Index  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Register to forums    Log in

 
FORUMS Canon Cameras, Lenses & Accessories Canon EF and EF-S Lenses
Thread started 05 Feb 2007 (Monday) 20:50
Prev/next
sponsored links
(this ad will go away when you log in as registered member)

Replacing Canon 17-85 with Sigma 17-70, but is it misfocusing?

 
pythagpython
Member
148 posts
Joined Dec 2006

New York City, NY
MORE INFO

Hey guys,

I decided to get a Sigma 17-70mm to replace my Canon 17-85. It turns out that it isn't so much of a party as it should be. A little background:

I have had the Canon 17-85 for a little over a month now and want to get rid of it because of horrific distortion, CA and OK picture quality. This is especially since most of my photos are taken at 17mm.

So I got the Sigma 17-70 today and was really excited, but when I tested it out, it has been giving me some stress. Pictures taken at 70mm look really bad, as if they are out of focus. It looks like there is some "shadowing". Is there something wrong with it? Please help me out.

Here are some examples:

Sigma @70/4.5

HOSTED PHOTO
please log in to view hosted photos in full size.

Canon @ 70/5.6

HOSTED PHOTO
please log in to view hosted photos in full size.
Feb 05, 2007 20:50

Canon Digital Rebel XT | Canon 70-200 f/4 L | Canon 50 1.8 | Tamron 17-50/2.8 | Sold (Canon 17-85 IS, Canon 28-135 IS)

LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as registered member)
pythagpython
THREAD ­ STARTER
Member
148 posts
Joined Dec 2006

New York City, NY
MORE INFO

Here is another (worse) case of this:

Sigma @70/4.5

HOSTED PHOTO
please log in to view hosted photos in full size.

Canon @ 70/5.6
HOSTED PHOTO
please log in to view hosted photos in full size.
Feb 05, 2007 20:54

Canon Digital Rebel XT | Canon 70-200 f/4 L | Canon 50 1.8 | Tamron 17-50/2.8 | Sold (Canon 17-85 IS, Canon 28-135 IS)

LOG IN TO REPLY
pythagpython
THREAD ­ STARTER
Member
148 posts
Joined Dec 2006

New York City, NY
MORE INFO

Bump, any suggestions?

Feb 05, 2007 21:25

Canon Digital Rebel XT | Canon 70-200 f/4 L | Canon 50 1.8 | Tamron 17-50/2.8 | Sold (Canon 17-85 IS, Canon 28-135 IS)

LOG IN TO REPLY
lungdoc
Goldmember
lungdoc's Avatar
2,101 posts

Joined May 2006

St. Catharines, Ontario Canada
MORE INFO

Exif data? Presume tripod used? If slow shutter speed it could be the IS helping the Canon look better. You Might want to try a focus test that's more precise/standardized such as described here http://focustestchart.​com/chart.htmlexternal link
Some also use three AA batteries lined up 3/4'' apart focusing on the middle one.

I guess in the end if it really is off you need to return it if new or repair it if used.

Good luck.

Feb 05, 2007 21:37

Mark
My Smugmugexternal link Eos 7D, Canon G1X II, Canon 15-85 IS, Canon 17-85 IS, Sigma 100-300 EX IF HSM, Canon 50mm 1.8, Canon 85mm 1.8, Canon 100mm 2.8 Macro, Sigma 50-150 2.8, Sigma 1.4 EX DG , Sigma 24-70 F2.8 DG Macro, Canon EF-S 10-22, Canon 430EX,

LOG IN TO REPLY
Rumrunner
Goldmember
Rumrunner's Avatar
1,865 posts

Joined Jun 2006

El Paso, Texas
MORE INFO

Are the photos cropped?

Feb 05, 2007 22:05

Gear List

LOG IN TO REPLY
pythagpython
THREAD ­ STARTER
Member
148 posts
Joined Dec 2006

New York City, NY
MORE INFO

The photos are cropped 100%, taken on a tripod with remote.

Feb 05, 2007 22:10

Canon Digital Rebel XT | Canon 70-200 f/4 L | Canon 50 1.8 | Tamron 17-50/2.8 | Sold (Canon 17-85 IS, Canon 28-135 IS)

LOG IN TO REPLY
pythagpython
THREAD ­ STARTER
Member
148 posts
Joined Dec 2006

New York City, NY
MORE INFO

Oh, and IS was turned OFF on the tripod for the canon.

Feb 05, 2007 22:10

Canon Digital Rebel XT | Canon 70-200 f/4 L | Canon 50 1.8 | Tamron 17-50/2.8 | Sold (Canon 17-85 IS, Canon 28-135 IS)

LOG IN TO REPLY
pythagpython
THREAD ­ STARTER
Member
148 posts
Joined Dec 2006

New York City, NY
MORE INFO

Ok, did the focus chart and it is misfocusing. I think I will have to send it back. What do you guys think? I just wish that I could be loving this lens.

HOSTED PHOTO
please log in to view hosted photos in full size.
Feb 05, 2007 23:21 as a reply to pythagpython's post 1 hour earlier.

Canon Digital Rebel XT | Canon 70-200 f/4 L | Canon 50 1.8 | Tamron 17-50/2.8 | Sold (Canon 17-85 IS, Canon 28-135 IS)

LOG IN TO REPLY
pythagpython
THREAD ­ STARTER
Member
148 posts
Joined Dec 2006

New York City, NY
MORE INFO

This is as opposed to the canon, which apparently focuses fine. Sigh... what awful luck...

HOSTED PHOTO
please log in to view hosted photos in full size.
Feb 05, 2007 23:25 as a reply to pythagpython's post 4 minutes earlier.

Canon Digital Rebel XT | Canon 70-200 f/4 L | Canon 50 1.8 | Tamron 17-50/2.8 | Sold (Canon 17-85 IS, Canon 28-135 IS)

LOG IN TO REPLY
pythagpython
THREAD ­ STARTER
Member
148 posts
Joined Dec 2006

New York City, NY
MORE INFO

Ok, so what do you call this? Back focusing? This really stings Sigma's reputation in my mind. I mean, really, what are the chances that my first Sigma lens will have a defect!? Should I give them another try?

Oh yeah, both were taken on tripods, 100% crop.

Feb 05, 2007 23:28

Canon Digital Rebel XT | Canon 70-200 f/4 L | Canon 50 1.8 | Tamron 17-50/2.8 | Sold (Canon 17-85 IS, Canon 28-135 IS)

LOG IN TO REPLY
gcogger
Goldmember
2,554 posts
Joined Mar 2003

Southampton, UK
MORE INFO

I had exactly the same thing with my first copy of this lens. The second one is better (although I don't think it's perfect).

Feb 06, 2007 02:34

Graeme
My galleriesexternal link

LOG IN TO REPLY
Annabel ­ Doskey
Member
Annabel Doskey's Avatar
41 posts

Joined Jan 2007
MORE INFO
banned

f/4.5 @70mm on this lens is wide open for that extension. Try reshooting the focusing chart at f/5.6 and then f/8.

Feb 06, 2007 04:49 as a reply to gcogger's post 2 hours earlier.



LOG IN TO REPLY
Ospi
Goldmember
Ospi's Avatar
1,015 posts

Joined Jun 2005

Brisbane, Australia
MORE INFO

Bah looks like im back focusing big time. Now the question is, where do you send it to get repaired?

Feb 06, 2007 05:53

Canon EOS 40D
Canon 10-22mm f/3.5-4.5 | | Canon 70-200 f/4L IS | Sigma 17-70mm f/2.8-4.5 DC | Sigma 50mm f/1.4 DG HSM | Canon 580EX II
Full Gear |Galleryexternal link


LOG IN TO REPLY
pythagpython
THREAD ­ STARTER
Member
148 posts
Joined Dec 2006

New York City, NY
MORE INFO

Ospi wrote in post #2663565external link
Bah looks like im back focusing big time. Now the question is, where do you send it to get repaired?

It seems like this is a common problem with this lens. WTF is wrong with Sigma's QC?! :mad: I think I'm going to send it in for a replacement.

Feb 06, 2007 06:40

Canon Digital Rebel XT | Canon 70-200 f/4 L | Canon 50 1.8 | Tamron 17-50/2.8 | Sold (Canon 17-85 IS, Canon 28-135 IS)

LOG IN TO REPLY
Ospi
Goldmember
Ospi's Avatar
1,015 posts

Joined Jun 2005

Brisbane, Australia
MORE INFO

pythagpython wrote in post #2663693external link
It seems like this is a common problem with this lens. WTF is wrong with Sigma's QC?! :mad: I think I'm going to send it in for a replacement.

Yeah QC does seem to be a bit of a problem, then again i think they would rather risk not being as precise with their lenses in order to make them cheaper and rollout faster and take the hit with the 5% odd focusing problem.

though when i spend $400 i like to think its going to arrive 100% perfect.

Feb 06, 2007 06:43

Canon EOS 40D
Canon 10-22mm f/3.5-4.5 | | Canon 70-200 f/4L IS | Sigma 17-70mm f/2.8-4.5 DC | Sigma 50mm f/1.4 DG HSM | Canon 580EX II
Full Gear |Galleryexternal link


LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as registered member)

4,332 views & 0 likes for this thread
Replacing Canon 17-85 with Sigma 17-70, but is it misfocusing?
FORUMS Canon Cameras, Lenses & Accessories Canon EF and EF-S Lenses

NOT A MEMBER YET? CLICK HERE TO REGISTER TO THE FORUMS
Registered members get all the features: search, more forums, private messaging, thread follow, notifications, own gallery, own reviews...




Send feedback to staff    •   Jump to forum...    •   Rules    •   Index    •   New posts    •   RTAT    •   'Best of'    •   Gallery    •   Gear    •   Reviews    •   Polls

COOKIES DISCLAIMER: By using this site you agree that some cookies will be stored on your browser. For unlogged users we store one session id cookie. For registered members we store (in addition to login session cookie) only cookies that are essential for required functionality. We do not store any personal tracking data in cookies or other browsers' data storage methods.

POWERED BY AMASS 1.33version 1.33
made in Finland
by Pekka Saarinen
for photography-on-the.net
Spent 0.00235 for 4 database queries.
PAGE COMPLETED IN 0.03s
Latest registered member is kimtw3035
676 guests, 488 members online
Simultaneous users record so far is 5175, that happened on Jun 16, 2015