85 1.8 vs 100 2.0

Is the larger aperture of the 85 worth the loss of focal length from the 100 in your guys' opinions? I'll be shooting in low-lighted, smaller venues on a Rebel. Also, is there any optical difference between the two? Does one have better bokeh than the other, etc? Thanks.

The 100 is also a pretty small, compact lens...However, I know this is about aperture... and yes... getting away from f1.4 and f1.8, is starting to stretch the boundaries of low light venues...

But if you settle for a F2.0 (which I'd love to own just for the compact size of it) why not consider the 100 f2.8 macro?... The reviews of it in the lens section, are nothing but the best... It has what is said to be the best "ring type" USM auto focus...

And, if you're going to go the F2.0 route, than why not consider the Canon EF 135mm f/2L USM AutoFocus Telephoto Lens? Again the general consensus for it here is that it's the best...

Per your PM:
I love primes, but the "L" zooms have to start weighing in here, especially when considering the purchase of more than one of the primes...

Specs for th 85mm f1.8
Construction 7 groups / 9 elements
Angle of view 28° 30'
F stop range 1.8-22
Closest Focusing Distance 0.85m / 2.8 ft.
Maximum Magnification 1:7
Filter Size 58mm
Dimensions (Length x Diameter) 3.0" x 2.8" / 75 x 71.5mm
Weight 15 oz. / 425g

Specifications for the 100 f2.0...
Construction 6 groups /8 elements
Angle of view 24°
F stop range 2.0-22
Closest Focusing Distance 0.9m / 3 ft.
Maximum Magnification 1:7.3
Filter Size 58mm
Dimensions (Length x Diameter) 3.0" x 2.9" / 75.0 x 73.5mm
Weight 1.0 lbs. / 460g

Specs for the 100 f 2.8 Macro
Construction 8 groups /12 elements
Angle of view 24°
F stop range f/2.8-32
Closest Focusing Distance 0.31m / 1ft. (film plane to subject)
Maximum Magnification 1:1
Filter Size 58mm
Dimensions (Length x Diameter) 3.1" x 4.7" / 79.0 x 119.0mm
Weight 21.1 oz. / 600g

Specs for the 135L f.2.0
Construction 8 groups /10 elements
Angle of view 18°
F stop range 2.0-32
Closest Focusing Distance 0.9m / 3 ft.
Maximum Magnification 1:5.3
Filter Size 72mm
Dimensions (Length x Diameter) 3.2" x 4.4" / 82.5 x 112.0mm
Weight 1.7 lbs./ 750g

I'd like to own each one of these... I already have the 85mm 1.8... and it's great... but I'd consider the move to f2.8 zooms with IS next...

Most of the time I need all the light I can get in those venues, so f/1.8 helps. I can't speak from experience but everything I've seen and read, they're pretty much the same optically.

Keep in mind, in theory, you also need a little more shutter speed to hand hold the 100. So in practice you may lose more like 2/3 stops (1/3 for aperture and 1/3 for increased shutter speed).

Build quality, optically, AF performance wise, the 85 1.8 and 100 2.0 are a wash.

Johnstoy: I already have the 100mm 2.8 Macro, but I don't think the 2.8 will serve me that well under low lighting...Also, I was considering the 135, HOWEVER, it is almost 3x the price of the 85 and the focal length might be a little much for smaller venues.

Bacchanal: Word on that shutter speed point, didn't even think about that.

I actually just read a review that was making me lean toward the 100; check it out:

http://www.wlcastleman​.com …iews/85_100_135​/index.htm

EDIT: This review is based on a film camera, so I didn't take into account the cropping effect of the Rebel...

I liked the FL of the 100 on my 10D. On my 1D2 I find it is a bit too long for the venue I shoot...
Why not give it a try by setting the 70-300 at 85 and 100mm respectively (or have a look in the EXIF of recent shots).

The 1/3 stop makes very little difference.
It's easier to crop the image of the 85mm then to add some space to the image of the 100mm