Thinking of swapping. DOF worries. Examples?

Discussion in 'This or That? (MFT only)' started by christianwaite, Aug 26, 2013.

  1. christianwaite

    christianwaite Mu-43 Rookie

    12
    Aug 26, 2013
    I'm thinking of swapping out from a Canon 550d with Sigma 30mm f/1.4 to an Olympus OM-D EM-5 with Panasonic/Leica 25mm f/1.4.

    Now I read/get told all the time that the sensor size affects Shallow DOF/Bokeh, but I think this is mistaken. From what I can gather is it's just the difference between a 50mm lens and 25mm lens to get the effective FOV and nothing to do with the sensor size (although you are having to go to 25mm instead of 50mm FF BECAUSE of the sensor, so....).

    Anyway, 5mm difference doesn't seem like a lot to me, so I'm hoping I'm not going to loose much shallow depth of field. Has anyone got any good examples and can sooth my apprehension on this matter. I'll probably end up with the Voigtlander 17.5 at some point, but only the 25mm 1.4 to start with.

    Thanks for any advice
    Christian

    P.s. Here's a shot from the 550d with the 30mm at 1.4
    29.06.13 - 16.35.47.jpg | Flickr - Photo Sharing!
     
  2. Neftun

    Neftun Mu-43 Veteran

    408
    Jul 15, 2012
    Norway
    Patrick Kristiansen
    The math behind DOF is very simple. It is determined by the diameter of the aperture. larger diameter, shallower DOF. The diameter is calculated by dividing the focal length with aperture number. 30mm/1,4= 21,4mm. 25mm/1,4=17,9.mm. Some difference yes. The complicating part is when you consider which apertures are usable on the lenses in question. The PL 25 is excellent wide open imo. Dunno about the sigma. If it is mushy until say, 2,5 the diameter of that opening is 30mm/2,5=12mm and you have more dof than the PL25.

    DOF aside, the oly mentioned has a far superior sensor to the canon, so you cannot lose, really.

    Examples with the PL 25 are plentiful on this forum. Just chech out its image thread:)
    Patrick K
     
  3. jamespetts

    jamespetts Mu-43 Top Veteran

    803
    May 21, 2011
    London, England
    The previous poster is correct: the difference in depth of field is limited. There will, of course, be a difference in angle of view: a 25mm lens on Micro Four Thirds has the same angle of view (not taking into account the different aspect ratio) as a 50mm lens with 35mm film or a 35mm sensor.

    The 25mm f/1.4 lens is a very good lens indeed, and is more than useable wide open. At maximum aperture down to about f/2.8, it is a little soft at the corners (although corner sharpness is rarely needed for a normal lens at maximum aperture in any event), but it is sharp in the centre at any aperture and just as sharp in the corners from f.2.8 down.

    The out of focus rendition is also delightful.
     
  4. christianwaite

    christianwaite Mu-43 Rookie

    12
    Aug 26, 2013
    Thanks.
    I know it's a good lens/system and that the sensor is probably better than the 550d (I don't think it's a particularly good sensor at all). I was just tossing up between the Fuji's with 35mm 1.4 and the OM-D with 25mm 1.4. Fuji will probably give me a bit more bluryness, 4/3 probably a bit less. But as long as in practice isn't not a massive amount then I think I'm ready to drop some money on it and swap completely over.

    Just got the wife a Lumix with the 20mm 1.7 and I must admit I even like that :)

    Cheers
    Christian
     
  5. jamespetts

    jamespetts Mu-43 Top Veteran

    803
    May 21, 2011
    London, England
    Think quality over quantity - that and, from what I understand, the Fujis are slow to focus compared to Micro Four Thirds.
     
  6. christianwaite

    christianwaite Mu-43 Rookie

    12
    Aug 26, 2013
    Well the Fuji's have some of the best quality, but their focus is sluggish at best compared to an OM-D.

    Going from 550d to OMD should give me a boost in quality and loss in size/weight and a lot of boost in style :p. Just wanted to hear it from people who use the system that I wasn't going to loose too much shallow DOF as 90% of my pictures atm are portraits/candids in darkly lit rooms.
     
  7. kinlau

    kinlau Mu-43 Top Veteran

    836
    Feb 29, 2012
    Make sure you test out the EVF in the conditions you just mentioned. I much prefer an optical finder when it's dark.
     
  8. Depends which version of the Sigma 30/1.4 you have. If it's the first version then that lens is quite soft and glowy at f1.4 anyway so for decent image quality it should only be regarded as an f/2 lens at best which removes it's mathematical advantage relating to aperture and sensor size. The Panasonic isn't "perfect" at f/1.4 either but is much, much better than was the Sigma. I also remember not being able to use my copy of the 30/1.4 on any Canon body that didn't have focus micro-adjustment. Having said that, while your example image is not exactly pixel-level sharp it is a bit better than I remember the Sigma being capable of at f/1.4.

    Where the Canon should have an advantage (in bright light) is that it has a native base ISO 100 setting whereas the E-M5 has a base ISO 200, but the Canon also has poor dynamic range in the highlights compared to the Olympus so the E-M5 can handle overexposure to compensate here again.

    An E-M5 will also be much better for quick "grab shots" of infants because you can use the rear screen for composition and select focus and trip the shutter by using the touchscreen. One of the best advantages of a Micro 4/3 camera over a traditional DSLR is that it will get you out of the "must take every image by peering through a viewfinder" rut and will allow you to take different approaches towards photography.
     
  9. rnagoda

    rnagoda Mu-43 Veteran

    260
    Jun 12, 2012
    Tucson, AZ
    Robert
    If you are looking for a real big boost in performance, you might hang on to your money, or just look into a different lens rather than a different body/system. I know the accepted thinking around here is that the 18MP Canon Rebels like your 550D are terrible, old dinosaurs of cameras, but it simply isn't true. They don't have the build of the OM-D, certainly, but they are great cameras and if you aren't getting pictures you are happy with with your 550D then it's a bit of mythology to presume you'll get them with the OM-D sans a change in your approach to photography in general.
     
  10. krugorg

    krugorg Mu-43 Hall of Famer

    Jul 18, 2011
    Minnesota USA
    Welcome to the user group, Christian!

    I don't do a lot of shallow DoF stuff with the OM-D and PL25 (or my APS-C stuff), but I did remember seeing the OOF comparison between the Fuji and the m4/3 setup here:

    http://findingrange.com/2013/03/27/x-e1-vs-om-d-e-m5-part-2-fuji-xf-35mm-f1-4-vs-panasonic-25mm-f1-4/

    It seems closer than this to me, but I have never shot a comparison (and all I have is 35/1.8 on APS-C). One thing about the PL25, in my view, is that it works very well wide open for candids/portraits. Also, with the OM-D's IBIS, you can handhold at crazy slow shutter speeds... great for still life, or forced subject movement at night time.

    P.S. Did you check out the examples in the PL25 image thread here?
    https://www.mu-43.com/f80/panasonic-leica-25mm-f-1-4-dg-summilux-image-thread-15938/
     
  11. christianwaite

    christianwaite Mu-43 Rookie

    12
    Aug 26, 2013
    I would have thought the EVF being enclosed in a hood would handle well in most lighting situations. Have you had issues with EVFs before? I was looking at the XPro1 because it had an OVF, but the newer EVFs seem to be very good.

    My change has nothing to do with not being able to get shots I'm happy with. Weight/size is the main point, but also faster autofocus, good lenses that are plentiful second hand (and light/small) as well as modern features like the flip screen and LCD focus points. Also with it being small and more discrete with the back LCD flipped up and shooting from the hip, I'm hoping I'll be carrying it around a lot more for street photography, something that I actually use my iphone for (queue the screams).

    Thanks Luckypenguin, these are all good bits of info. I didn't realise base ISO was 200, but I'll invest in some ND filters as I struggle to shoot fully open at 1/4000th @ISO100 anyway and often will resort to an ND filter on the Canon. The sigma Is only 3-4 months old, so probably is the newer version, I know my mates is a lot softer at 1.4, but I still find this slightly soft, not enough to bother me though. I love the touchscreen focus, I've been playing with the wifes GF5 and it is very nice to play around with when you're trying to be a bit discrete with family & friends who don't like their photo being taken (but who will be annoyed if there's no photo's of them with our little one).
     
  12. Ulfric M Douglas

    Ulfric M Douglas Mu-43 Hall of Famer

    Mar 6, 2010
    Northumberland
    All depends :wink:
    If your 30mm is really great wide-open you're going to notice a bit less blurry background than the 25mm because at those focal lengths there does seem to be a significant different going the 5mm from one to the other, in terms of DOF.
    If, however, the Lumix is getting used at F1.4 all the time and the Sigma is stopped down a bit ... well, you know the story.
    I'm just going by examples found all over t'internet,
    I own neither lens/system.
     
  13. Halaking

    Halaking Mu-43 Top Veteran

    667
    Dec 17, 2012
    Los Angeles
    Morris
    I used a D550/ T2i, I would say OMD with 45mm @1.8 is about T2i with 50mm @2.8 or 60mm micro @2.8, so you do lost some DOF. M4/3 lenses usually much sharper at wide open!

    The focus system also different, M4/3's CDAF is fast, but the focus point is little bit bigger like small square, I get used to it within a week.
     
  14. christianwaite

    christianwaite Mu-43 Rookie

    12
    Aug 26, 2013
    So either that statement is wrong, or I am wrong.

    It is my assumption these days that a 50mm 1.4 will have the same image characteristics (so DOF/Bokeh) on both a 4/3 camere and a full frame camera. The only difference being the 4/3 will be like doing a 50% crop of the image. So to get around that problem you'd have to get a 25mm to get the same FOV which in turn will loose you some shallow DOF.

    Please someone correct me if I'm wrong.
     
  15. rnagoda

    rnagoda Mu-43 Veteran

    260
    Jun 12, 2012
    Tucson, AZ
    Robert
    Look at it this way - with a 50mm f/1.4, on the T2i you get a 1.6x crop, so you are looking at the full frame equivalent of an 80mm f/2.24 versus with a m43 camera (2x crop) where you are looking at the equivalent of a 100mm f/2.8. To get the equivalent of a 50mm f/1.4 on a T2i you'd need something like a 31.25mm f/.875 (so the best you'd do is a 35mm or 28mm at 1.4, likely) whereas on m43 you'd need a 25mm f/.7 - so you could use the Voigtlander 25mm f/.95 which would be very close (if you're cool with manual operation).
     
  16. fredlong

    fredlong Just this guy...

    Apr 18, 2011
    Massachusetts USA
    Fred
    Here's the short version

    25mm on m4/3 has approximately the same field of view as 50mm on "full frame". At f/1.4 the 25mm on m4/3 has about the same depth of field as 50mm at f/2.8 on "full frame"

    For m43 vs APS
    25mm at f/1.4 approximately equals 30mm at f/2 for field of view and depth of field

    The exposure is always the same: f/1.4 always gets you the same amount of light across all formats and focal lengths.

    Fred
     
  17. spatulaboy

    spatulaboy I'm not really here

    Jul 13, 2011
    North Carolina
    Vin
    They are correct, you get slightly deeper DOF in m4/3 compared to APS-C. But the difference is small. The photo you use as an example can easily be done on m4/3. If you want to really blur out the background, the Olympus 45mm f1.8 or 75m f1.8 will give you that extra nice separation.

    These are all from the PL 25:

    <a href="http://www.flickr.com/photos/vftsai/6990908196/" title="Panasonic Leica 25mm f1.4 by Vincent-F-Tsai, on Flickr"> 6990908196_37e3fa26d6_z. "480" height="640" alt="Panasonic Leica 25mm f1.4"></a>

    <a href="http://www.flickr.com/photos/vftsai/8552424969/" title="Laura at the lake by Vincent-F-Tsai, on Flickr"> 8552424969_66968246f8_z. "640" height="480" alt="Laura at the lake"></a>

    <a href="http://www.flickr.com/photos/vftsai/8445196842/" title="Winter ride by Vincent-F-Tsai, on Flickr"> 8445196842_64204cc6f1_z. "640" height="427" alt="Winter ride"></a>
     
  18. rnagoda

    rnagoda Mu-43 Veteran

    260
    Jun 12, 2012
    Tucson, AZ
    Robert
    The flipside of all of this being that if you need to shoot wide-open and don't want a paper-thing DOF, that can be nice too! :thumbup:
     
  19. Neftun

    Neftun Mu-43 Veteran

    408
    Jul 15, 2012
    Norway
    Patrick Kristiansen
    That is incorrect. The 45mm@1,8 has an aperturediameter of 25,00mm, an 50mm@2,8 has 17,85mm. Dof is not determined by sensorsize, but focallength and aperture. Add that to your other statement, which I agree to, that m4/3 lenses tend to be great wide open and many others are not, m4/3 is no slouch for shallow dof-photography. It is not the awesomest, but no slouch.
     
  20. Neftun

    Neftun Mu-43 Veteran

    408
    Jul 15, 2012
    Norway
    Patrick Kristiansen
    That is absolutely true. Easier to get more in focus when wanted.