Single Focal Length Lense vs Moderate Zoom Lense

M

M1CEtro

Active member
Hey guys, I'm going to be buying a Canon 7D body and am currently researching lenses. I will be using it for freelance videography with a major focus on shooting music videos. I have noticed that alot of photographers have multiple lenses including different single focal length lenses. But I must be missing something here. If I purchase a 18-200mm lense, is there really a purpose to me buying a single focal length lense in that range? a 50mm for instance? I would think not since the 18-200mm can be adjusted to achieve 50mm. Do single focal length lenses perform better or differently then the moderate zoom lense? Maybe as far as DOF is concerned? I have tried out a 18-135 lense on the 7D before and noticed that the DOF wasn't as narrow as I wanted for a few shots. Is there an advantage to the single focal length or should I be good with the 18-200?

Thanks in advance!
 
The zooms you are talking about are not ideal for video as they are slow and have variable f-stops. A big draw to "single focal length" or PRIME lenses is that they are often faster 1.2, 1.4, 1.8 or so and therefore are better for low light perfomance and have other advantages as well. If you want to have a zoom lens that you are using for video, most would suggest getting one that has a constant aperture, say 2.8. For example lets take a 24-70 2.8 lens. If you do a shot at 24mm and then push in for a 70mm shot with this lens you can keep your lighting setup the same. If you were using one of the lenses you mentioned then your fstop would most likely go down to 5.6 or whatever the case is depending on the lens and you would need to change your lighting. IF you are in controlled environments (music videos, narratives, etc) a prime kit is one of the best investments you can make. I personally do a lot of event videography and in turn choose to rely more on fast, constant aperture zooms. It's totally up to you but I would not suggest the lenses you mentioned and there are very good reasons for that. Do some research, there has been a million threads about this.
 
Generally, aside from wider aperture, you'll find that prime lenses are a bit sharper than zooms. Plus, zooms suffer from barrel distortion on the wider angles where primes at the same focal length won't.

If you're shooting in a very controlled situation where you'll have time to change lenses as you set up each shot, primes are the way to go. If you're shooting in something a little more fast-paced where you won't really have time to switch lenses, a zoom is probably the best bet.
 
Frankly, if you're going to go with a cheap zoom then I don't understand the point of using a DSLR for video in the first place. The real strength of a DSLR is that you can put some great glass on it. Be it modern L-Series or vintage primes, the lenses really determine a good chunk of your video quality. I know a lot of people who buy a DSLR with a cheap kit lens and then wonder why their footage looks poor. IT'S THE GLASS. DSLRs are not great video cameras. They're not even good video cameras. The strength they have is their large sensor which allows you to put professional lenses on them.

If you really want to go with a zoom, make sure you get a constant aperture (at least 2.8) and not something with a huge range as it will soften the image.
 
what is it with DSLRS that makes every "joe-never-used-a-still-camera-before" think they're going to start making music videos?

and what is it with music videos anyway? granted im not in LA, nashville or NY. but i know of very few people making real money making music videos. im talking about mutual ROI money. not the $500 here $1000 there, local artist with no real following, every couple of months money

M1CEtro, i really, truly, sincerely am not trying to be ugly. but the question you're asking here (and the very similar ones you've asked before) clearly indicate that you have no idea what you're getting into.

bear with me. and please, nobody get upset until you read my whole post here...

from where you are now, a 5D or 7D is too much camera for you and a lot of extra money very poorly spent.
it would be like me thinking im going to buy an alexa and just start making features...
i promise that with the experience and knowledge you have now, you will have the same result from a T3i that you will from either of the higher priced models. yes, they behave differently. but until you fully understand the answers to these questions. it wont make much if any real difference in your productions.

I have tried out a 18-135 lense on the 7D before and noticed that the DOF wasn't as narrow as I wanted for a few shots.
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you're drunk on buzzwords and blurry backgrounds. how are you going to maintain focus with that narrow DOF once the artist starts moving? does your camera or your "lense" support continual autofocus? or will you also have a follow focus and someone to operate it?

since the 18-200mm can be adjusted to achieve 50mm. Do single focal length lenses perform better or differently then the moderate zoom lense?
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pardon my oblique simile. but this is like asking "since a microwave oven makes food hot. do i really need a full size, traditional oven to cook a turkey?"

YES. there is a HUGE difference in aesthetic quality, image sharpness and light requirements between a prime (PRIME is the term for a"single focal length" LENS)
and an even remotely similarly priced zoom lens. http://en.wikipedia.org/wiki/Prime_lens

im not trying to talk you out of following your dream. all im saying is that there is SOOOO much more to making videos than just a BEST BUY DSLR and a $300 lens.
not to say that you HAVE TO have a $50,000 set of lenses to make a great music video. you dont need a 5D or even a T2i. you can make a GREAT video with a 1983 pawn shop VHS camera.

it just sounds to me, from your posts. that you need a LOT more photographic education before you go blindly buying a bunch of DSLR gear...

you ARE asking the right questions - KEEP em coming! just make sure you know what youre getting into : )
 
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Wgzn, I appreciate your post. And you are right I am very inexperienced with shooing DSLR's. But I have been doing video editing for years just with lower grade cameras. I have unique creativity that I'm able to express through visuals and music videos is just a starting point that eventually is going to branch out into other avenues. The 7D from what I've read is the better "overall" camera and I plan to use it for many other projects other than music videos in the future. I get alot of sh*t from people for being a newbie, but everybody has to start somewhere and I'm trying to learn as much as I can. I'm a determined individual so a lot of that "you don't know what you are doing" talk is going in one ear and out the other, because I already know that. But it's still not going to stop me from trying to find out...Thanks

Any other input is greatly appreciated guys!
 
18-200 is not "moderate zoom", but even if you were thinking of a more moderate 24-70, image quality won't be as good as with primes; the problem with primes is that they are, well, primes: you can't zoom in or out, you have to move your feet or change lenses, and sometimes that's not an option; but they are usually faster and they deliver much nicer images (sharper, and specially with much nicer bokeh; maybe you don't know what that is yet, but it is really, really important, it's the reason pro photogs pay $2K for a lens instead of $400); plus, they make you work to get your picture (you have to move your feet), which kills laziness, which is a very good side effect; you may want to look at my sharpness and bokeh tests: http://www.similaar.com/foto/lenstests/lenstestsa.html - http://www.similaar.com/foto/lenstests/bokehtests0.html
 
good spirit M1CE!

im not sure if ive chimed in on your other posts. but the 7D and 60D are nearly identical for video quality. BUT as i recall, the magic lantern hack works with the 60D and NOT the 7D. and though ive not deployed it myself, many folks here wouldnt think of using a canon dslr for video without magic lantern - look into it before you commit!
 
Hello Norman. Thanks for the info and the websites to your tests. Because I'm not as experienced as you guys, I can't really make a confident determination from those pictures you posted. I'm not sure what it is I should be focusing on or looking for within those pictures. I just know that some of them look different than others but can't tell between some of them which has better *quality*. Do you have some kind of final conclusion on the lenses used? Or advice at what I should be getting from it? Also, I know that bokeh refers to the blur of the background created by narrow DOF, but could you show me two pictures comparing an example of "good" bokeh vs. "bad" bokeh? Thanks
 
Wgzn, I was under the impression that magic lantern was an software/firmware update released by Canon that Canon owners could download for their cameras? Are you saying that is a hack that I must obtain or you are saying there is a hack to the software/firmware that adds additional functionality? Do you have a link where I can get more info. Can't seem to find the right magic lantern on wikipedia lol.
 
Magic Lantern is third-party. It adds all sorts of extras that Canon didn't include in the original firmware, such as a defeat for AGC and manual gain control (though recent Canons like the 60D already have AGC-off and manual gain, albeit not as clean as ML and not added by ML in these models), focus assist, expanded ISO selections, adjustable bit-rate on the compression, and much more.

http://www.dvxuser.com/V6/showthread.php?248171-Magic-Lantern-Firmware
 
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You need to get used to shooting with a DSLR. I would suggest a T2i or T3i with a 17-50/2.8IS. The Canon one is the priciest and best, with the Tamron & Sigma a good alternative.

That's a good starting point, and shoot exclusively with that for a few months before you get more gear - then you'll have a better idea what you need.
 
about bokeh: it is the smoothness and non-remarkability of out-of focus parts of the image; I know it sounds strange, but the biggest difference between a picture taken with a point-and-shoot and one taken with a real camera is that in the former everything is in focus, in the later the background is blurred, and doesn't call your attention; you create beautiful images by taking things out; one very effective way to do so is to blur them, by narrowing your depth of field (the depth of the image that is in focus)

out of focus highlights are a fast and easy way to judge bokeh: they should be round and homogeneous (no shiny center or contour, and no green halo); it's not everything there is to bokeh quality, but it's fast and easy

zooms and cheap lenses deliver ugly bokeh (out of focus, but showing artificial detail, thus not smooth)
if you look at my bokeh tests you'll see the tamron 17-50 f/2.8 non-VC (a great lens in every other respect) delivers non-homogeneous highlights, whereas my leitz elmarit-R 35mm f/2.8 has nearly perfect bokeh
http://www.similaar.com/foto/lenstests/bokehtests0.html

here you can see a comparison of the canon 50mm f/1.8 II and the canon 50mm f/1.4
http://forums.overclockers.com.au/showthread.php?t=472344
they are roughly the same in terms of sharpness, it is bokeh (and build quality) that sets them apart:

here you can see two things:
http://1.bp.blogspot.com/_ZoApFAh9O...AAl0/q6w3bH01xmc/s1600/bokeh20+comparison.jpg
* first, slow lenses (say, f/3.5 instead of f/1.7) deliver very little bokeh, meaning stuff is only slightly blurred
* second, a zoom will usually have uglier bokeh than a prime


***

I also think you should start with something like a 600D and a tamron 17-50 f/2.8 non-VC (the VC version is much softer), then build up from there as you learn and get a better grasp of what you need and why
 
MICEtro, do not get the 7D unless you need to shoot stills at 8fps or you will be using an external HD monitor for pulling focus. There are other cameras that will do more and cost less.

The 60D has identical video quality to the no 7D, plus a few extra features (basic audio controls, swivelling LCD). And you can install Magic Lantern to make it even better than the 7D. It will also not overheat like the 7D does. The 600D offers pretty much the same benefits as the 60D, though adds a 3x crop zoom mode, loses Kelvin WB balance adjustment, and sacrifices some of the ergonomics of the larger 60D.
 
@MICEtro

1) Zoom lenses don't go faster than f2.8. If you need a faster lens (< f2.8), your only option is to get a prime lens. In shooting video with a Canon DSLR, there are two major reasons why a set of fast prime lenses (< f2.8) are often preferred than a single zoom lens (f2.8 or above) covering the same focal length range:

- There are a lot of limitations of using these DSLR as a video cam, such as digital aliasing issues, which often make you want to have more blurry background than really necessary. In such situations, a f1.4 prime lens will help a lot as compared to even a top f2.8 or f4 zoom lens.

- A constant slow shutter speed such as 1/60 needs to be used even in low light, making you want to shoot at a very small aperture number such as f1.4.

2) You can safely ignore all the "lens A being sharper than lens A" or "prime lenses being sharper than zoom lenses" arguments, as they don't really matter much in still photography (they start to matter only if you want to impress a rich client and plan to make more than 1000s of dollars out of every single image you make) and much less in shooting video (due to much small resolutions used in video).

BTW, top Canon zoom lenses, such as 16-35 f/2.8, 24-70 f/2.8, 24-105 f/4, and 70-200 f/2.8 or f/4, can compete with just about every consumer-grade prime lenses in terms of sharpness, contrast, color, and build quality.

3) if you mainly shoot music video, magic lantern (which is a hack, not supported by Canon) won't help you much, as you will have to use a separate audio recording system everywhere. If you want good build quality and decent control, 7D is about the best in the current Canon DSLR product line next to ID Mark IV.
 
henryqiu said:
2) You can safely ignore all the "lens A being sharper than lens A" or "prime lenses being sharper than zoom lenses" arguments, as they don't really matter much in still photography (they start to matter only if you want to impress a rich client and plan to make more than 1000s of dollars out of every single image you make) and much less in shooting video (due to much small resolutions used in video).
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Disagree. I've shot video wide open on a vintage lens that was noticeably softer than an alternate camera shot with a sharper lens. I had to "soften" the look of the other camera to match, which was a real shame. And for stills, even more so.

3) if you mainly shoot music video, magic lantern (which is a hack, not supported by Canon) won't help you much, as you will have to use a separate audio recording system everywhere. If you want good build quality and decent control, 7D is about the best in the current Canon DSLR product line next to ID Mark IV.
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I really couldn't disagree more.
I would appear that you are under the impression Magic Lantern is just an audio solution.
The folks who swear by Magic Lantern do so because of the video-camera tools it offers, including (but not limited to) live exposure zebras, histogram, and focus tools. It also keeps track of lens and camera settings via a log file for each video recorded, and offers shortcuts to help ergonomics (you can reassign button functions, etc). All very useful stuff.
My personal favorite is the "magic zoom", which creates a square magnification area on your display so you can pull accurate focus while filming. Otherwise, adjusting focus on a tiny camera screen is extremely difficult. Especially if shooting very low DOF stuff like a music video. I wouldn't dream of using a camera without ML these days for that.

Meanwhile, for music videos, I would strongly recommend the 60D's articulating display, as it makes those "artsy" shots easier to manage. Combined with Magic Lantern, I think it is the most capable DSLR in terms of features available for video purposes.
 
if you mainly shoot music video, magic lantern (which is a hack, not supported by Canon) won't help you much, as you will have to use a separate audio recording system everywhere.
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add another disagree here. most "music videos" (and by that i mean conceptual or "fake live" efforts) dont use the recorded audio from the camera for anything other than syncing anyway.
 
M. Gilden said:
I've shot video wide open on a vintage lens that was noticeably softer than an alternate camera shot with a sharper lens.
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+1 on sharper lenses making a difference, though any lens will be soft(er) with aperture wide open.

M. Gilden said:
I would appear that you are under the impression Magic Lantern is just an audio solution.
The folks who swear by Magic Lantern do so because of the video-camera tools it offers, including (but not limited to) live exposure zebras, histogram, and focus tools. It also keeps track of lens and camera settings via a log file for each video recorded, and offers shortcuts to help ergonomics (you can reassign button functions, etc). All very useful stuff.
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Exactly. Even with ML on my T2i, I still run double-system sound. The ML audio settings help for cleaner reference audio, but my main uses for ML have to do with video. My #1 feature is the focus assist.
 
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I have the GH1, GH2, 7D (2 of them) and a T3i, and I would suggest the T3i above the 7D for video work.

As for the "build quality" argument, I find that rather funny. I've shot thru rain and snow with nearly all of my cameras, from the original 300D to my newest T3i. No problem, they've handled it as well as my 1Ds, 1Dm2 and 7D's.

There's definitely times that I prefer my 7D, 1Dm2, 1Ds, as I go thru the bush, in the mud etc, but that's something few here would ever go thru.
 
+1 for sharper lenses making a difference, even in video mode, plus my tests here, checking all my lenses at different settings, center and corner, at 1080p resolution:
http://www.similaar.com/foto/lenstests/lenstestsv.html
I see big differences

on the other issue: I love ML, really, really love it; and I have never used the manual audio gain, or the increased bitrate; but I'm sure I'd cry a lot if I had to go back to a camera without zebras, live histogram while recording, custom cropmarks, peaking, zoom-in while recording...
(and I donated twice to prove my love; small amounts, though: I'm not a pro, this is just a hobby for me)
 
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