Question about the 20mm 1.7 prime

Discussion in 'Native Lenses' started by Mloot, Jun 25, 2013.

  1. Mloot

    Mloot New to Mu-43

    Jun 25, 2013
    I just purchased the G5 for my wife as a gift. In a couple of weeks, we will be going to visit some caverns that should be similar to Carlsbad, if not quite as grand. As long as the caverns have some lighting to highlight the features, would this lens be the one she would need to take photos without using a flash (which, I believe, is frowned upon)? TIA.
  2. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    The 20mm focal length (40mm 35mm or "full frame" equivalent) might be a little tight depending on the size of the cave, although you're right in looking for a lens with a larger aperture if you want to shoot in a situation with minimal available light. I would think the wider field of view of the Olympus 12mm f/2 might be an even better choice although at twice (or more) the price of the P20.

    I know in "touristed" caverns like Carlsbad permanent lighting is generally installed, so a large aperture may not be totally necessary and the wide end of the kit zoom (which I presume came with the G5) may be sufficient. However, in non-developed caves if you are limited to using available light (or that cast by headlamps, for example) then a "fast" lens is going to be more important. You might want to do a search on Flickr for the particular cavern you are planning to visit to get an idea of what sort of lighting might be installed and what sort of apertures others are able to shoot with.
  3. Chris5107

    Chris5107 Mu-43 All-Pro Subscribing Member

    Jan 28, 2011

    You definitely want a low f-stop lens in a cave even if it is well lit it will be lower light than you are normally used to. It may also help to practice a little with your camera to see what ISO values you can tolerate. Shoot some photos in a poorly lit room at ISO 200, 800, 1600, etc. and see how high you can jack it up before you see unacceptable noise. With a modest ISO and a fast (low f-stop) lens, you should be able to pick up some nice photos. Use the wall or other solid objects to steady the camera too.

    There is a big difference between the f1.7 on the 20mm lens and the f3.5+ on the kit zooms. That is why that lens is so popular.

    Focusing in low light conditions may prove challenging but it can be done.
  4. elavon

    elavon Mu-43 All-Pro

    Sep 1, 2012
    Tel Aviv Israel
    Regarding ISO the G5 will give you good results up to 3200 beyond this you will get to much noise. If the light is good stick to value bellow 800 then your photos will be almost noiseless. Another measure if possible, is to use a tripod. I highly recommend getting the P20 it is a little sharp, easy to carry and fast lens that will serve you well. I do not go out with my camera without it.
  5. JoeV

    JoeV Mu-43 Regular

    Aug 22, 2012
    Albuquerque, New Mexico, USA
    Joe Van Cleave
    Even with an f/1.7 lens you're going to want a tripod. I suggest finding out ahead of time if tripods are an issue at the caverns you'll be visiting.

    If the location is tripod-friendly then having a wide angle lens of moderate max aperture is more cost-effective, since the exposure will be multi-seconds long. At f/1.7 there's very little DOF, so the images might be focus blurred rather than motion blurred. Best to use a smaller aperture and a sturdy tripod.

    You might want to practice ahead of time with such time exposures, making certain you've enabled long-exposure noise reduction in the G5 menu. You'll also want to experiment with white balance, since artificial lighting can be a mix of halogen and/or fluorescent.
  6. Narnian

    Narnian Nobody in particular ...

    Aug 6, 2010
    Richmond, VA
    Richard Elliott
    Most commercial caverns do not allow tripods (trip hazard in a small confined space with lots of people) so a fast lens is your best bet. Depending on the conditions (high humidity, mold, dust, etc.) you will want to not change lenses.

    I take two cameras into caves - my GX1 with the 20/1.7 and my LX5 which will give me lower light capability than the 14-45 zoom.

    The 17/1.8 would be an excellent choice as well.
  7. sam_nl

    sam_nl Mu-43 Rookie

    Jun 19, 2013
    Recently I visited an old mine in Germany.. My G5 with P20 pleasantly surprised me and I got some great shots!
    But next time I'd bring a monopod or tripod to capture stunning shots!
  8. MajorMagee

    MajorMagee Mu-43 All-Pro

    Feb 24, 2011
    Dayton, OH
  9. ntblowz

    ntblowz Mu-43 Veteran

    Nov 13, 2011
    Auckland, New Zealand
    The new 20mm F1.7 MKII will be announced shortly I think, with the much needed AF boost update and even lighter than MKI
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