Depth of Field Apps & Scales: Also, Considering Minolta Roxxor X 50mm f/1.4

Discussion in 'Adapted Lenses' started by larrytxeast, Mar 5, 2013.

  1. larrytxeast

    larrytxeast TalkEmount Rookie

    Feb 23, 2013
    The Minolta Roxxor X 50mm f/1.4
    I'm on day 8 with my Sony NEX-C3 kit. I'm currently working to expand the accessories & so forth. I've added a generic spare battery & charger, UV and polarizer filters. I added a Nikon "G" adapter for my old manual focus (1980?) Nikon Nikkor 50mm f/1.8. Having heard good things about the Canon FD 50mm f/1.8, I've purchased one of those & an adapter as well, waiting on it to arrive.

    Meanwhile, I've heard persons say good things about Minolta's lenses. I've seen a mint-condition Minolta MD Rokkor-X 50mm f1.4 for sale for $50 plus shipping. I found this link that talks about the different versions of this lens, I'm not sure which version this is.

    Anyway, I am considering it, based on many people saying such good things about it, plus of course it's a 1.4 vs 1.8 etc. That said, my thinking is that, as neat as it perhaps it to be able to use different lenses on the Sony NEX via adapters, is there any real sense in having 3 different 50mm manual-focus lenses? (I got the Nikon one for only $5 about 2½ years ago, it's in rough shape but optically it seems fine and the focusing and f-stops work fine.) Or is there something special about a Roxxor X 50mm f/1.4 that makes it a worthy stand-out lens from the others?

    Note: I mainly would use such a lens for portraits of my kids & other such portraits.

    Depth of Field
    Also: I am finding out from first-hand experience just how shallow depth-of-field can be. Yesterday I took shots of my son, using the Nikon, at f/2 and f/2.8 from 4 feet away. Wow you talk about shallow depth of field. It was HARD getting the eyelashes in focus. I think I saw later on from a depth-of-field calculator that I had about .16 feet of depth-of-field at f/2.8 or something like that. Wow. That's about 2 inches. No wonder it was so hard getting the shot in focus.

    Anyway, my question is, what is a good app for depth-of-field calculations for an Android device? Also, I noticed that the online calculators I used ask you what camera you use. I'm not understanding why that matters. I understand depth-of-field varies based on how close you are (close-up, shallow; far-away, deep) and the focal length (wide-angle, deep; telephoto, shallow) as well as obviously the f-stop, but I didn't think the CAMERA mattered.
  2. Bimjo

    Bimjo Super Moderator Subscribing Member

    Oct 28, 2011
    Washington State
    Perfectly feasible to have more than one 50mm lens, for a couple of reasons: 1) they're cheap, so why not? 2) as a general rule large aperture lenses are more prone to CA, so having a 1.7/1.8/1.9 to use as a general use 50 makes some sense. My general use 50 is a f/2.5. 3) sometimes you want razor sharp and sometimes you want dreamy, hard to do both with one lens. 4) did I mention that they're cheap?

    I use this DOF app on my iPhone, it's available for Android as well: Depth of Field Calculator for Android

    Each camera has a different Circle of Confusion ( CoC ). Using the wrong CoC in the calcualation can result in DOF calculation errors, so the app wants to know what camera you are using.

    And if you think the DOF is shallow @ f/2.8 wait until you see what is is @ f/1.4. ;) 
  3. larrytxeast

    larrytxeast TalkEmount Rookie

    Feb 23, 2013
    Yes, the thing is, I forgot about Pentax. No one mentions them either, though. Coming from Nikon, it might be easier to get used to, because the focus & f-stop rings don't move in the opposite direction vs the Nikon, as the Canon & Minolta would. Yet like the others and unlike the Nikon, you get 1/2 f-stop clicks, the Nikon lenses tend to do only full f-stop clicks.

    Yes, I wonder if I really NEED f/1.4 for the shots I do, or if it's just my getting carried away. From only 4 feet away my experiments suggest I should only open up as wide as f/2.8 anyway, maybe even f/4 (or in-between there if possible). F/2 was a real challenge; maybe the f/1.4 and f/2 shots are more ideal for head-shoulders shots of full-grown adults from (I'm guessing) 7 feet away, not small kids from only 4 feet away.
  4. Nubster

    Nubster TalkEmount Veteran

    Jan 5, 2013
    West Virginia, USA
    For real. Grabbed this shot just a bit ago...eyes are sharp, eye lashes are not...that's how razor thin the DOF with the ROKKOR 50mm f/1.4. I love this lens.]

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