75 or Voigtlander?

Discussion in 'Native Lenses' started by tjdean01, Jan 10, 2014.

  1. tjdean01

    tjdean01 Mu-43 Top Veteran

    Feb 20, 2013
    I've recently learned that the aperture and only the aperture determines shallow DOF. The only reason the 75/1.8 usually seems to have a shallower DOF is NOT because it's a longer lens, rather, but because it's a longer lens the subject is filling more of the frame. So, while i like this lens, I now realize that I will get the exact same shallow DOF with the 45/1.8 if I step a little closer...and that (or any of the adapted nifty 50s) are much cheaper than the 75.

    So that leaves $1000 for me to buy another lens. 42/1.2 looks nice, but why spend $1500 for a 1.2 when I can get a 0.95 42.5mm Voigtlander for $1000? I'm actually going to use an old 35mm film camera (with the same Konica lenses I'm using on m43s) to experiment with shallow DOF.

    But, when it's said and done, for shallow DOF, wouldnt' the Voigtlander be the best bet?

  2. stratokaster

    stratokaster Mu-43 All-Pro Subscribing Member

    Jan 4, 2011
    Kyiv, Ukraine
    The DOF is determined by the aperture and the distance between the camera and the subject. However, the amount of background blur is determined by the diameter of the entrance pupil of the lens which equals focal length divided by F-number. It means that 75/1.8, at the same magnification, will deliver the same amount of background blur as a hypothetical 37.5mm f/0.95 lens.

    At the same magnification the DOF will be the same. But the 75mm lens will still give you much greater amount of background blur because it's longer.

    All of this applies to normal shooting distances (not infinity and not macro).

    42.5/0.95 will give you more shallow DOF and greater amount of background blur than 75/1.8.
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  3. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    You'll start a 50 page argument about DOF here, but essentially you're right. DOF will be the same reardless of focal length *if* the subjec size, sensor size and print size remain the same. However DOF is an illusion. It's "apparent". So other things can give the appearance of shallow DOF.

    But..... Aperture is only one reason to buy a lens.The angle of view and working distances are very different between the lenses you're talking about. A longer lens with the same DOF and subject size will have different perspective, due to the different shooting position. Also you'll have more or less of the background as an element of the image (more for wider angle lenses). So regardless of DOF the images from different focal lengths will look fundementally different. If you want the look of the 75mm, nothing you can do with the 45mm will give you that. Sometimes the differences will be small. Sometimes not.

    So there are many reasons apart from DOF for choosing any lens. Sure a 20mm 2.8 and a 300mm 2.8 have the same DOF for the same subject size. But which one would you choose to shoot a pride of lions with?

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  4. RoadTraveler

    RoadTraveler Mu-43 All-Pro

    Nov 23, 2012
    I cannot comment on any of the other lenses you mentioned, I can only share that I really like my Voigtlander 42.5. After years of ignoring my Leica M camera and manual lenses and only using autofocus glass, a return to experiencing manual control (now on m4/3) has been a creative pleasure, first with the Voigtlander 17.5, then others followed. Asking yourself how much you like or dislike manual lenses might help steer you.
  5. MAubrey

    MAubrey Photographer

    Jul 9, 2012
    Bellingham, WA
    Mike Aubrey
    Quite, but there's a catch.

    At the same magnification of the subject, you'll have the same amount of DOF, but the longer focal length of the 75mm will also magnify the out of focus areas more than the 45mm will, too (i.e. more telephoto compression), which will result in more apparent blur than you would otherwise have. With less magnification of the background, the 45mm will have more background in the picture than the 75 and that will give the appearance of less background blur despite the fact that the mathematical depth of field measurement is identical.
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  6. Dramaturg

    Dramaturg Mu-43 Top Veteran

    Jun 7, 2013
    MAubey said it simply right - with the same framing the faster lens (regardless of the FOV) will give you shallower DOF. Though the background blur will be different at different FOV.

    For example, if you shot 25mm 1,4 wide open at half a meter and 45mm 1,8 wide open at one meter from a model (in order to get the same framing), Panaleica will have 1cm less DOF (2cm against 3cm). Hence the faster is the lens, the less DOF.
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  7. kevinparis

    kevinparis Cantankerous Scotsman Subscribing Member

    Feb 12, 2010
    Gent, Belgium
    you obviously feel DOF is an important factor in your choice of lens. there was thread recently to which I contributed some images


    shallow DOF when it works ...is wonderful... but it is a dog to get right in most normal non static circumstances.

    it all depends on your photographic desire... personally I could live with a 17/1.8 and the 75/1.8... and maybe a 25 in there

    my 45 or my large collection of nifty 50's have barely been used since i got the 75

    also check out this thread


    great examples of what is possible with m43 and first party lenses

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  8. uci2ci

    uci2ci Mu-43 All-Pro

    Jun 22, 2012
    Los Angeles, CA
    Very informative discussion.
  9. walter_j

    walter_j Mu-43 Top Veteran Subscribing Member

    Sep 10, 2013
    Hagwilget, B.C., Canada
    I have the 75, but I like it because it's crazy sharp! A portrait taken from 10 feet away, and I can see an outline of myself in the person's eye. It's awesome. Shallow DOF is just a bonus for me. Perhaps I could get the same sharpness with a voightlander, but I'm not sure. I like the build quality of the voightlander, and can see that lasting forever. I don't see the oly 45 lasting very long (I have the Voightlander 17.5).
  10. tjdean01

    tjdean01 Mu-43 Top Veteran

    Feb 20, 2013
    Over the past year I've seen a lot of your posts. Many of which teach me something. I understand now. My new knowledge was only part of it! I was right about DOF, but what I'm actually looking for is not necessarily DOF, but amount of background blur. Thanks! I now see why all those shots from the 40-150 or my 135s seem to have nicer bokeh. I was just assuming--without really looking back at them--that they gave that because I was zoomed in closer to the subject.

    Las Palm as: fun, useful calculator!

    MAubrey: Good explanation. The 45 would kind of stretch the background vs 75, thus making it look sharper, in which case the 75 would be preferred.

    And Flash, thanks for your input too. Unfortunately, I now want both of the lenses :frown: So, my Vivitar 28/2 (which is good at f2) is better for low-light, due to camera shake, but the Pentax 50/1.7 (which is good at f2), will give me better blur. I just looked through the shots and I can see it now that I know what I'm looking for. I like the following shot (50mm, appx f2), but would like a bit more separation

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  11. Whtrbt7

    Whtrbt7 Mu-43 Veteran

    Jan 7, 2014
    IMO the 75 is more an outdoor lens and the 42.5 is more of an indoor/really dark places lens. If you use a simple DOF calculator, you can get how wide your DOf is, near, far, and hyperfocal distances, and the diameter of the circle of confusion. What forms background separation of the subject from the background is if your subject is within the depth of field for the distance, aperture, and focal length you are at.
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  12. pdk42

    pdk42 One of the "Eh?" team

    Jan 11, 2013
    Leamington Spa, UK
    If shallow DOF is your desire, it might make sense to venture into a larger sensor format until the urge subsides!
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  13. HappyFish

    HappyFish Mu-43 Top Veteran

    Sep 8, 2012
    Some thoughts to me quality of bokeh and blur is important
    Also what are you taking pics of ?

    People ?
    Can you control subject to background difference ?
    As in portraits get close to them put them in front of a background that is further away
    If ya can't control it or say are your in your home then 75 is to long get really close with a 42 range or even less lens would be my option

    One other thing longer lens can help cut down angle of view which can be important
    Say at a park a 25 lens up close could get you a nice dof look but also include all kinda background mess the 75 or longer can do better narrow the angle and isolate the subject

    Shooting people sometimes I want to get the surroundings in the frame other time I want to isolate them

    IMHO these are more why I choose a lens than dof alone
    Also why many pros have a 70-200 2.8 lens live on a body it's the most amazing portrait range lens :)
    A 35-100 panny 2.8 could be a great option to ?

    So think
    How big is my subject ? Car or people or tiny birds
    How far will the background be and can I control placement and distance
    How close can I get vs the subject to background
    Example my kids at the park or my kids in my house
    Do I want to show some background or narrow the angle of view

    Example couple in front of beautiful woods shooting a bit wider I could show some of that woods and have them fill say half the frame
    Or if I am at a crappy location with one tree in a parking lot I could use a long lens put them a bit closer to the tree get back some and could get a great background making you think they are in front of a forest :)

    When I shoot weddings I can't control the ceremony and how far away I am or the subject is
    but I can control bridal portraits in both of those situations

    So would I get the 75 or the CV 42.5 ?
    I do own the 75 an amazing lens a must have IMHO
    Don't own a 42 range cause I have FF gear and 85 prime

    I would take the 75 and say a 45oly for a bit more than a CV42.5 and have the best of both
  14. Whtrbt7

    Whtrbt7 Mu-43 Veteran

    Jan 7, 2014
    So I own both lenses. I feel like both have their specific purposes. Indoors, the 75/1.8 is still useable but it seems like I can only capture a face with the lens when I'm up against the walls. It's a great lens but I think the 42.5/0.95 really works well for portraits indoors. The 75/1.8 outdoors however is great for portraits when you do have the distance from the subject. The background compression (not DOF) can really take away messy backgrounds with the 75/1.8 that the 42.5/0.95 can't do at farther distances. When you do close the distance though, the 42.5/0.95 can obtain pretty good background compression and make those 3/4 portraits excellent. Again, DOF is a function of focal length, length to subject, and aperture but that's only a part of the story when considering portraiture. Background compression is a function of focal length, distance to subject, distance from subject to background, aperture, and angle of view. Quality of bokeh does matter as well but I don't think most people (non-professionals) pay as much attention to bokeh unless it is overly distracting.
  15. EarthQuake

    EarthQuake Mu-43 Top Veteran

    Sep 30, 2013
    Background compression (perspective) is a function of distance to subject/background and nothing else. Focal length, aperture and angle of view have nothing to do with it.

    Focal length may alter distance to subject/background because it forces you to move to maintain a certain crop, but this doesn't mean focal length determines perspective. Focal length can be an important consideration for predetermined framing, like a head shot, head and shoulders, full body, etc, as it determines the distance you need to be from the subject, and thus the perspective, but its important to realize that change in perspective does not come from a change in focal length, in comes from a change in distance.

    Aperture may make the background more or less blurry, but does not alter the background compression/perspective in any way.

    Its very easy to test this, pick a fixed position to shoot from. Take a shot with a 100mm lens, take another shot with a 50mm lens. Crop the 50mm lens in post to the same framing as the 100mm lens shot, you will see identical background compression/perspective. Even a 25mm lens or a 12mm lens will provide the same background compression as a 100mm lens with a photo taken at the same position, just at a different angle of view. Again, cropped to match, perspective will be the same.

    There is a better explanation here: http://photography-on-the.net/forum/showthread.php?t=672913

    People often refer to lenses and their qualities re: perspective as if its the focal length alone that determines perspective. Some will say you can't take a portrait with a wide angle lens because of perspective distortion. While its true that you shouldn't take a headshot with a wide angle lens (because you will need to be much too close, not because of the FL of the lens) you certainly can take portraits with wides, but generally environmental portraits where you maintain a similar distance to your subject as you would with a longer focal length lens.
  16. LowriderS10

    LowriderS10 Monkey with a camera.

    May 19, 2013
    Sensor size also plays a role in this! ;) (Just to stir the pot a bit).

    This is a hard decision...do you want AF or not? How good is the Voigtlander wide open? The O75 is stellar wide open, so there's no real need to stop down...if the Voigtlander is so-so up to f1.4 or 1.8 (I don't know if it is or isn't), then it loses its advantage. Do you need the longer FL? I love using my O45 1.8, but the O75 gives me the working distance I usually like for street photography. Also...there's the QUALITY of the bokeh to consider. The PL25 has lots of bokeh, but I don't like the way it looks. The O75 gives me a Canon 135L-esque bokeh...simply dreamy.

    A lot of this depends on personal preferences, not just technical specs.
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