Settle this bet please...

[Hommie]

Do this:

 

[tofu_girl]

I'm going to take some pics of a ruler when I get home and see if there's any frontal focus problems at 1.8. It seems to be a general problem for the 50 f1.8 with a lot of ppl in the forums and not something I picked up on when doing research for this lens. I guess I shouldn't complain too much since this lens is pretty inexpensive...

thanks to those who replied.

 

[Hommie]

Mine is taken on a canon 50mm at F1.4. Focus point at the word 'Canon'.

 

[freelancer]

I'm going to take some pics of a ruler when I get home and see if there's any frontal focus problems at 1.8. It seems to be a general problem for the 50 f1.8 with a lot of ppl in the forums and not something I picked up on when doing research for this lens.

Front/back focus testing requires some understanding of the focal plane and DOF. At F1.8, you need to be around 7 to 8 feet away from the target to get some decent DOF, anything too near the camera will result in a DOF so thin and added to your dSLR focus tolerance, you may not get good enough test results. If you are using a Canon 300D/350D, the AF accuracy is within depth of field as specified by Canon. On the pro cameras, the AF accuracy is within one third depth of field.

The other point to note is to have sufficient ambient lights when you do your testing. If you like, let me have a look at your test results. Have seen a number of 50/1.8 with front focus issues but when we did a more controlled test, it invariably for most of the lens copies, are issues from the test setup and we find the lens to be within the Canon specs.

 

[Stoned]

Well firstly I'd like to say that it's pretty rude to respond to someone who's just trying to help(nightwolf) in such a curt manner. The thread after all is about something so trivial as a bet over lens sharpness(have you too much free time?) so there isn't really any reason for people to respond other than out of kindness to indulge your trivial thread. Being on a forum, please treat other members with basic respect.

Back to your question.
After giving both shots the once over, it appears that in the f1.8 image the material just to the top right is sharper than the logo. Obvious front-focusing. It appears to be so in the f2.8 image as well except that it appears sharper due to the increased DOF. Send your lens for calibration.

 

[Jed]

- In both photos, the logo is indeed at the center (roughly near the left armpit of the guy).

Not doubting you, but I must be looking at the wrong pictures, or doing something wrong (not my computer I'm using, so entirely possible!).

To me, the main Crumpler logo, which I assume was the point of focus, is not in the middle of the frame. Can anyone else verify?

Which then leads to the question of, if the logo is not in the centre but the centre focusing point was used, how did you focus on the logo? Focusing, locking and recomposing does NOT afford accurate focus.

Aside from that,

Actually IMO neither of those two shots are properly focused. Neither logo is really sharp, truth be told, and the more limited DOF at f1.8 just makes it look worse. If DOF were the only problem, the background should be less of a worr than the foreground. The background here seems to drop away at an alarming rate. Also, the subject used isn't unfortunately the best test subject - it's composed of puffy white lines and lacks fine detail.