Newbie question

[MomAndrea]

Hi

I currently own a Canon Rebel 35mm camera and I am looking to upgrade to a DSLR. I have 2 lenses for my current camera, an 18-55 and a 70-300 (I think). Would these lenses work on the Rebel XT as I have the opportunity to buy a used body at a great price.

Thanks.

 

[MomAndrea]

Nobody?

 

[AndrewWG]

I am not too sure, but I would guess that if they are Canon brand lenses, they should work on the Rebel XT. If they are third party lenses like Sigma, they may or may not work. Hope this helps at least a little.

Welcome to the board!

 

[MomAndrea]

Thanks so much . The lenses are Canon.

I was beginning to wonder if my question was just too silly for anyone to answer .

 

[AndrewWG]

No, not too silly at all. None are too silly for this board! I had the same problem when I got my Canon 30D. I had some older lenses from my film Rebel and wanted to use them, but the two I wanted to use were older Sigmas and they wer etoo old to use. They could have been re-chipped to be used with the camera a few years ago, but Sigma stopped doing that unfortunately. I do, however, think that many of the newer lenses will probably give you better photos than the older lenses did. I don't have evidence of this, but the technology has come a long way. Some older lenses will always be superior to the newer ones from what I have read. There are always exceptions to the rule.

 

[Groucho]

I'm not a Canon user, but I know that they did change lens mounts at some point, and lenses for the old mount won't work on the new cameras.

I believe the new mount is the "EOS" mount, and that it was introduced when they went to autofocus cameras. So generally speaking, if it's an autofocus lens, then it's an EOS mount and will work on a new Canon DSLR. I think that the Rebel line didn't exist before the EOS mount was introduced, so probably all Rebels use an EOS mount, but I very well could be mistaken on that. I'm sure a Canon expert could correct me if I'm wrong.

 

[mike_r]

If the lenses say EF on them then you should have no problem using them on either a xt or an xti. Canon still uses the EF line and also there newer line called EF-S.

 

[MomAndrea]

Thanks! I just checked and the lenses DO say EF on them. I am so excited, I'm getting a new camera . I guess I'll be back with more questions soon.

 

[mike_r]

If you are going to buy it at a local camera store, you could also bring the lenses with you so you can try them on the camera so you can make sure that it will autofocus. Places like Best Buy and Circuit City usually have them chained down so you wont be able to mount them.

 

[MomAndrea]

Thanks Mike, that's a great idea. I am buying it from a local camera shop. Well, it's not really local, it's a couple of hours away, but it's not a big box store.

 

[seashoreCM]

Don't forget that, once you get the lenses to fit, even though they still focus let alone autofocus correctly, that you need to recompute the millimeter focal length ratings.

Because the sensor in a digital camera, even a DSLR, is smaller than a 35mm film frame, what was originally a wide angle lens will probably be a regular angle lens and what was once a regular lens will be a telephoto lens. The lens is still projecting the same image into the camera body and the distance between the lens and the film plane is the same, but the smaller sensor of course spans a smaller portion of the image or field of view.

(Math Ph.D. needed) Take the number 43-1/4 (diagonal of a 35mm frame) and divide it by the diagonal of the sensor in millimeters to get a number called the crop factor. (Or the camera instructions will tell you the crop factor which is the same for that body and sensor given any 35mm film camera lens that fits.) Multiply the crop factor by the millimeter rating (such as 18 for a quite wide angle, or 55 for nearly a traditional regular angle, or 70 for a little telephoto or 300 for real telephoto) and you will come up with the 35mm equivalent focal lengths for your new camera and lens combination.

Your question was not silly; it was difficult.

Digital camera hints: http://members.aol.com/ajaynejr/digicam.htm

 

[MomAndrea]

seashoreCM, thanks so much for the information, it is appreciated.

Knowing all of that, should I just get the kit with the lens (Canon 18-55mm EF-S Lens) or attempt to use my own lenses?

Andrea

 

[mike_r]

When I bought my rebel xt brand new it was an extra 100 for the kit at the time, had i known what i know now i would have saved the 100 and put it towards another lens. I ended up using it for 2 weeks or so and bought a used canon 28-135 Image stabalized and that lens gets used more than the kit lens which hasnt been used in quite a while, its probably buried in one of my camera bags, lol.

 

[MomAndrea]

Right now on B&H the difference between the body alone and the kit is $65. I may still be able to get a used body cheaper from a local shop though. I need to find out if they also carry used lenses.

 

[Master Mason]

I'm not a Canon user, but I know that they did change lens mounts at some point, and lenses for the old mount won't work on the new cameras.

I believe the new mount is the "EOS" mount, and that it was introduced when they went to autofocus cameras. So generally speaking, if it's an autofocus lens, then it's an EOS mount and will work on a new Canon DSLR. I think that the Rebel line didn't exist before the EOS mount was introduced, so probably all Rebels use an EOS mount, but I very well could be mistaken on that. I'm sure a Canon expert could correct me if I'm wrong.

Your correct, the rebels came after the EOS mount switch

 

[seashoreCM]

should I just get the kit with the lens (Canon 18-55mm EF-S Lens) or attempt to use my own lenses?

Assuming your own lenses fit and work, you might as well just use them for starters.

If and when you find you need a wider angle, you could buy just one more lens for that. I am making a wild guess that your 18-55mm lens will probably be equal to 36-110mm view equivalents on the digital SLR body. Thirty six millimeters is the typical regular view for a point and shoot camera.

If you want to buy one lens to be both a wide angle lens for the digital camera and a super wide angle lens for the film camera, you may have a dilemma. Putting a digital camera's lens on a film camera may fit but is not recommended. Here, the sweet spot of the lens might not span the bigger film frame and you get blurry and/or dim corners. Meanwhile a lens designed to be super wide angle for a larger film frame might have more geometric distortion even in the field of view spanned by a smaller sensor.