Archive for July, 2009

Facebook Using Profile Photos in Ads

Posted in News, Social Networking, The Web on July 20th, 2009 by Jeff – 1 Comment

As it turns out, Facebook can use your profile photo in ads. You can disable this easily enough but if you use AdBlock Plus, you’ll need to disable it before adjusting your Facebook settings. If you do not, you won’t be able to see the form.

From Jim M. Goldstein’s blog, this is the series of steps required for you to

All you have to do to prevent this is sign in to Facebook and click through to (get ready) -> Settings -> Privacy -> News Feed and Wall -> Facebook Ads -> Appearance in Facebook Ads and click “no one.”

And remember, if you use Firefox and AdBlock Plus you will need to disable AdBlock Plus in order to actually see the settings to disable the use of your photo in advertisements.

Of course, if you want to see your smiling face in online dating ads, just leave things the way they are.

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Sigma 10-20mm F/4-5.6 Wide Angle Lens

Posted in Photography on July 13th, 2009 by Jeff – Be the first to comment

I recently purchased the Sigma 10-20mm F/4-5.6 EX DC HSM wide angle lens for shooting landscape photographs with my Canon EOS 40D. I rented the Tokina 11-16mm F/2.8 and the Canon EF-S 10-22mm f/3.5-4.5 USM lens before making my purchase for a reasonable comparison. (I recommend LensProToGo for renting camera equipment.)

Long's Peak

Rocky Mountain National Park with the Sigma 10-20mm f/4-5.6

The Sigma 10-20mm lens is a reasonably well built lens compared to it’s Canon counterpart. The Canon just felt very cheap, the body was plastic, tolerances weren’t great and it felt lightweight. The Tokina, by comparison, is built like a tank so it fit well into my build quality standard. It’s bigger, well constructed and has great optics. The Sigma is in between the Tokina and the Canon in terms of construction. It’s lighter but doesn’t leave one with the sense that it’s built poorly that the Canon 10-22mm did.

For optical performance the Tokina was superior to both lenses. The f/2.8 aperture didn’t hurt either. There seemed to be more barrel distortion on the Tokina and the zoom is limited but I didn’t find that to be a big detraction since ultra-wide angle lenses make objects look pretty small anyway. The Canon and Sigma do have more zoom which is a nice but not critical feature for me.

Where I have a problem with the Sigma is with lens flare when shooting the sun. Whenever I’m shooting sunrises and sunsets, there isn’t a nice clean star burst like I’m used to with better lenses, such as the Canon EF 17-40mm f/4L. It has a unique splitting effect at the ends of the starburst that is unattractive. Further, and more importantly, the flare isn’t a nice, tight and manageable effect, it blows out the entire frame. A technique that I learned where you use your finger to block the sun in one frame then shoot another with the sun fails to resolve this issue. It’s just ugly. Note that when I get this effect I’m shooting f/16-f/22 with a polarizing filter and graduated neutral density filters.

I have not tried the Tokina in these conditions for comparison.

Sunset on Long's Peak

Sunset on Long's Peak

The last comparison is price. The Sigma is the least expensive of the three UWA lenses I tried. I ultimately made the purchase based on price and the fact that I could easily get back 80% of it on if it just wouldn’t work. It doesn’t seem like a risky gamble at all. And I do get some reasonably nice pictures from it. The Canon didn’t present me with a compelling reason for it’s higher price (the Canon brand isn’t important to me for this type of lens).

Regardless, if you avoid the situations where the Sigma fails, it’s price point makes it a good choice for APC-S sensor Canon cameras.