EF to EF-S?

<p>I have just acquired an excellent condition Sigma APO 70-300 for Canon. I think this must be their EF mount?<br /><br />Sigma says this lens won't work on a 7D because parts are no longer available. <br /><br />The EF-S mount pictured on Wikipedia, which is claimed to function on the 7D, looks identical to my Sigma's mount. Same number, arrangement, and shape of chips on both mounts. Has anyone tried the original EF mount on an EF-S mount Canon? I don't have a Canon camera on hand.<br /><br />If it will not function as-is on a 7D, is there an adapter for "old Canon to new Canon" that would let it function like the M42-to-Canon adapters do?<br /><br />Thanks for your help!</p><div></div>

<p>Whole lens</p><div></div>

<p>Nevermind.</p>

<p><a href="http://metku.net/index.html?sect=view&n=1&path=mods/efs/index_eng">http://metku.net/index.html?sect=view&n=1&path=mods/efs/index_eng</a></p>

<p>Not EVEN going to DO this to my lens, but at least I got my question answered.</p>

I don't think its mount problem as that looks like a EF mount and will mount on the 7D. However the camera and the lens might not talk the same lingo... ie the chip in the lens is out of date and sigma doesn't support rechipping it any longer.

However it shouldn't hurt anything to try it out on a 7D.

Phyliss,

The 7D will accept both the EF mount and newer EF-s mount as well. I use the 24-105 EF mount on my 7D and even used an old 1987? 70-210 canon lens on it as well.

What isn't compatiable is the FD mount.

EF-s mount lens won't work on the FF digital cameras such as the 5D and the 1D series bodies.

 

Confusing I know...

<p>Thank you, Peter. I'll shortly have the 28-135 kit lens to compare it to. If it's not a match, I could either sell the Sigma, and put the money toward a long lens that will work or just keep it and use it on a film camera.</p>

<p>Thanks for your info!</p>

<p>I expect the problem here is that older Sigma lenses are notorious for having compatibility problems on newer Canon cameras. The electronic language that Canon cameras and lenses use to talk to each other is secret; Canon doesn't tell other companies how it works. So third-party lens makers like Sigma, Tamron, and Tokina have to analyze the electronic signals and figure out for themselves how to make their lenses Canon-compatible. Tamron and Tokina seem to have done a pretty good job of this; I've never seen an electronic Tokina lens that failed to work on a newer Canon camera, but Sigma lenses have often needed to be upgraded ("re-chipped") to work on newer cameras. Apparently Sigma no longer offers this lenses for their older lenses, which explains why they say it simply won't work on a 7D.</p>

<p>Okay, I got the Sigma out and compared it to the two lenses at the metku site. The back of my lens matches the mount of the lens on the right on the first page in that it doesn't have the protrusion above the red line drawn on the lens on the left. In fact, the back glass on mine is a little sunken below the mount itself.</p>

<p>It also has an AF / M switch on the back edge of the barrel. So would that mean if it won't communicate in auto focus on the 7D, can I still use it as a manual lens on that camera?</p>

<p>any EF lens will fit any EOS body. EF-S lenses will only fit certain APS-C bodies (20D and newer)</p>

<p>You can try putting this lens on your 7D and see what happens. If the camera is able to control the aperture properly, but auto-focus doesn't work, then you could still use it as a manual-focus lens. But if the camera can't control the aperture, or doesn't correctly sense the range of available apertures, then the lens is probably just about useless on your camera. Another possibility is that your camera will simply display an error code and refuse to do anything at all while that lens is attached.</p>

<p>Thanks, everyone! As always, you're all a bottomless well of valuable information!</p>

<p>To be absolutely clear ... EF lenses will safely mount on EF-S cameras so don't be concerned about the physical aspects ... it's the electronics you need to worry about. Older non-OEM lenses may not be electronically compatible with newer cameras but will not damage them (you will get some sort of error ... typically Err99 ... just remove the lens and all is good again). Some lenses are known to not work with the latest bodies (this may be one of them) while other older non-OEM lenses work just fine. The only way to find out for sure is to try it.</p>

<p>Sigma are verry short sighted. I believe they buy or manufacture a number of kits to rechip the lenses that the changes in Canon bodies mandate. While they have kits in stock they will rechip a lens at no cost to the customer ,but when the kits are gone they stop. I have a really nice 300mm lens that is only useful as a paper weight.</p>

<p>Starting with the Canon 10D many sigma lenses would not work on the camera but would work correctly on Canon film cameras. Sigma at the time repaired (rechiped) or replaced lenses for free. However since the 30D there have not been any firmware issues with new sigma lenses (just occcational lens failure or lenses that have focusing issues because they weren't properly calibrated in the factory). This rechiping issue was a one time event. Nota constantly reoccuring issue. However many ofthe affected lenses were never returned to sigma for repair (the owners were never aware of the recall) and these occationally wind up on ebay or other used gear sites. </p>

<p>I personally use a Sigma 50mm on the original 5D without any issues. The sigma lens you showed is similar to Sigma Pentax mount lens I purchased 10 years ago so it is likely very old. Try it on your camera it it works go ahead and use it. If it doesn't there isn't much you can do about it. The parts needed to repair it as well as that lens are no longer made.</p>