Canon EF-S 17-85mm f/4-5.6 IS USM vs. Canon EF-S 15-85mm f/3.5-5.6 IS USM Lens

[sungkhum]

I've read the reviews here - and for the 17-85mm it is said getting a blurred background is hard at 85mm at f5.6 - while in the 15-85mm review it says 85mm f5.6 gets great shots...so is the extra money for the 15-85mm worth it or are they the same quality minus a little wider angle?





Thanks,


Nathan

[DavidEccleston]

The 17-85 is much softer, has more chromatic aberration, an older IS system. Check this comparison at 50mm, mouse over the image (or the arrow above it) to see the 17-85 results. And this comparison at 24mm really shows quite a big quality difference.


Also, using the flare comparison tool, the 15-85mm comes out ahead. Finally, the distortion test favours the 15-85mm slightly too.


In other words, the 15-85mm improves every optical aspect of the lens over the 17-85mm.

[sungkhum]

Ok, thanks - that is very helpful!

[Daniel Browning]

for the 17-85mm it is said getting a blurred background is hard at 85mm at f5.6

Yes, it's hard because it wont blur much unless the focus distance is close and the background is far. (Equally true for both lenses.) An 85mm focal length with f/2.8, f/1.8, or f/1.2 would do a lot better at giving you control over background blur. But the only way to get f/2.8 is to trade a lot of zoom range for it.

is the extra money for the 15-85mm worth it or are they the same quality minus a little wider angle?

Definitely worth it, in my opinion.

[neuroanatomist]

so is the extra money for the 15-85mm worth it or are they the same quality minus a little wider angle?

Optically, the 17-85mm is a mid-range consumer zoom, while the 15-85mm is one of the small handful of EF-S lenses that deliver optical quality close or equal to many L-series lenses (the others are the EF-S 17-55mm and the EF-S 10-22mm).

for the 17-85mm it is said getting a blurred background is hard at 85mm at f5.6

As Daniel points out, this is hard with any lens at 85mm f/5.6, not just the 17-85mm. The primary determinant of background/OOF blur is aperture (subject distance and focal length are also factors, but they tend to cancel each other out, e.g. to frame the same shot at a longer focal length, you need to be further away). If you picked out that particular statement because you are looking to use the lens for portraits, that's not an optimal use for the 15-85mm zoom, and you might want to consider the 50mm f/1.4 or 85mm f/1.8 instead.

[mmodica]

Getting nice bokeh won

[Pieter]

Let

[DavidEccleston]

If we

[sungkhum]

That

[neuroanatomist]

I've been eying the 85mm for portraits for a while now.

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It's a great choice! Here are some samples at 85mm on APS-C/1.6x:
[url="http://www.flickr.com/photos/dr_brain/5047278975/in/set-72157624462568231/lightbox/][/url]
Rebel T1i, EF 85mm f/1.8 USM, 1/2000 s, f/1.8, ISO 100


[url="http://www.flickr.com/photos/dr_brain/5047278975/in/set-72157624462568231/lightbox/][/url]
[url="http://www.flickr.com/photos/dr_brain/5036879564/in/set-72157624462568231/lightbox/][/url]
EOS 7D, EF 85mm f/1.2<span class="bbc_color"]<span style="color: #ff0000;"]LII USM, 1/1250 s, f/1.6, ISO 100</div>