04-21-2011, 08:33 AM
Hi everyone,
I have a question, and I hope you can help me find an answer.
I was comparing the MTF results published on this site between the old Sigma 17-70 f/2.8-4.5 and the new f/2.8-4 OS HSM. The basic problem is that I'm not sure how to interpret them, because tests were performed on very different cameras, which are 350D and 50D.
Basing on the areas reached by the graphes (good, very good, excellent) one could assume the old model is remarkably sharper, but again, I don't know if the camera change has to be taken into account somehow. It would not be the first time that a new model featuring image stabilization proves to be less sharp than the previous non-stabilized model, so I would not be very surprised. Other optical issues can easily be corrected via software, so my biggest care are image quality and resolution.
I own the old 17-70 and I'm considering an upgrade to the new version or to the Canon 15-85. To be sincere, I'm quite skeptical about my potential return on investment; my lens is tack-sharp at f/4.5-5 on the whole focal range, but since I use it as a travel and all-rounder lens, stabilization and/or wider range look attractive to me. I think the Canon is all-in-all better, but it's damn expensive and therefore I wonder if those advantages would be worth such an expense.
Thanks for any help/comment <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />
I have a question, and I hope you can help me find an answer.
I was comparing the MTF results published on this site between the old Sigma 17-70 f/2.8-4.5 and the new f/2.8-4 OS HSM. The basic problem is that I'm not sure how to interpret them, because tests were performed on very different cameras, which are 350D and 50D.
Basing on the areas reached by the graphes (good, very good, excellent) one could assume the old model is remarkably sharper, but again, I don't know if the camera change has to be taken into account somehow. It would not be the first time that a new model featuring image stabilization proves to be less sharp than the previous non-stabilized model, so I would not be very surprised. Other optical issues can easily be corrected via software, so my biggest care are image quality and resolution.
I own the old 17-70 and I'm considering an upgrade to the new version or to the Canon 15-85. To be sincere, I'm quite skeptical about my potential return on investment; my lens is tack-sharp at f/4.5-5 on the whole focal range, but since I use it as a travel and all-rounder lens, stabilization and/or wider range look attractive to me. I think the Canon is all-in-all better, but it's damn expensive and therefore I wonder if those advantages would be worth such an expense.
Thanks for any help/comment <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />