Focus issue with lens?

[fstopper89]

I have the Canon 35mm f/2.0 prime lens. It’s an older lens, but I have used it a lot for outdoor portraits over the summer and it always seemed very sharp. More recently I have used it for a few still-life kind of photos indoors and it seems to be having focusing problems. I am quite disappointed. I’m not sure if it’s human error on my part or if something may be wrong with the lens. I am always sure to keep the shutter speed fast enough for the lower light situations. I took some test shots today. It almost seems to be back-focusing. Or, it seems as if I select an AF point and it focuses on a different part of the image. Any thoughts?

I made a few shots of this scene and all of them seemed slightly out of focus: http://www.flickr.com/photos/roxanne_elise_photography/8569852185/in/photostream

Then I shot the same scene with my other lens, a Sigma 70-200. Seemed to not have any issues with focus. http://www.flickr.com/photos/roxanne_elise_photography/8569828653/in/photostream

Took this quick shot and the camera seemed to focus on an entirely different part of the image. I was very steady and did not focus-and-recompose. http://www.flickr.com/photos/roxanne_elise_photography/8570939320/in/photostream

My Sigma did a much better job focusing here even at a further distance. http://www.flickr.com/photos/roxanne_elise_photography/8570933826/in/photostream

So I tried some experiments putting the same 35mm lens on both my 5D Mark II and my Rebel T2i and used constant settings. If you go through this series of images, you’ll see the lens behaved similarly in both cameras, so the problem couldn’t have been the camera body. http://www.flickr.com/photos/roxanne_elise_photography/8570913386/in/photostream

There may be no clear-cut answers or insights to this problem. Like I said, I always was able to get nice, sharp photos in my outdoor portraits. It’s a fast lens, even faster than the telephoto Sigma, but the Sigma seemed to produce much better images in low light. Could something be wrong with the lens or the AF points?

 

[fstopper89]

And I just read some reviews on it, and a few people said it’s “weak” at 2.0 and much sharper at 2.8… which may be illustrated by the reason my series of close-ups of the crochet hats seemed nice and sharp at 2.8 while the images shot at 2.0 were awful… hmm.

[stef]

The edges are certainly OOF, but very few 35mm lenses can handle edges well. Even canon’s 35L sucks in the corners at wide apertures. Sucks bad.

 

Is there actually a question here? You’re the one that will know if there’s a focus issue. They’re pretty easy to recognize… if a lens is suddenly no longer sharp at the focus point when it used to be, then something is wrong. Compare it to older pics taken with that lens.

 

 

[dont.care]

try micro adjustment, 5d II really aint the best camera for it’s AF system.. Send it to Canon and have them adjust the lens to camera, or print out a chart, lean it on something, teather the camera and shoot the center of the chart and adjust the micro adjustment front or back until the top and bottom evenly drop out of focus..

 

[cameraclicker]

Your 5D #1 shows shallow DOF.  DOF will affect your indoor shots more because usually outdoor shots have more distant subjects.

The arc is equidistant from the convergence of the lines.  The red horizontal line is the centre line.  The red vertical line is tangent to the arc and vertical, perpendicular to the horizontal line.  The blue lines represent angle of view of a long lens and the green lines represent angle of view of a short lens.  It illustrates short lenses have more to deal with.

To test focus, you should lock the camera on a tripod and shoot a target.  When you recompose, the camera still indicates the focus point used to obtain focus, but not where focus was attained on your target.  If DOF is shallow, it is easy to move the camera forward or back slightly while recomposing.

 

If you think the lens is not focusing properly, send/take it to Canon.  They have the equipment to check and fix it.

 

Most lenses are sharpest around f/8.

 

[dont.care]

If it does it with every lens you have, even the ones that worked ‘previously’, I’d assume it’s a camera problem.. If it’s lens specific, I’d assume it’s a front or rear focusing issue. ..

Better to experiment before you spend $$

http://regex.info/blog/photo-tech/focus-chart

p5

[dont.care]

You want to clear that issue right up? buy this: http://www.adorama.com/CA3514AFU.html?gclid=COLckY_biLYCFQ-znQodMxEAfQ

[fstopper89]

Thank you everyone for your input. And to the person who mentioned microadjustment… that is like calibrating a lens to a particular camera, right? I know the 5DII can do that, but I do not know how. I heard about it before and didn’t even think about that.

[dont.care]

micro adjustment = google it

or you can try this : http://www.reikan.co.uk/focalweb/

 

microadjusting is stupid easy. that link i posted in the previous post pretty much tells you how to do it

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