paulso Posted August 23, 2010 Share Posted August 23, 2010 <p>I bought a 15-85 2 weeks ago trying to replace my 18-55 IS. While the 15-85 is almost 10 times more expensive, I surprisingly found that their IQ are roughly the same at most of the range and at around 50mm, the 18-55 IS is significantly sharper at the corner (try the top left corner).<br>http://www.dpreview.com/galleries/4359850282/photos/489589/18-55 <br>http://www.dpreview.com/galleries/4359850282/photos/489386/15-85 <br>This result is very different from here:<br><a rel="nofollow" href="http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=675&Camera=474&Sample=0&FLIComp=4&APIComp=1&LensComp=455&CameraComp=474&SampleComp=0&FLI=5&API=1" target="_blank">http://www.the-digital-picture.com/...74&SampleComp=0&FLI=5&API=1</a><br>In fact, it is closer to what described here:<br /><a rel="nofollow" href="http://www.photozone.de/canon-eos" target="_blank">http://www.photozone.de/canon-eos</a><br>The photozone said they have QA issues with their 15-85, I suspect I may have the same issue. I can think of 2 possibilities, either:<br />1. I am having a exceptionally bad 15-85 and a exceptionally good 18-55 OR<br />2. the-digital-picture have an exceptionally good 15-85<br>Can anyone tell me they also found that their 18-55 IS is better than their 15-85 so that I know it's not an QA issue cause otherwise I will have to figure what to do with this 15-85?</p><p >Thanks a lot in advance.</p> Link to comment Share on other sites More sharing options...
steve_wagner1 Posted August 23, 2010 Share Posted August 23, 2010 <p>The-Digital-Picture shows the 15-85 as substantially better across the board. At 50mm @5.6 the <a href="http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=675&Camera=474&Sample=0&FLIComp=4&APIComp=1&LensComp=455&CameraComp=474&SampleComp=0&FLI=3&API=2">difference </a>is stark. Given the <a href="http://www.the-digital-picture.com/Help/ISO-12233.aspx">rigorous testing standards</a> I trust his results. I think you can rest assured that you either have a bad copy or your test methodology is somehow a bit off-kilter. Maybe send it back for a new copy.</p> Link to comment Share on other sites More sharing options...
colin carron Posted August 23, 2010 Share Posted August 23, 2010 <p>I don't have a 15-85 to compare with but I have had two 18-55 lenses, one with IS and one without. They both worked really well. One of the problems of these cheap lenses is that 'the good is the enemy of the best'.</p> Link to comment Share on other sites More sharing options...
massimo_foti Posted August 23, 2010 Share Posted August 23, 2010 <p><a href="http://www.lensrentals.com/news/2010.03.06/this-lens-is-soft-and-other-facts">http://www.lensrentals.com/news/2010.03.06/this-lens-is-soft-and-other-facts</a></p> Link to comment Share on other sites More sharing options...
marc_bergman1 Posted August 23, 2010 Share Posted August 23, 2010 <p>To me the 18-55 IS looks sharper all over. </p> <p>How are you focusing? I would use live view and ensure all 4 corners of the chart are sharp.</p> <p>Are you using a steady tripod?</p> <p>If your tests show some de-centering, I would certainly exchange it.</p> <p>Let us know how your testing goes. The 15-85mm is a lens I am looking at.</p> Link to comment Share on other sites More sharing options...
craig_meddaugh Posted August 23, 2010 Share Posted August 23, 2010 <p>Brett, I wouldn't call the-digital-picture.com rigorous. He's only testing a <strong>single</strong> copy of a lens at a <strong>single</strong> focus distance. Given sample to sample variation in lens quality and the simple fact that lens performance varies by focus distance, I wouldn't want to extrapolate too much from his findings. </p> <p>The 18-55IS is a good lens. But so is the 15-85, so you might have a bum copy. Only real way to check is trade it in for another. Good luck</p> Link to comment Share on other sites More sharing options...
paulso Posted August 23, 2010 Author Share Posted August 23, 2010 <p>Hi All, I used a Gitzo carbon fiber tripod with arca swiss ball head, I used live view manually focus the top left corner in 10x magnification. I was suspecting my 15-85 is decentering, but sharpness of the top right corner seems the same as the top left corner.<br> One thing I did not mention is the 18-55 IS is made in Japan but the 15-85 is made in Taiwan.</p> Link to comment Share on other sites More sharing options...
paulso Posted August 23, 2010 Author Share Posted August 23, 2010 <p>sorry, i should say I focus and comparing the top right corner, not the top left corner.</p> Link to comment Share on other sites More sharing options...
PuppyDigs Posted August 24, 2010 Share Posted August 24, 2010 <p>I bought a new EF-s 18-55 IS from Amazon last year, hoping for a cheap sharp lens for my wife's XTi. It was terrible and the left side was really soft. I figured it was a defective copy and returned it. Shit happens. Now my 15-85 IS is one of the sharpest zooms I have owned, and I have owned many. It's also highly flare resistant. THe only bad thing I can say about it is suffers from heavy barrel distortion at the wide end, albeit a couple clicks in DPP and the barreling is corrected.</p> Sometimes the light’s all shining on me. Other times I can barely see. - Robert Hunter Link to comment Share on other sites More sharing options...
paulso Posted August 24, 2010 Author Share Posted August 24, 2010 <p>Thanks everyone for your reply.<br> Would anyone happen to have an image of something lots of black and white details (like a newspaper), took by 15-85 at around 50mm, from a distance of around 4 feet?That will help me do a good comparison of my lens to see if it's a bad copy.<br />Thanks a lot in advance.</p> Link to comment Share on other sites More sharing options...
sanjeet_vaishnav Posted August 25, 2010 Share Posted August 25, 2010 <p>I moved from 18-55 IS to 15-85 and extremely happy with the decision.<br> Originally my copy of 15-85 had issue of slanting horizon. For this I sent it to Canon Service Center at CA and they fixed that part and readjust focusing system and some other glass elements as a part of that. And after that my lens has become supreme. I have used 24-105 L also and 15-85 is equally good, better when it comes to light in front of lens.<br> 15-85 has far far better colors, contrast and sharpness than 18-55</p> Link to comment Share on other sites More sharing options...
paulso Posted August 26, 2010 Author Share Posted August 26, 2010 <p>Hi All,<br /><br />thank you for your reply. I really appreciate it cause it really frustrate me a lot for spending 10 times the money to buy a worst lens.<br /><br />I try the suggestion of some of yours -- shoot distance object, here is the low left corner crop for both lens with F5.6 roughly 50mm range.<br /><br />http://picasaweb.google.com/paul.so/IQ#5509603452870111298<br /><br />http://picasaweb.google.com/paul.so/IQ#5509603452673429810<br /><br />I am not sure with one is sharper, what do you guys think?</p> Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now