In the market for a Camera

[De_Cruelz]

LOL me or wu? :P

[fueltank]

LOL, he's chosen the dark side! If you're planning to do more sports photography you should get fast F2.8 lenses!

no. if you choose to do sport photography make sure your camera can do atleast 5fps IMO and get a fast memory card so you don't fill up your buffer too quick.

[De_Cruelz]

True, high FPS camera and fast memory cards allow you to capture more shots but a fast lens will also help focus faster, hence producing sharp, focused images

[fueltank]

True, high FPS camera and fast memory cards allow you to capture more shots but a fast lens will also help focus faster, hence producing sharp, focused images

opening to 2.8 gives you very shallow depth of field so you're going to find a few oof photos time to time.

Best to bump up ISO instead IMO. high ISO photo is better than an OOF photo.

[MrThanh]

shooting at the extremes of the lens' apeture range is usually soft too

[DC2R]

shooting at the extremes of the lens' apeture range is usually soft too

Not with my 24-70 2.8L and 70-200 2.8L IS. I shoot with them wide open and the results are tack sharp.

[MrThanh]

usually.

how are they at the edges?

[De_Cruelz]

Most of my sports/motorsports photographer friends shoot at only f2.8 and at zoom ranges beyond 150mm or so, the effects of a shallow DOF is less when compared to shooting at say 50mm. I guess thats why you see only fast white barrel, L lenses at most sporting events

Bumping up ISO only helps increase shutter speeds, not focusing speed of a lens. Also a fast shutter speed isn't exactly ideal for shooting motorsports as too fast a shutter speed and the car doesn't look like its moving.

[fueltank]

Most of my sports/motorsports photographer friends shoot at only f2.8 and at zoom ranges beyond 150mm or so, the effects of a shallow DOF is less when compared to shooting at say 50mm. I guess thats why you see only fast white barrel, L lenses at most sporting events

Bumping up ISO only helps increase shutter speeds, not focusing speed of a lens. Also a fast shutter speed isn't exactly ideal for shooting motorsports as too fast a shutter speed and the car doesn't look like its moving.

Not sure where you're getting this but a longer focal length actually produces smaller DoF when compared to a shorter focal length.

200mm @ 2.8, object 10m = 0.283m DoF
50mm @ 2.8, object 10m = 4.847m DoF

I'm not saying you won't get focus @ 2.8, you will but chances of OOF images are greater.

EDIT: However, the further the subject is, the bigger the DoF.

[De_Cruelz]

Again you are right, I guess I didn't word my sentences correctly. Instead of comparing in terms of mm, I should've described my example in terms of distance of the object. Now, obviously we wouldn't be shooting motorsports at a distance of 10m, I know I wouldn't!

How about we discuss it at a distance of about 50m instead?

So, 200mm at F2.8, object 50m away = 7.218m DOF. While there's not much of a margin for error shooting a fast moving object, its plenty to fit a whole car in focus unless ofcourse its a luxury limo

[SPL_K]

oof and dof means?

damn i got a lot of learning to do!

how does the aperture affect the zoom and quality picture?

[fueltank]

OOF = Out of Focus
DOF = Depth of Field

Aperture doesn't affect the zoom but the zoom can affect shutter speed. If you look down a really long pipe there is not as much light as when you look down a short length of pipe the less light, the slower the shutter speed you will need to get a proper exposure.

When you open up wide (lower f.stop number) the image quality (esp around the edges) can be soft.

[SPL_K]

could u post some examples?

[fueltank]

Nope, not all lens are of equal quality.
Get on some photography forums and do some reading on your specific lens.

[MrThanh]

Again you are right, I guess I didn't word my sentences correctly. Instead of comparing in terms of mm, I should've described my example in terms of distance of the object. Now, obviously we wouldn't be shooting motorsports at a distance of 10m, I know I wouldn't!

How about we discuss it at a distance of about 50m instead?

So, 200mm at F2.8, object 50m away = 7.218m DOF. While there's not much of a margin for error shooting a fast moving object, its plenty to fit a whole car in focus unless ofcourse its a luxury limo

depending on the angle of the car, I had a lot of trouble getting my DC5 comletely in focus @ f2.8. heck i even had issues @ f4.