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12/25/2007 09:05:42 PM · #1 |
Merry Christmas everyone!
The other day my family and I headed out to the tennis courts to take some christmas photos. For the photos I used my 50mm 1.8 lens. To start, I put the camera on aperture priority mode and set the aperture to f2.0. We took some shots, which looked good on the viewfinder. I know that the depth of field is pretty small with f2.0, so I manually selected an auto focus point and put that point on one of us. When I got home, I noticed that zoomed out the photos looked okay, but when you cropped the photos you could see that a lot of times, the auto focus had been a bit off. In this sample photo, it looks like it was focusing on the net rather than on us.
[thumb]//www.dpchallenge.com/image.php?IMAGE_ID=625722[/thumb]
And here is a close crop of the same image
[thumb]//www.dpchallenge.com/image.php?IMAGE_ID=625721[/thumb]
I guess my question is, do you think that the DOF given by f2.0 is just too small for this job, or was it a focusing issue?
Message edited by author 2007-12-25 21:09:42. |
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12/25/2007 09:07:20 PM · #2 |
fixy linky :) |
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12/25/2007 09:09:22 PM · #3 |
| I think it would of been a aperture issue, i very rarly use this lens for anything other than head shots. |
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12/25/2007 09:10:36 PM · #4 |
TCGuru,
Thanks for fixing the links. May I ask what I did wrong? |
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12/25/2007 09:12:28 PM · #5 |
The 50mm f/1.8 can be quite soft wide open and f/2.0 is pretty close to wide open. That doesn't so much look like focus error as it does a soft image. I say this because both the net and the racket in the back seem to have the same level of sharpness to me. Even at such a wide aperture, when you're that far away the DOF isn't necessarily going to be very shallow. It's all a matter of aperture, focus distance, and focal length that determine the DOF not just the aperture. What you could try to do is set up a piece of paper with writing on it and auto focus on it. If the image comes out clear and in focus, then you're good to go and you probably just missed the focus. If not, then post back and someone with a little more knowledge than me may be able to help you out.
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12/25/2007 09:12:39 PM · #6 |
don't link the whole url, just the image number when putting it in thumb :)
On the bright side, your dogs' front leg looks to be perfectly in focus :)
I think your aperture was just WAYYYY to narrow. When doing groups, use f8 or f10, you will come off better every time :)
ETA: ya, different lens too :) hehe
Message edited by author 2007-12-25 21:21:06. |
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12/25/2007 09:20:00 PM · #7 |
What I've found is that you need to be extremely careful with focus when using a lens like that. When in doubt, the lens will focus on solid, contrasty objects (e.g. nets/microphones/etc.) rather than soft non-contrasty ones like faces, and it's helpful to bear in mind that a focus point isn't quite a point - there's a small area around it that the camera can react to. What I do is end up using the middle focus point, and focusing it on the person's eyes.
But yeah, I agree with the other comments - for a shot like that, I wouldn't really go for f2, f8 or f10 is more like it, light levels allowing (just bump up the ISO instead of reducing the aperture if you're struggling, I'm sure the 30D can cope :) ) |
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12/25/2007 09:20:18 PM · #8 |
Thanks TCGuru, I guess aperture isn't the only thing I need to learn about!
I had a feeling that f2.0 would be too much. Oh well, lesson learned I suppose.
On a similar note, if I were to use this lens to shoot individual portraits, about what aperture would you recommend using? |
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12/25/2007 09:23:11 PM · #9 |
Originally posted by CaseyAllen:
Thanks TCGuru, I guess aperture isn't the only thing I need to learn about!
I had a feeling that f2.0 would be too much. Oh well, lesson learned I suppose.
On a similar note, if I were to use this lens to shoot individual portraits, about what aperture would you recommend using? |
Depends on the effect you want... if you want just the eyes in sharp focus, f2 will be fine. Adjust it smaller (higher number) if you want more and depending on how close you are. Just play with it a bit and get to know it first is the best thing I can tell ya... you learn more by doing. :)
ETA: On the other hand, you can go poke through [user]louis[/user]'s portfolio and see a variety of poses, apertures, lighting, and effects in under an hour :)
Message edited by author 2007-12-25 21:29:41. |
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12/25/2007 09:23:32 PM · #10 |
Originally posted by CaseyAllen:
Thanks TCGuru, I guess aperture isn't the only thing I need to learn about!
I had a feeling that f2.0 would be too much. Oh well, lesson learned I suppose.
On a similar note, if I were to use this lens to shoot individual portraits, about what aperture would you recommend using? |
for just head shots i use near as low as i can because i like the effect of just have the eyes in sharp focus :) |
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12/26/2007 12:16:03 AM · #11 |
Play with this:
//www.dofmaster.com/dofjs.html
Let's just guess that your camera is 10 feet from the subjects. You'll see your total DoF is only .91 feet. That's not much, certainly overkill, especially for a "self portrait".
f/8 would have only give 3.77 feet, which would have been plenty to work with, yet would have still minimized your subjects adequately.
Don't forget your DoF Preview button on your camera. It's a little hard to see, but quite useful for this type of thing.
Hope that helps. Good luck.
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