Stacked In Your Favor

Depth In The Mountains • Fine-Tuning Sharpness • The Hard Truth About Software
Gators by George Lepp

These Gators Are Sharp, And That’s No Croc. Lepp wanted every alligator in sharp focus, from front to back, so working from a tripod, he focus-stacked six captures at 170mm and ƒ/11, the sharpest aperture for the Canon EF 100-400mm f/4.5-5.6L IS USM lens. The gators did not move, and excessive water motion was eliminated using the compositing software Zerene Stacker. Canon EOS 5D Mark III at 400 ISO.

Depth In The Mountains

Question: I like to photograph the mountains in Washington state, most of which are 6,000- 10,000 feet. There are many opportunities to capture beautiful foregrounds, so depth of field can make the critical difference between a beautiful image and one that lacks clarity. I have a full-frame DSLR, and I use quality lenses ranging from 24 to 300 mm. I usually shoot around f/22. How could I improve my depth of field and sharpness? –J. Kenstowicz, Via the internet

Answer: You can increase your depth of field (DOF) and sharpness with two methods; one is simple, one not so much.

First, don’t photograph at ƒ/22. It may seem logical to use a narrow aperture such as ƒ/22 to attain more depth of field. But at narrow apertures, beginning about ƒ/16, light is diffracted as it enters the lens, and by ƒ/22 diffraction is detrimental to sharpness. When you are capturing a landscape in a single shot, you will achieve greater depth of field using a wider-angle lens and larger aperture, maximum ƒ/16. Be aware that the foreground will be emphasized and the distance minimized in this scenario.

In situations where I am shooting a landscape and want to achieve a great range of depth of field with absolute sharpness, and the foreground and distance elements are equally important, I incorporate the multiple-capture technique called focus stacking. Using a wider aperture, such as ƒ/8 or ƒ/11, and with the camera and lens locked in position on a tripod, I take a series of images manually focused at a number of points from close foreground to infinity. Overlap the depth of field areas slightly, and keep in mind that you can have too few focusing points, but not too many. At ƒ/8, you might need five focusing points in a landscape that goes from a close foreground to infinity, and at ƒ/11, possibly three. When you look through your lens to focus, you are viewing the depth of field as it would be captured at the lens’ widest aperture, so use this minimal depth of field as your basis for placement of your focus points, and use the depth-of-field preview button to check the overlap.

Assemble the captures in post-processing using focus-stacking software; my favorite is Zerene Stacker, which is fairly easy to use. It may sound complicated, but once you’ve done it a few times and you’ve achieved the outstanding results, focus-stacking will become the standard for your landscape photography, and it has excellent applications in macro as well.

As a cautionary note: If the wind is blowing foliage around, this technique won’t work; then you might have to revert to a single image and smaller aperture—but not ƒ/22.

Fine-Tuning Sharpness

Question: I realize that getting really tack-sharp photos requires good camera technique and the use of a solid tripod, along with lots of practice. With that said, I have heard a lot of discussion about whether lenses should be calibrated to the camera body using DotTune, LensAlign or FoCal by Reikan. Do you calibrate all your lenses or just some you feel are not focusing right, or stay away from it all together? –C. Andersen, Cora, Wyoming

Answer: Here’s the thing: The image in a DSLR’s viewfinder is not derived from the image on the sensor. In a perfect world, every camera and lens combination would be accurately calibrated so that the image in the viewfinder and the image captured on the sensor were identical. However, there can be slight variances. If your subject looks properly focused in the viewfinder, but your results consistently show misplaced focus in front (front-focused) or behind (back-focused), you need to recalibrate the camera for the specific lens so that the viewfinder autofocus will accurately display the focus range. In my opinion, it is very important to check the calibration between the viewfinder and sensor in every DSLR camera/lens combination you use, and correct it if necessary—especially with telephoto lenses, where the depth of field already is minimal. If you focus using Live View on the back LCD of the camera, the focus is coming directly from the sensor, and the results will match what you see. This is also true for mirrorless cameras.

Not every DLSR can be AF micro-focus adjusted, but all the major manufacturers have some models capable of calibration. Check your manual. The problem is relatively common, so it’s a good idea to check all new body/lens combinations before you put them into use in the field.

I typically use the LensAlign calibration tool from Michael Tapes Design. It’s a pretty simple process: Using the lens’ widest aperture, autofocus on the calibration target and scale through the viewfinder; take a photograph, then enlarge the image on your computer monitor and compare the achieved focus to the options on the scale. If necessary, make micro adjustments within the camera’s menu system, then repeat as necessary until critical focus is matched between the viewfinder and the sensor.

I have not used the Dot Tune or FoCal systems to calibrate my lenses, but after reading their info I think they employ a comparable process. I also found similar products like Datacolor SpyderLENSCAL, Focus Pyramid Autofocus Lens Calibration Tool and DSLRKIT Lens Focus Calibration Tool Alignment Ruler, and another called the Folding Card Lens Focus Calibration AF Micro Adjustment Tool.

Your question reminded me that I hadn’t calibrated my newer cameras and lenses, so I got out the LensAlign tool and went to work. My first test looked at the Canon EOS-1D X Mark II and Canon EF 100-400mm f/4.5-5.6L IS II USM lens, and the lens with a 1.4X tele-extender. The autofocus matched perfectly with no adjustment. Then I tested the Canon EOS 5DS R with the same lens combinations, and they were both front-focusing by a significant amount. Next I tested the Canon EF 500mm f/4L IS II USM lens on the EOS-1D X Mark II, and I expected it to be right on. I was wrong. The 500mm’s AF was significantly back-focusing at 500mm and a little less with the 1.4X (700mm) and the 2X (1000mm). The 5DS R was also significantly back focused with the 500mm and with each of the tele-extenders. So thanks for reminding me to check.

The Hard Truth About Software

Question: Can Lightroom 6 and older versions of Elements be updated? How do you compress 8MB, 12MB and 20 MP files to the 5MB that Outdoor Photographer requires for gallery submissions? Do Adobe Photoshop and Adobe Elements automatically generate a copy when I’m working on the files to improve them? –J. Voigt, Via the internet

Answer: A lot of questions here, all pertaining to products and procedures for image processing. First, despite the angst and anger many photographers expressed when Adobe introduced its subscription service three years ago, if you’re serious about photography, it really is a good deal. To be sure you always have the latest version of Photoshop and Lightroom, you need to subscribe to the Creative Cloud Photography plan for $9.99 a month. As there are improvements in the Adobe programs, the subscriber downloads the improved version for free.

If a photographer doesn’t want to subscribe, the alternative is to work with Photoshop 6 and do without the upgrades that Photoshop CC 2015.5 users are getting. How long Adobe will support new cameras with their RAW file formats in the non-subscription versions is anyone’s guess. There are rumors of a Lightroom 7, but as of this writing, nothing has been heard on the subject from Adobe. Upgrades to Elements must be purchased as new versions.

Generally, photography contest submissions are looking for maximum 4MB or 5 MB files. This is a considerable reduction from, for example, the 60MB RAW file produced by a 20MP camera. The file reduction process is achieved through image processing software such as Adobe Elements, Lightroom or Adobe Photoshop. Here’s a quick review of the sequence. First, change the Image Mode to 8-bit, which halves the size of the file. Then, change the Image Size resolution to the requested quality, such as 300 dpi. Next, change the Image Size dimensions to the maximum width requested, and the height will automatically adjust proportionately. Finally, save the file as a high-quality JPEG to compress it.

Whenever you are working on a file in Elements, Lightroom or Photoshop, save the altered file with a new format or file name; the original file will continue to be available unless you overwrite it by saving the changed file with the same name as the original. If the original file is in RAW format, it will be saved as a JPEG, TIFF or PSD format after it is optimized; the revised file can be accessed later for additional work (and possible resizing for submission to an OP gallery or contest).

One of North America’s best-known contemporary outdoor and nature photographers and a leader in the field of digital imaging and photographic education, Lepp is the author of many books and the field editor of Outdoor Photographer magazine. One of Canon’s original Explorers of Light, Lepp finds inspiration in advancing technology that fuels creative innovation and expression of his life-long fascination with the natural world.