photobydmb Loc: Nashville, TN

I'm a long-time 35mm shooter but relatively new to digital, and I'm still trying to figure out a few technical things. I recently bought a used Canon EOS 20D, which I assume has an APS-C sensor. While looking for a longer zoom lens for it I found the Tamron 75-300 f/4-5.6 at a good price on Amazon. The description says it will work with Canon EF mounts. My camera manual says the camera will accept ALL EF and EF-S series lenses. However, when I checked the compatibility feature on Amazon, it says this lens is NOT compatible with the 20D. Is that ONLY because the lens is for full-frame cameras, or is there some other issue? I can deal with the cropping issues, if that's the only issue. But is there some other reason this lens is not compatible with my camera? Will this lens not mount on my 20D? Are the electronics not compatible? Is the mirror going to slap against the back of the lens?

I used the search section here at UHH, as well as Google, Canon and Tamron and can't find any specifics. Hoping there are a few Canon shooters (or at least ONE) that can answer this for me.

Thanks in advance for any information!

dooragdragon Loc: Alma , Arkansas

MtShooter can probally help you out with this question, give him some time to read and reply .

lowkick Loc: Connecticut

While I'm not familiar with the 20D, I do have a 40D and 60D with APS-C sensors. Both EF and EF-S lenses should work on any Canon APS-C sensor cameras. However, only EF lenses will work on full frame sensor cameras like the 5D's and 6D's. It is not a question of the mount, but of coverage of the sensor. It has to do with the optics of the lens and, without going into detail, how much it covers the area of the sensor. An EF-S lens mounted on a full frame camera will not cover the whole sensor and will leave a dark border around your photos. I hope that helps you. Buy the way, if you have your sights on eventually getting a full frame camera, save yourself some money by only buying EF lenses now so you don't have to purchase new lenses later.

MT Shooter Loc: Montana

As the manual states, your camera will work with ALL EF as well as EFS lenses, not a problem, use it as you wish, it will do no harm to your camera. Just remember that ANY lens you put on that body will have an effective focal length that is 1.6 times the listed focal length. A 75-300mm lens will effectively become a 120-480mm lens on that camera due to its smaller sensor that can only capture a portion of the lens' projected image.

photobydmb Loc: Nashville, TN

Thanks so much for the quick and informative replies!

Now... One more question (I'm basically illiterate with this digital stuff): Realizing the sensor will only record a portion of the image, will the image I see in my viewfinder be the same as the image captured on the sensor? Or will I see everything the lens sees, but the sensor will only record a portion?

Yeah... I'm pretty confused... :?

Izza1967 Loc: Bristol, England

The Canon 20D viewfinder shows roughly 95% of what will be captured by the sensor so if its in the viewfinder it will be in the final image plus a little bit around the edge

HarryBinNC Loc: Blue Ridge Mtns, No.Carolina, USA

Your viewfinder is matched to the sensor. You will only see what will be recorded by the sensor.

Izza1967 Loc: Bristol, England

I think you will find it isn't matched to the sensor hence it states 95% coverage for the 20D

SharpShooter Loc: NorCal

DMB, I too started with a 20d five years ago. It was a fine learner camera.
DMB, I will have to respectfully disagree with Kicker on the point of the EFs lenses. I feel that crop camera users are done a disservice when they are told to get only EF lenses. The EFs lenses are designed specifically to use on crop cameras. Two lenses in particular are as good optically as the Canon L lenses but with less build quality and are hence considerably less expensive than the comparable L lenses. The two lenses I refer to are the 17-55 2.8 and the 15-85.
When I first went digital, after much recommendation, I immediately purchased the 24-105 L. And as much as I tried to talk myself into the fact that it was a great lens, in a month I had to break down and buy the 15-85, as the 24-105 was just NOT wide enough for an everyday walk-around, at least not for me.
What I'm saying is buy the tools you need to do the photography you do right now, and NOT what you may some day do.
Also, though the 20d is a fine camera, I would learn on it, then be looking for something with more mega-pixels, such as a new or used 60d or 7d, or even a Full-Frame. I took several VERY nice shots with the 20d that I can't do much with since the files are just to small. Just my 2cents.
Good luck and have fun shooting.
SS

CHG_CANON Loc: the Windy City

Others have confirmed the EF question. Here's a link to a wiki page that summarizes the technical details of the entire digital EOS line: http://en.wikipedia.org/wiki/Comparison_of_Canon_EOS_digital_cameras

cthahn

These are the problems you can have when using after market lenses. Call Tamron.

louish160 Loc: Vacaville, CA

One good thing to look at is the lens and camera mount. Red dot indicates EF.. White square indicates EF-S. If the camera has both, then both types will work. Do not try to fit an EF-S onto an EF only because the real element of the lens is further into the camera than an EF and you will damage the lens and or camera. Just match the dot/square.

sirlensalot Loc: Arizona

Best advice here is from louish 160. I have the lens you are talking about and have used it successfully on a 300D and a 40D. It also works on a 5D. The only thought that comes to mind is the lens you purchased is not a Canon mount, but just guessing.

drivered Loc: Capital District, NY

Thanks for posting that link.

photo169 Loc: Chicago,ILL

A lot of people misunderstand the 1.6x factor. You don't expand your focal length,you are only cropping the image to get an angle of view like 1.6x your lens focal length. You are not changing your len's focal length in any way.