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Thread: SLR Lens on DSLR

  1. #1

    Default SLR Lens on DSLR

    Wonder is there a so-call SLR lens term?

    Anyway if we mount a SLR lens on DSLR (450d), the focal length we need to multiply by 1.6 right? So if i have a Vivitar 70-210/2.8-4 APO, if I mount in on my 450d, it will become ~110-330mm lens? What about the aperture, does it remains?

    As the Vivitar 70-210/2.8-4 APO is attacked by fungus, do you think its good to send for cleaning or buy a new lens better?

  2. #2
    Member lennyl's Avatar
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    Default Re: SLR Lens on DSLR

    Quote Originally Posted by acitinium View Post
    Anyway if we mount a SLR lens on DSLR (450d), the focal length we need to multiply by 1.6 right? So if i have a Vivitar 70-210/2.8-4 APO, if I mount in on my 450d, it will become ~110-330mm lens? What about the aperture, does it remains?

    As the Vivitar 70-210/2.8-4 APO is attacked by fungus, do you think its good to send for cleaning or buy a new lens better?
    The focal length does not change. The apparent field of view changes. The depth of field, which is affected by focal length, does not change.

    Meaning, mounting a 100mm lens on your 450D will give you the same view through the viewfinder as mounting a 160mm lens on your film camera. Which is what most people are interested in. However, even though you have the same frame, at the same aperture setting, the 450D will have more things in focus.

    The aperture does not change. The aperture number is a ratio of focal length to diameter of aperture, and since both aperture and focal length does not change, it does not change as well.

    I'm not familiar with the Vivitar. But when fungus attack a lens, it may cause permanent damage to the glass by etching into the glass. Is the Vivitar a good lens? Is it worth saving? You have to decide for yourself.

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    Default Re: SLR Lens on DSLR

    Quote Originally Posted by acitinium View Post
    Wonder is there a so-call SLR lens term?

    Anyway if we mount a SLR lens on DSLR (450d), the focal length we need to multiply by 1.6 right? So if i have a Vivitar 70-210/2.8-4 APO, if I mount in on my 450d, it will become ~110-330mm lens? What about the aperture, does it remains?

    As the Vivitar 70-210/2.8-4 APO is attacked by fungus, do you think its good to send for cleaning or buy a new lens better?
    why not get a quotation from the servicing agent before deciding if you wish to send for cleaning or purchase a new piece?
    D800 | D700|16mm f2.8D|35 f1.4G|50 f1.8G|60mm F2.8D|85mm f1.4G|16-35 f4G|70-200 f2.8 VR2| SB900

  4. #4

    Default Re: SLR Lens on DSLR

    Quote Originally Posted by lennyl View Post
    The focal length does not change. The apparent field of view changes. The depth of field, which is affected by focal length, does not change.

    Meaning, mounting a 100mm lens on your 450D will give you the same view through the viewfinder as mounting a 160mm lens on your film camera. Which is what most people are interested in. However, even though you have the same frame, at the same aperture setting, the 450D will have more things in focus.

    The aperture does not change. The aperture number is a ratio of focal length to diameter of aperture, and since both aperture and focal length does not change, it does not change as well.

    I'm not familiar with the Vivitar. But when fungus attack a lens, it may cause permanent damage to the glass by etching into the glass. Is the Vivitar a good lens? Is it worth saving? You have to decide for yourself.
    err ... too chim for me to digest
    so in short, if i mount the slr 70-210 into 450d, its equi to:
    1. no change 70-210mm
    2. longer ~110-330mm
    3. shorter ~40-130mm

    as i am a total noob, therefore dunno vivitar 70-210/2.8-4 consider a good lens or not. but i like the aperture of 2.8-4, and its a macro lens somemore. think if wanna buy a new lens with that range would easily cost above 1.5k.

  5. #5

    Default Re: SLR Lens on DSLR

    Quote Originally Posted by spazzer View Post
    why not get a quotation from the servicing agent before deciding if you wish to send for cleaning or purchase a new piece?
    any shop to recommend?
    as i believe vivitar no more producing lens, and no service in singapore.

  6. #6

    Default Re: SLR Lens on DSLR

    Quote Originally Posted by acitinium View Post
    err ... too chim for me to digest
    so in short, if i mount the slr 70-210 into 450d, its equi to:
    1. no change 70-210mm
    2. longer ~110-330mm
    3. shorter ~40-130mm

    as i am a total noob, therefore dunno vivitar 70-210/2.8-4 consider a good lens or not. but i like the aperture of 2.8-4, and its a macro lens somemore. think if wanna buy a new lens with that range would easily cost above 1.5k.
    It will be no change, just like another 70-210 mounted on your 450d.

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    Default Re: SLR Lens on DSLR

    Quote Originally Posted by acitinium View Post
    any shop to recommend?
    as i believe vivitar no more producing lens, and no service in singapore.
    Contact a member here on CS nicknamed 'Fatigue'. He'll help you out.

  8. #8

    Default Re: SLR Lens on DSLR

    Quote Originally Posted by calebk View Post
    Contact a member here on CS nicknamed 'Fatigue'. He'll help you out.
    thanks pal, will pm him

  9. #9
    Member lennyl's Avatar
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    Default Re: SLR Lens on DSLR

    Quote Originally Posted by acitinium View Post
    err ... too chim for me to digest
    so in short, if i mount the slr 70-210 into 450d, its equi to:
    1. no change 70-210mm
    2. longer ~110-330mm
    3. shorter ~40-130mm

    as i am a total noob, therefore dunno vivitar 70-210/2.8-4 consider a good lens or not. but i like the aperture of 2.8-4, and its a macro lens somemore. think if wanna buy a new lens with that range would easily cost above 1.5k.
    If you just want the easy answer : it will look like a 110-330mm lens on a film camera. But keep in mind it is not exactly the same. The difference will be important to you in the future as you progress.

    If you're interested in what actually happens, and why they are called cropped sensor cameras :

    Mount the lens on a film camera. Take a photo. Develop and print it out into 4R.

    Now take a ruler and measure a rectangle 3.75 x 2.5 inches (6 inches divided by 1.6 x 4 inches divided by 1.6), in the center of that photo. Cut it out. This is exactly the view you would get from your 450D.

    You can, of course, enlarge the first print, so that when you cut out the center part, you end up with a 4x6 print.

    I tried to look up the Vivitar 70-210mm on Google. Found out a few things:

    1. It is not clear if there is an EF mount version of the lens. You can of course use a FD to EF adapter.

    2. It looks like it is manual focus only.

    3. I see prices below US$200 - used lenses, of course.

    You can get a Tamron 70-200mm f/2.8 for below $1k I think (US$700 at Amazon, check the price list in the sticky in Canon sub-forum for Singapore price). You can get lenses that cover that range much cheaper, but they have much smaller apertures.

  10. #10

    Default Re: SLR Lens on DSLR

    Thanks for your feedback.

    1. It is a film lens in 1st place, why the lens range changed when mount on a film camera?
    2. It is canon mount.
    3. Its autofocus
    4. I try not to get the BBB virus, therefore i try to salvage whatever avail to me currently.

    here a pic of the lens i found in the net



    Quote Originally Posted by lennyl View Post
    If you just want the easy answer : it will look like a 110-330mm lens on a film camera. But keep in mind it is not exactly the same. The difference will be important to you in the future as you progress.

    If you're interested in what actually happens, and why they are called cropped sensor cameras :

    Mount the lens on a film camera. Take a photo. Develop and print it out into 4R.

    Now take a ruler and measure a rectangle 3.75 x 2.5 inches (6 inches divided by 1.6 x 4 inches divided by 1.6), in the center of that photo. Cut it out. This is exactly the view you would get from your 450D.

    You can, of course, enlarge the first print, so that when you cut out the center part, you end up with a 4x6 print.

    I tried to look up the Vivitar 70-210mm on Google. Found out a few things:

    1. It is not clear if there is an EF mount version of the lens. You can of course use a FD to EF adapter.

    2. It looks like it is manual focus only.

    3. I see prices below US$200 - used lenses, of course.

    You can get a Tamron 70-200mm f/2.8 for below $1k I think (US$700 at Amazon, check the price list in the sticky in Canon sub-forum for Singapore price). You can get lenses that cover that range much cheaper, but they have much smaller apertures.

  11. #11
    Senior Member ZerocoolAstra's Avatar
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    Default Re: SLR Lens on DSLR

    Quote Originally Posted by acitinium View Post
    Thanks for your feedback.

    1. It is a film lens in 1st place, why the lens range changed when mount on a film camera?
    .
    .
    .
    Standard 35mm film measures 24 x 36mm.
    This is the common type of film used in film SLRs (and even in film compact cameras).
    The lens from a film SLR is designed to produce a circular image that is large enough to cover this entire 24 x 36mm rectangle.
    An entry-level digital SLR's image sensor is much smaller than 24 x 36mm.
    Nikon uses one that is 1.5x smaller than 35mm film [16 x 24mm].
    Canon uses one that is 1.6x smaller than 35mm film.

    Now imagine you use the same lens (from a film SLR) mounted onto a DSLR. The sensor captures only the central portion of the image, and hence what you see is a 'cropped' version of the image which would have been captured by a film SLR.

    This cropped image is equivalent to the view you would get if you had a lens with 1.5x (or 1.6x) the focal length.

    Hope my explanation is easy enough to understand.
    Bear in mind that having a cropped view is not quite the same as having more zoom.
    i.e. mounting a 200mm lens onto a DSLR gives you the same view as having a 300mm lens on a film SLR, but the DSLR doesn't give you this 'magical zoom'. It just captures less of the image to give you that illusion.

  12. #12
    Member lennyl's Avatar
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    Default Re: SLR Lens on DSLR

    Quote Originally Posted by acitinium View Post
    1. It is a film lens in 1st place, why the lens range changed when mount on a film camera?
    The view changes when compared between a film camera, and a digital camera.

    OK, third attempt. If you still don't get it, then I give up and admit I'm lousy at explaining things. Please also re-read the part about cutting out the center part of your 4R print.

    It is expensive (for now) to make a sensor the same size as a 35mm film. Canon chose to make it 1.6 times smaller (length wise). Nikon chose to make it 1.5 times smaller.

    Imagine what happens when you have a film camera, a 100mm lens, and only use part of the film negative. You have a smaller image on the negative, right?

    But with a negative, you can print it any size you want. Same 35mm negative, you can print 4R, 5R, 8R etc etc. With me so far?

    So now you have a film negative. Only the center part is used. Specifically, you're using an area about 16 x 24mm, out of a negative that measures 24 x 36mm. Let's assume the rest is black (if you print it out, it is a pure white border).

    Now you print an enlargement. Make it around 6 x 9 inches. Now, if you cut away the white border, you have a 4R print.

    What happens if you use a 150mm lens, but now you use the whole negative? And print the negative out into a 4R photo?

    The image should look almost exactly the same.

  13. #13

    Default Re: SLR Lens on DSLR

    thanks a lot for all your explanations
    really great to find cs clubbers so helpful, really appreciated.

    basically a dslr (cropped sensor) does not magically increase the range of the lens when compare to full framed.
    it just restricted to the the center viewable area of a full frame image. making us thinks it "zoom" into the center image.
    hope i get it right?

  14. #14
    Member lennyl's Avatar
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    Default Re: SLR Lens on DSLR

    Quote Originally Posted by acitinium View Post
    basically a dslr (cropped sensor) does not magically increase the range of the lens when compare to full framed.
    it just restricted to the the center viewable area of a full frame image. making us thinks it "zoom" into the center image.
    hope i get it right?
    Yes, exactly.

  15. #15
    Senior Member ZerocoolAstra's Avatar
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    Default Re: SLR Lens on DSLR

    Quote Originally Posted by acitinium View Post
    thanks a lot for all your explanations
    really great to find cs clubbers so helpful, really appreciated.

    basically a dslr (cropped sensor) does not magically increase the range of the lens when compare to full framed.
    it just restricted to the the center viewable area of a full frame image. making us thinks it "zoom" into the center image.
    hope i get it right?
    You've got it! phew! I thought my explanation got problem...
    Be careful when you use the phrase "full frame", because it doesn't specify a 35mm-size.
    There are medium-format cameras and larger in the market
    That's why Nikon refers to their 24 x 36mm cameras as FX.

  16. #16

    Default Re: SLR Lens on DSLR

    Quote Originally Posted by ZerocoolAstra View Post
    You've got it! phew! I thought my explanation got problem...
    Be careful when you use the phrase "full frame", because it doesn't specify a 35mm-size.
    There are medium-format cameras and larger in the market
    That's why Nikon refers to their 24 x 36mm cameras as FX.
    yes sir

  17. #17

    Default Re: SLR Lens on DSLR

    Quote Originally Posted by acitinium View Post
    thanks a lot for all your explanations
    really great to find cs clubbers so helpful, really appreciated.

    basically a dslr (cropped sensor) does not magically increase the range of the lens when compare to full framed.
    it just restricted to the the center viewable area of a full frame image. making us thinks it "zoom" into the center image.
    hope i get it right?
    Spot on!

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