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Can't decide on what lens.

Discussion in 'Native Lenses' started by swmlon, Aug 31, 2011.

  1. swmlon

    swmlon Mu-43 Rookie

    14
    Aug 22, 2011
    I've recently gone into the world of the m4/3 and so far I have been enjoying the freedom of using such a small camera compared to my Nikon (and I know my shoulders and neck are thankful too), but I've found the 14mm to wide for my liking and I've never been a fan of zoom lens, so I'm looking to sell both of these lens that came with my GF2 to get one lens.
    Up until yesterday, that choice was easy, I was going to get the 20mm f1.7, but going down to my local camera shop, they just got in stock the 25mm f1.4 DG and that has really thrown a spanner in the works. I'm a sucker for large aperture lens as I like to shoot in low light and loathe the use of flash.
    I'd just like some feedback from those who have used both, those who have been in a similar situation to myself. If you've owned both, do you still own them, or do you sell one or the other and why?
    Thanks
     
  2. mzd

    mzd Mu-43 Veteran

    241
    Nov 30, 2010
    Wisconsin
    I would say based on the information you provided, the decision would come down to how important the portability the 20mm pancake offers you on your GF2. Both the 20mm & the new 25mm are very highly regarded (at least all reviews of the 25mm have been glowing thus far). There is a rather large size difference though. So if a pancake sized lens isn't a priority for you, then you would probably be very happy with the new 25mm and the extra stop it provides you. It also has the new "nano coating" and I believe it will focus a bit faster (though the 20mm certainly focuses fast enough in practice).

    [edit] There is the 25mm review thread on here by soundimageplus, which it looks like you have found... he probably has the most experience with that lens on this forum.
     
  3. shnitz

    shnitz Mu-43 Top Veteran

    989
    Aug 25, 2011
    Austin, TX
    They're close enough in aperture that you aren't going to notice a difference for ability to get low-light photos. The 25mm is half a stop faster. If price is any issue, you'll have less blurry handheld photos with a 20mm/EVF than you would with a 25mm looking at the rear display. You are inherently much more stable when you're holding the camera against your face. You're going to have to be at ISO 1600, having to choose between 1/10 and 1/15 shutter speed to take advantage of that extra half stop afforded by the 25mm anyway. Given the size of the 25mm, I'd say that the GF2 with 25mm is about the same bulkiness factor as the GF2 with 20mm and EVF.

    You have to decide which focal length suits you better. The 20mm has a deeper depth of field, and a slightly wider view, along with being a much more compact and less expensive lens. The 25mm will have a more blur/bokeh and a classic "normal" field of view. It goes without saying the Leica is slightly optically superior, but you won't notice a difference unless you're comparing them side by side. Considering the 25mm costs almost double the 20mm's price, I wouldn't feel that I'd be getting my money's worth by going with the Leica.

    If you really want low-light, treat yourself to one of the many Voigtlander 25mm f/0.95 fully-manual lenses that's popped up in the classifieds section. Now THAT's a low-light advantage!
     
    • Like Like x 1
  4. mauve

    mauve Mu-43 Top Veteran

    892
    Mar 9, 2010
    Paris, France
    I was going to write about the same as shnitz, and there's no point in duplicating what he excellently said.

    Just to nitpick, it seems to me the difference between 1.7 and 1.4 is closer to 1/3 stop than 1/2. Not that it makes any practical difference. That's the difference between 800 and 1000 iso in low light situation, hardly something you'd notice.

    Cheers,
     
  5. shnitz

    shnitz Mu-43 Top Veteran

    989
    Aug 25, 2011
    Austin, TX
    It may seem that way, but you have to remember that f-stops are an exponential scale. If you work it out, let us say sqrt(2)=x, then :
    x^1=1.4
    x^1.5=1.7
    While a third of a stop faster would be x^1.3333 which is about 1.6
     
    • Like Like x 1
  6. mauve

    mauve Mu-43 Top Veteran

    892
    Mar 9, 2010
    Paris, France
    I confess I hate maths with a passion. Done too much of calculus and algebra in high school (majored in science), happiest day of my life was binning my casio fx 8000g when I joined law school.

    Perhaps you know the joke :

    a sociologist wants to assess basic math proficiency in the population. So he makes a panel, and conduct interviews.

    First to enter is a PA. He asks her "2+2", and she answers without an hesitation : "4".

    Next comes a FCA. The sociologist asks the same question, the accountant stops him, open his laptop, fires up excel, input numbers and answers confidently : "5".

    Then enters a Lawyer. After listening to the same question, he walks to the windows, half shuts the blinds, dim the lights and whispers to the sociologist's hear : "How much do you want it to be ?"

    Thanks for crunching the numbers !

    Cheers,
     
    • Like Like x 3
  7. Tom Swaman

    Tom Swaman Mu-43 Veteran

    Well, for me, this one is easy. if you liked a wide normal lens on your Nikon, the 20mm f/1.7 is a great choice. If you prefer highly sharp photos at wide apertures, the 25mm f/1.4 is the best choice. However, the latter takes in a narrower angle.

    Mauve, for your information and not to be argumentative, but to try to be helpful, f-stop varies geometrically and not logarithmically. This is because f-stop is related to the open area of the lens wg=hich varies with the square of the radius of that open area.

    Best regards,
    Tom
     
    • Like Like x 1
  8. addieleman

    addieleman Mu-43 All-Pro

    Aug 5, 2010
    The Netherlands
    Ad
    Doing the math...

    f/1.7 compared to f/1.4 is in stops

    i-ZjHxnFC-L. "formula" border="1" />

    or

    i-cGpDfpL-XL. "result" border="1" />

    :smile:
     
  9. Armanius

    Armanius Mu-43 All-Pro

    Feb 23, 2010
    Houston
    Muttley
    LOL!!! Being a lawyer, I definitely appreciate the joke! :rofl:

     
  10. Tom Swaman

    Tom Swaman Mu-43 Veteran

    To make this all useful, simple and functional, particularly for the barristers among us, the numerical difference in individual f-stops is a factor of 1.4 so the difference in half f-stops is 0.7.

    Tee Hee and regards,
    Tom
     
    • Like Like x 1
  11. ~tc~

    ~tc~ Mu-43 Hall of Famer

    Oct 22, 2010
    Houston, TX
    All I can say is I own a 20/1.7 and am not in the market for the 25/1.4.

    Different, sure, but not enough to justify the size and extra expense IMHO.

    Now, if I didn't have the 20 and was in the market now ... like all things m43 (EPL1 vs GF1, 7-14 vs 9-18, etc) they appear to have made the decision as difficult as possible. If the 25 was a pancake OR had IS OR was faster OR had better IQ, it would be a slam dunk ... but since it's not, it's not.
     
  12. swmlon

    swmlon Mu-43 Rookie

    14
    Aug 22, 2011
    I went into the Jacobs on Cannon Street in London to have another look at both lens. I was really leaning towards the PL25, from my rather rudimentary testing in store, I really liked how it performed, it focused faster (by a hair) than the 20 and that bokeh to my eye was smoother.

    But, in the end, I had to remember why I bought into the m43 system, and that was to carry as small a setup as I can get, and if you want small, you need to go pancake lens, so in the end, I went with the 20mm and got shooting straight away. :thumbup:

    All I need to do now is sell the 14mm and 14-42mm, go with my one camera/lens setup and get shooting.