MikeScone wrote:
piperknitsRN wrote:
I think I'm starting to understand the Aperture/Shutter Speed/ISO triangle, aka the Exposure triangle... in a rudimentary way. But I'm wondering how the components of "area mode" and "focus mode" and metering come in to play.
That's an interesting comment on the state of technology - when I started in photography it was the aperture/shutter speed pair. ISO (then called ASA) was a fixed number for film, obviously, so at a given ASA there was one perfect exposure made up of a spectrum of apertures and shutter speeds. Now, ISO can be changed as easily as the other two, so it becomes three-dimensional.
"Area Mode" and "Focus Mode" - I expect you're asking about the autofocus settings.
Focus modes, first: on the D3100 you've got four choices if you're using P, A, S or M exposure modes - AF-A, AF-C, AF-S and Manual. If you're using full Auto or one of the PhD scene modes, you only get to choose autofocus or not.
- Manual is what it sounds like. You focus the lens.
- AF-C is 'continuous' autofocus. The camera tries to keep the subject in focus as long as you hold down the shutter button halfway. You'd use this for subjects that are moving, so the camera will continually refocus to keep the subject focused as it moves.
- AF-S is 'single' autofocus. The camera focuses, then stays at that focus point as long as you hold the shutter button halfway. This is best used for non-moving subjects, obviously. If you're going to use "rule of thirds", you can point at the subject, focus and hold the shutter, then pan away to put the subject on a one-third line. The camera will hold focus at the original point.
- AF-A isn't a setting in itself, really. It just lets the camera choose whether to use AF-C or AF-S. It will try to decide if the subject is moving, and if it is, it will switch to AF-C.
Area modes set how many autofocus sensors are used, and what the area modes do (and which you can select) depends on the focus mode you chose. The D3100 has eleven sensors, scattered around the picture area. You can choose one of four area modes:
- Single Sensor: Just what it sounds like. The camera looks only at one sensor, and you pick the sensor using the four-way rocker switch on the back of the camera.
- Dynamic Sensor: If you are in AF-A or AF-C mode, it works like single-sensor (that is, you choose the sensor point), but the camera will switch to a nearby sensor if the subject moves a bit.
- Auto-Area: The camera decides what the subject is, and focuses on it. In the D7000, the viewfinder shows you which sensor(s) the camera has chosen, so if it's decided to focus on something other than what you expected, you can let up on the shutter and try again. I think the D3100 works the same way. At least on the D7000 this mode is very good, and I use it almost all the time. If I happen to be shooting something where the camera's consistently choosing something odd, I'll switch to single sensor.
- 3D Tracking: This is like a combination of "Single" and "Auto-Area". You choose the focus point, and if the subject's moving and you're in AF-A or AF-C mode, the camera moves the focus point from sensor to sensor to follow it as long as you hold down the shutter halfway. This mode, with AF-C, is best if you're shooting something moving quickly, like a bird or a bunny.
I tend to leave the camera at AF-S and Auto-Area most of the time, and manually switch to AF-C when I'm shooting birds or other moving targets. Note that the camera will, by default, only shoot when something is in focus, so if you're using AF-C the camera will try to focus all the time, but will only fire when it decides the subject is in focus. That's probably what you want, but you can change the default by one of the setup menus.
There are also selectable modes for metering - but I wouldn't worry about them. Set the camera to Matrix and leave it there. Modern Nikons do an amazing job of setting exposure, even in unusual situations, in Matrix mode. Center-weighted metering is useless - it makes your D3100 react like a 1970's film camera.
You could switch to Spot metering if you want to make sure that the camera is only metering for a very small area in the center of the image, but really it's seldom necessary. I almost never use it. Try Spot metering if you're trying to take a picture of a bunny in a deep shadow, with light all around and behind it (although, come to think of it, you'd probably still get better results with Matrix and flash).
Dear Mike:
You are a great help and very patient with your explanations; I really, truly appreciate it! (I just spent half an hour wrestling with the silly camera strap to buckle and secure properly--boy what a hassle; but I'm tired of walking around with my camera in my hands like some rare, precious gem).
I never did more than take snapshots with film, and I can't say anything I'll ever do with a DSLR will qualify as more than a snapshot... but I'm having fun learning about it, and nice folks like you are extremely helpful.
Incidentally, I think AF-C mode tends to frustrate me when I've got a moving bunny--it keeps trying to focus on the (moving) bunny and as soon as the bunny has turned around or gone about its business, the camera decides it's focused and I get a picture of something I didn't want
--usually a bunny bum. So, I've used it, but I haven't been particularly happy with the results... I figure most of my frustration with my photography skills is a result of lack of knowledge--not the fault of the camera. I know it can do amazing things, I just have to be patient with myself and accept that the learning curve is going to be steep.
I appreciate your comments on all the different modes and the comment about metering--
that made it crystal clear to me that I should, as you say, leave the camera on "matrix" and let it get on with its business
.
My prime lenses (50mm and 35mm) came in today along with my SB 400 flash. I'm pleased with the flash; when I tilt it upwards, I don't get "demon eye glare" from Simon, my REW (who is supposedly a New Zealand but I think is a mix because while he's grown since I adopted him in late October, he hasn't gotten
huge, either). I'm a bit puzzled with the 50mm lens, though. I ordered a UV filter for it--same size as for the 35mm (a 52mm UV filter) and as far as I can tell, it doesn't fit. Should I have ordered a 50mm UV filter instead? This probably sounds like the dumbest question ever, but I suppose I should read up on things a bit before I buy:embarrassed:.
I just walked around campus and my neighborhood today and took pictures (because really, there's only so many pictures of bunnies I can take before even
I start to get bored). I
really wanted to take candid pictures of people, but I felt very strange about it, and was also self-conscious about having such an expensive (for me, and probably for most people) camera on my person, so I was cautious. I felt less like a potential mugging victim on campus (where it's finals, and considerably less students around that usual) but I still felt a bit goofy... I guess I'm going to have to get over that if I want to take pictures of things other than the bunnies eating hay!
That said, even a dummy like myself can get "pretty good" pictures from a DSLR. I'm certain they are nothing amazing like I could get if I knew what I were doing
, but the detail and clarity (of any of the pictures I didn't completely screw up) is amazing. Even the photo quality of the pics I took on "auto" amazed me, as I'm used to the quality of my sad, old point and shoot. It turned out to be a sunny day today (which is rare this time of year in the Pacific Northwest) and I got some neat shots of the main drag through my neighborhood, including some colorful street artwork (murals). Mostly it was just nice to be out in the sunshine, although it was a cold day.
Thanks so much for your help, Mike!
