Why is this blurry?

[sigler]

Hi,

Why are these pictures blurry on the left side but not on the right? Look at the kids faces. I'm using a Canon 10D with the 28-135 USM lens.

I'm sending my camera to Canon due to a HORRIBLE dust problem on the sensor...should I send the lens too?


This was one 60th, F 4.5 (Trying to avoid the dust appearing on the pic)

http://homepage.mac.com/rsigler/blurry1.jpg%20

This one was shot a 180th, F6.7
http://homepage.mac.com/rsigler/blurry2.jpg%20

Thanks,

Rob

[lightandlife]

Very interesting shots.

Just a wild conjecture.
In the second pic, f11 or f16, might have given you a sharper image.

With a wide aperture and a relatively lower quality lens, corners would be blurred. Both shots show this effect.

In the first pic, the plane of camera and the imaginary line of people were not parallel. The right side was closer to you (as in _\ rather than = ).

If you had used central focusing point only, and aimed at the center of the pic, then the first pic might be a sign of front focusing. In the second shot, the left side is closer to you (as in /_). A sharper image on the right side suggests a possible backfocusing. 10D can be either front focusing or back focusing, but not both.

Take more pics on a tripod using a remote to eliminate camera shakes. If this tendency continues, it could mean that the sensor plane is not parallel to the viewfinder plane (as if you are using a tilt lens).

[pwagner]

I don't think that using a wide aperature will reduce the dust problem. I don't see dust at this size reduction, but I'll trust it is there. If you have only one lens and put it one just once and never removed it, make sure you tell Canon that and they will hopefully not try to charge you for sensor cleaning (perhaps you got a repackaged camera return and the previous owner got the dust in there). The more daring dSLR owners usually clean their own sensor, but if your camera came dirty you are entitled (in my opinion) to having Canon be clean when you bought it new.

1/60 of a second should be fast enough... but just barely. I suspect you are using the camera on the basic "green" setting of the mode dial. That means the camera uses all the focus sensors and might have chosen poorly. Unfortunately, to set the center-only focus point (or, better still for the first shot, all the horizontal points), you will need to use one of the "creative" modes.

The 10D and 28-135 is a great set of equipment. However, the 10D is a very serious camera body that requires some training, practice, and experience to get great results.

[RichardtheSane]

I agree about the aperture, you would need to be at a minimum of F11 to get sharpness throughout. Also I suspect you were at 28mm for the first shot at least. With the lens at it's widest, and the aperture also at it's widest the lens you have is at it's softest.
Add to that the fairly shallow dpeth of field at the wide aperture then that could explain the problem.

Will you get the chance to do the shots again?

[photography By Evangelos]

You are not the only one who has problems with this lens. I also have shots that are not in focus you distance and you F-stop should have been ok with this lens. How far away were you? What were you ISO set at? Are you using the center A/F point? I soot weddings and love this lens how ever it is not 100% in A/F with my 2 10D cameras I often am in low light and use the lens at F5.6 to 4.5 at 60 of a sec with IS on and center focusing point selected in one shot mode and often get the middle of the frame out of focus about 35% of the time at 135mm and 50mm not sure why the center is out of A/F and the backgrounds are in A/F on both 10D's is it driving me nutty. I should have the center in sharp A/F I am sending both cameras in to canon this week with my 28-70 L,17-35L,28-135IS,851.8 all have problems with the 10D.

[lightandlife]

For 10D to have a focus problem, it has to be front or back focusing consistently on a tripod. (This problem without a tripod could mean consistent user habit or camera shakes between the time a shot is composed and that when the shutter is released. This does not apply to you, but I am saying this for others who have similar problems.)

If it front focuses roughly 50% of the time, and back focuses the other 50% of the time, I don't know. Since you are a professional, I would rule out camera shakes. Me thinks: 50-50 means it is not a 10D problem. Perhaps Canon repairshop will determine the cause. I may be wrong due to inexperience.

[KennyG]

I have responded to this in another thread. The 28-135 has been known to have soft focus at the left side. You should send the lens to Canon and ask them to re-align it. Changing apertures is just masking the problem.

You will have to get to grips with doing your own sensor cleaning. Use the blower method as per the manual, which will clear all but the worst. If I sent mine back every time it needed cleaning it would spend more time with Canon than with me.

[sigler]

I just ordered some pec-pads and the "solution." (The name escapes me)

Thanks for all of the advice.

BTW...I did get a few pics of the full group that look ok...not great, but ok.