Canon 50mm Advice.

[Seanoog]

I am seeking some advice regarding a dilemma I have,
regarding Canon Fit 50mm Lens.

Similar to the thread listed: with regards Prime Lens
http://forums.overclockers.co.uk/showthread.php?t=18391812


I have Canon 550D + 50mm 1.8 MK2 (Hoya UV Filter + Hoya Polarizing Filter)
Tripod + Canon 70-200L F4

For the past year they have been a wonderful combination on a low budget.
But I have always lusted for the Canon 50mm 1.4.
However until the weekend past, when I was photographing the Armagh Rally,
I usually used my Canon 70-200L F4 for MotorSport.

On certain stages, I tried the 50mm.
Kept the exact settings:
(AV Mode, Raw, High Speed Shooting, AI Servo, ISO 100-400 varied)
But was shooked that 1 out of ever two pictures was soft
(when shooting in High Speed Suscession)
Commonly this was in good light, commonly all pictures where taken at 1000s Secound, so not camera shake.
So I am fearing that the lens was unable to auto-focus quick to keep the cars in focus. Would this be a good hypothesis?


This leads me to my next choice!
Do I keep the lens, or considering upgrading?

Obvious choices been:
Canon 50mm 1.4
Sigma 50mm 1.4


Can members give me some tips, or advice.
Regards Seanoog.

 

[Seanoog]

The 50mm 1.8 is fine, I just wouldn't use it for Motorsport - as you've found out for yourself.

The (Canon) 50mm 1.4 is a great lens but I would question the upgrade if you are on a budget. If you think it will be similar to your 70-200 you will be disappointed. The AF is nowhere near as quick.

Thanks for all your replys, guys.
I have always bought good len's, trying to stay within a reasonable budget. Not that I have been afraid to invest a little more than the buying the most basic lens when it would be benificial - (70-200L F4).

But as you have suggested, upgrading the Lens to either Canon/Sigma 50mm, will see no massive improvement in AF performance there is little benifit in spending the money, on the two I initially suggested
Can any one suggest other lens (Prefarably Prime) that would significantly improve AF Performance, too meet my MotorSport requirements?

Or am I destined to enjoy, Rally'ing from my 70-200L Lens?