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Physics of lens attachments

Discussion in 'Accessories' started by OlyPannyMan, Jan 30, 2015.

  1. OlyPannyMan

    OlyPannyMan Mu-43 Rookie

    16
    Dec 21, 2014
    I'm kind of interested in getting a fisheye lens for my 4/3 and m4/3 gear, but I don't feel like spending tons of money for one. Yes, there's the Rokinon/Samyang/etc. 7.5mm but I don't like presetting the aperture. I have an adapted 50mm f1.7 Rokkor that I've used on a few occasions so I'm not merely predicting that I won't like it...I've experienced the procedure and I know I won't.

    I got to wondering about the "auxiliary fisheye lens" attachments, which are really filters I guess. I know that the more glass you put in front of a lens, the more you degrade the image. But I've had great luck with my Raynox closeup lenses, which also add glass between subject and sensor. I know some like no glass solutions like extension tubes but I can just unclip (not even unscrew) the Raynox and get back infinity focus. The AF works either way. Despite the extra glass, the images are sharp, so there are at least some exceptions to the rule. Something like that, only fisheye, would be great.

    So what is the deal with the auxiliary fisheyes? Raynox makes yet their website doesn't recommend them for DSLRs---they're for video cameras. Of course other brands make them and I'm sure most are total junk, but I think if anybody could do it, Raynox would. The few reviews that I could find on amazon and elsewhere seem to indicate that a fisheye attachment intended for a video camera can't focus when added to a DSLR lens. Is it something along the lines of using a lens designed for a shorter flange-to-sensor distance?
     
  2. wjiang

    wjiang Mu-43 Hall of Famer

    A 7.5 mm fisheye that starts from f/3.5 is a completely different experience to a 100mm equivalent telephoto that starts at f/1.7. I barely ever touch either focus or aperture control on mine as the DoF at hyperfocal is HUGE - f/3.5 and slightly short of hyperfocal for indoors, and f/5.6 and at hyperfocal for outdoors.

    Regardless of brand, close up dioptres are way easier to make than telephoto/wide converters, as they just reduce the minimum focus distance. The specific lens and converter combo also seems to make a huge difference - the Panasonic GWC1 (wide) works really well with the 14mm and 12-32mm lenses, for example, but is pretty bad with the PL15mm. Your best bet for IQ is a specially mated combination, e.g. Panasonic 14mm + DMW-GFC1 (fisheye).

    Then there's also the Olympus 9mm f/8 body cap fisheye...
     
  3. Steven

    Steven Mu-43 All-Pro

    May 25, 2012
    USA
    as already was mentioned, Rokinon fisheye does not really require any settings adjustments in use. I would reconsider getting it, it is very sharp.
     
  4. agentlossing

    agentlossing Mu-43 Hall of Famer

    Jun 26, 2013
    Andrew Lossing
    Never heard anyone else say they dislike aperture rings...

    EM10•GX1•EP1•GF3•9mmBCL•17mm2.8•30mm2.8
     
  5. OlyPannyMan

    OlyPannyMan Mu-43 Rookie

    16
    Dec 21, 2014
    Thanks for the replies. I already have the 4/3 (not m4/3) 9-18 so I'm not without a superwide. It's nice having a zoom instead of a prime, Too bad there isn't a good telecompressor for it...say a .7x that could make it a 6.3mm f2.8 ~12.6mm f4 lens. Or a .25x in front could turn the basic kit lens into a 3.5mm-10.5mm fisheye.
     
  6. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    I suspect the Oly 9mm BCL will give better results than most adapters, and it's probably smaller and maybe cheaper.
    And you don't have to set the aperture [emoji12]

    Barry
     
  7. Aperture rings? Ugh! :smile:
     
    • Like Like x 1
  8. agentlossing

    agentlossing Mu-43 Hall of Famer

    Jun 26, 2013
    Andrew Lossing
    I very, very much doubt that. BCL has pretty spotty performance in my experience so far. And the f8 limitation is maddening. It's not all it's cracked up to be.

    EM10•GX1•EP1•GF3•9mmBCL•17mm2.8•30mm2.8
     
  9. listers_nz

    listers_nz Mu-43 Veteran

    255
    Nov 22, 2013
    Christchurch, New Zealand
    Simon
    Do you have the Panasonic 14mm lens? If so then there is always the Pansonic DMW-GFC1 fisheye conversion lens. Haven't used one myself, but if it is as good as the wide angle conversion lens then it should be fine. The difference between this and one of the cheap auxiliary lenses is that this is designed to pair with this lens.
     
  10. pellicle

    pellicle Mu-43 All-Pro

    Feb 10, 2010
    Southport, OzTrailEYa
    pellicle
    As someone above mentioned the GWC-1 I will toss in that I used to have the Oly9-18 43rds lens and liked it when there were no other alternatives.

    Since getting the 14 and then the GWC-1 I sold my Oly

    14+9-18adapted.

    Its a heaps more compact arrangement and image quality is good.

    It is of course not quite as wide. I would favor the 7.5 and the 14+GWC-1 as a way to get 3 focal lengths

    My blog post comparing IQ between the zoom and the adapted 14mm

    http://cjeastwd.blogspot.com/2013/10/panasonic-079-wide-adaptor-on-14mm.html
     
  11. OlyPannyMan

    OlyPannyMan Mu-43 Rookie

    16
    Dec 21, 2014
    I started shooting in 1977 and to my recollection, most SLR lenses had aperture rings---mirror lenses didn't (I never owned one but I think many allowed for neutral density filters to give the photographer a way of controlling light coming into the camera).

    But in my comment about apertures, I meant that I don't like to open my 50mm f1.7 so I have the light to focus, then close it down to shoot. I remember once I was trying to get a good shot of a bug and the light was low. I had one of my Raynoxes on the lens, so I was just a few inches away and I was using flash. By the time I got it focused, got the aperture set, and shot, the bug was gone. So there you go. I could say the same about my legacy Vivitar 70-210 lens while trying to get shots of a redwinged blackbird. As I age and my eyesight fails, focusing on a moving object becomes more and more challenging.

    Now you can say that the extensive depth of field of a fisheye covers a ton and all and I've owned wideangles, seen dof charts. I'm sure it does. Maybe you can set it and forget it. Or maybe you bump the focus ring/aperture ring and don't get the shot you thought you would. I've shot many photos with the camera nowhere near my eye so it wouldn't always be apparent to me that the shot was focused where intended or exposed as I might want it.

    If the forum thinks I'm stupid for my comments about apertures, so be it. I don't rag on people for their preferences but apparently I don't merit the same consideration.

    Maybe I'm just in the wrong website. Everybody here loves their m43 and nothing wrong with that---but I started with 43, so I adapted what I had rather than sell it off (probably taking a loss) and start again. The hitch is that I still love my E-30 so the 43 lenses stay, regardless. I don't mind the bulk as much as many of you probably do, anyway. Maybe if the Rokinon could be attached to the E-30 I'd be more tempted.
     
  12. agentlossing

    agentlossing Mu-43 Hall of Famer

    Jun 26, 2013
    Andrew Lossing
    That makes perfect sense, it's just not a use-case I'm familiar with. No offense meant, at all. Macro and long telephoto are definitely hard to use stopped down.

    EM10•GX1•EP1•GF3•9mmBCL•17mm2.8•30mm2.8
     
  13. listers_nz

    listers_nz Mu-43 Veteran

    255
    Nov 22, 2013
    Christchurch, New Zealand
    Simon
    • Like Like x 1