WHAT HAS WORKED FOR ME

I have tried many different adapters over the years on the original Canon 1Ds, Canon 1Ds Mark II and Canon 1Ds Mark III; the following adapters worked well: 

1. •Cameraquest - these are made by Kindai and relabeled by Cameraquest (unless Cameraquest changed their supplier recently). In 2005 I had both Cameraquest and Kindai adapters and examined them side by side - they looked and felt identical. I have no direct evidence that Cameraquest is relabeling the Kindai product, but that was my informal conclusion.
   

2. The Cameraquest price costs about the same as buying Kindai from Japan, so there really is no financial advantage to buying one versus the other. The adapters are nicely made and in 2005 time frame the best option when it came to infinity focus. During 2006 and 2007 Ebay was flooded with low cost adapters made in China (or elsewhere in Asia). In comparison the Cameraquest / Kindia adapters prices at $175 are among the most expensive options, but their quality is much better.
   

3. Some people have sent their Cameraquest / Kindai adapter to HappyPageHK and Rudolf (HappyPageHK’s real name) has programmed the focus confirmation chip and installed the chip onto the adapter. I do not know how much Rudolf charges for this service, but he always receives glowing reports on the photography forums, so I assume his prices are fair.
   

4. If you are looking for the highest quality option - going with a Cameraquest / Kindai adapter with a custom installed focus confirmation chip is probably the best choice. But beware, it is not cheap. The added effort may be worthwhile for a Contax 21mm F2.8 Distagon, but probably not for a 50mm F1.7 Planar.
   

5. •HappyPageHK - currently sold on Ebay at ~$75 per adapter. These are the focus confirmation variety and I currently use them with all my lenses. The quality has been very good and HappyPageHK’s service has been excellent. Adapter thickness has varied +/- ~.007 from batch to batch. He uses mid-grade adapter - definitely a step below the Cameraquest / Kindai grade, but better than the el-cheapo ones for $25 on Ebay.
   

6. HappyPageHK now codes each adapter to YOUR preferred focal length and aperture setting - cool! This means you EXIF will reflect the correct focal length which is very nice when reviewing images a year later. Also, in my opinion the focus confirmation is more accurate when the adapter is coded with the correct focal length and aperture for the lens in use.
   

7. Update - In April 2009 I purchased one of HappyPageHK’s new black “pro” adapters to use with the Contax 100mm F2 Planar on the Canon 1Ds Mark III. A brief update was added to the 135 Blog.
   

8. •Son Min Pham - these are customized adapters with varying thicknesses depending on which lens you plan to use the adapter with. Due to variances in the Canon 5D’s mirror box, this might be best solution for 5D owners if other adapters are not working well. I have NOT used Son’s adapters. Son produced these in several batches in the 2007 time frame. He may not have any stock left at this time.
   

9. •Fotodiox - I did not have good results with Fotodiox adapters a couple years ago (2005-2006 time frame). Today Fotodiox offers a “Pro” version which guarantees infinity focus. Odd marketing - sell two adapters - the one that works and the other that sorta works...?... They run about $80 on Ebay. The Fotodiox Pro adapters are ~1.49mm thick, so their guarantee of infinity focus is suspect since 1.425mm is the general consensus for proper focus at infinity on Canon dSLRs,
   

10. •Hoada - I recently received one of their focus-confirmation type adapters with a lens purchase. The adapter appeared to be of mid-grade quality (on par with the HappyPageHK). The adapter was ~1.42mm thick, so it should work well with most (if not all) Contax C/Y lenses. The focus confirmation chip work well too, but was coded for 50mm F1.8 and showed the Canon EF 50mm F1.8 II as the lens used in the EXIF info.
    

11. •DSLR Exchange - There were design and quality controls issues, so adapter thickness varies considerably from batch to batch. There is no way to distinguish one batch from another, so you will need measuring tools. Some adapters were so thick that they would not mount on a Contax lens. Other so thin that they rattled. The DSLR Exchange adapters also use a set screw. Aside from the thickness issues, they were nicely made and work well enough if you find a good one. Some were even anodized in snazzy colors such as cherry red and lime Kool Aide.