Canon EFS?? Does Crop Exist???

[DSLR noob]

guys I used to think thew way he did so I know what he's asking.

You're wondering why make an EF-S lens for a camera with a crop if it doesn't adjust for the crop AND can't be used on a full frame, or film camera? The answer, cheaper. The lens going back into the camera more, does NOT change the focal length. 18 is 18 and 30 is 30 and so on. The EFS lenses aren't meant to "undo" any cropping, but rather be cheaper ot make. also to be able to make lenses wide enough to still be wide after a crop. Without that recession, you'd never be able to shoot with a 10mm lens, or at least wihtout paying a hell of a lot (you'd still have to pay a lot).

 

[ksmattfish]

So my question still stands, why EFS

Why EF lenses? They won't work on medium or large format cameras.

Why medium format lenses? They won't work on large format cameras.

Why not make all lenses with enough coverage so that everyone using any camera with a format up to 20"x24" can use them? Because it would be silly to carry around, or pay for a lens that will cover 20"x24" if all you need it to cover is 17mm x 25.5mm.

Focal lengths that give a "normal" angle of view by format, followed by "crop factor":

APS-C 31mm x1.6
35mm 50mm x1
6x4.5cm 75mm x0.66
6x6cm 80mm x0.62
6x7cm 100(ish)mm x0.5
4x5in 150mm x0.33
8x10in 300mm x0.16

All of those focal lengths, coupled with those formats, give an angle of view of approx 47 degrees.

 

[Digital Matt]

The only reason Canon has made EF-S lenses is to make cheap super wide angle lenses. The lenses are smaller and lighter, and as a result, the image circle is smaller. This is why the lens needs to be closer to the film plane, thus the new EF-S mount. Compare the price and performance of the 18-55 kit lens to a 17-40L and you'll see why Canon invented this technology. To offer cheap lenses to go with cheap DSLRs, and keep consumer's happy.

 

[usayit]

The only reason Canon has made EF-S lenses is to make cheap super wide angle lenses. The lenses are smaller and lighter, and as a result, the image circle is smaller. This is why the lens needs to be closer to the film plane, thus the new EF-S mount. Compare the price and performance of the 18-55 kit lens to a 17-40L and you'll see why Canon invented this technology. To offer cheap lenses to go with cheap DSLRs, and keep consumer's happy.

I'm not totally in agreement... the 18-55mm EF-S lens is basically consumer lens which can't be compared to the 17-40L. There are two other EF-S lenses in similar focal range that are between $500 and $1000 which is at or more than the cost of the 17-40mm L. From my point of view.. EF-S was developed for one reason only..... marketing....

On the other hand.. I have a 19-35mm Tokina that costs about $150 bucks about par wiht the 18-55mm kit lens in an EF mount. The Tokina "plastic wonder" is a great bang for the buck lens by the way.

Oh yeh.. if you look up the formula for a lens' focal length (try wikipedia) you'll notice the formula has nothing to do with the size of the sensor (image circle). Crop factor was just a way to bring a new format (APS sized sensor) to a crowd used to seeing things through a 35mm viewfinder.

 

[usayit]

Lots of Pentax Pros really made use of the 645 format several years ago and an adapter was made to mount 645 lenses, which is x0.66 times the 35mm format, on Pentax 35mm bodies. The adapter was pretty nice... and made a pentax 35mm body the perfect backup camera for a Pentax 645 system. Kinda like mounting a 35mm EF lens to a camera with APS-C sized sensor...

 

[Stevedevil]

As a final point to this I set up my camera on a tripod and set my EFS lense to 35mm and took a photo, then changed the Lens to my 28 - 80 EF lens, and again set this at 35mm and took another, overlayed them in Photoshop, and hey presto, exactly the same size, It does seem a little funny that a lense is being Manufactured ONLY to fit on a EOS camera, Will stick to EF from now as not to find myself purchasing more equipment only to find that the EFS will not fit and become Ebay fodder, Thanx for all replies, good reading, Steve

 

[Alex_B]

As a final point to this I set up my camera on a tripod and set my EFS lense to 35mm and took a photo, then changed the Lens to my 28 - 80 EF lens, and again set this at 35mm and took another, overlayed them in Photoshop, and hey presto, exactly the same size,

learning by doing

 

[EOS_JD]

As a final point to this I set up my camera on a tripod and set my EFS lense to 35mm and took a photo, then changed the Lens to my 28 - 80 EF lens, and again set this at 35mm and took another, overlayed them in Photoshop, and hey presto, exactly the same size, It does seem a little funny that a lense is being Manufactured ONLY to fit on a EOS camera, Will stick to EF from now as not to find myself purchasing more equipment only to find that the EFS will not fit and become Ebay fodder, Thanx for all replies, good reading, Steve

Only by upgrading to a Full Frame camera will the EFS lens be unuseable and anyway the resale value of the good Canon EF-S lenses is still pretty high.

the EF-s 10-22 is a superb lens.

I note you set up your lens with your own camera. To see the difference the crop factor makes you'd need to set up your camera at 35mm and see what you see compared to a full frame camera set at 35mm.

The 1.6 multiplication to the focal length of a lens on a crop camera is toi equate it to the same field of view that you'd get from a FF camera.

So the view from 35mm on your 1.6 crop camera would be the same as the view of 21.875 (to be exact) on a Full Frame Camera.

21.875 * 1.6 = 35

I appreciate some say the crop does not exist and that is correct but the effective focal length of your 18-55 on the crop camera you have will still be 28.8-88mm (rather than the other way round that you thought).

 

[Alex_B]

So the view from 35mm on your 1.6 crop camera would be the same as the view of 21.875 (to be exact) on a Full Frame Camera.

21.875 * 1.6 = 35

in your thread it is not clear to me if you refer to 35mm focal length, or 35mm film/FFsensor.

This sentence is very confusing to me ... it will be more confusing for beginners.

 

[lostprophet]

Only by upgrading to a Full Frame camera will the EFS lens be unuseable and anyway the resale value of the good Canon EF-S lenses is still pretty high.

or a 1.3x crop camera

 

[tempra]

or a 1.3x crop camera

Or an EOS 10D

 

[EOS_JD]

or a 1.3x crop camera

Yes you are quite correct my error!

 

[EOS_JD]

Or an EOS 10D

10D wouldn't be classed as an upgrade though. I appreciate the 10D doesn't take EF-S lenses.

 

[EOS_JD]

in your thread it is not clear to me if you refer to 35mm focal length, or 35mm film/FFsensor.

This sentence is very confusing to me ... it will be more confusing for beginners.

OK Maybe I should not have used 35mm as the focal length but that was what was meant.