Film lens

[snoopygirl79]

Hi all,

I'm getting myself in a pickle thinking about lenses and I just need something clarified!! I have a DSLR, Canon 350D (not sure what it's called in the US). My Dad used to have a Canon film SLR so he gave me all his lenses and one of them was a 24-85mm which cost him quite a bit at the time so I've been using that ever since.

Is there a difference between digital and film lenses? Or is it only in reference to the sensor size? So, is this 24-85mm lens not what it says on the tin cos my sensor size is different to a SLR film camera? Does it equate to a different size?

If that makes any sense to anyone, I'd appreciate any help!!

Thanks

Vick

 

[jann1033]

Hi all,

I'm getting myself in a pickle thinking about lenses and I just need something clarified!! I have a DSLR, Canon 350D (not sure what it's called in the US). My Dad used to have a Canon film SLR so he gave me all his lenses and one of them was a 24-85mm which cost him quite a bit at the time so I've been using that ever since.

Is there a difference between digital and film lenses? Or is it only in reference to the sensor size? So, is this 24-85mm lens not what it says on the tin cos my sensor size is different to a SLR film camera? Does it equate to a different size?

If that makes any sense to anyone, I'd appreciate any help!!

Thanks

Vick

i think what you are asking is will it make a difference in the focal length,. you'd multiply the length by 1.6 to see what the lens would appear like with your camera so approx 38-136. it isn't really quite that length though since it crops rather than magnifies the photo ie you will not get the detail a true 136mm lens would give you due to magnification, more like if you took a photo at 85mm then cropped it out to equal a photo of 136, it would be bigger but not any more detailed than at 85...if that makes sense
http://www.millhouse.nl/digitalcropfactorframe.html .........for a visual....

 

[photo_chick]

The 350D is the Rebel XT.

TEh crop factor does affect focal length, btu here is my conclusion... IF you have not used those lenses on a 35mm or full frame sensor DSLR then don't get the headache worrying about it. Just get a feel for it on your current body and learn how it works on there.

I finally, after weeks of reading got my head wrapped around exactly how it works.. I think.... The lens is not actually changing the size of anything. The lens is still the same magnification. The area of the image your sensor captures is smaller. So when you go make a 4x6 print it will appear larger because something will take up more space in that frame as opposed to 35mm film which is slightly larger.

Am i close guys?

 

[jann1033]

sounds right to me...that is why (i would guess )they call it a crop factor ,it's like cropping a photo. it's less of the photo ( than what you would have without the crop factor ie on a 35mm frame)displayed in the same area so that section appears larger but not more detailed( like it would if it were actually magnified with a longer lens length)

 

[Master Mason]

Time to break out ObliO's famous example again

The circle is what the lens "sees"
The yellow is what would be recorded on a 35mm camera
The pink is what is recorded on a 1.6 crop camera.

to me that is the easiest way to think about it.

 

[jann1033]

i was trying to find that one as well, couldn't and so linked to the other one...maybe we should make that one of the stickies since it comes up alot?

 

[Groucho]

The actual difference between the digital and film lens is that the digital ones are specifically designed for the smaller sensor. The focal length numbers are the same and subject to the same crop factor adjustment.

A film lens is designed to create an image big enough to cover the full 35mm negative. The digital lens only has to cover the smaller sensor, so they can be lighter and smaller. A digital lens will mount on a film SLR just fine, but will suffer from heavy vignetting (the corners will be black, because the lens is not covering the while negative.)

The digital lenses will also usually have a slightly different coating, which is supposed to work a little better with a digital sensor, though this is a fairly minor issue from what I can tell.

Hopefully that helps explain it...

 

[Master Mason]

The actual difference between the digital and film lens is that the digital ones are specifically designed for the smaller sensor. The focal length numbers are the same and subject to the same crop factor adjustment.

A film lens is designed to create an image big enough to cover the full 35mm negative. The digital lens only has to cover the smaller sensor, so they can be lighter and smaller. A digital lens will mount on a film SLR just fine, but will suffer from heavy vignetting (the corners will be black, because the lens is not covering the while negative.)

The digital lenses will also usually have a slightly different coating, which is supposed to work a little better with a digital sensor, though this is a fairly minor issue from what I can tell.

Hopefully that helps explain it...

See and Mr ObliO has helped us out with that in the past as well too

This is what a for digital lens looks like,
the circle is what the lens sees
yellow lines is what a 35mm sensor would see
pink is what a 1.6 crop would see