Do I need a step down or a step up?

btj288btj288 Registered Users Posts: 8 Beginner grinner
edited April 1, 2010 in Cameras
Ok I currently have a 28-135mm lens (72mm diameter) and I want to buy a fisheye attachment that has a diameter of 52mm. Would i need a step down or a step up to fit the fisheye attachment onto my current lens?

Thanks!

Comments

  • RichardRichard Administrators, Vanilla Admin Posts: 19,962 moderator
    edited March 29, 2010
    btj288 wrote:
    Ok I currently have a 28-135mm lens (72mm diameter) and I want to buy a fisheye attachment that has a diameter of 52mm. Would i need a step down or a step up to fit the fisheye attachment onto my current lens?

    Thanks!

    Step down. The first number refers to the lens diameter, the second to the filter or whatever you are attaching to it. (I think lol3.gif)
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  • ziggy53ziggy53 Super Moderators Posts: 24,131 moderator
    edited March 29, 2010
    Richard wrote:
    Step down. The first number refers to the lens diameter, the second to the filter or whatever you are attaching to it. (I think lol3.gif)

    15524779-Ti.gif

    Step-Up rings
    These rings will help you use a filter or other kind of accessory that is LARGER than the lens diameter size.

    Step-Down rings
    These rings will help you use a filter or other kind of accessory that is SMALLER than the lens diameter size.
    ziggy53
    Moderator of the Cameras and Accessories forums
  • engrmarianoengrmariano Registered Users Posts: 28 Big grins
    edited March 29, 2010
    72-52 would cause vignetting (?)...
    5D II + BG- E6 • 550D
    18-55 IS • 15 2.8 Fisheye • 24-70 2.8L • 50 1.8 II • 70-200 2.8L IS • 100 2.8L Macro IS • Kenko 1.4X & 2X
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  • btj288btj288 Registered Users Posts: 8 Beginner grinner
    edited March 29, 2010
    Thanks! I have a fisheye attachment but it is a Zeikos X 0.43 58mm so there is not much distortion. Is there any way to get the maximum distortion out of my current attachment (using certain shutter speeds or apertures possibly)?
  • craig_dcraig_d Registered Users Posts: 911 Major grins
    edited March 30, 2010
    btj288 wrote:
    Thanks! I have a fisheye attachment but it is a Zeikos X 0.43 58mm so there is not much distortion. Is there any way to get the maximum distortion out of my current attachment (using certain shutter speeds or apertures possibly)?

    I doubt changing aperture will have any effect on this, and I'm sure changing shutter speed won't. My guess is that you'll see more fisheye effect if you zoom out all the way.

    Does your camera have a crop-frame sensor? I wonder if the lack of distortion is just caused by your camera throwing away the outer portion of the image, where the fisheye effect is strongest.

    Other than that, all I can suggest is getting a real fisheye lens instead of a cheap adapter lens like this one. The cheapest usable one I know of is the Peleng 8mm circular fisheye (which on a crop-frame DSLR will come close to filling the frame). I have one. It's not bad at all, but it shows a lot of flare around the edges.
    http://craigd.smugmug.com

    Got bored with digital and went back to film.
  • btj288btj288 Registered Users Posts: 8 Beginner grinner
    edited March 30, 2010
    What would happen if I used two step down rings (72mm-58mm and a 58mm-52mm)?
  • RichardRichard Administrators, Vanilla Admin Posts: 19,962 moderator
    edited April 1, 2010
    btj288 wrote:
    What would happen if I used two step down rings (72mm-58mm and a 58mm-52mm)?

    I suppose that would create additional focusing issues. Since you are attaching an active optical element, you probably would need to use manual focus anyway so it might not matter. You will get more vignetting because of the increased distance. Again, it might not matter. Rings are cheap, though, so why use two?
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