The first time I ever heard there was an f/1.0 lens I said whaaaaaa… that's crazy. Then I read all the facts about it and was disappointed. It's not sharp, has bad chromatic aberration, and the insane price tag. Lame. Although, chromatic aberration isn't a big deal because it can corrected. The sharpness… with that low of image quality the price can't be justified. It's expected though at f/1.0. All lenses are considerably less sharp at their widest apertures minus the Canon 70-200mm f/2.8L IS II and all the version II's of all the super telephoto line. All this considered I decided to buy it to see what it was like. 

So all lenses aren't made the same. You can get a model that back focuses, focus ring is loose, or is below standard sharpness for it's model. You can also get an anomaly that's better than its peers. In my case I got a copy that was unbelievable sharp. How sharp?

Here's an image taken with the Canon 50mm f/1.0L wide open. The light source was a string of Christmas lights on a tree about 2ft away from the subject. Pretty much shows how much light this lens soaks up! Notice the extreme painterly bokeh in the background.

Comparison Part I

Out of the current 50mm lenses the widest is the Canon 50mm f/1.2L. This lens has the widest aperture, least amount of sharpness, and least contrast out of the three I'm comparing. When I owned this model I noticed the difference in quality from my Sigma at first shutter. After seeing the difference, I decided to sell it. The price of the Sigma is around $350 street, and the Canon 50mm f/1.2L being $1200. You can buy three Sigmas for the price of the Canon! The Canon 50mm f/1.4 focuses the fastest, and is in the middle of the road in all other regards. It's sharpness can be better than the Sigma from copy to copy. The major issue with the Sigma is it's missed targets from time to time. At 1.4, a miss focus can cost you a shot, one of the reasons that people like to go with the Canons. My copy of the Sigma didn't have any issues with this. If I was to tell you to buy a 50mm, I'd tell you to buy the Sigma. At the time of this review the Sigma EX DG 50mm Art lens is close to release (pretty excited to see the engineering going into that).

Here's a comparison of the image quality between Canon 50mm f/1.2L, Canon 50mm f/1.4, and Sigma EX DG 50mm f/1.4, (left to right) at the 1.4 aperture. ( I didn't take these three, they're from The Digital Picture. Very thorough reviews of camera equipment. Visit it!)

Comparison Part II

Now that I've asserted that the Sigma is the best choice to go with, I'll start comparing it to the Canon 50mmm f/1.0L.
I started by grabbing the good' ol test chart and shooting both lenses at f/1.4. I took a photo of the Canon 50mmm f/1.0L wide open with some pretty amazing results. I mounted the camera on a tripod, took three shots for each frame below and picked the best from each one. I actually had to mov the Sigma in closer because it was slightly wider than the Canon. For some reason the definition of "50mm" varies slightly between manufacturers.  I then cropped the center of the frame so you can see the differences better.

Looking below you can see the Sigma 50mm at 1.4 first, then the Canon 50mm at 1.4, last the Canon 50mm at 1.0. The Canon is actually sharper at 1.4 then the Sigma, it also has less chromatic aberration (the Sigma shows a lot of green fringing), What's mind blowing is that you can clearly see that the Canon is actually sharper at 1.0 then at 1.4!?! It does show a lot of chromatic aberration and does loose contrast. The performance wide open is strangely stellar. 
The other notable difference between lenses is the flaring. The frames follow the same order as above. The Sigma does a pretty good job of controlling flare. The Canon at 1.4 has notable flare and at 1.0 creates intense rainbow flares. 
This can be viewed as bad engineering or artistic difference. I actually like it a lot! The Canon 85mm f/1.2L II USM actually produces a similar flare. Here's an example of how it can be used artistically in a photo…


So who should buy this lens and why? Those who...
  • have a good chunk of change they can spare
  • are collectors (because this lens is no longer made, with a predicted price of $15k by 2030)
  • really want to set their work apart
  • shoot in extreme low light (it's the great equalizer at weddings)
  • want the depth and bokeh of the 85mm f/1.2L II USM while maintaing the perceptive of a 50mm
  • want bragging rights

Do I recommend buying this lens? If I had received a standard copy, probably not. If you have the extra money go for it. You might get lucky and get a phenomenal copy! I think it should be standard practice for ISO crops to be pictured with auctions on eBay. It allows proper pricing for the seller and more confidence for the buyer. I'm fairly sure that the guy who I bought mine from was unaware of what he had.