Need fast AF lens

mattgal · 26 Sep 2010 at 19:52

Hi, I need a fast 400mm or 500mm lens that won't break my bank.

I was taking some air show pics this morning (will post some on another thread) and i nearly cried when i took a photo of 2 planes making a cross and the focus was not as fast as the planes (obviously).

Pls help. I'm open for about €300-€400 tops.

Thanks

(saw the sigma 170-500mm. pretty decent)

p0ss3s3d · 26 Sep 2010 at 20:03

170-500mm won't AF fast.

At that budget your going to struggle. Something like a 70-300IS/VR canon/nikon will be about as quick as you can find.

mattgal · 26 Sep 2010 at 20:18

i have so far a canon 75-300mm USM

p0ss3s3d · 26 Sep 2010 at 20:30

The 70-300 is a fair bit quicker apparently.

The next step-up is a 120-400/150-500mm. They'll be quicker but still not lightning fast. Expect about £500-£650.

mattgal · 26 Sep 2010 at 20:35

O_o that's about ...... a lot of money. I'm only a hobbyist and would like this lens to use it in an airshow and some ( i doubt) nature photos.

mattgal · 26 Sep 2010 at 21:38

I don't want this to EVER happen again

Bluelion · 26 Sep 2010 at 21:46

mattgal said:
I don't want this to EVER happen again

I don't think the lens' AF speed is at fault there Mattgal. At the distance planes are away from you, the AF speed of the lens doesn't matter much as the lens will be focusing almost at infinity. So unless the body hunted for a focus point just before that shot, I don't think a faster lens will significantly help without spending megabucks, like £3000+.

I see you were shooting at F8 @ 255mm on a 450D. Were you using continuous focusing and locking on before the planes got together, or were you using press-to-focus single shot mode? The former might help you get it sharp in the future.

FreeStream · 26 Sep 2010 at 22:01

Canon 70-300 USM IS. Sold mine for £320 (€375) and that is pretty much the best your going to get.

robmiller · 26 Sep 2010 at 22:13

I'm willing to bet the issue is 90% technique, 9% AF on the body, and 1% AF on the lens. Just because it's "auto" focus doesn't mean there's no technique and you can just point the camera at a subject and get an in-focus result.

mattgal · 26 Sep 2010 at 22:50

I was using continuous focusing.

the other "Lock" . i don't know what it is.

if it means that i was always pointing the middle dot on the plane, then yes.

^^Gord^^ · 27 Sep 2010 at 00:06

The AF would have been thown off by the other aircraft entering the frame. If you shoot using only the centre AF point rather than all of them you can prevent this from happening.

robmiller · 27 Sep 2010 at 00:57

mattgal said:
if it means that i was always pointing the middle dot on the plane, then yes.

While focussing, though? As in, you acquired focus on the plane, tracked it (while continuing to focus), and took a burst of shots?

Amp34 · 27 Sep 2010 at 01:02

TBH I doubt the AF of the 70-300 IS is much faster than the 75-300*. I had the 75-300 IS (similar to the standard 75-300) and it's not much worse than the 70-300 IS.

TBH to really see any difference you'll be looking at around £700 for any lens that is 400mm+ and has a fast AF, that would be a used 400 f/5.6. Alternatively you may be able to squeeze a well used 300 f/4 into something near that budget, not 400mm but it will be if you subsequently buy a 1.4TC, however you would lose a little AF speed.

*If it is the lenses "fault" as already mentiond.

mattgal · 27 Sep 2010 at 09:51

^^Gord^^ said:
The AF would have been thown off by the other aircraft entering the frame. If you shoot using only the centre AF point rather than all of them you can prevent this from happening.

so if i use the single point focus instead of the 9, will i see a difference? will there be issues when shooting say...5 planes in one shot? (you know.. like the red arrows and stuff. they're always a group)

robmiller said:
While focussing, though? As in, you acquired focus on the plane, tracked it (while continuing to focus), and took a burst of shots?

exactly

^^Gord^^ · 27 Sep 2010 at 21:08

mattgal said:
so if i use the single point focus instead of the 9, will i see a difference? will there be issues when shooting say...5 planes in one shot? (you know.. like the red arrows and stuff. they're always a group)

Shooting with a single AF point means less chance the AF could be frown off by something else. It will help but it isn't the only factor at play.

Shooting multiple aircraft in formation will be fine.....

All AF points displayed, only the centre AF point is active, straight from the RAW file without editing.

mattgal · 27 Sep 2010 at 23:02

ohh. thanks

robmiller · 28 Sep 2010 at 02:03

You should probably spend some time practising tracking stuff, really — cars on a relatively busy road might be a good choice, if you can do it without freaking out the drivers! More than perhaps anything else in photography, this is about technique and a knowledge of how your camera behaves. There's a lot of magic in modern autofocus, and you're going to get frustrated unless you know how to actually harness that magic.