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Thread: Pentax K 50mm f1.7 - any good?

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    Senior Member simonclivehughes's Avatar
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    Pentax K 50mm f1.7 - any good?

    I have one of these lenses and I'm wondering if it is worth spending $150 to get an adaptor to be able to use it on my G1 and GH1? The lens appears to be almost mint. Any comments?

    Cheers,

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    Senior Member Rawfa's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Simon, I have the exact same lens and I have just received my Pentax K adapter (BTW, the adapter is cheaper here http://myworld.ebay.com/ciecio7/). I've tested it yesterday really briefly and it seemed very sharp, but I'm going to really text it this weekend and probably post some more photos. In the meanwhile you have one here: http://forum.getdpi.com/forum/showthread.php?t=8994

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    Senior Member simonclivehughes's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Rafa,

    I just saw your other thread! the lens looks definitely very sharp, but I'd be interested in seeing some pictures that give a better idea of the bokeh if possible. Many thanks for responding, and thanks for the tip on the less expensive adapter.

    Cheers,

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    Senior Member Rawfa's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Simon, I will take my new lenses for a test drive this weekend for sure. You may just get lucky and see some bokeh

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    Senior Member simonclivehughes's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Rafa,

    Not sure if you can answer this but do you think the Pentax 50mm f1.7 is better than the Nikon 50mm f1.8? I have both and already have the adapter for Nikon F. If the Pentax lens is significantly better, I might spring for the adapter.

    Cheers,

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    Senior Member pellicle's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Simon

    I'm not sure if this answers your questoin, but I'm trying to standardise on legacy manual focus lenses on my G1 as I simply don't want to be spending hundreds on adaptors when I could put that into a much nicer modern lens for the camera. I initially thought that Canon FD would be a good idea and bought an adaptor (from ciecio7 (whom rawfa mentioned above) and 50 + 28mm FD lenses to go with it (and a few extension rings to make maro nicer). The adaptor was the dearest part.

    Now as I had an EOS camera set before buying the G1 I talked myself into getting some OM lenses to make some comparisons between the G1 and the EOS as the FD lenses won't mount on the EOS ...

    This so convincingly demonstrated to me that the G1 outdid the EOS 10D that I sold almost all of my EF stuff (which I'd been keeping since my EOS Film camera times in the hope that I'd get a Full Frame 5D or something, the G1 has me thinking I'll likely not bother with that either as its a good enough compromise for me)

    So having 2 different 50's hanging around I thought I'd test them which you can read here.

    Essentially I found that if you use them at nearly wide open that there are noticeable differences, but if you are stopping them down then the OM had the edge.

    Now, here is where things are getting tricky for me, you see I also purchased an FD 300 for photographing some birds that were nesting near me ... (what the heck it wasn't dear). This of course led me to wondering "hmmm ... will the OM 300 be better? I dug about and got an OM 300mm f3.5 lens and having used it side by side with the FD300 I can say that

    * optically they are really close (I mean really close)
    * operationally I prefer the FD for its smoother inner focus mechanism and for its better tripod mount.

    So, since I have a leaning towards the Canon stuff I'll now be selling the OM stuff as its marginal improvement over the FD lenses does not outweigh the benefits of operation and only having one adaptor system.

    First time you go out and realise you've got an FD and an OM lens with you but brought FD adaptors you'll understand what I'm talking about.

    So what I'm saying is, that if you don't have a legacy 35mm lens just yet, then think about systems before.

    So if you see some really sweet and tidy OM stuff on Ebay from Finland that'll be me

    (unless I decide to keep some of the OM gear for 35mm film work, and sell just the 300 :-)

    so, make life easy and stick with whichever system you'll likely prefer.

    Personally I'll bet that the Pentax makes a fine lens ... that'll open you up to a vista of other pentax mount stuff which you can take use of ... besides Nikon lenses aren't really cheap.
    Last edited by pellicle; 24th July 2009 at 09:31.

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    Senior Member simonclivehughes's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Pellicle,

    Thanks for the detailed comments. I do understand your point about multiple adapters and different lens systems. At this point, I have a Nikon system with a D700 and I'm just starting to get some primes to replace the DX zooms I had with my D300s. I already had the 50mm AF f1.8, the 60mm AF f2.8 Micro, the 85mm AF f1.4 and the 300mm AF f4. I'm expecting UPS to deliver my Zeiss 35mm f2 lens this morning. I also have the Panny 4/3-to-u4/3 adapter (with a Nikon F adapter) and (2) of the Camerquest u4/3-to-Leica M adapters (from when I had more M glass).

    At this point, I'm trying to look for Nikon F lenses that I can then also use on the G1/GH1. Having said that, I also realized I had this Pentax 50, hence my question as to how good it is Vs the Nikon nifty fifty.

    At this point, for the rest of the lenses, I'm leaning toward the Zeiss 21mm f2.8 and possibly the Zeiss 100mm f2 lens. So, obviously I'm leaning toward the Nikon system as my main source of lenses for the G1/GH1. My main goal for these lenses, other than the obvious use on the D700, is for the GH1 and its video capability to be able to get shallow DOF for a more film-like look.

    Cheers,

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    Senior Member pellicle's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Hi

    Quote Originally Posted by simonclivehughes View Post
    At this point, for the rest of the lenses, I'm leaning toward the Zeiss 21mm f2.8 and possibly the Zeiss 100mm f2 lens.
    one of the Zuiko OM lenses I bought was the 21mm f3.5 ... I was thinking that this would double up as a compact little 'normal' lens for the G1 and when stuck onto a 35mm film body would give me wonderful wide angle ability (wider than the kit lens) with adding just a light film body.

    After testing this over a weekend I was quite surprised to find that the Kit lens was very nearly identical to it in quality and bokeh.

    My negs looked beautiful but for some stupid reason I thought I'd just drop the money onto the Olympus 9-18 digital zoom and see. Again I was surprised that 4000dpi scans of film (Nikon LS-4000) were not significantly more detailed than the Olympus zoom (and I get AF and manual focus zoom assist too ;-)

    I'm keeping the little 21mm for the simple reason that I'm going to use it on my EOS film camera with HIE (and when my freezer runs out of that another) IR black and white film. The OM => EOS adaptor was only about 40 bucks so I'm perhaps going to keep my OM lenses for use on that body.

    So really I find that for use with the micro 4/3rds camera the modern lenses work out better in many ways (says a fellow with some C mounts) and aside from manual telephoto lenses and macro with extension tubes I wouldn't bother with legacy lenses for wide angle or normal ... I don't even really bother with my 28 or 50 much now, unless using the 50 for macro on extension tubes. Not worth carrying all the clobber ...

    not sure if that helps :-)

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    Senior Member pellicle's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    my wife asks me sometimes if I can give a short answer

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    Senior Member simonclivehughes's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    I agree that the kit lenses on the G1 and the 14-140mm on the GH1 are very, very good. The main issue for me though is the speed of those lenses. I'm looking for better shallow DOF and IQ and background quality at those shallow apertures, specifically for the video on the GH1, but also for the G1 too.

    Cheers,

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    Senior Member Rawfa's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Simon, the last time I've tested the nikon 50mm f1.8 was like 2 or more years ago with a Nikon D40. I really cannot remember. I've posted some new photos with the Pentax though.

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    Senior Member pellicle's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Quote Originally Posted by simonclivehughes View Post
    The main issue for me though is the speed of those lenses. I'm looking for better shallow DOF and IQ and background quality at those shallow apertures,
    when using the kit lens at 45mm there isn't a lot of difference to a 50.

    Now if you're thinking of a 50 as it looks on full frame 35mm then I'm afraid it'll be really hard to get that look you'll need an f0.95 25mm to get that shallow 50f1.8 look you can get with a 35mm camera

    this is taken at a Funeral of a relative last year with a 50mm on a full frame camera

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    Senior Member simonclivehughes's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Rafa,

    Thanks for the heads up on the additional pictures... they look good. I think I'm inclined to just wait and see how the Nikon 50 works out rather than spend money on an adapter that might give me much the same look.

    Ciao,

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    Senior Member simonclivehughes's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Quote Originally Posted by pellicle View Post
    Now if you're thinking of a 50 as it looks on full frame 35mm then I'm afraid it'll be really hard to get that look you'll need an f0.95 25mm to get that shallow 50f1.8 look you can get with a 35mm camera
    No, I'm not mistaking it that way... I know the 50 will act as a 100mm FOV lens, it's the speed I'm looking for over the kit lens. I want to be able to isolate against a nice bokeh background.

    Cheers,

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    Re: Pentax K 50mm f1.7 - any good?

    Now if you're thinking of a 50 as it looks on full frame 35mm then I'm afraid it'll be really hard to get that look you'll need an f0.95 25mm to get that shallow 50f1.8 look you can get with a 35mm camera
    Not really. All the dof tables and such are good only for perfect lenses. In real life situations, this is different. It all depends on the lens you use and the light more than the aperture.

    In other words, you do not need f/0.95 25mm lens on an m4/3rds camera to get shallow dof.

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    Senior Member pellicle's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Hi

    Quote Originally Posted by Vivek View Post
    Not really. All the dof tables and such are good only for perfect lenses. In real life situations, this is different. .
    well interestingly I find that in real life it does. For example I once wrote this page showing the differences of DoF between a Nikon Coolpix (with a 2/3 sensor) and a 20D using lenses of the same angle of view.

    To simplify, it is the diameter of the aperture hole which matters for DoF.

    There is some javascript there to swap out images (which may take a little time to load from that server) which show what I'm talking about.

    If you hold your mouse over the left hand side image you'll notice it swaps out to an image which has the same sized hole (forgetting F numbers) as the image for the Coolpix.

    So if I am taking a photograph where I want to stand in the same place, cover the same angle of view and still get the same DoF in that example I posted above you'll need a big aperture hole.

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    Re: Pentax K 50mm f1.7 - any good?

    It does not. I am not talking about tripod mounted comparison shots with a zoom and one prime.



    A 25mm lens, aperture f/4 on G1.

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    Senior Member pellicle's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    I wish I had a full frame 35mm to make this comparison

    but tripod or no tripod does not effect the DoF

    I have never seen the slightest indication that a zoom at F2.8 gives any different results to a prime at f2.8 assuming the same focal lengths are used.


    But please try the experiment yourself (compare a full frame 35mm with a 50 f1.8 against a 25mm at f1.8)

    If the rules were so wrong, then I wouldn't be typing this on a pc because none of physical laws would work making a PC fine in theory but not in the real world ;-)

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    Re: Pentax K 50mm f1.7 - any good?

    Pellicle, Again, the dof tables (there are no "rules", they were all based on assumptions and approximations) do not consider many factors. The most important of all is the thickness of the glass (AA, IR filter pack) on the sensor which varies from cam to cam. Even a variation of 0.1mm affects the aberrations dramatically.

    For example, the Olympus pen F Zuiko macro 38/3.5 gives creamy smooth OOF renditions on the G1 while I have never seen that on any film, under any lighting conditions, ever.

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    Senior Member pellicle's Avatar
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    Re: Pentax K 50mm f1.7 - any good?

    Hi

    Quote Originally Posted by Vivek View Post
    Pellicle, Again, the dof tables (there are no "rules", they were all based on assumptions and approximations) do not consider many
    but I'm not concerned with them, only what I see on the images ... as I posted example of above.

    :-)

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