Nikon 50mm F/1.8D Help

[Prestige593]

I am using a D7000 with a 50mm 1.8D lens. Indoor photos with a pretty good amount of light. While taking photos of my 9 month old, only about 1 out of 8 comes out in crisp focus. I seem to get a lot of slightly out of focus shots. She is sitting still while I am shooting and not moving around much. What am I doing wrong here? I am using it in AF mode and do not want to switch to manual because I don't think that I can do a better job than the camera.

[NJMurphy]

If you're shooting wide open (f1.8) your depth of field is very short, so if you miss your focal point, the final image will look out of focus.

Are you selecting the focal point, or are you allowing the camera to? Best to select it yourself; the camera will choose whatever point is closest to the lens, better you select the point, and if you're shooting portraits, that point should be the subject's eyeball.

[Prestige593]

OK, good to know. I am shooting in aperture priority, selecting 1.8, and leaving the focal point up to the camera. Should I set it to a different setting? Also, what if the subject is not facing directly forward? How do I get the entire face in focus?
My main objective is to be able to take shots without using a flash, and since this is a 9 month old I can't get her to pose. I have to shoot when the facial expression is right. I seem to get the shots I want, but they are slightly out of focus and it is starting to wear my patience.

[NJMurphy]

Never never never never let the camera choose the focal point. Ever. Select the center point, focus and recompose. To get more of your composition in focus, try stopping down to f2.8 or even 3.5.

And never let the camera choose the focal point. Ever.

[RABaker]

One thing you have to realize when shooting at such a large aperture like f/1.8 is that the total depth of field (DOF) is very small. If you are 3 feet away from your subject, the total DOF is only about 0.8 inch. (At 4 feet the DOF will be about 1.5 inches and at 5 feet it is about 2.5 inches.) As recommended by NJMurphy, never let the camera select the focus point. You need to know exactly which focus point will be used and make sure you use it to cover the most important feature (usually the eyes; or the closest eye). Also realize that if you use the central point to obtain focus and then recompose, you must be extremely careful not to move the camera closer to or farther from the subject as you recompose. In my 3-foot example above, moving the camera by as little as 0.5 inch can make the point you focused on slightly blurred.

My personal approach to a set of circumstances such as you have been dealing with is to set the camera on AF-C (continuous focus) and select a focus point that will allow the composition I want. Then I place the focus point over the closest eye (or whatever) and wait with the shutter release half-pressed for a good expression. That way, if I happen to shift my body position while waiting, or the child happens to move slightly, the camera will (usually) stay focused on the feature I have selected.

Shooting with available light can be very rewarding, but it can also be fairly demanding. At large apertures you are working at the "edge of the envelope" and there is little or no room for error. Just a slight movement of the camera can make a significant difference in the image. In order to get a better feel for how much DOF you have to work with at various apertures, check out the online DOF Calculator at:
http://www.dofmaster.com/dofjs.html
Just select your camera, the lens focal length, the aperture and the distance to the subject to get a calculated DOF for those circumstances.

Good luck,
Richard Baker

[Prestige593]

NJMurphy & RABaker, Thanks for the tips. This will help me out tremendously. I'm going to try and shoot a little smaller and see what I come up with. Ill also try to move to an area where I can get a little more light to help things out.

[Riepejer]

I have that same lens and same camera but I never use the lens. In my opinion shooting at f/1.8 the images come out too soft. Another thing that wasn't mentioned here was your shutter speed. If your little one is moving just a little and your shutter speed is not fast enough to compensate for that the images will be blurred. With my D7000 if I do not want to go below a certain shutter speed I will use auto ISO. Are you familiar with Auto ISO?

Jerry

[MarkD]

There are a couple of things you can try. You need to stop down to an aperture that allows more depth of field (DOF). Try f/2.8 or f/4. You also need a fast enough shutter speed to prevent blur. Try to get 1/60 sec or faster. To do this you'll have to raise the ISO. Your D7000 should give good results at ISO 1600 or 3200. Avoid underexposure as that causes noise. Ideally you want to use low ISO's, but sometimes the lighting conditions are such that you have no choice.

Another alternative is to use flash. If you're worried about it, talk to your pediatrician. If you still don't want to use flash, get an accessory flash and use bounce flash. With bounce flash you aim the flash at the ceiling (which has to be white). That way the flash is not directly into the baby's eyes.

[Prestige593]

Thanks for all of the help, Im going to try a few of the ideas that you guys mentioned. In regards to flash, I prefer not to use it because, and I dont know what the term is, when the (I guess its called) pre-flash blinks, she closes her eyes and I lose the look. I am still a to novice to start getting into bounce flash and such , but I am interested in looking into it. Without getting too technical, what equipment should I be looking at? Once again, thanks for all of the help and ideas.

[RABaker]

"I am still a to novice to start getting into bounce flash and such , but I am interested in looking into it. Without getting too technical, what equipment should I be looking at?"

Actually, modern cameras make bounce flash a snap (if you have the necessary white ceiling/walls nearby). For your camera I would strongly recommend the Nikon SB700 flash (or the SB900 if you want all the bells and whistles along with a little more power and are willing to pay the higher price). If the SB700 is too expensive, a Sigma EF610 DG Super is also quite highly thought of and often recommended by photographers in whom I have confidence (I have not used it myself). If you are willing to buy used, either the Nikon SB600 or SB800 would be a good choice.

If you use the Nikon flashes in the default TTL-BL mode (automatic through-the-lens flash metering with ambient light balance), basically all you have to do is put the flash on the camera, turn it on, point it toward the ceiling/wall, and shoot your shot. I shoot most of my indoor images with the camera set to either aperture priority (A) or programmed exposure (P) and the bounce flash as described above. When it is a person who is my subject I also slightly extend the built-in bounce card (usually about 1/3 to 1/2 extended) to ensure I get a highlight in the eyes. It is a very simple technique that is pretty much fully automated once you point the flash where you want it, but provides infinitely better lighting than direct flash.

"In regards to flash, I prefer not to use it because, and I dont know what the term is, when the (I guess its called) pre-flash blinks, she closes her eyes and I lose the look."

There are at least a couple kinds of pre-flash. The one that I think you are referring to is "red-eye reduction." This mode is supposed to cause a person's pupils to reduce in size to reduce the likelihood of red-eye in the image when using straight-on, direct flash. Like you, my experience with this mode is that it often causes people to blink and my image catches them with their eyes closed. I now always turn red-eye reduction pre-flash off. As far as I'm concerned, it causes more problems than it solves. The second kind of pre-flash is used by most modern cameras/flashes to determine the correct exposure. However, this flash is so quick and followed by the main flash in such a short time that most people cannot even detect the fact that it has occurred. I think I have been using my SB800 (which uses the pre-flash to determine exposure) for about 10 years or more and I have never had an issue with this type of pre-flash. So, based on my personal experience my advice is: On any camera/flash you use turn off the red-eye reduction pre-flash and use bounce flash whenever possible. Use on-camera direct flash only when there is no choice - like outdoors or when the ceiling is too high or too dark to use bounce. If you encounter red-eye, take care of it in post processing.

[By the way, off-camera flash is superior to on-camera direct flash but that is a subject for another discussion...]

Good luck,
Richard Baker