17-85MM IS Lens vs 28-135/IS Lens

[imran_ahmed]

I had a 20D and the kit lens 18-55 mm was a real 'dog' compared to Nikon D70

kit lens. So I sold 20d and bought EOS 5D earlier this year. In an exchange

deal I also aquired a 350D and bough the 17-85 IS lens for it. I have used the

17-85 on 350d and older 28-135 on 5D. Now contrary to me expectation the older

lens is sharper. Is it due to lens itself or more pixels on 5D ?

[dogbert]

My understanding is the bigger the format the less sharp the lenses need to be to produce a sharp image - this is due to less magnification required to produce any given image size. Photozone suggests the 17-85 is sharper than the 28-135, but my guess is that the larger format of the 5D is sufficient to offset this.

[mormegil]

The test would be to put both lenses on the 350D and see which is the sharper of the two.

 

It could be you got an extra sharp 28-135 or not as sharp 17-85.

 

My old 17-85 (which I sold when I went 5D) was about as sharp as my 24-105 (which I consider sharp).

 

You could consider yourself lucky that you have a sharp 28-135.

[yakim_peled1]

>> Now contrary to me expectation the older lens is sharper.

 

1. Expectations can be deceiving.

 

2. Both are considered good consumer zooms.

 

3. If you see this then it must be true, at least for the samples you have.

 

Happy shooting,

Yakim.

 

 

P.S. No 24-105/4 in your future?

[carl_weller]

Hey Yakim,

 

did you get the 24-105 in the end?

 

Just wanting to compare thoughts, mine has made me wonder if I really need many of the

lenses that now seem to sit in the closet unused...

 

regards,

[yakim_peled1]

No.

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00Hpmp&tag=

 

Happy shooting,

Yakim.

[PuppyDigs]

"My understanding is the bigger the format the less sharp the lenses need to be to

produce a sharp image - this is due to less magnification required to produce any given

image size. "

 

I guess if you only made 5 x 7 prints this might be true. However, my real ife experience

has been the exact opposite. The 5D has been extremely revealing of lens defects

compared to my 20D and film cameras. I had to sell off half my lens collection after buying

a 5D and replace with L series zooms and primes. Even my EF 50 1.4 USM and 50 1.8 (MK

I) sucked on my 5D. Of course I enjoy viewing images full screen on my Cinema Display

and making 12 x 18 prints.

[anson_ko]

Is that bad? I am getting the 5D later and will test it out. I have some L lenses and non L lenses. Any pics that shows the difference?

[matthias_meixner2]

Due to the larger sensor pixel density on the 5D is lower than that of the 350D. Therefore, while it may be the case that images taken using the 28-135 on the 350D are less sharp than those taken with the 17-85 on the 350D, while images taken with the 28-135 on the 5D are sharper than those taken with the 17-85 on the 350D.

[francis_beaumont1]

It may have been my copy, but the 28-135mm lens on a Canon 400D was a disaster. It was really really soft. The 17-85mm on my 20D was acceptable but not as sharp as the cheapo kit lens.