Focal lengths and when to use them?

MatthiasClaflin
MatthiasClaflin Website User Posts: 674 Just Starting Out
The way I understand it, a 50mm lens has a 50mm "focal length". That being said, as I understand it, the larger the "focal length" the closer the subject appears and the shallower the depth of field tends to be. A 50mm has become something of a standard for videographers/filmmakers. I was just wondering, what other focal lengths you all use and when you use them? Do you use ultra wide or fisheye lenses? Do you use 85mm+? If so when and why? I am in the market for another lens, but I'm not sure what lens to get after 50mm,

Comments

  • Mandalorian
    Mandalorian Website User Posts: 79
    You are correct, 50mm is the focal length of that lens.  Focal length is the distance from the sensor or imaging plane to the focusing point of the lens.
    Usually it seems that wide angle lenses (lower focal length number) are used for settings where you want to see more of the scene (ie. landscapes), and telephotos (higher focal length number) are used for portraits or other, more intimate shots.
    Personally, I just got a wide prime and 2 zoom lenses.  Combined, I have 18mm, then the full range from 28-200mm.  This is not only really good for run-n-gun shooting, but allows me to learn what focal lengths I use most often and which primes I should consider later on.  I think this would be a really good idea if you're not sure what you want yet.
    Most professionals have a standard range of focal lengths, with at least 1-2 wide lenses, a medium, and some telephotos.  For example, maybe a 25, 35, 50, 75, 85, 100, etc.
    In addition, here are some awesome articles that have a lot of great information about lenses:
    Understanding Camera Lenses
    Depth Of Field
    Hope this helps you in your decision.  :D
  • rgbii
    rgbii Website User Posts: 965 Just Starting Out
    I've always liked around 50 - 85mm, but it really depends on the situation. Too long and it will compress or flatten things out a bit, and too short can distort your image, especially around the edges or anything too close to the lens.  That said, in most cases I find 50mm too long when shooting in most homes and tend to use around 30mm, give or take, but have gone down to 18ish if needed, which will work fine as long as nothing  gets too close to the lens, especially talent.
    Indoors or out, if you need to control what's behind your talent, you can use a longer lens and move it back to reduce what's seen behind them compared to a closer and wider lens.
  • Triem23
    Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,956 Ambassador
    Trivia Note, as it's not come up in this thread: "50mm" is a common prime, because it's considered to be that focal length (on a 35mm camera) that "matches" the field of view and distortion curve of a human eye.
    So, yeah, anything shorter than 50mm "widens" the space and anything greater than 50 "compresses" the space.
    What lens to get? If you ask 20 film makers and videographers you'll probably get 10 different answers. Generally speaking you'll get the best image quality from a prime, since it's not going to have additional glass for a zoom range, so light has less lens bouncing to do. There have been many films shot using only primes. Zoom lenses will be more flexible because of varied focal length, but will, usually, be a little softer, and, unless you're going for a higher-quality (and priced) lens, you'll end up with a smaller aperture that closes more at the zoom end, whuch means you need more light.
    For most "dramatic" film/video work, the most useful ranges (in my opinion) are about 20mm to about 100mm. Anything below 20mm is going to start to "fisheye" and anything over about 100mm is really going to start to "flatten." Anything from about 35-100mm is flattering for people. Outside that range and you start getting distortion, which may-or-may-not be desired.
    Wide angles are usually more troublesome to get, and actually needed more that you'd think. As rgbii noted, once you're shooting inside, say, something in a bedroom, wide angle are going to be what you want. (But, remember, anything below about 18-20mm, and it's going to look fisheye.) Very long zooms just aren't going to be used as much, unless that superzoom is part of the shot concept (i.e. starting in close to something distant, next to something huge, then pulling out to show the distance/huge. A good example is your typical "car on bridge, pull out to show the entire city" shot.). But long zooms aren't that useful when shooting general dialog or action. Why the heck would I want to get 100 feet back from the actor and zoom in to a shoulders-up shot, anyway? Now I either have to yell action cues or get a radio, right?
    I don't know your camera setup, but for Canon DSLR's the 24-75mm L-series lens is a great choice. It's wide enough to be useful in enclosed spaces, the zoom is enough to give you some magnification. Actors look good throughout the entire focal range, and the f2.8 aperture through the entire zoom range gives you good light. On the other hand, that's a $1500 lens, and, for the same amount of money, you could probably get three decent primes--say a 35mm, a 100mm, and something else, depending on if you'd rather get a 300mm for long shots or an 8 or 15mm fisheye.
    My DSLR lenses are a Rokinon 8mm Fisheye, a Canon EF24-75mm f/2.8L, a Canon 18-55mm f/3.0-4.6(The stock lens with my first body, but I keep it for that little extra wide between 18-24) a 50mm f/1.8 prime and a 70-300mm f/4.0-5.6. And a Lensbaby. If I were to purchase another lens at this point, I'd either want a 100mm Macro with 1:1 magnification or the Canon 70-300mm F/2.8L.
  • MatthiasClaflin
    MatthiasClaflin Website User Posts: 674 Just Starting Out
    edited July 2014
    Thank you all for your informative answers. I do appreciate all the time you took to respond.
    I'm specifically looking for a lens for action scenes. I could probably shoot an entire short film on a 50mm, however I find the camera shake hard to control and the focus a pain when shooting a fast moving scene. Of course the focus is only an issue at the lower f/stop ranges. However, as I understand a 28mm at f/2 would be have a deeper depth of field than a 50mm at f/2. Also it would be much easier to control the shake. However, is 18/24/28mm going to have too much distortion? 
    I am just now starting to watch movies looking at scenes and wondering "what lens are they using"? I am not sure what is being used for action scenes. I'd assume it would be easier with a wide lens. You have better control over camera shake, and focus on the fly, however I have heard of people using longer focal lengths so the image is more flat, meaning your actors can be further apart and still appear to be hitting one another.
    What do you all use for action? Do you stick with a "portrait" lens? Or switch to a wide? What aperture do you recommend?
    I've been avoiding the 18-55mm kit lens because I don't think that the lens is as sharp as the 50mm, and it definitely isn't as flattering as the 50. I am using an ASP-C camera (the T3i). I looked into the Tokina 11-16 but I don't like the amount of distortion on that lens. I've debated the 35mm f/2 but I am afraid it won't be a big enough difference from the 50 I have to even bother with. 
    Thanks everyone for reading and giving your advice. I appreciate it. Also, I'm looking for something around (or under) $500, meaning L glass is kinda out of my price range, otherwise the 24-74mm would be at the top of my list.
    PS - Anyone know anything about this http://www.bhphotovideo.com/c/product/801084250-USE/sigma_549101_28_70mm_f_2_8_ex_dg.html">lens?
  • rgbii
    rgbii Website User Posts: 965 Just Starting Out
    edited July 2014

    Also, I'm looking for something around (or under) $500, meaning L glass is kinda out of my price range, otherwise the 24-74mm would be at the top of my list.
    PS - Anyone know anything about this lens?
    I've never used that lens, but I do have the sigma 17-50 2.8 and probably use it more than my Canon 24-105L 4.0, especially for indoor/lowlight situations. Looks like B&H has an 'instant savings' on it right now bringing it down to $519.
    http://www.bhphotovideo.com/c/search?Ntt=sigma+18-50&N=0&InitialSearch=yes&sts=ma&Top+Nav-Search=
  • Mandalorian
    Mandalorian Website User Posts: 79
    I'm specifically looking for a lens for action scenes. I could probably shoot an entire short film on a 50mm, however I find the camera shake hard to control and the focus a pain when shooting a fast moving scene. Of course the focus is only an issue at the lower f/stop ranges. However, as I understand a 28mm at f/2 would be have a deeper depth of field than a 50mm at f/2. Also it would be much easier to control the shake. However, is 18/24/28mm going to have too much distortion? 
    I am just now starting to watch movies looking at scenes and wondering "what lens are they using"? I am not sure what is being used for action scenes. I'd assume it would be easier with a wide lens. You have better control over camera shake, and focus on the fly, however I have heard of people using longer focal lengths so the image is more flat, meaning your actors can be further apart and still appear to be hitting one another.
    What do you all use for action? Do you stick with a "portrait" lens? Or switch to a wide? What aperture do you recommend?
    I've been avoiding the 18-55mm kit lens because I don't think that the lens is as sharp as the 50mm, and it definitely isn't as flattering as the 50. I am using an ASP-C camera (the T3i). I looked into the Tokina 11-16 but I don't like the amount of distortion on that lens. I've debated the 35mm f/2 but I am afraid it won't be a big enough difference from the 50 I have to even bother with. 
    Thanks everyone for reading and giving your advice. I appreciate it. Also, I'm looking for something around (or under) $500, meaning L glass is kinda out of my price range, otherwise the 24-74mm would be at the top of my list.
    PS - Anyone know anything about this lens?


    It depends on what sort of visual style you want your action to have.  If you're going for more of a Bourne look, you'll be using longer focal lengths (50mm+) to flatten the action (sell hits easier like you said) and give it a more frenetic feel since it will be easier to have a natural shaky cam feel without trying as hard.
    It sounds like that's not quite what you're wanting though.  If you're wanting something more like avengers, where you can clearly see the action all around, the camera is more stable and fluid, then you might want a wider lens (25-35mm I'd say).  Going wider could yield more distortion like Triem23 mentioned depending on the lens, so watch out for that.  It will be somewhat more difficult to sell your hits, but your audience will be able to absorb what's going on more easily.
    Here are two images from wikipedia that give a pretty good illustration of a few different focal lengths:
    One
    Two
     

    To counter the Depth of Field issue, close down your aperture more if possible.  If it's low light then I can see why you would want to open it up, but it will be a lot easier to keep everything in focus with a smaller aperture (f/8-22).
    Kit lenses usually aren't as good as others, which is why they're bundles most of the time.  This isn't always the case, but it is most of the time as far as I've seen.  They are a good, cheap way to learn the basics of lenses though, so if it fits on your price range and has most of the lengths you want, it could be good for the time being.  The Tokina seems to be a really popular lens, but from my observations, the people getting it usually have a pretty rounded out set already and are just looking for something to fill out the wide end.  I'd get some more standard lenses before getting that one.
    I don't have any lenses to recommend for your price range, but I'm sure someone else can chime in there.  Good luck.

  • Triem23
    Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,956 Ambassador
    edited July 2014
    Don't forget to take into account the 1.6x crop factor of a Canon t3i (Which, btw, is the same DSLR I use for video). Which means that a 50mm is acting more like an 80mm on that camera. (BTW I recommend EF lenses over EF-S lenses. EF lenses will work on a crop-sensor and a full-frame. EF-S lenses only work on crop-sensors. Go all EF--that way, if you upgrade to a full-frame body, your glass goes with you)
    A side effect of the crop factor of an APS-C sensor is, since it's using the center part of the lens image, with very wide EF lenses it's cropping out the edges of the image, where the most distortion occurs.
    I think Mandalorian covered it pretty well--basically, for action, it's the same "it depends" you'd go through with any other shot. For fight scenes specifially, however, a bit of telephoto flattening can be useful if your actors... how can we put this... aren't very good at fighting. In that specific case the flattening can let you position actors farther away from each other for safety--but, if you look at Orange Pekoe's latest, "Urban Creed: NPC Takedown" you'll see what you can do with a wide lens at close range with actors who are very good at the fight choreography. But this is a case of choosing a lens based on actor safety, not aesthetics.
    (And trust me--actors who aren't physically skilled, who are clumsy, etc, are very very dangerous to have to do staged combat with. Years ago in a stage play I had two rather intensive fights--one of my fight partners was the 6'7" huge-but-clumsy guy, and the other was the slightly smaller than me black belt. It was the fight with the black belt that had audience members asking after the show if I was ok--because we were both good enough to just go for it and make it look really good. SAFELY. Neither one of us were out of position and there were no injuries. The big clumsy guy, on the other hand, was the fight that audience would tell me looked fake. but, during the six weeks of that show, the clumsy guy managed to fracture my jaw one night, a rib another night, and, one SPECTACULAR night, he missed a mark and physically threw me through the drywall... then, more-or less following the choreography, he picked me up and slammed me into the wall again, which ended up cracking the ply behind the drywall. Actually, that may have been the one that go my rib.  Point being, during any kind of action, fight or stunt work, my primary, secondary and tertiary concern is actor safety. Lens comes 4th. ;-) )
    That Sigma lens gets pretty good reviews: Listed as weak on autofocus (put, shooting video on a t3i, the autofocus is near-useless anyway) and having a noisy focus motor, but I didn't see any major issues in the reviews on image quality, other that being a bit soft at f/2.8. Offhand, my guess is you'd get something about 70% of the image quality of that Canon L-glass at 33% (or 12% if you get that used one) of the price. A good deal. And the reviews I saw for that lens were looking at still. Since video is only shooting at 2MP, not 14MP, the line skipping might sharpen things up a little bit for video.
    Reviews of that lens:
    http://www.fredmiranda.com/reviews/showproduct.php/product/97/cat/37
    http://www.ishootshows.com/2010/10/18/comparison-review-tamron-28-75mm-vs-sigma-24-70mm-f2-8/
  • Ben
    Ben Website User Posts: 51
    edited July 2014
    Lots of good conversation here, and plenty to add to it when I get the chance. I've rented a dozen or so different lenses that I like over the past few years, and I own my go-to Canon L, the 50mm f/1.2 which is insanely fast and bright.
    More on all this later, but my main suggestion is to stay away from third-party glass, it's usually not as good as OEM Canon stuff if that's what you're shooting. Rokinon is a good value, but low quality glass, plain and simple. People buy it because they can afford it, not because it's good. I adored my Sigma 30mm f/1.4 EX prime for a few years, but then the focus ring locked up on me.
    More suggestions later. But for action, you're going to want a zoom -- either on the wider end or the deep deep deeper end.
  • MatthiasClaflin
    MatthiasClaflin Website User Posts: 674 Just Starting Out
    Thanks everyone for helping out. I appreciate the feedback.
    I shot a music video a while back with a 50mm f/1.4 and fell in love with it. When I went to buy a lens, I bought a 50mm f/1.8 because that was what I could afford. I personally hate it. The 1.8 doesn't work with my follow focus rig. Focus pulling is not nearly as smooth and the more I shoot, the more I realize how much sharper the 1.4 was at different aperture settings. Later in the year I rented a 70-200 for a concert, and found it to be amazing, once again realizing how much I have come to dislike cheap glass.
    Moral of the story is that once you've used nice glass, you don't really want to go back, and at this point, I'm starting to reconsider "buying" lenses and possibly renting based on the project instead while I save up for L glass, or something closer to it.
    What do you all think? How long do you rent before it isn't worth it anymore? Or do you just rent for life?
  • Mandalorian
    Mandalorian Website User Posts: 79
    It is amazing how that works isn't it.  When I got my new lenses, I instantly disliked shooting with the lenses I'd used in the past.  When you get less visual artifacts and disturbances, as well as a metal body and better mechanics, going to cheaper stills glass is painful.
    There is definitely a price to be paid for nicer glass though.  IMO, it's totally worth it.  Just make sure you know what you're getting before you click "Buy," and if possible, get your hands on it and try it out first hand before making a decision.
    Personally, I'll be purchasing all of my own glass.  A couple reasons for that.  I want to have glass with me all the time since I like to just shoot video and pictures just for fun, and it will save me in the long run for personal projects.  It also will work out for me since I'll be doing some owner op renting.  That way, I can get more experience, make good contacts, and charge more for my time.
    I've worked with a friends production company on a few projects where they rented some really nice lenses though.  It worked for those projects and it saved them money in the process by not having to fork out tons of cash to get cinema grade primes.  Then they do all the post and deliver to the client with a quick turnaround.  That way, they could crank through projects quickly and save as much as possible.  They don't really do any rentals of their gear, so owning high grade lenses doesn't fit their business model.
    When looking at whether to purchase or rent, look at what you plan to do with your lenses and camera.  Are you planning to rent them out to others along with yourself in an owner operator type deal, or do a lot of projects under your company/name?  If so, buying may be a good option for you.  If you want to do projects for lots of clients, but don't want the hassle of maintaining gear and filling out a good set of lenses, then going the rental route may work best for you.
    If the return on investment for owning your own lenses isn't good enough, consider buying.  Have fun making the hard choice.
  • Triem23
    Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,956 Ambassador
    You are certainly going to want to own at least one good lens. If nothing else, just to shoot on a whim. For video work, that 24-70 L glass is a good one to own, and it's good for general photo work as well.
    So, owning that one lens which covers most of my needs leaves me free to rent good glass if I need to go longer or wider. Now, how long to rent? It's another "it depends." I don't need to go much farther than 70mm more than a couple of times a year. Rental is $50/weekend. I could rent for years and not need to buy the 70-300mm f/2.8 L. Now, if I needed that lens once a month, then I would save up to buy.
  • SimonKJones
    SimonKJones Moderator Website User, HitFilm Beta Tester Posts: 4,450 Enthusiast
    In terms of renting or buying, it comes down to the kind of work you're doing. If you do sporadic, specific projects then renting is going to be best. If, on the other hand, you're in constant work, shooting pretty much everyday, you're going to want your own lenses.
    If you're still ramping up your work, it probably makes sense to rent for a while, try out lots of different lenses, figure out which ones you like, and then invest once the work reaches some kind of stability and you know exactly what to buy.
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