action photos, use shutter or aperture priority

[dirtbikejunkie]

for taking action photos I have been choosing either shutter priority or full manual... I then set shutter speed to desired speed and adjust ISO as needed (and if manual mode aperture).

I cover dirtbike races and don't always have time to really dial things in on manual mode, so about 60-70% choose shutter priority, usually set the speed about 600-1000 and adjust ISO from 100-1200 to comensate for light as necessary.

In the past this has been using the kit lens with my drebel.

However, I just picked up a new canon 70-200mm f4 L lens, and now I am wondering if instead of opting for shutter priority I should opt for apereture to always take advantage of having an addition f-stop? For example, this coming weekend I will be covering a desert race, the lighting should be fairly good, so I was thinking of using aperture priority and setting it at F4, assuming it will mostly be adjusting for exposure with a shutter speed of 600-1200 (which is the range I desire).

I want to capture as sharp images as possible with a small depth of field (blurred background), but not sure which approach works best?

any thoughts?

[JamesJWeg]

How fast does that camera and lens focus? you may need more DOF to account for any lack of focus speed, especially in a dessert race where speed should be high.

James.

P.S. did you see this thread?

http://www.dgrin.com/showthread.php?t=8638

[Shay Stephens]

Your priority in action shots is to have a fast shutter speed. So if you now find yourself with a faster lens, you can exploit that by choosing an even faster shutter speed, or having a smaller aperture (wider DOF). I wouldn't suggest using aperture priority in this case for action.

In bright daylight you can use a shutter speed of 1/2000 - f/4 - ISO 100. If narrow DOF is your goal, I would up the ISO as needed if you were in lighting conditions darker than full sunlight to maintain your shutter speed.

Will it make a difference if you choose aperture priority, probably not. But you do run the risk of a slow shutter speed with changing conditions. In the end, it comes down to finding what works for you. If it works, don't worry about it. If it doesn't work, then use another technique.

for taking action photos I have been choosing either shutter priority or full manual... I then set shutter speed to desired speed and adjust ISO as needed (and if manual mode aperture).

[JamesJWeg]

I am new to race shooting myself, but people keep advising me to keep the shutter speed down to show some background blur while panning to give the feeling of speed. I am listening to it all though, I'm open to try it all and see what works for me.

James.

[dirtbikejunkie]

How fast does that camera and lens focus? you may need more DOF to account for any lack of focus speed, especially in a dessert race where speed should be high.

James.

P.S. did you see this thread?

http://www.dgrin.com/showthread.php?t=8638
some good info on the thread u suggested, didn't think to search in that forum.

I think as shay has suggested it's going to take some experimentation and just find what works.