Shutter; how fast for moving objects for sharp pic?

GenEOS, Are you trying to say that my brain is too slow?

In thinking about the shot more, I may have half-way depressed the button to auto-focus and then fully depressed the button later, when she was swinging closer to me and now longer in focus.

That would be my guess based on what I've read. I'm not familiar with the 300D - does it offer "A1 Servo" mode so that the auto focus can track moving objects? If so, use it.

If that isn't an option, you'll have to get a deeper DOF (using a smaller aperture) and remember to minimize the time lag between focus and shutter.

Another alternative would be to switch to manual focus and prefocus on a spot in the swing's travel - then release the trigger as she passes through that focus plane.

dsze wrote:
GenEOS, Are you trying to say that my brain is too slow?

Not at all!

Have you tried the AI focus, it may help track when the sbject is moving like that..

The f/4 is most likely causing the blur, not the shutter speed. That lens at f/4 has a very small dof. If you were standing 10 feet away, the dof would have been about 3 inches. As already mentioned, kick up your ISO. I use ISO 400 and AI Servo in good lighting to track small radio controlled planes. I usually get shutter speeds of 1/1000-1/2000 sec.
Scott

You probably have a ruler mounted on the bottom of one of those, to improve your focus.

---Bob Gross---

shutter speed

i s'pose it's sorta off dsze's original topic... anyway, there are 2 components to a mechanical shutter
- mirror movement + iris 'constricting'. this is the mechanical 'slap/click' bit that is felt when you depress the shutter release. it's also why mirror lockup is useful - to prevent magnified vibrations. on some of my older slr's, the mechanical action took as long as 1/60th of a second (or longer on some). i believe on my 10d and 300d, it's around 1/200th or so. remember the old pinhole/box cameras where the photographer would take off the lenscap, and then walk back and put it back on a few seconds later. oops - major digression....


- curtains moving over film/sensor to obscure light from entering the exposed sensitive area. it's kinda like the lightbar on a copy machine when it goes over a document. only instead, it's a little window that slides across to let light in very quickly. on the 10d, i can set the shutter to 1/4000. this means as the curtains travel across, any one area of the sensor receives only 1/4000 sec of light. if you were taking a photo of a very fast object, it could move between the time one side of the sensor was exposed and the other - leaving not a blurry image, but an askew one.

there are also electronic shutters which electronically cut off the signal after 1/x second (well... cutoff processing the signal), but we won't go into that.


i don't, however think this was dsze's problem. i'm guessing it may have had to do with area of focus and the object (girl on swing) leaving the area of focus. we'd have to see a photo, though.

Not a bad idea Bob!. I'll see if the owners will give it a go. Copies to Measurebaters Anonymous.
Scott

I had a similar problem with my grand daughters a couple of years ago. Your speed is ok. The problem is the focus time, if the swing is moving towards or away from you. You can shoot from the side or use manual focus and select a point in the swing to take the picture.

Phil has the answer, I think.

Try this: focus where she is at the highest point of motion, either when she gets all the way back, or when she is all the way forward. At each of those points there will be a momentary halt to her motion, and that's where your best chance to catch her is, both from the standpoint of your reaction time and how fast the required shutter speed will be.

Your depth-of-field will be very shallow, so this is going to be tough. Try is several times. Also, remember to switch the lens to manual focus when you are focused on the right point so it won't hunt when you try to fire.

I would try a slower shutter speed (say 1/350th) and higher ISO to minimize your aperture setting (and thereby maximize your zone of focus).

Just so you don't get discouraged, and so you know how good this lens is, turn the ISO and shutter speed down for a few shots, and take a portrait with the lens wide open of her sitting on the swing motionless. The background will be blurred, and if you make the shot nice and tight, you'll get a portrait that will make you less unhappy about not getting the action shot you want. This will especially work well if you shoot late in the afternoon when the light is softer and warmer.

I hope this helps. Good luck.

Mike

Very Fast...

http://www.pbase.com/l​ec_d30/galleries

Click on the picture when you get to the site...

All with a 300D and a lot cheaper lens than the 70-200 F4L

Regards,


lec_EOS

Just as an example, I have photo's of my lurcher when he's running shot at 1/640th of a second and they are sharp @ 400mm.

I would say that those who are suggessting it is a focus issue are bang on there because I am sure your shutter speed is quick enough