Comparing Lenses

My search for a great “all-around” lens continues. When I first purchased my Digital Rebel in April 2006, it came with the 18-55 kit lens and I purchased a Tamron 70-300 lens as well. After some time, I purchased the Tamron 28-75 because I wanted a better lens for my photography. Therefore, I sold the kit lens. The image quality of the Tamron was great. However, the zoom range was limiting. Unfortunately, I missed the wide angle aspect. Therefore, I purchased a Sigma 17-70 to provide the wide angle perspective. I frequently changed lenses using my Sigma 17-70 for wide angle and the Tamron 70-300 for further away shots.

I reached my pinnacle of frustration when the family went to Florida for a week. After missing so many shots at Sea World changing lenses, I decided to obtain a super-zoom lens. I read the reviews that bemoaned the image quality of the superzooms. With such a wide range, these lenses do not produce sharp images. Yet, I was willing to live with that compromise. So, I purchased the Sigma 18-200 DC OS. Afterwards, I sold the Sigma 17-70.

The first big test was a trip to the Caribbean for my 7th Anniversary. I was sold as it produced beautiful images of my wife and the landscape. The next test was a trip to Shenandoah National Park. Once again, the images I returned with were impressive. I did notice a bit of loss in the sharpness. However, it was nothing I dwelt on.

During the winter, I took photos but the spring time signaled a change for me. The cherry blossoms were in bloom and I went to take some photos. I went on a Friday evening to take pictures of them during the dusk and I returned early in the morning to get them during the dawn. Contrary to my initial position, I began to have greater concern about sharpness and image quality. If I was making the effort to rise during the early hours, I wanted my camera and lens to return the favor and provide excellent photos. Therefore, I began using the Tamron more often.

In June, I went to Cape Cod for a photo safari. During that trip, I used the Sigma quite often. When I began reviewing my images, I noticed a definite loss in sharpness. As a matter of fact, I noticed vignetting at the telephoto end. It was so bad that I sent the lens in for repair. It returned with improvement but the confidence was lost.

Also, I noticed that images other photographers made of similar images were much sharper. Some of this can be attributed to post-processing. However, I realized that my quality demands had grown. Now, how much quality was I willing to compromise for one-lens convenience?

I decided to compromise on the convenience and pursue quality. Therefore, I purchased the Canon 24-105 lens. This would provide me with more reach than the Tamron. However, I had the confidence of the “L” lens reputation for image quality.

I decided to do a head-to-head lens comparison. I went outside and I took my three lenses (Tamron 28-75, Canon 24-105, Sigma 18-200). I placed my camera on a tripod and I took photos of my home at various apertures and at various zoom lengths.

Tamron Aperture (2.8, 4.0, 5.6, 8.0, 11.0, 16.0, 22.0) & Tamron Zoom (28, 35, 50, 75)

Canon Aperture (4.0, 5.6, 8.0, 11.0, 16.0, 22.0) & Canon Zoom (24, 35, 50, 75, 105)

Sigma Aperture (4.0, 5.6, 8.0, 11.0, 16.0, 22.0) & Sigma Zoom (18, 28, 35, 50, 78, 105, 135, 200)

Using the Canon ZoomBrowser software, I was able to do a side-by-side comparison of the images. The best images were typically between 5.6 & 11.0. I was surprised to see how soft the Tamron images were at a 2.8 aperture compared to those from 5.6 to 11.0. My main criteria was image sharpness and I looked at color quality.

However, for head-to-head competition, I used the F8.0 as the comparison aperture. It was no surprise that the Sigma performed the worst. The difference was noticeable immediately. However, the results between Canon and Tamron are mixed. The Canon outperformed the Tamron head-to-head at the 35mm & 50mm. Also, the Canon’s 24mm image was sharper and provided more detail than Tamron’s 28mm. However, I was surprised that Tamron performed much better than Canon at the 75mm length. Usually lenses do not performed well at their extremes. Overall the competition was close. This was quite surprising considering the Tamron is 40% the cost of the Canon. Although, the Canon provides IS and a wider focal range.

Considering how close the competition was either this Tamron is a very good lens or the “L” series reputation is over-hyped. I hope for the former.

-Roger