Canon 50mm f/1.4 compared to 50mm f/2.5 Macro

I am trying to decide on the 50 f/1.4 or the 50 f/2.5 Macro.
Is this typical of the distortion of the 50 f/1.4?
http://www.pbase.com/image/24157481
From what I read on photozone.de the macro has no distortions or vignetting
wide open and the f/1.4 does. I assume that is why it has a higher optical
rating. But this photo with the f/1.4 was at f/13 (hardly wide open) and to
me there is a lot of distortion. Is it the lens or something about the shot?
The tradeoff between the lenses appears to be:
The macro is slower to focus, cannot work in as low a light, but has no
distortion or vignetting.
The f/1.4 can focus faster, work in lower light, and give more blur, but
has noticable distortion.
How wide an aperture do you need to blur the background for a given focal
length? What is the relationship of subject distance, focal length and
aperture? When would a f/1.4 be needed to blur a backround where the 2.5
wouldn't cut it?
How important is AF speed on a 50mm (I've never had an AF SLR)? I can see
the need for fast AF for a 70-200mm zoom since that is the lens I have used
(manual version) to shoot horses etc. I have normally used my manual focus
50mm to shoot static subjects so I really don't know the value of fast AF at
that focal length. Do people use 50mm for alot of action shots? Do people
use macro lenses of different focal lengths for compositonal flexability
(because of wider FOV) or just because they cannot afford a 100mm? I am
already planning on getting a 100mm 1:1 macro lens so I will have macro
capability.

TIA
Chris

 

I think you will find f/2.5 +- 1/2 stop or so to be typical of a 100mm
lens. And in 50mm FL f/1.4 to f/1.8 to be common and inexpensive.
Basic stuff. I made a similar decision a few years back. A fast 50 or
a slower one with Macro. What about the 100mm? Macro or not? So here
is some food for thought. If you are going to get a 50mm prime lens,
why not make it a fast one? The 100mm is likely to be around f/2.5 macro
or not. Thus adding Macro to your 100mm will not cost you any lens
speed where as adding Macro to the 50mm will cost you 2 stops. Usually
the longer your Macro is the better. Gives better stand off distance
which can help with lighting or shy creatures. I choose to go with a
fast 50 and a 105mm macro. I have not been sorry.
There are ways to get a non macro lens to go close up. One is with a
close up "filter" (diopter)on the lens and the other is with extension
rings or bellows (adjustable extension ring). The filter does not loose
any of your lens speed (not really a concern as you should be on a
tripod and be stopped down a lot for most macro work) and the extension
rings do not add any distortion. They do have their own limitations
though. They may not support some of your camera's automation features.
Unless you are taking close up shots of coins or stamps you won't miss
not having the flat field of a true macro lens so you can most likely
get by with the rings or filters.

 

What is distorted? Not the trees, only the roof.

So, is it distortion, or is it that the roof is actually curved?

Something to think about.

 

Get the 50mm 1.4 there is some barrel distortion but thats common in most lens's at the widest aperature. You will be delighted with
the sharpness of this lens for the price.


Cheers

 

lens's at the widest aperature.

I thought a lens' drawing was independent of aperture ?

 

Barrel distortion is a function of the quality of the optics and how close to the lens edge you get. Such as a wide angle lens at a
large aperature.

Heres some info on the 50mm http://www.photo.net/equipment/canon/ef50/

Cheers