Site Sponsors
Results 1 to 5 of 5

Thread: GF1 with Pentax lenses

  1. #1
    Senior Member mediumcool's Avatar
    Join Date
    Oct 2010
    Location
    South Australia
    Posts
    1,486
    Post Thanks / Like

    GF1 with Pentax lenses

    I bought an adapter for P/K lens to M4/3 on eBay in early December, and it has finally arrived. Nicely enough made, with reasonable smoothness when mounting and unmounting lenses. Not bad for less than $20.

    Tried it out with my 50mm f1.4 first and was a bit disappointed; set the lens to infinity and shot some rainy street scenes in Adelaide. Not very impressive but then I suspected that the adapter might allow focus past infinity, which it did; ah hah! This was one of the few shots from Chinatown that is pleasant to look at and sharp where it matters. But look at the enlarged section below ...



    1/640 f2.8 iso 200



    Shot some more with the 50 in the backyard late this afternoon. No fringing here.



    This one hand-held 1/400 f2.8 iso 100

    Another which is more interesting in monochrome, dead bamboo and grass.



    Then I decided to strap my elderly Pentax-M 200 f4 on to the GF1 for some backyard testing. All pix were shot wide open at f4 using a tripod.


    1/160 f4 iso 200

    And again in mono, processed in C1.



    One last 200mm shot, of some grass and a shrub dying off in mid-summer, which again looks better in monochrome. Processed this in C1, with dodging in Photoshop to give roundness to some of the leaves.



    Love the idea of never having to go into a darkroom again!
    Last edited by mediumcool; 14th January 2011 at 04:34. Reason: changed *dismounting* to *unmounting*; it’s not a horse!

  2. #2
    Senior Member mediumcool's Avatar
    Join Date
    Oct 2010
    Location
    South Australia
    Posts
    1,486
    Post Thanks / Like

    Re: GF1 with Pentax lenses

    forgot notification!

  3. #3
    Senior Member Tesselator's Avatar
    Join Date
    Aug 2010
    Location
    Japan
    Posts
    695
    Post Thanks / Like

    Re: GF1 with Pentax lenses

    Nice test shots MC. Too bad about the fringing - some lenses do that. My questions are: Does it do that on other digital cameras? and Does it go away stopped down? Usually f/2.8 will kill it in a 1.2 or 1.4 lens - that it doesn't here is kinda sad but at what point does it?

  4. #4
    Senior Member mediumcool's Avatar
    Join Date
    Oct 2010
    Location
    South Australia
    Posts
    1,486
    Post Thanks / Like

    Re: GF1 with Pentax lenses

    Quote Originally Posted by Tesselator View Post
    Nice test shots MC. Too bad about the fringing - some lenses do that. My questions are: Does it do that on other digital cameras? and Does it go away stopped down? Usually f/2.8 will kill it in a 1.2 or 1.4 lens - that it doesn't here is kinda sad but at what point does it?
    Funny thing is that I’ve probably shot more with the 50 FA and the old 200/4 on the Panasonic than on the camera I bought them for, the GX20 Samsung!

    Some quick tests with the 200/4 on the GX20 showed red fringing (?) which I haven’t tried fixing yet in C1 or PS. But if I ever want to use it on a paying job, I’d better make sure I can fix it, or convert everything to B&W!

    Must do some tests with the 50 starting at 1.4 and going all the way down to see what happens. And do it on both cameras. But fringing seems dependent on the subject too.

    I have also been using some ancient Mamiya 645 lenses with a new Leaf Aptus 22 back, and am surprised at the lack of fringing (35, 45, 50 shift, 80 macro all look pretty good). I believe the long backfocus on medium format helps, and the sensor site density on the Aptus is quite low—22mpx over 1700+ square millimetres.

    I also want to get a Mamiya/Pentax adapter so I can have tilt/shift on the Samsung with the Mamiya lenses; that will be interesting. And maybe a waste of money.
    Last edited by mediumcool; 14th January 2011 at 05:45. Reason: added *site*

  5. #5
    Senior Member mediumcool's Avatar
    Join Date
    Oct 2010
    Location
    South Australia
    Posts
    1,486
    Post Thanks / Like

    Re: GF1 with Pentax lenses

    Thinking about sensor density, the Aptus 22mp sensor seems to have less than a quarter of the photosites per sq/mm compared to the 12mp 4/3 sensor in the GF1.

    Aptus 22 has less than one-third of the density of the Pentax/Samsung 14.6mp APS.

    Compare the Aptus to a Canon 22mp full-frame and you get approx. 50% reduction in photosite density with the bigger chip.

    4/3 sensor area is about 225 sq/mm, APS-C about 370, *real* 35 is 864, and Aptus 22 is 1728.

    Next thing to do is look at the JPEGs ex-camera and see if they are any different fringe-wise, on both the Samsung and the GF1.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •