Posted by David Clapp on September 26, 2008 at 2:27 PM
Elliot / Mike / everyone, I thought I would write this rather than responding to my FOR SALE post. Look out Mr Robinson here comes the techy babble :-)
Regarding adapters I have to totally disagree about spending money on expensive adapters. I have one expensive adapter at about £70 and its literally no different than the others besides build quality. Some have AF confirm chips others dont, but in the end if you want super high spec machined adapters because you think they will cause you less issues and setting up then read on.
Lets consider mounting a Contax Zeiss lens on an EOS body. To get perfect imagery you need to have an adapter that is the right thickness for the lens and that thickness to be even across the whole adapter. Literally all the adapters I have on my lenses had to be 'shimmed' to achieve infinity focus as shown on the lens. The involved using placing layers of electrical tape and packing tape between the adapter before connecting, to increase the thickness and push the lens further away from the camera sensor. This brings IF where it should be marked on the lens. Once this is achieved, the adapter stays on that lens forever and the IQ will be at its peak.
I tested 6 adapters I had using a micormeter. The correct thickness is supposed to be 1.42mm for Contax, but after testing them all evenly the results were not as expected. The most expensive adapters varied by over 0.10mm, and four out of the six Ebay cheapos were only + or - 0.03mm. But this as all beside the point...
Each lens responds differently to each adapter thickness. It doesnt matter whether an expensive one or cheap one is used as I found out. None of the Contax kit I adapted worked perfectly without adaptation using the tape method, all the IF points were out, except the 28-85 which fitted the expensive adapter like a glove. The AF confirm chip is super accurate as well which is a complete surprise.
In conclusion its a total crap shoot; a Contax 28mm f2 Holywood lens I adapted perfectly with a chinese adapter that was 1.54mm thick, totally over spec. No manner of tape would have brought it in line so I had to go looking for a bad adapter, how novel. It is imperative that this lens focuses exactly where the infinity mark is, as it has a floating element that needs to be placed correctly to render sharp images across the frame. Also having this registration slightly out, in otherwords the lens focusing past infinity, causes problems with depth of field often reducing it, so its essential to address these problems as soon as a purchase is made.
If you get into alternative lenses it can become a huge frustrating headache to get them working properly, but it has nothing ot do with buying Cameraquest, its to do with each individual lens. Think about it, these lenses were made for film, this capture plane was never exact, a digital snesor is far more precise. And boy oh boy does it open your eyes to shit glass you may have considered to more than satisfactory. The levels of testing I subject the kit to made me learn so much about my current lenses and the levels of quality you can achieve with far cheaper glass. For example I now only use the 24-105 when I travel as its rather questionable in this new light. Sometimes speed and IS is essential over the best IQ especially as I travel a lot, but I also take the 35-70 and use this whenever I can as it renders unsurpassable images in that focal length even at f5.6. Every tried that on the a 17-40... errgh its cringe worthy
The answer to the 17-40 may be just around the corner, the 14-24 on a 1DsIII is an exciting possiblilty I am testing this weekend. This lens claims to kick the biggest arse ever and will mean my setup for landscapes consists of only one Canon L out of the six lenses I use should it be the answer to my prayers. It will cover the 14mm L, the 21mm Zeiss and 24mm L all for the price of a grand. I'll keep you posted.
Who would have thought I would go back to where it all began, manual focus manual aperture and be as happy as larry. I craved for lightweight AF when I had my T90 and bag of primes some six years ago, now look whats happened!
Please add any comments, questions, I would be happy to help.
Discussion
4 repliesRegarding adapters I have to totally disagree about spending money on expensive adapters. I have one expensive adapter at about £70 and its literally no different than the others besides build quality. Some have AF confirm chips others dont, but in the end if you want super high spec machined adapters because you think they will cause you less issues and setting up then read on.
Lets consider mounting a Contax Zeiss lens on an EOS body. To get perfect imagery you need to have an adapter that is the right thickness for the lens and that thickness to be even across the whole adapter. Literally all the adapters I have on my lenses had to be 'shimmed' to achieve infinity focus as shown on the lens. The involved using placing layers of electrical tape and packing tape between the adapter before connecting, to increase the thickness and push the lens further away from the camera sensor. This brings IF where it should be marked on the lens. Once this is achieved, the adapter stays on that lens forever and the IQ will be at its peak.
I tested 6 adapters I had using a micormeter. The correct thickness is supposed to be 1.42mm for Contax, but after testing them all evenly the results were not as expected. The most expensive adapters varied by over 0.10mm, and four out of the six Ebay cheapos were only + or - 0.03mm. But this as all beside the point...
Each lens responds differently to each adapter thickness. It doesnt matter whether an expensive one or cheap one is used as I found out. None of the Contax kit I adapted worked perfectly without adaptation using the tape method, all the IF points were out, except the 28-85 which fitted the expensive adapter like a glove. The AF confirm chip is super accurate as well which is a complete surprise.
In conclusion its a total crap shoot; a Contax 28mm f2 Holywood lens I adapted perfectly with a chinese adapter that was 1.54mm thick, totally over spec. No manner of tape would have brought it in line so I had to go looking for a bad adapter, how novel. It is imperative that this lens focuses exactly where the infinity mark is, as it has a floating element that needs to be placed correctly to render sharp images across the frame. Also having this registration slightly out, in otherwords the lens focusing past infinity, causes problems with depth of field often reducing it, so its essential to address these problems as soon as a purchase is made.
If you get into alternative lenses it can become a huge frustrating headache to get them working properly, but it has nothing ot do with buying Cameraquest, its to do with each individual lens. Think about it, these lenses were made for film, this capture plane was never exact, a digital snesor is far more precise. And boy oh boy does it open your eyes to shit glass you may have considered to more than satisfactory. The levels of testing I subject the kit to made me learn so much about my current lenses and the levels of quality you can achieve with far cheaper glass. For example I now only use the 24-105 when I travel as its rather questionable in this new light. Sometimes speed and IS is essential over the best IQ especially as I travel a lot, but I also take the 35-70 and use this whenever I can as it renders unsurpassable images in that focal length even at f5.6. Every tried that on the a 17-40... errgh its cringe worthy
The answer to the 17-40 may be just around the corner, the 14-24 on a 1DsIII is an exciting possiblilty I am testing this weekend. This lens claims to kick the biggest arse ever and will mean my setup for landscapes consists of only one Canon L out of the six lenses I use should it be the answer to my prayers. It will cover the 14mm L, the 21mm Zeiss and 24mm L all for the price of a grand. I'll keep you posted.
Who would have thought I would go back to where it all began, manual focus manual aperture and be as happy as larry. I craved for lightweight AF when I had my T90 and bag of primes some six years ago, now look whats happened!
Please add any comments, questions, I would be happy to help.
I don't mind the tech stuff at all
as I don't understand it .
I just go out and take pics with crap gear
Cheers
John
Interesting stuff! Thanks for sharing!