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What makes a lens good for Portraits?


musikpro

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<p>Hello everyone,<br>

From the reading I've done, it seems that the nice blurred background, and crisp eyes and face have a lot to do with the f/stop. I've gathered that its the nice low f/1.8-4 lenses that give that characteristic DOF.<br>

Am i correct so far?<br>

How does the focal length come into play? How I understand it, as long as you use the correct f/stop to shutter speed ratio, the exposure should be correct, and using varients of those two, you can change the DOF, and how much of the subject/scene is in focus.</p>

<p>I'm shooting with a Canon 30D (digital Rebel XT). Can anyone recommend lenses for portrait type photography, as well as some good resources for me to read up on more techniques etc...</p>

<p>Thanks,<br>

-Errin<br>

P.S. I just registered here, so I don't have any of my photos up yet. I'll upload a few when I get a chance.</p>

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<p>Lenses are like paint brushes. there are different kinds and they do different things depending on the look and feel you want for the shot. i've never seen a lens that said portrait lens on the side of it. it's just whatever you like. go have fun!</p>
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<p>Focal length impacts perspective. Take, for example, a head-and-shoulders portrait. To fill your frame nicely with a <em>short</em> focal length lens (say... 30mm), you'd have to be physically quite close to your subject. When you're standing that close, the natural effects of perspective can cause things like large-looking noses. When you stand back a few feet more, the perspective changes dramatically, and more flatteringly. But in order to get the same framing, you need a longer focal length. Perhaps 50 or 80mm.<br /><br />If you have a typical kit zoom lens that came with your 30D, you can try these effects for yourself - perspective doesn't change with quality of lens, or with aperture.</p>
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<p>Thanks for that description Matt. That effect of having the proportions skewed was one of my problems. I like getting a nice close crop on the subject, but whenever I tried it wasn't very flattering. I'll try backing off and letting the zoom do its thing.</p>

 

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<p>To consistently obtain flattering portraits, the photographer has to understand (among other things) perspective, camera height and angle, and posing. A good bookstore will have books that are devoted to the finer points of portrait photography. Start there.<br>

If you are primarily interested in just finding out how to obtain blurred backgrounds, you can do that with a longer focal length easier than with a shorter focal length. I recommend the 85mm f/1.8 for portraits.</p>

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<p >When accepting advice, be sure to ask why? Ask again why? Until you are satisfied you are getting the right stuff. </p>

<p > </p>

<p >The chief attribute of a portrait lens is its ability to reproduce the human face with correct perspective. Consider that the nose will be closer to the camera then the ears. This being true, consider it likely that the camera will render the nose too big and the ears too small. Mostly we are taking about minuscule errors not likely to be noticed however the subject has a built-in self image of their likeness. This is derived from their view of themselves in the make-up mirror or shaving mirror. Stated another way, you win when your portrait duplicates this perspective.</p>

<p > </p>

<p >Now before we begin an explanation, keep in mind that photography is both an art and a science and you are free to plow your own rows. However these rows have been plowed before you were a gleam in your mother’s eye. Stated another way, pay some attention to me.</p>

<p > </p>

<p >You don’t need any special lens to shoot a portrait. You do however need to step back further than you think. By stepping back you increase the ratio of the nose to ear distance and that’s all that’s necessary. The problem is we have a strong tendency to compose in the viewfinder. We can’t seem to allow blank space around the subject so we work in too close and we use a lens that is too short. </p>

<p > </p>

<p >The tried and true camera-to-subject distance and the ability to compose in the viewfinder and achieve the correct perspective is satisfied when the focal length of the lens is 2 ½ times the diagonal measure of the sensor chip or film. Most books and teachers reference the 105mm as a portrait lens. This is true for the 35mm full frame camera. The full frame measures 24mm by 36mm and the diagonal measure is 43mm. Thus 43 x 2.5 = 107 a weird value that opticians round down to 105mm. Now 2 ½ times the diagonal is just a rule of thumb that places you in the ballpark. Hollywood cine photographer use 3x.for close-up shoots.</p>

<p > </p>

<p >How can you apply this data? Your camera is a Canon 30D. The sensor measures 15mm by 22.5mm. This size is called APS-C. It was derived from a failed film/digital hybrid design that was introduced by all the major players 20 years ago. The format was called Advanced Photo System. The ratio of height to width was called the Classic format. The diagonal measure of your chip is 27mm. Now wide angle is 70% of this value and shorter, that’s 19mm or shorter. Normal meaning normal perspective is 25mm ~ 30mm. Telephoto is 200% of normal or about 55mm or longer. Now for the $64,000 answer. Portrait is 27 x 1.5 = about 40mm. </p>

<p > </p>

<p >Remember what I said – Ask why? and ask why? again. </p>

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<p>Wow.... I'm very impressed with the quality of responses you have all provided. Thank you for your valuable input. I have never heard of that focal length to diagonal ratio before... I think that probably is the answer to what was going to be my next question, about the "prime" focal length of a lens. <br>

I will look for some books on portrait photography; I most definitely want to know more than just how to blur the background! Any suggested authors/photographers to keep an eye out for?</p>

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<p >As discussed above, the “normal” lens for any camera is one that has a focal length that is an approximate match equal to the diagonal measure. Now in the early years of photography lenses were fixed as to focal length. We purchased a 50mm or a 135mm etc. Some zooms were available but the quality was poor and the price was too high. With the advent of the modern zoom, fixed focal length lenses continue but diminish in popularity. In the vocabulary of the modern era another word for fixed focal length is “prime”. Opticians will tell you, it is much easier to make a “prime” and as a rule of thumb they are sharper and faster (allow more light to enter) than a zoom. This is because a zoom is built using multiple moving lens elements thus the design is a compromise in many regards.</p>

<p > </p>

<p >As to focal length: A camera lens is a converging lens. This means the light rays are caused to bend inward. This causes an image to form at some distance behind the lens. Long projection distances act like telescopes. Short projection distances yield tiny images that cover a wide field-of-view. </p>

<p > </p>

<p >The focal length is a measure of the distance lens-to-image. On a simple lens we measure from about the center of the lens barrel to the surface of the chip or film when the camera is focused on a far distant object. Most lenses must be made using a complex design meaning multiple lenses are combined to correct for optical errors. A complex lens consists of many glass or plastic lenses called elements. Some elements are strong and some are weak as to power. The focal length will be the combined power of this array.</p>

<p > </p>

<p >A true telephoto is one with a focal length appreciably longer than the diagonal of the film or chip. Such a lens is truly called a long lens. Long lenses are awkward; they stick out in front of the camera too far. A true telephoto has a long focal length however the barrel is much short than its long lens counterpart. This shorter designed is due to clever use of lens elements that shift the measuring point forward, away from the center of the barrel. Some telephotos have a measuring point (called the rear nodal) shifted so that it falls in the air way out in front of the lens. This keeps the lens barrel as short and manageable. </p>

<p > </p>

<p >A wide-angle must have a short focal length. More often than not, a short projection distance, lens-to-film or chip, will interfere with internal camera mechanism. Thus it is desirable to lengthen out the “back focus”. To accomplish the design used is called an inverted telephoto. The wide-angle view is comparable to looking through binoculars backwards. </p>

<p > </p>

<p >A “normal” is one that about equals the diagonal measure of the film or chip. This gives a view with a perspective about equal to the human experience. The angle of view will be 53º. </p>

<p > </p>

<p >More if you ask. Nobody said this stuff is easy. </p>

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<p>a 70-200 or a 135 f2 works very well for a full frame camera, however with your sensor, the 135 f2 would be too long unless you have a large studio space.<br>

If you were to shoot a 70-200 @ 70 mm your 1.6 crop sensor would act like a 112 mm lens which wouldn't be bad at all. Go out to about 85 mm on it and you will be roughly equivalent to 135 mm. I would suggest a 70-200 2.8 Non IS because it is very sharp (truly, one hell of a lens) and has really nice bokeh for a lot less money than the IS version.<br>

One book that is simple to understand and can really get you going in the right direction is Scott Smith's "Studio Lighting Made Simple"</p>

<p>Hope this helps,</p>

<p>Pete</p>

<p> </p><div>00TZZ4-141285684.jpg.ea5c05e7c9acfa7b81a7d86e04cbacc2.jpg</div>

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<p>A large amount of the successful pro's I know who shoot portraits on 35mm (full frame) format, use the 70-200mm f2.8 (Canon, Nikon and Sigma, all have pro versions of this model) the majority of the time. It provides the flexibility of a zoom, the clarity of a pro lens. Whilst it's heavier than a prime and may not have as wide an aperture, it's rare in my experience that you'll need anything much less than f3.2 in portraiture (shooting f2.8 at 200mm will give only a few inches of DoF which can be restrictive more than creative sometimes), so anything like the 135mm f2 or the 85mm f1.8 seems like over kill in my opinion, they may offer a little more clarity due to less elements (perhaps not enough to tell the difference?) and be lighter for the same reason, but you trade a great deal of versatility for that. Also bear in mind extra compression can be quite flattering offered by shooting at 200mm rather than 70mm. IS (VR for Nikon) or non-IS in my opinion doesn't make a bean of difference to the quality of the image.<br>

As an example of pro's that use this lens a lot for portraiture, to name just a few off the top of my head:<br>

Jerry Ghionis, Damien Lovegrove, Annabel Williams, Jo de Banzie.<br>

Just my 2 cents<br>

T</p>

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<p >As to the full frame 35mm: </p>

<p >Early cameras had to be quite big because the ability to make prints and enlargements came later. Glass plates preceded film. With no ability to enlarge, the size of the original camera produced image was the size delivered. Many print sizes in common use today are hand-me-downs from common window and cabinet glass of that era. The key point is the size of camera shrank due to technology i.e. the film got better so the cameras got smaller. Please don’t lesson escape you. Tomorrows digitals we be tiny because the sensors will evolve. </p>

<p > </p>

<p >Thomas Edison invented the motion picture Kinetoscope system. It was designed for penny arcade viewing. They year was 1889. He and his chief engineer bargained for film with George Eastman. Kodak was making a 70mm roll film. The three settled on 70mm silt down the middle for economic reasons. Thus 35mm was born. The Kinetoscope system needed sprocket holes on both edges of the film to engage the camera’s film transport mechanism. With sprocket holes, the width available on the 35mm film for the image was 24mm. The film direction in the Edison camera was vertical. The height of the image was set at 18mm. For years, Cine projected images stemmed from an 18mm x 24mm film image.</p>

<p > </p>

<p >The German camera company Leitz set about to make a camera that utilized the now plentiful 35mm Cine film. The year was 1924. Chief engineer O. Barnack designed the camera so the film travel was horizontal. Mr. Barnack retained the 24mm but doubled the 18mm thus 36mm became the length. The format size became 24mm by 36mm.</p>

<p > </p>

<p >So popular was the 35mm that most every photo book and teacher references it when the talking lenses and applications. If your film or senor is different in size, what then? Most teaches are highly experienced with the effects of the full frame 35mm thus they make the reference. Strangely the old 8x10 and 4x5 and 2 ½ x 2 ¼ master photographers don’t make similar comparisons. </p>

<p > </p>

<p >OK, how do we characterize the differences, smaller sensor to the full frame? The optical difference can be explained by a Focal Length Multiplier or perhaps better stated as a Magnification Factor. This is the math used to make the comparison. In my opinion, the use of such a comparison to teach a newbie is futile, they are likely unfamiliar with the 35mm full frame and its mighty arsenal of lenses. </p>

<p > </p>

<p >Nevertheless, to calculate a multiplier or factor we divide the diagonal measure of the sensor we will be using into the diagonal measure of the venerable 35mm film frame. Thus for the APS-C v.s. the 35mm the math is 43 ÷ 27 = 1.6. Consider the 105mm, you can divide this value by 1.6 to figure out the equivalent for the APS-C. Thus 105mm ÷ 1.6 = 65mm. Suppose you mount an 80mm on your APS-C. What is its equivalent for the full frame 35mm. Math is: 80 x 1.6 = 128mm. </p>

<p > </p>

<p >Nobody said this stuff is easy.</p>

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<p>Hi Jeff,</p>

<p >The Canon G10 will do an excellent job for portraits. Don’t let anyone tell you otherwise.</p>

<p >I was unable to find the size specifications for the CCD chip but I can calculate it from the data. Based on published pixel data the format ration is 1.33 meaning the length of the CCD imaging area is 1.33 times the height. OK so what? The lens supplied a zoom 6.1mm ~ 30.5. We are told this is the equivalent of a zoom lens 28mm ~ 140mm for the full frame 35mm. Thus the CCD is smaller 6.1 ÷ 28 = 0.22 meaning the CCD is 22% of a full frame. Now the full frame diagonal is 43mm so 43 x .22 = 9.5 so now we know the diagonal is 9.5mm. Multiplying this by 2.5 = about 24mm as the ideal portrait focal length for this camera. Since the range of the zoom is 6.1mm ~ 30.5mm, the ideal is achieved when the zoom is set to just short of maximum. </p>

<p > </p>

<p >Please understand that 2.5 times the diagonal for portraits is just a rule-of-thumb and some will argue that it’s gobbledygook. However it is based on the viewing distance most folks gravitate to when viewing finished portrait prints. That distance is about equal to the diagonal measure of the print. This combination delivers a perspective about equal to the make-up or shaving mirror. This is a perspective that sells better and wins contests.</p>

<p > </p>

<p >Best of luck. </p>

 

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<p>It may help you to think about photography through painting. If you want to paint the portrait of your model how far would you be from your model? Would you be 10cm far? Would you be 300m far looking the model through telescope? Distance gives many answers.</p>
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  • 2 weeks later...

<p>I've seen wonderful portraits shot at distance, with wide angle lens, at f16, with no flash, in broad daylight, with no shade that incorporated architecture, reflections in a pool, and a jet plane over head.</p>

<p>I've seen great portraits taken close up at f/1.4 and ISO 3200 with a telephoto.</p>

<p>The best lens for a portrait means nothing if the photographer is limited in his imagination. It's only a tool.</p>

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<p>well youve already received lots of sensible and useful answers, so maybe i can take the liberty of saying that its not the lens that makes a good portrait but the photographer. and that equally there <em>is</em> no correct or incorrect lens...it all depends on the situation, personal taste and the effect you are trying to achieve.<br>

although, having said this, wide-angle lenses really arent all that flattering on people, its true.<br>

but of course that may be the effect you want? everything has its time and place.</p>

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