Are more focus pts. better for Birds In Flight ?

[Logo10heli]

Are more focus pts. better for capturing BIF ? For example, I'm looking at the D300(s) and the 51 focus points. It has more cross-type sensors than my D90 and choices of how many focus pts. to use. Also 3-D tracking, etc. This gets a bit overwhelming for an enthusiast.

I'm also looking at a new D7000 as the sale price is really tempting. It has 39 focus pts. However, some owners have expressed disappointment with the AF performance of the D7000.

This camera purchase will mostly shoot BIF , and ground-based wildlife. I'd really like to get it right.

[TCav]

According to Nikon's mauals, 3-D Tracking is for when the subject is stationary and you move the camera to reframe the image, while Dynamic Area is for when the subject is moving within the frame.

On my D90, I've selected the center AF point, and locked it with the Focus Selector Lock. I tried 3-D Tracking for soaring raptors, but wasn't pleased with the results, so I went back to Dynamic Area.

For locking the center focus point (the only cross type sensor) and using Dynamic Area, I suppose more focus points, especially more cross type focus points, will make keeping a moving subject in better focus. But it seems to me that when the subject is a bird and the background is the sky, it shouldn't be hard for Dynamic Area to keep the subject in focus, so more focus points may not help very much.

[zig-123]

I tend to use:
single point center using AF-Continuous and shutter release set to C-Hi on the D7000. I use both 9 focus point and 21 focus point settings in " blue sky"situations where the background isn't cluttered. But, for the most part, single point works best for me. I want to control what the camera is focusing on.

I will add that there are a lot of other factors that all effect your results- some of which might be confused as AF limitations within the camera body
1- As an example using a fast lens i.e. f2.8lens wide open will allow more light thus reach focus faster. If your using a 70-300mm lens in low light, it will usually hunt. Some people may atribute that to the AF system, but it's the lens' inability to allow enough light in to achieve focus that's the cause. Unless there is a depth of field situation, my aperture for the 70-200mm f2.8 VR is set at f2.8.

2- a lot of blurry images blamed on slow AF systems are a result of not using the proper shutter speed. BIF shots usually require shutter speed settings of 1/1600sec or 1/2000sec.

3- High shutter speeds require lots of light. In the morning, when birds are most active proper light isn't always there requiring a boost in ISO settings.
I typically use the ISO sensitivity control to: ON with a maximum ISO set to 1600 and the minimum set to 100. I then, set my minimum shutter speed to 1/640sec. The reason I set the minimum shutter speed that low is to allow the camera to automatically reduce the ISO when I'm trying to shoot shore birds that are wading. In those situations, you can get away with slower shutter speeds. This also means that I don't have to waste time adjusting my settings.

4- Even when using the settings above, I continue to have my D7000 mounted to a monopod. It provides a stable platform especially for those lenses that do not have VR. i.e. the 300mm f4 ED IF AF.

As for getting a D300 or the D7000, both are good cameras. The D300 has a 8fps frame rate while the D7000 has a 5.5fps rate. The D300 has the larger buffer. The D7000 has a 16mp sensor which also had a higher dynamic range and better low light performance. The D300 is built like a tank.

Get the camera that has the features most important to you as both are excellent and will serve you well.

I would like to add that the D90 is no slouch either. If I were in your shoes, my first step would be to get the lens you want and try it out with your existing camera. I know that there are some tempting sales going on right now, but there will be more sales in the new year and especially when the D7000 replacement arrives.

[TCav]

I agree with Zig. A big part of the AF performance is the lens' maximum aperture. I use a Tokina 100-300mm f/4 constant aperture lens, and get some nice resutlts. Anything dimmer and you'll have trouble focusing, whatever camera body you're using.

[Ozzie_Traveller]

G'day all

May I join & congratulate Zig on his excellent response above
[ It's 'excellent' as it mirrors the way I do it ]

Seriously - Zig has spelled out one of the photo techniques that many of us 'oldies' use regularly, and that 'newbies' are often unaware of the precise how-to's ...

Good on yer mate
Regards, Phil

[Logo10heli]

Thank you all for taking the time to post helpful comments. I will check my D90 focus settings, and try to be patient and check my camera/lens combo more thoroughly before jumping ship.

I'd like to post a photo taken Christmas Eve afternoon on my way home. I noticed several Bald Eagles near a limestone quarry. The water had frozen and the birds were sitting on the ice out in the middle. It was an overcast day with snow flurries but no snow at this point in time. This is a terrible photograph but one of the sharpest of the group. I was shooting in Manual at f/8 and 1/500. Now I know that I should have been at 1/2000 . The old school of hard knocks. D90 w/Sigma 50-500 OS. I was resting the camera/lens on my car window sill. Needless to say how disappointed I was when I downloaded these photos.

This is cropped in-camera for uploading purposes. No PP. Comments and suggestions are welcome.

Manual, 1/500, f/8, ISO 200, 500mm, Active D-Light. Normal, Pict. control VIVID, Sharpening 7, Contrast = Act. D-light, Brightness = Act. D-light, Saturation +1, VR turned off as I was resting on window sill. AF area mode 3D, Center focus pt. = Wide, Auto ISO = ON

[Wingman]

FWIW, I use both the D300s and the D90 for a different kind of BIF's: aviation photography. I set my D300s on the 3D - Tracking and hardly lose any to focus issues. The D300s locks on and holds focusing solidly. On my D90 (secondary usage), I use the continuous focusing mode and it is set at the 11 point 3D tracking and while not as good as the D300s, I still get more keepers compared to another brand of camera I was using (not Canon, Sony or Olympus).

I also think the performance of my D300s is enhanced by the 70-200mm f2.8 lens that I use that has the internal ultrasonic focusing which is very fast. On my D90 I use the Tamron 18-270mm and it actually has a rotating barrel which is noticeably slower. I also own a Sigma 150-500 with the HSM (Hypersonic Motor). Focusing is fast but not as fast as my Nikkor 70-200...perhaps due to the Sigma's larger size as well as Nikkor's better mechanics???

Here are links to
a. Images taken with the D300s + 70-200 f2.8: http://www.airliners.net/photo/USA--...cd4799995bc426

b. Image taken with the D90 + Tamron 18-270mm f3.5-6.3: http://www.airliners.net/photo/ABX-A...cd4799995bc426

Hope this helps.

Jehan

[TCav]

According to Nikon's manuals, 3D Tracking is for stationary subjects when the camera moves, while Dynamic Area is for moving subjects. I've used Dynamic Area for BIF and aircraft out of Andrews AFB, and been pleased with the performance. I tried 3D Tracking and didn't like it as much.

Is everybody saying they like 3D Tracking better than Dynamic Area?

[Logo10heli]

Thank you Wingman for your comments. Wonderful airplane images !

Originally Posted by TCav

Is everybody saying they like 3D Tracking better than Dynamic Area?

Not I. But to be fair, I use my equipment on two 10-day vacations a year and a free day here and there in between. Hardly enough to form an opinion, or master the art.

I've been a bit under the weather recently and foresee more days indoors. Are there some simple static tests I could perform with my D90 and 50-500 OS on a tripod to see if I have a front or back focusing issue ? Or perhaps a bad copy of this lens ?

[zig-123]

Regarding the subject of checking your lens for correct focusing,
Here are two articles written by Thom Hogan on AF troubleshooting.
Both are worthwhile reads as they help illuminate the variables involved in AF.

http://www.bythom.com/autofocus2.htm

http://www.bythom.com/autofocus.htm