Sharpeness of EF-S 15-85mm: Should I be disappointed?

Should my new EF-S 15-85mm produce sharper pictures?

The first additional lens I bought for my Rebel XSi was the 50mm 1.4. Compared with the stock lens (EF-S 17-55 mm) I was blown away. Especially the difference in sharpness was amazing for me. Suddenly, my pics were crisp and clear.

This motivated me to upgrade the stock lens. The 50 mm is somewhat limited as a all-purpose lens. After quite some research I got the relatively new EF-S 15-85 mm. Overall I am very happy with it.

Nevertheless, when I compared the sharpness of my sample pictures then the difference between the stock lens and the new zoom lens is not that large. Sharpness is definitely better. However, comparing all three lenses, the new EF-S 15-85 is somewhere in the middle between the two. The 50 mm is still substantially sharper then the new zoom lens.

I was hopping for something that is closer to the sharpness of the 50mm. Should I be disappointed? Is that what you would expect? Or would you say that this is defective?

I am a complete newbie, not only here on the site but also to photography - so please be gentle...

Post some pics with EXIF data.

Fixed focal length lenses (prime lenses) like the 50mm are almost always sharper than zooms; some photographers completely avoid zoom lenses (even the super-dooper expensive ones) for that very reason. It depends on each specific copy of the lens to an extent, which means that you may have an exceptionally sharp copy of the 50mm 1.4. Prime lenses are known for their sharpness especially when stopped down to an aperture of f/4 and above, at which point they have no competition from (most) zoom lenses.

Raw? Filters? EXIF?

muusers wrote in post #10582336
Raw? Filters? EXIF?

+1, also what camera are you using...Could be possible that you need to dial in a bit of MA because its not spot on focusing

But in general one sad weakness of the 15-85 seems to be a bit of copy variation....

Primes are usually MUCH, MUCH sharper than zooms! They are great on ONE focal length. There are some zooms that have prime-like IQ, such as new 70-200mm f/2.8 II, but those zooms are pretty expensive.

I'm assuming your stock lens was a 18-55 not 17-55.....

The sharpness of the zoom is normal. Primes will produce much sharper images than the zoom. But primes fail to capture some shots a zoom can take in certain situations.

KenjiS wrote in post #10582411
+1, also what camera are you using...Could be possible that you need to dial in a bit of MA because its not spot on focusing

But in general one sad weakness of the 15-85 seems to be a bit of copy variation....

The OP has an XSi/450D, so no go on the MA unfortunately.

I'm not seeing any real lack of sharpness with the 15-85, but it probably is a tad soft wide open. Are your photos noticeably softer than this one? Post some examples and camera settings.

O.k. lets try to upload some pics.
* No filters
* Crop was done on the RAW files and represents a 100% resolution
* Camera: Rebel XSi
* I just used the automatics (P) to choose the correct settings on the camera.
* The forest is about 1 km away
Let me know if there is a better way to go.

Here's the stock lens (EF-S, 18-55):

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The next two photos are from
1. EF-S 15-85 (left)
2. EF 50mm (right)

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I don't think it's the lenses.

What is the focal point supposed to be in those pics?

Why not use manual mode and shoot them all the same aperture, speed, iso, etc?

Try spot focusing instead of letting the camera choose/guess what to focus on.

I always tried to use exactly the same spot to focus on.
Still, the bottom line I take from this thread so far: Try again! This time with:
* Spot focus, to make sure that the focus is the same
* Manual mode

Thanks guys.