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    Advice re DoF please

    IMG_0215 by Roy Widdowson, on Flickr
    Advice regarding DoF please;I notice that this image has a nicely blurred background which makes the musician stand out,so did my aperture of f5.6 and the distance from me to the subject(exif says approx 3.29)combine to give the shallow DoF?

    Also,would that have been enhanced if a lens of around 50-200mm had have been used?I'm hoping to acquire such a lens at the weekend and trying to learn in advance how to create that shallow depth of field when I consider it to be appropriate ie outdoor portraits etc.

    #2
    Advice re DoF please

    This was rubbish.
    Last edited by Astolat; 31-05-2018, 08:53.

    Comment


      #3
      Re: Advice re DoF please

      DOF is governed by 3 factors.
      FOCAL LENGTH OF THE LENS
      1.The focal length of a lens has a major effect on the depth of field.
      2.A wide angle lens has much greater depth of field than a telephoto lens
      3.The sensor size doesn’t have any direct effect on the depth of field.
      However, as APS-C and smaller sensors have the effect of altering the field of view of a lens, shorter focal length lenses are used in order to get the same field of view as a traditional full frame camera, therefore the depth of field for a given field of view will be greater.
      APERTURE
      1.In simple terms the smaller the aperture the greater the depth of field
      2.Unfortunately as we need to satisfy the exposure needs as well as depth of field, we are sometimes struggling.
      CAMERA TO SUBJECT DISTANCE
      1.The closer the subject is to the lens, the shallower the depth of field in actual distance terms.
      2.On my 150mm f2.8 lens @ f2.8 and a distance of 50cm, the depth of field is 8mm. Increase the distance to 1.5 meters and the depth of field is now 40 mm once the distance is 150 meters the depth of field has risen to about 25 meters.

      If you want more advice, message me
      Alan

      No longer using Canon but still teaching new Canon users (and others) the gentle art of Photography.

      http://www.springfield-photography.com/

      Comment


        #4
        Re: Advice re DoF please

        Roy, there are several free and paid apps available for your 'phone or tablet that will rapidly calculate the DOF for you based on the 3 factors Alan has identified (I have Hyperfocal Pro, DOF Calculator and Photo Tools - I am sure there are many others). Being on the 'phone, you can use it in the field. Of the 3 apps mentioned, I prefer Hyperfocal Pro.

        Hope this helps.
        John Liddle

        Backwell, North Somerset - "Where the cider apples grow"

        Comment


          #5
          Re: Advice re DoF please

          I agree with John, apps. are helpful but the best way is to practice as you are often not able to take the time to use an app as if you do you will miss the shot. Get to know your gear. I teach people photography and I get them to practice with their kit, using all apertures at all focal lengths and varying camera to subject distances. This helps them to understand the capabilities of their own kit.
          I do use apps for set piece landscape shots where I have time to check.
          Alan

          No longer using Canon but still teaching new Canon users (and others) the gentle art of Photography.

          http://www.springfield-photography.com/

          Comment


            #6
            Re: Advice re DoF please

            Agreed Alan - there is no substitute for practise, practise, practise!
            John Liddle

            Backwell, North Somerset - "Where the cider apples grow"

            Comment


              #7
              Re: Advice re DoF please

              Thank you for all your replies,they are most helpful in getting me to understand DoF.
              I'll continue to experiment at every opportunity.
              Roy

              Comment


                #8
                Re: Advice re DoF please

                Roy, not sure you've had a completely clear answer to your question about whether a new lens would have given you a different depth of field. So for clarification (I think): as Alan explains, the simplistic answer is no, the depth of field you will get at 3.19m using f/5.6 at 55mm is exactly the same whether you use an 18-55 or 50-200.
                But with the 50-200 you would be able to use an aperture of f/3.5 instead of f/5.6. According to DoF Calc this will give you a dof of 0.550m compared to 0.883m, so not actually a massive difference at that distance. In your specific example, I suspect (others may disagree) that the far shore is so far away it wouldn't actually have made any discernible difference, which is why experimentation is needed.
                Canon EOS 7D
                EF-S 10-22mm 1:3.5-4.5 USM, EF 24-105mm 1:4 L IS USM, EF 50mm 1:1.8, EF 70-300mm 1:4-5.6 IS USM
                Luminar 4, Aurora HDR Pro, Silver Efex
                flickr: http://flic.kr/ps/LXWuy

                Comment


                  #9
                  Re: Advice re DoF please

                  Hi Alex,
                  Thank you for that,the lens I'm after has an aperture range of f4 to f5.6(Sigma 50-200mm f/4-5.6 DC OS HSM),which will give me plenty of scope I think(?) for both shallow and deep DoF's depending on where I'm using it.eg;next week I'll be visiting a local tropical bird centre,so the extra reach will be an advantage.It's more likely I'll need to use higher f numbers there to get images with good DoF.
                  Hope that makes sense to you?
                  Roy

                  Comment


                    #10
                    Re: Advice re DoF please

                    To get shallow DOF all of the following help....wider aperture, closeness to subject, greater distance of subject to background, longer focal length.......and of course the converse is true.
                    I'm suggesting you just keep in mind these factors when you shoot....in practical real world terms you don't normally have control of all of them, so best to just learn and apply the principles.

                    With your 18-55 wide open is f5.6.....you could have had a nice blurry background if a wider aperture was available say f2.8


                    To make the most of DoF control I'd suggest you get a standard prime like the 50mm f1.8...nice and cheap and great fun for DoF experimenting....or another great lens is the 85mm USM f1.8...around £230....and much better DoF control than any zoom....and equivalent to a 135mm full frame field of view.

                    beware if you choose a longer focal length....you'll have to step back further to frame the same shot which increases DoF. The great benefit of a longer focal length is a more flattering perspective in portraiture due to less distortion.
                    Last edited by @imagesBV; 30-05-2018, 21:04.
                    Brian Vickers LRPS

                    brianvickersphotography.com

                    Comment


                      #11
                      Re: Advice re DoF please

                      Thanks Brian, I'm on a limited budget,so it'll be just my current 18-55,and then a longer lens at the weekend-both pre-owned.
                      I will have to work with what I've got, though I'm happy with my Liverpool event images re DoF.
                      Roy

                      Comment


                        #12
                        Re: Advice re DoF please

                        The advice to get either the 50mm 1.8 or the 85mm 1.8 is excellent. Both these lenses are very good and a reasonable price. You will also benfit from the additional sharpness that they offer. A full frame lens on an APS.C camera will give better results as you are only using the cenral are of the lens, where its performance is at its best.
                        Alan

                        No longer using Canon but still teaching new Canon users (and others) the gentle art of Photography.

                        http://www.springfield-photography.com/

                        Comment


                          #13
                          Re: Advice re DoF please

                          Thanks Alan,I take your point about those lenses,but I don't think I'll be taking many images where a fast prime lens is essential,at least not for the time being.
                          I'll certainly experiment though with the lenses that I'll have for now,you explained DoF very well in your earlier reply,which will help me greatly on my journey into DSLRs.
                          The lens I've now decided to order this weekend is the Canon EF-S 55-250mm f/4-5.6 IS STM which I think will be a good general purpose one.
                          Roy
                          Last edited by Guest; 30-05-2018, 23:16.

                          Comment


                            #14
                            Re: Advice re DoF please

                            Canon EF-S 55-250mm f/4-5.6 IS STM which I think will be a good general purpose one.
                            Plenty of people here will agree with you, there has been a lot written about that lens on this site and we are all pretty happy with it. Nice and light as well, decent image quality and a good match for the 550D body. Great value for money and I'm sure you will enjoy it.
                            EOS 6D, 6D Mk II, 80D, 70D, 100D, 200D, M50, M100. Canon 10-18, 18 - 55, 55 - 250 IS STM lenses, Canon 16 - 35 mm F4L, 35 mm EF-S macro, 50 mm F1.8 STM, 60 mm EF-S macro, MPE-65 macro, 85 mm F1.8, 200 mm F2.8 L II, M 15 - 45 mm, M 22mm F2, M 32mm F1.4. Sigma 24 - 35 F2 Art, 135 mm F1.8 Art, 17 - 50 F2.8 DC, 105 mm OS macro, 100 - 400 C, 150 - 600 C.

                            Comment


                              #15
                              Re: Advice re DoF please

                              You can also use the dof preview button, may help get the look you want.

                              Sent from my Nexus 6P using Tapatalk

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