Zoom lens technique

<p>Just as a point of reference, do most photogs use zooms:</p>

<p>a. by choosing a specific focal length, (eg. 50mm, 35mm etc.) then composing the picture?<br>

b. by zooming in/out to compose the picture?</p>

<p>Are there specific optical issues involved (eg. lens is only calibrated to be at it's optical best at 50mm, not 52.5mm)? Is it just based on preference, the situation or personal style?</p>

<p>Thanks for any thoughts.</p>

<p>I pick the vantage point and what I want in the image and then use the zoom accordingly. I lean towards ultrawide for the effect. When I'm not shooting landscape, I tend to keep to the extremes and use it as two primes in one and crop later.<br>

>>Are there specific optical issues involved<br>

If the lens you're using doesn't have a constant f stop there could be an issue, but for landscapes you're stopped down so who cares. Most quality zooms have a constant f stop so with there shouldn't be an issue anyway.</p>

<p>Most of the time I will choose the Camera Vantage point, for the Perspective I want and then choose the FL to suit the Shot, I want.

<p>

<p>When shooting under the pressure of time or without adequate aforethought, or not having the time to get the correct viewpoint - I use the zoom to frame and get the shot - usually shooting wider than tighter - thus allowing more cropping options later: Stuff the Perspective, if absolutely necessary.

<p>

<p>I guess I use a Zoom lens for less than 1/3 of my images – I think this fact is relevant.

<p>

<p>WW

 

</p>

</p>

</p>

</p>

</p>

</p>

</p>

<p>@ Reagan: Thanks for thoughts. Re f stops. All my zooms have constant f stops so that shouldn't be an issue.</p>

<p>@ William: Thanks for input. I am aware of the benefits of primes over zooms (I assume this is what you are refering to) and am moving in that direction--unfortunately, I don't have the entire range covered, yet. Also, when I travel, I tend to favour zooms for greater flexibility with less baggage.</p>

<p><em>“I am aware of the benefits of primes over zooms (<strong>I assume this is what you are referring to</strong>) and am moving in that direction”</em></p>

<p>No I wasn’t, not really.<br>

I was making the point that <strong><em>because</em></strong> I use Prime Lenses so often, I need to be in the right position to use a Prime Lens, properly.<br>

Therefore, when I use a zoom, I tend to get to the correct Camera Position and I know (in advance) that I want 16mm or 24mm or 35mm . . . etc.<br>

Also it is relevant that I did some Cine work – and the Camera Position is set for Perspective, then the FoV is chosen for The Shot.</p>

<p>WW</p>

<p>I choose perspective/POV, then, if possible, zoom to crop. However, when doing street photography or very fast events, I choose a focal length, and work from that.</p>

<p>I don't have any particular technique. I just judge where to stand based on what I see with my eyes, and then I use the zoom to fine tune the composition. It's basically more of a cropping tool than it is a perspective one, for me. I may not be a great photographer, have the best equipment, or choose the most interesting subjects, but at least my compositions are good.</p>

<p>I would rarely think about IQ differences between, to use your example, 50mm and 52.5mm - these differences are so trivial that they would not be visible in a final print, and even if they were slightly visible under extremely close inspection, creating an effective composition is much more important.</p>

<p>It would also be very unusual for me to set the lens to a specific focal length before setting up the shot. Choices of focal length can affect many aspects of the composition: framing, relative "size" of foreground and background elements relative to the subject, ability to throw various parts of the scene more or less out of focus, and so on.</p>

<p>It is hard to be too specific about the process of setting up a shot, but generally it might go sort of like this:</p>

<ul>

<li>I see a subject or element of a subject that interests me.</li>

<li>I think about various ways to shoot this subject - close, near, low, high, and much more. I often move around the subject watching how elements of the scene arrange themselves in interesting ways.</li>

<li>I often, but not necessarily always, try to see the scene within a frame. I might create an impromptu "frame" with my hands and/or view the scene through the viewfinder. (I also find it useful to view the scene with only one eye if I look directly at it.) Some photographers use a "framing tool" - a piece of mat board cut to the intended dimensions of their photograph.</li>

<li>I put the camera on the tripod if it isn't already there and compose the shot. If I'm using a zoom I'll adjust as necessary to frame the subject the way that I think works best.</li>

<li>There's more, but I'll stop now...</li>

</ul>

<p>This, of course, describes a fairly slow and deliberate process that isn't always possible or appropriate. Some subjects (I shoot street, some sports, birds in flight, etc) simply require you to have developed the instincts to respond nearly instantly to the scene. Eventually, you begin to be able to think about framing the subject effectively even in these circumstances... and occasionally you actually pull it off! :-)</p>

<p>As Luis points out, when shooting some subjects where you might work quickly and spontaneously, using a prime can be advantageous - and this has nothing at all do do with image quality. Street photography and certain types of sports photography are good examples. I sometimes shoot street with a zoom - there can be great reasons for doing so - but at other times I may shoot with a couple primes or even a single prime, especially when working in close quarters.</p>

<p>About primes and zooms: I use both. You can make excellent photographs with both, and in various circumstance either could be the better choice.</p>

<p>Dan</p>

<p>Once I've decided which of my zooms to use, 24-105mm or 70-200mm, I don't concern myself with focal length and simply compose in the viewfinder. I do tend to leave a little room around the "ideal" crop in case I later decide to rotate the image a degree or two. I normally shoot aperture preferred and select the aperture based on the DOF that I want. My zooms are constant aperture.</p>

<blockquote>

<p>Are there specific optical issues involved (eg. lens is only calibrated to be at it's optical best at 50mm, not 52.5mm)?</p>

</blockquote>

<p>When I use a tripod once I have the focus set I often switch the l,ens to manual focus to lok it in. However sometime I deside to zoom in or ot a littel to adjust the cropping that may occur if I print it on 11X14 paper. If you adjust the zoom after you se thte focus you might get an out of focus image. Many zoom lenses are not parafocal which means the focus point will shift if you change the zoom. </p>

<p> that great at 24mm (barrel distortion and some vignetting). So when I have a need for 24mm on a shot I often switch to my 17-40mm which is opticaly much better at 24mm. Otherwise you might have tocorrect for barrel distortion later on the computer. IN other words it you have some overlap in focal lengths I would recommend using the lens that is optically best in the range you are using. For the focal length of 70-105 the 70-200 is the better choise however the 24-105 is not that bad at 105mm so I might not bother with a lens change.</p>

<p>How do I choose the focal length for my zoom? I generally don't. When I decide to take a shot I decide what field of view I want and then use the lens that will give me that field of view. I then adjust the lens as necessary to get what I want. <br>

I have the 24-105 lens which is not</p>

<p>Thanks for your thoughts. Obviously, we all have our own methods. I was just interested in a casual survey to see what others are doing. It's always good to challenge your own beliefs and assumptions.</p>

<p>Just remember that using a zoom is not an alternative to driving/hiking/walking to the best vantage point for the right perspective. Only then should you use the zoom to fill the frame with your composition.</p>