Resolution Vs. Sharpness

Crowded Pixels • Extender Percentages • Shedding Light On Adobe Lightroom • Protection • Laminates • Storage Is In The Cards

An example of the possibilities of the Canon EOS 7D with an APS-C image sensor having 18 megapixels. The image of a flying brown pelican was captured using a Canon EF 500mm lens with an EF 1.4x tele-extender attached (1120mm with 1.6x crop factor), ISO 400, 1/350 sec. at f/11. Note the sharpness in the enlarged inset.

Crowded Pixels
Q I’m interested in stepping up to the highest-resolution APS-C-sensor camera (18 megapixels) available, but I’m concerned about reports of image softness and muddiness from some reviewers and blog sites on the Internet. They blame the problem on excessive numbers of pixels on such a small surface. Can you offer your insights and test results on this topic?
G. Corbett
Via the Internet

A The 18-megapixel APS-C sensor has the advantage of higher resolution if you photograph with quality optics. I’ve frequently photographed over the last few months with the Canon EOS 7D, which has this sensor and consistently yields images with excellent sharpness and color.

The smaller sensor, combined with higher resolution and fast capture, has some real advantages for wildlife photography. When you want to go long, the smaller sensor adds a crop factor of 1.6x, a significant boost that I used on my recent trip to Africa. More pixels means you can crop the image even further in postprocessing without loss of image quality. But there’s a trade-off with another technological advancement that’s important for wildlife photographers: expanded ISO. The cameras with the best response at high ISO are those with full-frame sensors and lower pixel counts because the pixels are larger and spaced further apart, minimizing cross-pixel contamination and noise. With the 7D, I’m able to use ISOs of 400 to 800 with excellent results, but I’d be reluctant to go higher in most situations.

If you’re looking to solve both problems, that is, you want the crop factor of the smaller sensor and the high speed of expanded ISOs needed to photograph wildlife, you should consider the Canon EOS-1D Mark IV, the Nikon D3X or the Nikon D3S (using the DX format). If you shoot mostly landscape and highly detailed design, you want to stay with the full-frame cameras.

Extender Percentages
Q When I shoot with my 500mm lens, I get the tack-sharp images I need 90% or more of the time. When I add the 1.4x tele-extender, the number of sharp images drops to about 70% to 80%. But when I use the 2x, the success rate drops to no more than 10%. The images, even when in focus, are very soft, almost like a soft-focus filter was used. I use the 500mm on Gitzo tripods with Wimberley heads, mirror lockup and a cable release. Is there a trick to using the 2x that I’m missing?
T. Wilkes
Via the Internet

A The percentages you’re achieving with the 500mm lens alone and with the 1.4x tele-extender are realistic when using a tripod under field conditions, so I’m pretty sure your technique isn’t the culprit. The results you’re getting with the 2x tele-extender are bothersome. You should be able to do better. I would expect a sharp result 60% or more of the time in the field, even considering that you’re shooting at 1000mm. I’m assuming that you’re using the camera manufacturer’s matched tele-extender for optimum results. Still, it’s my opinion that even under the best conditions, you’ll lose approximately 20% of the overall quality (sharpness and contrast) with the tele-extender. That said, if you start with a high-quality prime lens coupled with a matching 2x, the quality loss should be barely visible.

So here’s the question: Is the problem with the tele-extender or your technique? One way to answer that question is to ask another: Have you ever achieved even one sharp image using your 2x tele-extender? If the answer is yes, the problem is probably the photographer. If the answer is no, your 2x is possibly faulty. The way to find out is to borrow an identical 2x and set up a controlled comparative test on a stationary, finely detailed subject. Use your tripod, lock up the mirror, and shoot both wide open (ƒ/4) and stopped down (ƒ/8 to ƒ/11) with both tele-extenders. Choose a lower ISO and a faster shutter speed; that means there must be reasonable light on the subject. With all of these variables controlled, you can achieve the best possible result from each combination. Review the results on your monitor at 100%, and you should be able to tell if there’s something wrong with your tele-extender and proceed accordingly.

Shedding Light On Adobe Lightroom
Q I’m an amateur photographer, but I do try to get the best image results possible. For several years, I’ve been using Elements as my photo software. You’ve recommended Lightroom. What advantages does Lightroom have over Elements, and does it require use of Photoshop?
R. Black

A Lightroom is an excellent software for editing images (separating the keepers from the throwaways), for preliminary optimizing and for keywording, cataloging and filing your images for quick and easy retrieval. Elements and Photoshop don’t have the cataloging capabilities and aren’t as efficient for editing and initial optimization.

My own workflow begins with Lightroom, where I first attach keywords and copyright data to each image. Then I edit the images to determine which are of sufficient quality and content to keep. Lightroom allows me to quickly compare images side-by-side at 1:1, not an option in Elements and Photoshop.

Once I’ve selected the images I want to save, I do some preliminary optimizing in Lightroom, using the Develop functions, such as cropping, sharpening, and improvement of color and exposure. Sometimes, this work in Lightroom is all I need to do. But often, I’ll bring the finished Lightroom image into Photoshop for more fine-tuning using the powerful processing options.

My own workflow begins with Lightroom, where I first attach keywords and copyright data to each image. Then I edit the images to determine which are of sufficient quality and content to keep. Lightroom allows me to quickly compare images side-by-side at 1:1, not an option in Elements and Photoshop.

There’s always more! The new (as of this writing) Lightroom 3.0 public beta 2 previews some new features that I find to be the best methods for sharpening and noise reduction I’ve seen anywhere. And (at last!) Lightroom is offering a way to add a watermark to images that I’m going to post on the web.

Q I just spent a lot of money on a professional-level 70-200mm f/2.8 L IS lens. Should I invest in a UV filter to protect the lens from dirt or will this introduce aberrations?
P. Nelles

A A UV filter is often used to protect the front element of a lens from abrasive dirt, salt water and blowing sand, or from breakage due to careless handling. That said, any filter placed at the front of the lens will cause some degradation of the image, albeit ever so slight. When you stack more than one filter, the impact is visible. So if you want to use a filter such as a polarizing, warming or neutral density for photographic effect, you should remove the UV filter first. I personally don’t use any filter on my professional lenses unless it has a definite photographic purpose.

Q A friend of mine recently showed me some prints he had made and then sent out to be laminated. The impact of the modern lamination process was impressive and gave the prints a greater feeling of depth. Have you used lamination?
D. Blackburn
Via the Internet

A I use laminates on large panorama prints that are too unwieldy for traditional glass framing, but they can be used only on glossy or semi-gloss media. Canvas and watercolor papers can’t be laminated. The laminate protects the print from fingerprints, dust and moisture, and is far less expensive (and much lighter) than glass would be for such large pieces.

Most laminators offer three coating varieties. A glossy finish typically is unsuitable for photographs because of its highly reflective surface. The matte finish obscures the detail in the image and kills the contrast and color. A satin or semi-gloss laminate typically works well because it matches the surface of the print media, cuts some glare and doesn’t obscure the detail or color. Laminating a print takes it out of the realm of archival fine art, so this may not be an option for expensive gallery sales. Done properly, a laminated print will last a long time without yellowing or bubbling—so far, my longest test is 15 years.

Storage Is In The Cards
Q Because CF cards have greatly increased in capacity, why not use them on long trips to store my photos, eliminating the need to carry my laptop and hard drive on board airliners? I generally take around 800 shots on a two-week trip, all done in RAW.
R. Dandridge
Summerville, S.C.

A We hear you. Carrying equipment on airliners gets tougher all the time. As of this writing, you can get 16 gigabyte cards for as little as $100, but a really good, reliable, extremely fast card such as the Hoodman UDMA RAW will cost more. Taking extra cards along and leaving your images on the capture media until you get home isn’t a bad idea, except that you have no backup.

When I’m working in the field, I get my images into two locations as soon as I can, typically each evening. The evening review isn’t just about storage; it also gives me an idea of how well my equipment is working and how successful my photographic decisions have been for the day’s shoot, and allows me to consider adjustments that need to be made for the next day.

If you don’t want to carry your laptop along to perform these functions, the next best option is an external viewing and storage device; good units are sold by a number of companies, including Epson, HyperDrive, Jobo and others. The price varies based on storage capacity and the quality and features of the viewer. With my two-location rule, in this scenario I’d use the viewer for my primary storage and save the cards for backup—and carry them home in separate places. Consider it an insurance policy; when you go on a once-in-a-lifetime photo trip, you want to come back with your pictures.

For information about upcoming seminars and digital-imaging workshops, visit If you have any tips or questions, address them to: OUTDOOR PHOTOGRAPHER, Dept. TT, George Lepp, 12121 Wilshire Blvd., Suite 1200, Los Angeles, CA 90025-1176 or online at

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.


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