I can't get a sharp picture for the life of me!

[jlau]

Camera: 7d


Lens: 17-55mm f/2.8


I bought this lense SO I could shoot in low lighting. The boyfriend thinks its the lense. I think its me. So what am I doing wrong? Some pictures are coming out sharp but very few and inconsistently. The rest are very soft.


I have tried various ranges, shutter speeds, iso's and aperture settings.


Is it because of my low shutter speeds? At 1/50 and 1/20 with apertures of f/5 my boyfriend can get a perfectly sharp shot in similar lighting (5dII with kit lens). Are my hands just not still enough? Am I choosing horrible objects to focus on? I'm getting frustrated because I can't fix what I don't know is wrong.









Two examples of the sharpest I can get...

[Sean Setters]

We need more info:


1) What shutter speed/aperture were you using in those shots?


2) What were you focusing on exactly?


3) Was Image Stabilization (IS)on?


It also might help if you found a way to give us access to the full-sized images so we can see what you're seeing.

[jlau]

I was focusing on the canon lens box, where the words "EFS 17-55MM F/2.8 IS USM" ARE


1/100 sec


f/2.8


iso: 3200


focal length: 55mm


metering mode: center weighted average


yes IS was on


the below is a crop of the area that I was focusing on at 100%


http://img190.imageshack.us/img190/1862/cropr.jpg

[Daniel Browning]

the below is a crop of the area that I was focusing on at 100%


http://img190.imageshack.us/img190/1862/cropr.jpg

Looks like a depth of field and/or focus problem. Your target is not flat. The text on the left is more distant than the text on the right. And you'll notice that the text on the right is sharper, because it is more within the depth of field.


It's probably not a lens problem, but if you want to make sure, try shooting a flat target with liveview at 10X magnification and a tripod.

[jlau]

Hmm...Depth of field and or focus...How do I correct that? If I stop down then I lose light in low light settings...=S

[Daniel Browning]

Hmm...Depth of field and or focus...How do I correct that? If I stop down then I lose light in low light settings...=S

The first thing is to make sure that your focus is dead on. Your image appears to be front-focused slightly.


The second thing is that there is no way to shoot low light with deep depth of field. If you stop down and increase ISO, then you lose the advantage of having a large sensor: the noise will be as bad as a digicam (depending on how far you stop down). You can of course add more light (flash, etc.), but then you're not shooting "low light" anymore. The best solution is to learn how to use the thin DOF to your advantage. For example, if this was a portrait instead of a picture of a box, you would have one eye in focus and one eye out of focus. If you moved to the left, then both eyes would be in focus because they would both be the same distance from you.


Learning to get sharp pictures with thin DOF is difficult, but you'll get better with time.


Good luck!

[jlau]

Thank you so much! That was very helpful!

[Sheiky]

He means that it can be both in this case. It is hard to judge seeing what we see. The thing is: the bigger your aperture (smaller f-number), the less DOF you get. So if you want to shoot indoors in lowlight and still have a nice DOF, you need to take a flash or a longer shuttertime. That's the only ways you can correct it...


Also when there isn't a lot of light present, the AF can be somewhat less accurate as well. I suggest you trysome outdoor photo's to judge the image sharpness. And not only at f2.8, but try a few values. Hope this helps a little





I see some people are faster then me :P





By the way, also try lower iso values. iso 3200 isn't really nice and when you use the incamera highiso noise reduction, your photo's will soften a little. Try iso 100 or so with noise reduction off. Then you can really see the true sharpness of this lens. I love this lens too

[jlau]

I see I see, thank you all for the insight. I will indeed try some outdoor photos at different aperture settings...this is all starting to make some sense.


What I don't understand though is why is my boyfriend (5DII+kit lens) able to capture sharp images at f/5.6, 1/50 shutter speed, iso 2500 without flash in low light, but I can't? When I do similar settings there is little to no light!

[Vince]

Well~ thats difference between Full frame and 1.6x body...... Full frame sensor getting more lights into, am I right?