I'm frustrated and I need help - 40d focus problem

len20

I've had an unusually large number of soft-focused shots in my last 2-3 gigs. I just bought the 40d in May. I was taking wonderfully sharp photos with it until recently.

I have two lenses: Canon 50 1.8, and Tamron 28-75mm 2.8.

I need a diagnosis of this problem. First is it me or is it my equipment? Maybe I'm daft, but I have a hard time believing that it's me. I'm shooting with shutter speeds above 1/50, and I'm concentrating on keeping my hands quite when I'm shooting.

Second, if it's the equipment then is it the lenses or the camera? I seem to get similarly inconsistent results with both lenses. I know they're not pro lenses, but they should be better than this I would think.

Help me out. I'm really getting frustrated. Here are some photos with the EXIF attached.

1. This is the kind of sharpness (his left eye) that I expect to be consistent with this camera and lenses.


2. The rest show the terrible or soft focus problems with the same EXIF


3.


4.


5.


6.

ziggy53

Hi Len,

You are right in that the first image of this series is wonderfully sharp. I see single pixel focus accuracy and the hair and eyes are just beautifully sharp.

The next two gentlemen show a left-to-right camera blur. At the shutter speeds of 1/100th it is possible to induce this kind of blur in portrait orientation by "mashing down" on the shutter.

Did you feel rushed in these images? Did you practice proper technique of half-pressing the shutter to achieve focus lock and then holding your breath while you gently squeeze through the focus button until exposure?

If each shot does not have that kind of deliberate and careful technique it is possible that you may have inadvertantly caused the blur. The camera is more difficult to hold in the portrait orientation and I've done this same thing myself, usually when I'm feeling pressured for time.

It's worth practicing to see if proper technique can solve the problem.

Another possibility is a loose lens element, that only shows up in portrait orientation. Since the blur I see is in the same direction as the shutter travel, it's possible that the slight slap of the shutter could cause this same type of blur.

The little boy sitting on the floor definitely shows the blur and you can see it clearly in the eye highlights. This shot only has 1/50th and at 60mm requires extremely good technique.

I would have used a flash in all of these images and that would have allowed a shutter speed of 1/250th. It would have also required a matching of the ambient exposure and, at these light values and apertures, that would have probably required a higher ISO to blend the ambient and flash.

For the little girl, the shutter speeds are up and blur is not a problem. The prime focus is on the girl's clothing in the first image, not on her face. It looks like this is the 50mm, f1.8 lens and either the camera chose the clothing because it was an easier focus target or the camera and lens simply missed focus. The 50mm, f1.8 does give me less consistent focus than the EF 50mm, f1.4 USM and I have switched over to that lens mostly for that reason.

I can't tell whether you used a single focus point or not but this really should have had a single point focus selected and then use the focus dot closest to her left eye, which might have required a little bit of focus and recompose as well. f4 might have been a better choice just because of how close you were to the subject.

The final image of the little girl shows prime focus on her nose, which is also central to the image. Her eyes are only slightly soft and I think both local and global USM could recover this image pretty easily.

The lighting on the final image is also a little flat and some careful contrast adjustment, probably using Curves, could add some "pop" to the image.

len20

Ziggy,

Awesome. Thank you for your response. It sounds like I've got some technique issues to work on. This is better news than an equipment problem since it requires no money and more time with my camera rather than being without it while it's repaired.

I want to say that I was concentrating on squeezing the shutter button gently after focus, but the images don't lie. If that's what you see, that's what I've got to work on. I am using a single center point focus, which requires me to recompose. Perhaps I'm not steadying the camera in that motion.

I've also been using the AI Focus mode rather than One Shot auto focus. Would that give me problems? I shoot a lot of kids, so I was hoping that that focus mode would help me prevent the subject from moving out of the focal plane when I'm using a wide aperture.

Last thing, the photographer with whom I shot the wedding yesterday suggested that I use the back focus button instead of depressing the shutter button halfway to focus. What do you think?

Thanks again for your help!

NeilL

ziggy53 wrote:

Hi Len,

You are right in that the first image of this series is wonderfully sharp. I see single pixel focus accuracy and the hair and eyes are just beautifully sharp.

The next two gentlemen show a left-to-right camera blur. At the shutter speeds of 1/100th it is possible to induce this kind of blur in portrait orientation by "mashing down" on the shutter.

Did you feel rushed in these images? Did you practice proper technique of half-pressing the shutter to achieve focus lock and then holding your breath while you gently squeeze through the focus button until exposure?

If each shot does not have that kind of deliberate and careful technique it is possible that you may have inadvertantly caused the blur. The camera is more difficult to hold in the portrait orientation and I've done this same thing myself, usually when I'm feeling pressured for time.

It's worth practicing to see if proper technique can solve the problem.

Another possibility is a loose lens element, that only shows up in portrait orientation. Since the blur I see is in the same direction as the shutter travel, it's possible that the slight slap of the shutter could cause this same type of blur.

The little boy sitting on the floor definitely shows the blur and you can see it clearly in the eye highlights. This shot only has 1/50th and at 60mm requires extremely good technique.

I would have used a flash in all of these images and that would have allowed a shutter speed of 1/250th. It would have also required a matching of the ambient exposure and, at these light values and apertures, that would have probably required a higher ISO to blend the ambient and flash.

For the little girl, the shutter speeds are up and blur is not a problem. The prime focus is on the girl's clothing in the first image, not on her face. It looks like this is the 50mm, f1.8 lens and either the camera chose the clothing because it was an easier focus target or the camera and lens simply missed focus. The 50mm, f1.8 does give me less consistent focus than the EF 50mm, f1.4 USM and I have switched over to that lens mostly for that reason.

I can't tell whether you used a single focus point or not but this really should have had a single point focus selected and then use the focus dot closest to her left eye, which might have required a little bit of focus and recompose as well. f4 might have been a better choice just because of how close you were to the subject.

The final image of the little girl shows prime focus on her nose, which is also central to the image. Her eyes are only slightly soft and I think both local and global USM could recover this image pretty easily.

The lighting on the final image is also a little flat and some careful contrast adjustment, probably using Curves, could add some "pop" to the image.

Very nice, Ziggy! Thanks!

Neil

ziggy53

len20 wrote:

...

I've also been using the AI Focus mode rather than One Shot auto focus. Would that give me problems? I shoot a lot of kids, so I was hoping that that focus mode would help me prevent the subject from moving out of the focal plane when I'm using a wide aperture.

Last thing, the photographer with whom I shot the wedding yesterday suggested that I use the back focus button instead of depressing the shutter button halfway to focus. What do you think?

Thanks again for your help!

I find that AI focus works best in sequences and short bursts. It is not unusual for the first image to be soft and then subsequent images in the burst tend to hold focus pretty well. If you shoot single images I think that one-shot mode works better, as long as the subject isn't moving too quickly towards or away from your position.

You still won't get perfect images every time, but you can count on a fairly good keeper rate. Neither of those lenses is going to be great in an action situation. A true action/sports lens might be required for an even better performance but the Tamron should be pretty good except in the fastest action.

The 50mm, f1.8 is not really designed for action and you have to practice with that lens to get the best from it. I found with that lens I had to half-depress the shutter button sometimes several times to get it to finally "look" sharp. I often used manual focus with focus confirmation for better results.

I honestly don't know if the AF-On button will help or not. Surely something to try. Note that you can change the action of that button with a custom function so you might try different combinations.

pathfinder

The 28-75 f2.8 Tamron can be exquisitely sharp, but it also can be slower to focus than many OEM lenses. I like that lens, I stlll have mine, and use it quite a bit, but for truly pixel sharp images, it does require precise focusing with a single AF point properly placed in Single Shot mode, and good shutter release technique.

Like Ziggy said, using flash will help images to be much sharper, due to the faster effective exposure duration.

len20

pathfinder wrote:

The 28-75 f2.8 Tamron can be exquisitely sharp, but it also can be slower to focus than many OEM lenses. I like that lens, I stlll have mine, and use it quite a bit, but for truly pixel sharp images, it does require precise focusing with a single AF point properly placed in Single Shot mode, and good shutter release technique.

Like Ziggy said, using flash will help images to be much sharper, due to the faster effective exposure duration.

Thank you for your input, Pathfinder. That restores my confidence in that lens.