Canon 18-55 IS better IQ than 15-85

[paulso]

<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>

 

[steve_wagner1]

<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>

[colin carron]

<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>

[massimo_foti]

<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>

[marc_bergman1]

<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>

[craig_meddaugh]

<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>

[paulso]

<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>

[paulso]

<p>sorry, i should say I focus and comparing the top right corner, not the top left corner.</p>

[PuppyDigs]

<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>

[paulso]

<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>

[sanjeet_vaishnav]

<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>

[paulso]

<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>