Silly question.

[DIW35]

Can anyone tell me what the difference is between a Canon EF lens and a EF-S lens? I have a 40D body, so does it matter which of the two types I use?

[miniman]

EF-S lenses are, I think, specifically for DSLRs with a 1.6x crop factor. They do work with the 40D.

Guess this answers my "so what did you buy" question when reading your other thread!

[megy]

If you have a loo at the bayonet rin on your camera if you see a red dot it is for EF lenses, if there is a white dot about 30 degrees clockwise from this then thats the line up dot for EF-S lenses. I believe the 40D is EF-S compatible.

[Famous Graham]

EF-S and EF lenses will work on an EF-S capable camera.
EF-S lenses won't work on an EF camera, only EF lenses.

EF-S "capable" bodies are those with the APS-C sized sensors (whcih result in the 1.6 crop factor mentioned above) and are the 300D, 350D, 400D, 20D, 20Da, 30D and 40D.

The 10D, 5D and 1D range are not capable of mounting EF-S lenses.

[DIW35]

Ok so far. I now know that both types of lens will fit my camera body. However, I am none the wiser as to the difference between the two types.

When I finally get round to purchasing another lens(es) for my camera, what type should I be looking to get, assuming that one is better than the other, or has some other advantage I can make use of?

[S. Gonzales Esq.]

AFAIK, the EF-S lenses don't poduce an image large enough to cover a full-frame sensor. If you could fit them to a full-frame camera you would see vignetting (severe light fall-off) at the edges of the picture. EF lenses generally cost more, but you can keep them if you upgrade your camera body.

If you're keeping your current body, there's much less potential benefit in buying EF lenses.

Edited by S. Gonzales Esq. on Friday 30th November 00:20

[flat-planedCrank]

DIW35 said:

Ok so far. I now know that both types of lens will fit my camera body. However, I am none the wiser as to the difference between the two types.

When I finally get round to purchasing another lens(es) for my camera, what type should I be looking to get, assuming that one is better than the other, or has some other advantage I can make use of?

The EF-F lenses are designed for digital APS-C (1.6x crop factor) cameras such as the 400D, 40D, etc..
If the lenses you require are EF-S and you don't see yourself moving to a Full Frame camera (like the 5D) or a APS-H camera (like the 1D mk3), both considerably more expensive options, then get the EF-S lens

There is no inherent benefit in going for EF-S over EF. In fact, for Canons' L series lenses (their top-of-the-range series) there are none with an EF-S mount. If an EF lens fits your requirements / budget, then go for it

Because there are 'crop factors' for the different sensor sizes there can be a bit of confusion over whether designed-for-digital EF-S lenses are effected by this. They are
Eg. An EF 50-100mm lens would be identical to a EF-S 50-100mm on a camera like the 40D.
(In 'old terms', or Full-Frame-sensor camera terms, they would effectively work like 80-160mm lenses (50*1.6, and 100*1.6).

Finally other lens manufacturer's have similar lens ranges that are designed for APS-C cameras only. Eg. Sigma has 'DC', and Tamron has 'Di II'


Hope this helps

Edited by flat-planedCrank on Friday 30th November 02:36

[Famous Graham]

DIW35 said:

However, I am none the wiser as to the difference between the two types.

The S stands for "Short back focus". The rear element extends further back from the mount so it gets closer to the sensor.

As said, if you're not planning on changing bodies for a while, just go for the lens that suits best regardless of EF/EF-S type. But be aware you might have to replace it if you change cameras.

[DIW35]

I think that fianlly clears it up. Having only just persuaded my better half that I really couldn't do without a 40D, despite the cost, I reckon I would be really pushing my luck to try and justify a few thousand for a 'pro' body, even if it is a few years down the line.

So far I have been quite happy with the photos I have been getting with the 40D. Considering I used my T90 for 15 years or more before changing to digital, I think this current camera should last me for a while. I'm not one of those who has to have the latest model, especially when the model I have probably has more functions than I am likely to use.