ef-s

[rojo]

not sure if it has been talked about here, but my one question is why if the ef-s lens are specifically designed for a 1.6 crop factor and it will not fit on a regular 35mm format, why not just call the numbers what they really are. 18-55 =28-88. if that's what it is, that's what it is. i am new and this can be way off base, just a ? by the way thanks for this site it has helped out in many way's

[Icebreaker]

Someone can probably give a more technical answer, but the skinny is that an ef-s lens sticks deeper into the camera. Thus if put on a regular slr the mirror would hit. At least this is my understanding.

[MrChad]

The length is the same as film but, the field of view is slightly less.

Thus the EF-S lens length is the correct length as stated but the effective field of view is the same as a 28-88 or what have you.

[rojo]

i agree with you guy's, maybe it's a pondering thought to canon. why not just give them the numbers they are?

[DaveG]

i agree with you guy's, maybe it's a pondering thought to canon. why not just give them the numbers they are?

Simply because we all thought that the 1.6 and 1.3 conversion was going to be transitionary - and may well still be - it was easier to convert it to what we all understood to be the field of view of a 35mm lens. When you incorporate Nikon's 1.5 and god-knows-what 4/3rds are it seems to make sense to convert them as kind of a base value.

Besides if you put the kit lens on the drebel and call it that and then the 24-85 regular lens how do you differentuate?

[timmyquest]

The fact of the matter is that a 28mm lens is a 28mm lens no matter what camera its on.

If you take a 50mm lens and put it on a medium format camera vs a 50mm lens on a 35mm camera you'll get how this works. Focal length is all about the lens and has nothing to do with the camera.

[CoolToolGuy]

The 35mm film format has become such a standard that the camera manufacturers use the 35mm focal lengths as a reference. As was mentioned above, a 28mm is a 28mm is a 28mm. But the angle of view (how much width) that a given focal length covers is defined by the size of the frame or sensor that records the image. For a Mamiya 645 medium format camera, an 80mm lens is the 'normal' size, and for a 1.6 crop factor camera, 28mm is considered the 'normal' lens.

Hope this helps.

Have Fun,

[ScottE]

When I first got my D60 a few years ago I spent a lot of time trying to compare lenses to field of view on my 35 mm cameras. Now, after hardly using my 35 mm cameras for a couple of years, I think of the D60 framing as normal. Thank goodness it will be the same on my 20D when it arrives. I now have to go through a conversion process to select the correct lens when occasionally I shoot 35 mm. Fortunately I find it easier to multiply by 8/5 than by 5/8 in my head.

The 35 mm framing equivalents are only useful to people who switch formats all the time. The rest of us get used to the framing on our D30/D60/10D/300D/20D's and never think about 35 mm equivalents any more.

Ever since my 500 mm lens started framing like an 800 mm I have liked the smaller framing. The only thing I have missed is a true wide angle and that may well be answered with the new 10-22.

[booggerg]

Well, when you buy lenses you still take the focal length and * 1.6.

[Jesper]

not sure if it has been talked about here, but my one question is why if the ef-s lens are specifically designed for a 1.6 crop factor and it will not fit on a regular 35mm format, why not just call the numbers what they really are. 18-55 =28-88. if that's what it is, that's what it is. i am new and this can be way off base, just a ? by the way thanks for this site it has helped out in many way's

Because 18-55 are the real numbers. You just want to call it "28-88" because that's the equivalent field of view on a 35mm film camera. Other aspects, like the depth-of-field, are not the same as on a 35mm camera.

Why should we continue to compare 1.6x crop factor cameras to 35mm cameras all the time? Just because so many people are familiar with 35mm cameras? In a few years, when most people starting with photography haven't ever used a 35mm camera, it will only be more confusing if we multiply all focal lengths by 1.6. Then people will be asking why we're calling a 18-55 an "28-88".

[rojo]

thank's for the input. as i said i am new and do not know how to link web sites, found this one. [http://www.sweeting.org/mark/lenses/canon.php] it discusses angle of view.