Digital vs Film SLR lenses

[JJF]

Hi all,

I was just wondering about the diffrences between lenses for film SLR's and those for DSLR's. I heard at some stage that when using a film lens gives an magnification factor on the lens, 300mm becomes 400mm and so on.

Are there any drawbacks using a film lens on a DSLR? I personally like photographing birds, and I am looking at buying a 70-300 of some sorts (for my new 350D), would it be wise to consider a film lens (giving an extra 100mm) or should I rather stick to the lenses designed for DSLR's.

Regards,
JJF.

[SuzyView]

Welcome to the forum. All EF lenses fit all Canon EF cameras. EF-S lenses only fit certain cameras like the 20D and 30D and XT and XTi. Canon's film cameras are what is called FF fullframe 100% = 100%. The 10D, 20D, 30D, XT, XTi have sensors that take in the information from a lens with a 1.6x factor so a 50mm EF lens will be 50mm x 1.6 giving it a 80mm length instead. If you are used to a 50mm lens, then purchase the 35mm version if you are planning to get any of the cameras above. If you have a 5D, that is already a FF camera with a FF sensor. No cropping - magnification. I hope this helps. There's only the EF-S lenses to be careful of. They don't fit FF cameras.

[blam]

Welcome to the forum. All EF lenses fit all Canon EF cameras. EF-S lenses only fit certain cameras like the 20D and 30D and XT and XTi. Canon's film cameras are what is called FF fullframe 100% = 100%. The 10D, 20D, 30D, XT, XTi have sensors that take in the information from a lens with a 1.6x factor so a 50mm EF lens will be 50mm x 1.6 giving it a 80mm length instead. If you are used to a 50mm lens, then purchase the 35mm version if you are planning to get any of the cameras above. If you have a 5D, that is already a FF camera with a FF sensor. No cropping - magnification. I hope this helps. There's only the EF-S lenses to be careful of. They don't fit FF cameras.

that answers a lot for me even though I didnt ask the question

Thanks!

[Wilt]

Hi all,

I was just wondering about the diffrences between lenses for film SLR's and those for DSLR's. I heard at some stage that when using a film lens gives an magnification factor on the lens, 300mm becomes 400mm and so on.

Are there any drawbacks using a film lens on a DSLR? I personally like photographing birds, and I am looking at buying a 70-300 of some sorts (for my new 350D), would it be wise to consider a film lens (giving an extra 100mm) or should I rather stick to the lenses designed for DSLR's.

Regards,
JJF.

The 'magnification factor' is better stated as "it's as if you cropped off part of the frame". See this illustration of APS-C (1.6 crop format) vs. a FF subject capture...

http://i69.photobucket.com/albums/i63/wiltonw/cropfactor1.jpg


It has been stated that wide angle lenses for 1.6 crop are a particular challenge, because of the oblique angles that the light rays strike the edges of the frame with a conventional lens. Often the 'digital' lens is designed so that the light rays do not strike the sensor at such an oblique angle, leading to improvements in the chromatic aberrations that can result from oblique light rays coming from the lens.

[tweatherred]

The other issue with EF-S and other "digital" lenses is that they leave less clearance between the back element and the mirror as non-full frame cameras have a smaller mirror to flip up during an exposure. This becomes an issue when peopl ask about adapting lenses across mounts.

[cdifoto]

Also, the "crop factor" still applies to those "digital" lenses...

[runninmann]

To elaborate on Wilt's point, The "film lens" will not give you greater magnification than the "digital lens". The object will be the same size regardless of whether you use an EF or and EF-S (Canon nomenclature) lens of the same focal length. 300mm will be 300mm regardless of lens type or sensor size.

[SuzyView]

This crop factor of the 20D makes me crazy sometimes. I really love the 17-40 as a wide angle lens on my EOS 3, especially for large landscapes. On the 20D, I feel it should be wider, but I live with it. I think this is the reason why so many 20D users are going to the 5D. The FF is really wonderful.

[blam]

isn't the crop ont eh 20D 1.6? and arent most prosumer DSLRs in teh 1.5-1.6 range?

the 1D is a 1.3, correct?

I haven't seen any 1.0 yet, do they exist?

[tsaraleksi]

isn't the crop ont eh 20D 1.6? and arent most prosumer DSLRs in teh 1.5-1.6 range?

the 1D is a 1.3, correct?

I haven't seen any 1.0 yet, do they exist?

The 5D and the 1Ds & 1Ds Mk II are both full frame, i.e. 1x.

[blam]

oh snap....so that's whewrew the price difference comes in........interesting.

[Hellashot]

FF lenses are not magnified when they are put on a small sensor dSLR. The dSLR simpley cannot record everything the lens is seeing and "crops" the image for you. It will make your images "appear" to have been taken on a longer lens, but I can do the same thing by cropping the image afterwards on my 5D. :)

[Permagrin]

This crop factor of the 20D makes me crazy sometimes. I really love the 17-40 as a wide angle lens on my EOS 3, especially for large landscapes. On the 20D, I feel it should be wider, but I live with it. I think this is the reason why so many 20D users are going to the 5D. The FF is really wonderful.

You should cave Suzy and go 5D, you'll never be sorry!

[JJF]

Thanks for all the helpfull replies. It is better thus to buy a normal film lens (or EF equivalent) for upwards compatability to the 5D+? Does anyone know if the Sigma range of lenses for dslr's (DG series I believe) have the same issues, ex. does the 70-300 APO MACRO2 DG fit on the 5D?

[runninmann]

Sigma designates their lenses designed specifically for APS-C (1.6x crop factor) sensors "DC". To my understanding, the "DG" designation has more to do with the optics being designed to better control or mitigate the effects of the reflective digital camera sensors, regardless of sensor size.