Digital SLR Lens Vs. Film SLR Lens (mm)

[zenderfall]

This is something I found interesting. I used to own a Canon EOS IX Lite (very rare and strange camera) yeah, I know, I had it for about 2 years and had quite a few SLR lens with it. What I noticed is that with this particular camera, I had to use a *multiplier* to find out the real Lens is. For example, a 22-55mm lens (the included kit lens) is actually a 36-88mm, or what they put in print, a 35-90 mm.

I never knew what that meant, because I didn't have a 35mm film body to mount the lens on and compare the differences, in short, I want to know if the same lens looked through by a dRebel and then through a 35mm SLR would yield a different focal length.

Now, with a new 300D/dRebel, I find this camera is the same-it has *35mm equivalence* and its kit lens, which has an 18-55mm lens (which is not a super wide angle BTW) is actually a 28-90mm. What does the multiplier really *mean*?

I know that the 18-55 can't be mounted on 35mm film cameras, but if it could, would you in theory have a wide angle 18mm-55mm lens? Do I need to offset a 1.6x multiplier on every lens I slap onto the debel body?

Thanks, I'm hoping some people out there with a 35mm and dRebel body can help.

[Michael Fanelli]

A multiplier isn't real!

A lens has a certain focal length. It is independent of the camera it is used on. A 50mm lens is a 50mm lens.

However, the field of view changes. A 50mm lens on a 6x7 camera is a wide angle, on a 35mm it's "normal", on an APS digital camera, its a mild telephoto. People who use multiple formats, such as 35mm and 6x7 understand this and never really talk about "multiplier factors."

The "35mm equilvalent" is just marketing. The vast majority of photographers are used to using 35mm. These "equivalent" values are just a mental aid that says "if you use this 50mm lens on an APS sensor it sorta kinda looks like the 80mm lens you used to use".

Instead of worrying about these things, start thinking about what the lens does on the format you have chosen. When I grab a 45mm lens for a 6x7 camera I don't think "Hmmm, what would this be if I were using 35mm?" The same goes for the Rebel: worry what it looks like on the Rebel, not some other irrelevent format. You should not worry about 35mm if you aren't using 35mm!

What I noticed is that with this particular camera, I had to use a *multiplier* to find out the real Lens is. For example, a 22-55mm lens (the included kit lens) is actually a 36-88mm, or what they put in print, a 35-90 mm.

I never knew what that meant, because I didn't have a 35mm film body to mount the lens on and compare the differences, in short, I want to know if the same lens looked through by a dRebel and then through a 35mm SLR would yield a different focal length.

Now, with a new 300D/dRebel, I find this camera is the same-it has *35mm equivalence* and its kit lens, which has an 18-55mm lens (which is not a super wide angle BTW) is actually a 28-90mm. What does the multiplier really *mean*?

I know that the 18-55 can't be mounted on 35mm film cameras, but if it could, would you in theory have a wide angle 18mm-55mm lens? Do I need to offset a 1.6x multiplier on every lens I slap onto the debel body?

Thanks, I'm hoping some people out there with a 35mm and dRebel body can help.

[darkman]

Instead of worrying about these things, start thinking about what the lens does on the format you have chosen. When I grab a 45mm lens for a 6x7 camera I don't think "Hmmm, what would this be if I were using 35mm?" The same goes for the Rebel: worry what it looks like on the Rebel, not some other irrelevent format. You should not worry about 35mm if you aren't using 35mm!

This sounds just like what I told someone recently when he was concerned about a 100mm 1:1 macro lens on a drebel. He coulnd't grasp magnification is size of the image on the sensor divided by the size of the object. Somehow he thought the lens magnification somehow increased.

I finally told him not to worry and just look through viewfinder and take the picture.

Mike

[another view]

I finally told him not to worry and just look through viewfinder and take the picture.

Mike

Good advice. It's really more of a crop factor than a magnification factor, but after using your camera you'll just know what lens to grab. Like Michael says, 50mm is different on every different format.

It's not a bad thing to talk about though - some DSLR's are (in comparison to 35mm) full frame, 1.3, 1.5, 1.6 and probably others. This way you know what you're looking at, after all you will use the 35mm lenses on the DSLR body. Since mine's a 1.5, I knew my 20mm lens would only have the angle of view of a 30mm so at some point I'll have to get something wider. That disadvantage works out to an advantage with my 80-200 f2.8 - it's now a (in terms of angle of coverage) 300 f2.8.

[darkman]

disadvantage works out to an advantage with my 80-200 f2.8 - it's now a (in terms of angle of coverage) 300 f2.8.

For MY photography I found the 1.5x it to be a disadvantage. However, I'm really liking the sigma 12-24 even better than my canon 17-35L. The extra "reach" in dof is great for landscapes.

Now that I have the sigma, I really can't complain on the long end. It does open up some new oportunities! Plus now I have a 12-24, 24-70/2.8L, 70-200/2.8ex and a 1.4x tc (that's collecting more dust than ever). I still find I rarely use beyond ~150mm.

Mike

[zenderfall]

Thanks for all the replies. I guess I shouldn't worry about the lens factors and just keep on shooting. Photography isn't all about focal length, or maximum aperture. Its about pictures after all.

For MY photography I found the 1.5x it to be a disadvantage. However, I'm really liking the sigma 12-24 even better than my canon 17-35L. The extra "reach" in dof is great for landscapes.

Now that I have the sigma, I really can't complain on the long end. It does open up some new oportunities! Plus now I have a 12-24, 24-70/2.8L, 70-200/2.8ex and a 1.4x tc (that's collecting more dust than ever). I still find I rarely use beyond ~150mm.

Mike

[another view]

I'm really liking the sigma 12-24 even better than my canon 17-35L. Mike

Heard that's a great lens, it's next on the list for me!