until next time for Bill Nye. The TRUE genius.

According to the numbers found in both trials together, it seems my best range is somewhere between 9.0 and 10.0 with some decent work being done anywhere upwards of 13.0 and all the way down to 7.1. That being said, it's probably safe to say I can stick in that range for the BEST and SHARPEST photos. 

Try this out for yourself. When I first read this I was like, "Oh LAAAAAAAAAMME." and followed up with giving the computer screen a huge thumbs down gesture while making a "pbbfffffft" sound. Yes I am a very mature gentleman thanks for asking. But the experiment was actually super easy to set up and the results were very helpful. 

Some easy tips to set up:
1. Definitely use a tripod. If you don't then you might as well just go stare at a wall instead of attempting to do this experiment. OR perhaps get another surface or prop to rest your beautiful camera on. Genius!

2. Get a cable release or IR remote to release your shutter without jigglin' that cam'ra. I was actually feeling rather rebellious so I did not use one, (and my wallet was empty so I couldn't go buy one...) but they are super cheap and I picked up a remote today for only 30 bucks! If you find yourself in a similar predicament or are feeling just as badass, then go ahead and use a self-timer to release your shutter for better clarity.

3. If your camera has the setting, definitely use mirror lock-up. This will keep your mirror inside the camera from flipping this way and that and shakin' 'round like it's 1999. It'll most likely be in your custom functions menu where you can select Mirror Lock-up and click enable. Afterwards make sure to disable it it for standard shooting. 


Try this out. Let me know what you think. (Cue "Bill Nye Theme Song")