So you are looking for a new camera lens or you went out and bought a brand new D-SLR digital camera with the kit lens. Now you want to produce 11 x 14 or 16 x20 or larger sharp prints.  You will need a good tripod and know your camera lens sweet spot. The lens sweet spot is the aperture or F-stop setting which produces sharpest image possible.

The lens sweet spot is determined by which F-stop or aperture to get the sharpest image. All lenses have a sweet spot.  What we are going to determine is what aperture will produce the sharpest image.  A simple rule of thumb is to take the widest aperture and stop it down 2 full f stops or 2 full aperture values ( see chart below).  Let’s say you have a lens with a maximum F-stop of F4.  That would make the sweet spot of your lens about F8.  The problem is this may not be the exact sweet spot for your particular lens. The only way to really know is to test the lens for yourself or you may find it in a lens review article in one of the many photography magazines.  The problem is that your lens may not have been tested or at least may not have identified the sweet spot of your lens.

Full F-stop Chart

Your lens may have other F-stops not listed on this chart above.

The chart above gives the corresponding aperture value to F-stop.  As each aperture value increases it cuts the light in half.  As each aperture values decreases it doubles the light.

So let’s test the lens.  The first thing I did was find a test pattern chart to test the lens.  I found one at http://www.graphics.cornell.edu/~westin/misc/ISO_12233-reschart.pdf You can print it right from the site or downloaded it.  Once downloaded you can print the test chart in the best quality your printer will allow you to print.   This is what you will need to run this test: your camera and lens; a sturdy tripod; a remote cable release; a board to mount the test chart on; the test chart.

Step 1. Attach the chart on the board with tape so that the chart will not move if there is any wind.

Step 2.  Find a bright spot outside and set the board with the chart in the sun.

Step 3.  Install your camera on a tripod.

Step 4.  Select the camera to aperture priority.

Step 5.  Focus your camera on the chart.

Test Chart Location Below

Next, we’ll start with full open.  Let’s say at f5.6 and shoot your first picture.  Next we’ll shoot a photo at each f-stop, making note of each photo’s f-stop so that when you import them you will know which F-stop corresponds to each photograph.  Be sure to use your remote shutter release cable and don’t move the camera through the whole process.  Please note  that any camera shake or movement will cause an inaccurate test.

After you finish, take your memory card and import into your favorite photo editing software.  (I use Adobe Lightroom 2.)  Open the photos in your editor and set the  magnification to one to one.  Use a side by side compare function if available.  Now, carefully inspect and compare each photograph to see which one is the sharpest.  Once you have determined which photo is the sharpest you have found your lens F-stop sweet spot.

If you are using a zoom lens you may want to repeat these steps for several focal lengths.  Let’s say you’re using a 70 to 200 mm lens.  First use 70mm then 130mm then 200mm. This will let you find the best F-stop for the sharpest picture at all F-stops.

The chart below shows the tests results I found with the lenses I have.

Conclusion.

One thing that I found when performing these tests is the better the lens quality the harder it is to find the exact sweet spot. These lenses generally had between two and three F-stops with the best sharpness. With some less expensive lens I found it easy to find a single F-stop sweet spot. But it is possible with higher end consumer lenses with ED glass (extra low distortion glass) you can get very sharp images.

Now you know what your lens sweet spot is.  Even if you have a less expensive lens, by using this knowledge, you will be able to get very sharp photographs with most lenses.  But, we do live in the real world.  Sometimes, because of low light conditions, or the need to adjust the depth of field, we may have to adjust our F-stop to our needs.  So, if the situation is right to use the sweet spot of your lens,  you will find you will get the sharpest pictures possible with your lens.

The Teleconverter

I was not happy with the test results on the Nikon TC-20E II 2X Teleconverter.   I have read other reviews of the Nikon brand Teleconverter that come to same conclusion. They also revealed that the Nikon TC-17E II 1.7x and Nikon TC-14E II 1.4x both had superior performance over the TC-20E II 2X Teleconverter.

If you are in the market for a new lens or camera, buy the best lens you can afford.  In my opinion, the lens is more important than the camera.  Consider this the lens has a life cycle of about 10 or more years and because the camera technology changes so fast, the camera’s life cycle is only 2 to 5 years.

So do your homework before you buy any camera, lens or teleconverter.

Please share your questions or comments below.

Happy sharp shooting.

Doug Niedermiller

Follow us on Twitter

Become a Fan on Facebook

Visit our other site www.dcmtravelreviews.com

One of my photos made Finalist in the Outdoor Photographer Magazine Mystical Adventures Photo Contest. This photo was shot in Gloucester, Cape Ann, Massachusetts in Lobster Cove by the small village of Annisquam.  Cape Ann is located on the coast some 43 miles northeast of Boston, Massachusetts. The GPS location for this shot is  Latitude 42.654855 Longitude –70.674945. Click on my photo below to register to vote in the Outdoor Photographer Magazine Photo Contest.  Voting is done by selecting your favorite photos and rating them 1 to 5 stars.  Every time you vote you are also entered automatically for a chance to win Polar Bear Photo Adventure for two. Of course, I would appreciate a vote for my photo!

Outdoor Photographer Magazine

Outdoor Photographer magazine is written by the world’s leading landscape, wildlife, sports and travel photographers. Each issue of Outdoor Photographer features advice on improving photography, reviews of the latest equipment and stunning photos. Learn more…

Save up to 79% on this magazine

View other great photography magazine!

This photo was shot in autumn  just after sunrise. First, I set up the camera on a tripod and shot 3 photographs at 3 different exposures; 1/4 sec. 1/15 sec and 1/60 sec. ‚all at F8. Then , I imported them into Adobe Photoshop Lightroom 2, then combined them with the Plugin Photomatix Pro 3.1, a program for processing in HDR  High Dynamic-Range photography. This allows one to see the detail in the shadows and highlights.  It also has the ability to create some pretty cool special effects. Then, I imported them back into Lightroom for final fine tuning. The camera I used was the Nikon D80 with a Nikon 16-85mm  Lens  and a Circular polarizer filter.  Camera settings, Aperture Priority, ISO 100, in RAW format and the Lens set to 16mm.

For more information on HDR or High Dynamic-Range photography and the program I use, Photomatix Pro 3.1. Photomatix Pro 3.1 is a standalone program and also has Plugins for Adobe Photoshop and Adobe Photoshop Lightroom 3.

You can also subscribe to Outdoor Photographer.  It’s a magazine designed for all levels of outdoor photographers.  There are always great photos and lots of tips to improve your photography.  This is my favorite magazine.

Map of Cape Ann Massachusetts. Click on the markers below to view more information.

Lens aperture, shutter speed and ISO are the three primary adjustments available to achieve a properly exposed photograph. These settings can also affect the image quality and artistic effects of your photography.

Lens Aperture

The aperture is the size of the opening in the camera lens at the moment a photo is taken.  Aperture is measured in fractions, so the larger the number, the smaller the aperture opening.  Shutter speed and aperture are the two primary controls for limiting the amount of light that hits the camera sensor.  Aperture also controls the depth of field.  A small aperture will produce a photograph with almost all objects in focus.  A large aperture will produce a photograph with a small amount  of the objects in focus.  This will give you control over what you want in focus. That is why I primarily use the aperture priority camera setting in my photography.

Typical apertures include:   f1   f1.4    f2     f2.8     f4     f5.6    f8     f11     f16     f22     f32    f45

Camera Shutter Speed

Shutter speed is the amount of time the shutter remains open when a photo is taken.  Shutter speed and aperture together determine just how much light hits the film or camera sensor.  The shutter speed is also a fraction, just like the aperture.  A shutter speed of 500 is actually 1/500, or “one five hundredth of a second. To hand hold a camera, the rule of thumb is a 50mm lens can be hand-held at 1/60 of a second.  A 200mm lens at 1/200 of a second and so on.  To achieve this you can adjust the apertures or the ISO settings.

Typical shutter speeds:  30s    20s    10s   4s   2s   1s   1/2s    1/4s     1/8s   1/15s    1/30s   1/60s   1/125s     1/250s     1/500s    1/1000s    1/2000s    1/4000s

Camera Sensor ISO

The sensitivity of film or camera sensor is measured by ISO, and the larger the number, the more sensitive the camera sensor.  ISO 100 needs a lot of light, like outdoors on a sunny day.  ISO 1600 doesn’t need much light.  However, higher ISO means more grain in the film and more noise in digital.  Digital images borrow the ISO scale to measure the sensitivity of film.  Just like the grain that’s added to film at higher ISO settings, more “noise” is added to digital images at higher ISO.  In general, as ISO goes up, quality goes down.  Some of the new mid to high-end D-SLR have improved the noise levels at the higher ISO settings up to ISO 1600.  Some of the new cameras have ISO settings between 100 and 102400.

Typical ISO settings:   50   100   200 400   800   1600   and high ISO 3200 6400

Conclusion

My basic camera settings I use related to this article  are: ISO 100 for best image quality  and set camera to aperture priority.  Also, use a tripod when ever possible.  All three settings work in concert and affect proper exposure.  All have their advantages an disadvantages, so experiment with all of  these settings and you will become a better photographer.

Reference

Hear is a nice Exposure Chart

Doug Niedermiller Photography